8.5: Fruits - Biology

Ovary Anatomy

Figure (PageIndex{1}): Cross section of Lilium ovary, showing A=Female gametophyte, B=Ovule, C=Locule, D=Placenta, E=Dissepiment. The label in red added to original contribution of File:Lilium ovary L.jpg provided by Jon Houseman and Matthew Ford. JonRichfield, CC BY-SA 4.0, via Wikimedia Commons.

Figure (PageIndex{2}): A Lilium ovary during the second stage of the four nucleate embryo. A-Micropyle, B-Integument, C-Antipodal cells, D-Synergid cells. Scale=0.1mm. Jon Houseman, CC BY-SA 4.0, via Wikimedia Commons.

Figure (PageIndex{3}): A Lilium ovary at the eight nucleate stage. A-Synergid cells, B-Vacuole, C-Micropyle, D-Polar nucleus, E-Antipodal cell, F-Integument. Scale=0.1mm. Jon Houseman, CC BY-SA 4.0, via Wikimedia Commons.

Transitioning from Flower to Fruit

Figure (PageIndex{4}): These two images show clusters of pear blossoms from the same tree. The cluster on the left is in an earlier stage of development. The corolla is still attached and the stamens are radiating outward to disperse pollen. In the image on the right, the corolla has fallen off and the anthers have shriveled. The calyx is still visible and, just below it, the semi-inferior ovary and hypanthium are beginning to swell. Eventually, these will swell to many times their current size and form the fruits we know as pears. Photos by Maria Morrow, CC-BY 4.0.

Figure (PageIndex{5}): Salal (Gaultheria shallon) is a shrub in the same family as blueberries and madrone trees. Each pendant, urn-shaped corolla will fall off, leaving the calyx behind. The inferior ovary will develop into a berry. In this image, younger flowers are being produced on the left side at the end of the inflorescence, while older flowers develop into fruits on the right side. Photo by Maria Morrow, CC-BY 4.0.

Fruit Anatomy

Figure (PageIndex{6}): A Zea mays kernel. This fruit is a caryopsis, the seed coat is fused to the pericarp. Labels are as follows: A=Pericarp, B=Aleurone, C=Tip cap, D=Endosperm, E=Coleorhiza, F=Radicle, G=Hypocotyl, H=Plumule, I=Scutellum, J=Coleoptile. Scale=1.4mm. Jon Houseman, CC BY-SA 4.0, via Wikimedia Commons.

Figure (PageIndex{7}): A diagram of a drupe. The pericarp of a fruit can be completely fused (as in Figure (PageIndex{7})) or separated into distinct layers: the endocarp (innermost), mesocarp (middle), and exocarp (outermost). A drupe is a fruit type with a stony endocarp enclosing a single seed, a fleshy mesocarp, and a thin exocarp. Image by LadyofHats, Public domain, via Wikimedia Commons.

Some Common Fruit Types


Figure (PageIndex{8}): These two images show the fruits produced from the head inflorescence of a dandelion. On the left, they are difficult to distinguish, forming a sphere around the receptacle. On the right, some of the fruits have been carried away on the wind, making the others easier to see. Each floret has produced an achene at the base (from an inferior ovary). Only the calyx remains, of the other floral whorls, and has formed into an umbrella-like structure for wind dispersal. Photos by Maria Morrow, CC-BY 4.0.


Figure (PageIndex{9}): A tomato is a berry. The pericarp has distinct layers,but all are fleshy. The exocarp forms a thin skin around a fleshy mesocarp. There are many seeds. Labels are as follows: A=Calyx, B=Peduncle, C=Exocarp, D=Mesocarp, E=Endocarp, F=Funiculus, G=Seed, H=Placenta, I=Locule. Image of the tomatoes from © 2005 User:FoeNyx, CC BY-SA, via Wikimedia Commons with labels added by Maria Morrow.

Figure (PageIndex{10}): A hesperidium (citrus fruits) is a modified berry. The endocarp forms the skin around the segments, containing seeds and juice-filled trichomes. The exocarp forms an oily rind. A=Pith, B=Seed, C=Locule, D=Juice-filled trichomes, E=Endocarp, F=Mesocarp, G=Exocarp. Image of the orange slice from Paolo Neo, Public domain, via Wikimedia Commons with labels added by Maria Morrow.

Figure (PageIndex{11}): A pepo is another modified berry. The exocarp forms a (somewhat) tough rind (A). The mesocarp (B) is still fleshy. It contains many seeds (C). Image from User:Tomia, CC BY-SA, via Wikimedia Commons with labels added by Maria Morrow.

Accessory Fruits

Figure (PageIndex{12}): A pome is an accessory fruit made from a fleshy hypanthium. The papery core is the pericarp, which contains the seeds. Eric Guinther, CC BY-SA, via Wikimedia Commons.

Figure (PageIndex{13}): Strawberries are accessory fruits formed from a swollen receptacle. The receptacle reddens and swells, pushing the developing fruits outward. The fruits are achenes that look like seeds, stuck to the outside of the receptacle. The calyx of the flower is the green, leafy part. If you look closely, you can see the styles attached to the achenes. Full strawberry photo author unknown, licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Sliced strawberry photo by Paolo Neo, Public domain, via Wikimedia Commons.


Content by Maria Morrow, CC-BY 4.0

Indian Institute of Vegetable Research (IIVR)

In this article we will discuss about:- 1. Introduction to IIVR 2. Mandate of IIVR 3. Vegetable Varieties.

Introduction to IIVR:

Vegetable research in India got boost with the establishment of All India Coordinated Research Project (AICRP) on vegetable crops during 1971 at Indian Agricultural Research Institute (IARI), New Delhi. The status of AICRP on vegetables was elevated to the level of Project Directorate of Vegetable Research (PDVR) during 1986 with headquarters at IARI, New Delhi.

During 1992, the headquarters was shifted from New Delhi to Varanasi and PDVR was up-graded to the level of national institute under ICAR during 1999 and was named as Indian Institute of Vegetable Research (IIVR). The research programmes of IIVR are broadly organized into 3 major divisions, namely, Crop Improvement, Natural Research Management and Crop Protection.

IIVR has well equipped laboratories on PGR Management, Vegetable Breeding, Genetics and Cytogenetics, Molecular Breeding, Transgenics, Tissue culture, Seed Technology, Agronomy, Soil Science, Crop Physiology and Biochemistry, Post-harvest Technology, Statistics, Economics and Extension, Integrated Pest and Disease Management, Residue Analysis and Bio-Control.

Gene-bank is also available for medium term storage of seeds of germplasm. IIVR has a well-developed 150 acre research farm and several glass houses, poly-houses and net-houses. The institute has a strong financial position as evident from the following budget allocation during the X five year plan.

Indian Institute of Vegetable Research is situated under the greater periphery of the Holy city Varanasi at 82.52°E longitude and 25.10°N latitude. It is located approximately 20 km from the heart of the city towards south-west on Varanasi – Adalpura Road.

The area receives an average rainfall of 1000 mm which is distributed over a period of more than 100 days with peak period between July and August. Scattered showers occur during winter months. In general, the temperature ranges from 5°C to 42°C. The coldest month is January while the maximum temperature is observed during May and June.

Mandate of IIVR:

1. To undertake innovative, basic, strategic, anticipatory and applied research for developing technologies to enhance productivity of vegetable crops, their nutrient quality and post- harvest management.

2. To provide scientific leadership in coordinated network research for solving location- specific problems of production and to monitor breeder seed production of released/ notified varieties and parental lines.

3. To act as a national repository of scientific information relevant to vegetable crops and as a center for training for up-gradation of scientific manpower working on vegetable crops.

4. To develop high yielding, good quality, disease and insect pest resistant varieties/hybrids of selected vegetable crops.

5. To develop advanced production and protection technologies for selected vegetable varieties/hybrids.

6. To undertake germplasm collection, maintenance and documentation in vegetable crops.

Vegetable Varieties Developed at IIVR:

Efforts have been made to evolve high yielding varieties/hybrids with better quality fruits, resistance to biotic and abiotic stresses. The institute has developed 42 varieties/hybrids, which include 5 of tomato, 4 of brinjal 10 of okra, 6 of pea, 4 of cow pea, 2 each of bottle gourd, chilli, radish and ash gourd, 1 each of cauliflower, muskmelon, pumpkin, bitter gourd and French bean.

The brief description of these products is as follows:


DVRT-l (Kashi Amrit):

A determinate variety derived from inter-specific cross L. esculentum (cv.Sel.7) x L. hirsutum f. glabratum (acc. B6013′) through backcross pedigree method, fruits round, attractive red and fleshy with an average weight of 108 g, suitable for cultivation during ToLCV infested period, average yield 620 q/ha.

H-86 (Kashi Vishesh):

Resistant to ToLCV, developed using L.hirsutum f.glabratum B�′ x Sel 7 as donor parent following backcross pedigree selection method, plants determinate, dark green, fruits red, spherical, size medium to large, average fruit weight 80 g, first harvest at 70-75 days after transplanting yield 400-450 q/ha.

Kashi Hemant (IIVR Sel-1):

Developed through pedigree selection from a cross Sel-18x Flora Dade, plants determinate, fruits attractive red and round, 80 g, yield 400-420 q/ha.

Kashi Sharad (IIVR Sel-2):

Developed through pedigree selection from a cross MTH-6x Kalyani Eunish, plants indeterminate leaves broad, fruits attractive red, slightly oval, firm, thick pericarp longer shelf life, fruit weight 90 to 95 g, yield 400-500 q/ha.

Kashi Anupam (DVRT-2):

Developed by hybridization between L. esculentum cv.’Sel-7′ and L.hirsutum f. glabratum ‘B6013’, following backcross-pedigree selection, plants determinate, fruits large, flatfish round, indented at blossom end of fruit, attractive red with 5-6 locules medium maturity, 75-80 days after transplanting, yield 500-600 q/ha.


Kashi Taru (IVBL-9):

Plants tall and erect, (120-130 cm) with dark green leaves and stem, first flowering 45-50 days after transplanting, fruits long, purple (length 31 cm and diameter 5 cm) picking at 75-80 days after transplanting, average yield 700-750 q/ha.

Kashi Prakash (IVBR-1):

Plants semi-upright, stems and leaves green, fruits attractive with light green spots, calyx spiny, average weight 190 g, picking at 80-82 days after transplanting, average yield 650-700 q/ha. Hybrids

Kashi Sandesh (VRBHR-1):

A hybrid having semi-upright plant habit (height 71.0 cm) with green stem and purplish green leaves, flowers appear at 45 days after transplanting, fruits purple, medium size, round shape, fruit length 12.4 cm, diameter 10.2 cm and weight 225 g, picking at 76 days after transplanting, average yield 780 q/ha.

Semi-upright plant growth habit, height 90-100 cm, with light green stem and leaves first flowering at 35-40 days after transplanting, fruits light purple, long, soft texture, average length 13 cm and diameter 3 cm, first picking at 65-70 days after transplanting, average yield 800 q/ha.


Kashi Anmol (KA-2):

Derived from two cycles of simple recurrent selection from a Sri Lankan introduction, plants determinate, dwarf (60-70 cm) with nodal pigmentation on stem, green attractive pendant fruits, first picking at 55 days after transplanting, average yield 200 q/ha, moderately resistant to anthracnose, die back and Cerscopora leaf spot under field conditions.


Kashi Surkh (CCH-2):

An F1 hybrid of a cross between CMS line (CCA 4261) and Pusa Jwala, plants semi- determinate (1-1.2 m), erect and nodal pigmentation on stem, fruits light green, straight, length 11-12 cm, suitable for green as well as red ripe fruit harvest, first harvest after 55 days of transplanting, green fruit yield 240 q/ha, red fruit yield about 140 q/ha, tolerant to trips, mites and viruses.

French Bean:

Kashi Param (IVFB-1):

Developed through pure line selection, plants determinate (70 cm long) and leaves dark green, pod fleshy, length 14.7 cm, round, dark green, pod yield 120-140 q/ha.


Kashi Shyamal (IVRCP-1):

Plants dwarf and bushy, height 70-75 cm, branches 3-4 per plant, early flowering (40 days after sowing), first harvesting 48 days after sowing, 35-40 pods per plant, pod yield 70-80 q/ha, tolerant to golden mosaic virus.

Kashi Gauri (VRCP-2):

A bush type, dwarf, photo-insensitive and early variety suitable for sowing in spring, summer and rainy seasons, flowering in 35-38 days and pods ready for harvest in 45-48 days after sowing, pods 25-30 cm long, light green, soft, fleshy and free from parchment layer, resistant to golden mosaic virus, Psedocercospora cruenta and average green pod yield 100-120 q/ha

Kashi Unnati (VRCP-3):

A photo-insensitive, dwarf and bushy type (40-45 cm height), early variety suitable for sowing in spring-summer and rainy seasons, flowering in 30-35 days and pods ready for harvest in 40-45 days, 40-45 pods per plant with average pod length of 30-35 cm, the average pod yield about 125-150 q/ha, resistant to golden mosaic virus and Pseudocercospora cruenta diseases.

Kashi Kanchan (VRCP-4):

Bush type and dwarf (50-60 cm height), photo-insensitive and early variety suitable for sowing in spring summer and rainy seasons, flowers in 40-45 days, pods ready for harvest in 50-55 days, 40-45 pods per plant, pods dark green, tender, fleshy with less fibre and free from parchment layer, resistant to golden mosaic virus and Pseudocercospora cruenta, 150-200 q/ha green pods.


Kashi Mohini (VRO-3):

Plants tall, (110-140 cm), flowers at 4th-5th node during summer and 5th-7th node during rainy season after 39-41 days of sowing, fruits with five ridges, 11.3 – 12.6 cm long pods at marketable stage, suitable for summer and rainy season cultivation, yield 130-150 q/ha. resistant to YVMV under field conditions.

Kashi Mangali (VRO-4):

Developed through pure line selection, plants tall, height 120-125 cm, flowers at 4th to 5th node after 40-42 days after sowing, fruits five ridged, light green, yield 130-150 q/ha, resistant to YVMV under field conditions.

Kashi Vibhuti (VRO-5):

A variety with dwarf growth habit, plant height 60-70 cm during rainy and 45-50 cm during summer season, bears 2-3 branches with short-inter-nodal length, flowering starts on 4th to 5th node after 38-40 days after sowing, plant bears 18-22 fruits of 8-10 cm length at marketable stage, yield 170-180 q/ha, resistant to YVMV.

Kashi Pragati (VRO-6):

Plants tall (130-175 cm) with 1-2 effective branches, first flower appears after 36-38 days after sowing on 4th node during rainy season and 3rd node during summer season, fruits 8-10 cm in length at marketable stage, 23-25 pods plant and yield 180-190 q/ha during rainy and 130-140 q/ha during summer season, resistant to YVMV.

Kashi Satdhari (IIVR-10):

Plant height 130-150 cm with 2-3 effective branches, flowering at 42 days after sowing at 3rd to 4th node, 18-25 fruits/plant with seven ridges, fruit length 13-15 cm at marketable stage, yield 110-140 q/ha, resistant to YVMV under field conditions.

Kashi Lila (IIVR-11):

Medium plant height (110-130 cm), flowering at 30-34 days after sowing, suitable for cultivation during rainy and summer seasons as early crop due to low temperature tolerance, fruits have five ridges, green and 13-15 cm long, resistant to YVMV, yield 150-170 q/ha.


Shitla Uphar (DVR-1):

Plants medium tall, (110-130 cm), flowering at 38-40 days after sowing at 4th-5th node, fruits green, 11-13 cm long at marketable stages, yield 150-170 q/ha, resistant to yellow vein mosaic virus.

Shitla Jyoti (DVR-2):

Plants medium tall, (110-150 cm), flowering at 30-40 days after sowing at 4th-5th node, fruit green, 12-14 cm long at marketable stage, yield 180-200 q/ha, resistant to YVMV.

Kashi Bhairav (DVR-3):

Plants medium tall with 2-3 branches, fruits dark green, 10-12 cm long at marketable stage, yield 200-220 q/ha, resistant to YVMV under field conditions.

Kashi Mahima (DVR-4):

Plants tall, height 130-170 cm, flowering at 36-40 days after sowing at 4th-5th node, fruits green, 12-14 cm long at marketable stage, yield 200-220 q/ha, field resistance against YVMV.


Kashi Nandini (VRP-5):

An early maturing variety developed through pedigree selection from the cross P 1542 x VT-2-1, plant height 47-51 cm, flowers appear at 32 days after sowing, 7-8 pods per plant, pods 8-9 cm long, attractive, well filled with 8-9 seeds, shelling 47-48%, yield 110-120 q/ha, tolerant to leaf miner.

Kashi Udai (VRP-6):

An early maturing variety developed through pedigree selection from the cross Arkel x FC-1, plant height 58-62 cm, 50% plants bear flowers at 35-37 days after sowing, plants have dark green foliage and short internodes with 8-10 pods per plant, pods attractive, 9-10 cm long, filled with 8-9 bold seeds, shelling percentage 48, yield 100-110 q/ha.

Kashi Shakti (VRP-7):

A medium maturing variety developed through pedigree selection from the cross Hara Bona x NDVP-8, plant height 90-98 cm, flowers at 54-56 days after sowing, plants have dark green foliage with 11-12 pods per plant, pods 10.0-10.5 cm long, attractive filled with 7-8 bold seeds, shelling percentage 48-49, yield 140-160 q/ha.

Kashi Mukti (VRP-22):

An early maturing powdery mildew resistant variety developed through pedigree selection from the cross No. 7 x PM-5, plant height 50-53 cm, flowers at 35-36 days after sowing, pods 8.5-9 cm long, with 8-9 bold soft textured seeds, shelling percentage 48-49, yield 110-120 q/ha.

Kashi Kanak (VRP-2):

An early maturing variety developed through selection, plant height 50-55 cm, foliage dark green, pod straight, light green, length 7-8 cm filled with bold seeds, first picking at 55-58 days after sowing, green pod yield 60-80 q/ha.

Kashi Arati (VRP-3):

A mid season variety, flowering at 45-50 days after sowing, pods green, bold grain, average yield 80-120 q/ha. Radish

Kashi Sweta (IIVR-1):

Developed through selection from radish cv. Chetki, suitable for early harvesting, edible roots at 30-35 days after sowing, roots 25-30 cm long, 3.3-4.0 cm in diameter, straight, tapering with pointed tip, yield 450-470 q/ha.

Kashi Hans (IIVR-2):

Developed through selection, suitable for September to February planting, harvesting after 40-45 days of sowing, can stand in the field up to 10-15 days after edible maturity, moderately resistant to Alternaria blight, leaves soft and smooth like spinach, roots straight, tapering, length 30-35 cm, diameter 3.5-4.2 cm, yield 430-450 q/ha.

Ash Gourd:

Kashi Dhawal (IVAG 502):

Derived from a local collection, vine length 7.5-8 m, fruits oblong, flesh white, thickness 8.5-8.7 cm, seed arrangement linear, average weight 11-12 kg, crop duration 120 days, yield 550-600 q/ha.

Derived from a local collection, vine length 7.5-8 m, fruits round with average weight of 10-12 kg, fruit flesh white with 7 cm thickness, seed arrangement linear, crop duration 110-120 days, yield 55-60 t/ha.


Early maturing, can tolerate high rainfall during its vegetative growth, curds semi-dome type, white compact, fine texture, weight 300-450 g, yield 300-350 q/ha.


Derived from the cross between NDPK-24 x PKM through pedigree selection, vines short, leaves dark green with white spots, fruits green, spherical 2.5-3.0 kg at green stage, yield of 300-350 q/ha in 65 days of crop duration.


Medium vine, leaves sparsely lobed, colour dark green, fruits round, with open prominent green sutures, weight 650-725 g, half slip in nature, rind thin, smooth, pale yellow at maturity, flesh salmon orange (mango colour), thick, very juicy, T.S.S. 13-14% and seeds loosely packed in the seed cavity, post-harvest life better with good transportability, tolerant to powdery and downy mildew, medium maturity, yield 200-270 q/ha.

Bottle Gourd:

Long fruited hybrid with green vine and vigorous growth, fruit straight, light green, length 30-32 cm, average weight 780-850 g, yield 500-550 q/ha, suitable for rainy and summer season cultivation.

An early variety derived from the cross IC-92465 x DVBG-151, fruits light green, length 30 cm, diameter 7 cm, fruit weight 800-900 g and yield 480-550 q/ha, tolerant to anthracnose and suitable for rainy and summer season cultivation.

Bitter Gourd:

This variety has been derived from the cross IC-85650B x IC-44435A, having dark green and long fruits, mild spines, length 16-18 cm, fruit weight 90-110 g and yield 220-220 q/ha.

8.5: Fruits - Biology


Making food, medicine, and pleasure from plants.

The Latin words hortus (garden plant) and cultura (culture) together form horticulture, classically defined as the culture of garden plants. But today horticulture is more than garden plant culture. Horticulturists work in crop production plant propagation plant breeding genetic engineering plant physiology plant biochemistry landscape design, installation, construction, and maintenance and storage, processing, and transit (of fruits, berries, nuts, vegetables, flowers, trees, shrubs, and turf). They improve crop yield, quality, nutritional value, and resistance to insects, diseases, and environmental stresses. They make plants more adaptable to different climates and soils and better fit for food uses or processes. And they grow and improve plants used for medicines or spices.

Horticulturists can work in industry, government, or educational institutions. They can be cropping systems engineers, wholesale or retail business managers, plant specialists in the landscaping industry, propagators and tissue culture specialists (fruit, vegetables, ornamentals, and turf), crop inspectors, crop production advisors, extension specialists, plant breeders, research scientists, and educators. You'll find horticulturists in offices, laboratories, greenhouses, and out in production or research fields.

In college take courses in biology, chemistry, mathematics, genetics, physiology, statistics, computer science, landscape design and construction, and communications to complement plant science and horticulture coursework. Plant science and horticulture courses include plant materials, plant propagation, tissue culture, crop production, post harvest handling, plant breeding, crop nutrition, entomology, plant pathology, economics, and business. For many careers you must have a master's or doctoral degree.

In high school take basic courses in rhetoric and speech communications, mathematics, chemistry, biology, and computer sciences.

Download an 8.5-inch x 11-inch, printable poster for Horticulturist . (downloadable pdf format)
The second page of the download includes the career description above.

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Primary Contact:
Hannah Dankbar
Extension Local Food Program Manager
North Carolina Cooperative Extension
NC State University
[email protected]

The objective of the Extension Local Food Program is to facilitate the production, marketing, and consumption of food grown, caught, and raised within North Carolina.

North Carolina Cooperative Extension and many organizations and stakeholders are working with our communities on development and expansion of local food systems across the state. This Local Food website has been developed by North Carolina Cooperative Extension to provide local food systems resources and timely information to all residents and businesses across the state. The goal of the website is to provide information and link to resources from Cooperative Extension as well as from other NC organizations and state partners working on local food programming. It is a dynamic site and is intended to include new resources as they are developed over time.

Ritual Uses

Figure 8.8.5 The peyote cactus contains a hallucinogenic drug that is still used by some Native Americans for religious rituals.

Certain psychoactive drugs, particularly hallucinogens, have been used for ritual purposes since prehistoric times. For example, Native Americans have used the mescaline-containing peyote cactus (pictured in Figure 8.8.5) for religious ceremonies for as long as 5,700 years. In prehistoric Europe, the mushroom Amanita muscaria, which contains a hallucinogenic drug called muscimol, was used for similar purposes. Various other psychoactive drugs — including jimsonweed, psilocybin mushrooms, and cannabis — have also been used for millennia, by various peoples, for ritual purposes.

The recreational use of psychoactive drugs generally has the purpose of altering one’s consciousness and creating a feeling of euphoria commonly called a “high.” Some of the drugs used most commonly for recreational purposes are cannabis, ethanol (alcohol), opioids, and stimulants (such as nicotine). Hallucinogens are also used recreationally, primarily for the alterations they cause in thinking and perception.

Some investigators have suggested that the urge to alter one’s state of consciousness is a universal human drive, similar to the drive to satiate thirst, hunger, or sexual desire. They think that this instinct is even present in children, who may attain an altered state by repetitive motions, such as spinning or swinging. Some nonhuman animals also exhibit a drive to experience altered states. They may consume fermented berries or fruit and become intoxicated. The way cats respond to catnip (see Figure 8.8.6) is another example.

Figure 8.8.6 This cat is taking advantage of a catnip plant and apparently enjoying its psychoactive effects.

Addiction, Dependence, and Rehabilitation

Psychoactive substances often bring about subjective changes that the user may find pleasant (euphoria) or advantageous (increased alertness). These changes are rewarding and positively reinforcing, so they have the potential for misuse, addiction, and dependence. Addiction refers to the compulsive use of a drug, despite negative consequences that such use may entail. Sustained use of an addictive drug may produce dependence on the drug. Dependence may be physical and/or psychological. It occurs when cessation of drug use produces withdrawal symptoms. Physical dependence produces physical withdrawal symptoms, which may include tremors, pain, seizures, or insomnia. Psychological dependence produces psychological withdrawal symptoms, such as anxiety, depression, paranoia, or hallucinations.

Rehabilitation for drug dependence and addiction typically involves psychotherapy, which may include both individual and group therapy. Organizations such as Alcoholics Anonymous (AA) and Narcotics Anonymous (NA) may also be helpful for people trying to recover from addiction. These groups are self-described as international mutual aid fellowships, and their primary purpose is to help addicts achieve and maintain sobriety. In some cases, rehabilitation is aided by the temporary use of psychoactive substances that reduce cravings and withdrawal symptoms without creating addiction themselves. The drug methadone, for example, is commonly used to treat heroin addiction.


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Genetic studies in the fruit fly

The availability of multiple genetic tools made drosophila an ideal model system to decipher gene function and molecular pathways. Some examples of these tools are: the easy generation, through genetic crosses and offspring selection, of stable genetic stocks, the powerful genetic screens with mutagenesis or transposone insertion for gene disruption, the use of genetic transformation, the availability of tools allowing for conditional gene expression (GAL4/UAS system), the use of RNAi for conditional knock down and the more recent genome editing CRISPR/Cas9 technology [1].

Drosophila has a small genome of 180Mb with around 13600 genes. The full genome has been sequenced [2]. A global picture about gene expression, chromatin regulation, DNA replication, splicing (around half of the drosophila genes are regulated through alternative splicing), through the different developmental stages has contributed to the understanding of drosophila’s developmental regulation [3].

The genome of D. melanogaster is distributed in only 4 chromosomes (3 autosomes and one pair of sex chromosomes). One of the autosome pairs, known as the dot chromosome, is significantly smaller than the others [4]. The study of the sex chromosomes in drosophila has contributed to the understanding of sex determination and dosage compensation. In flies, the dose of X chromosomes in the chromosome complement is the responsible of male determination, and not the presence of the Y chromosome as it occurs in humans. The double X chromosome sensing in drosophila is made at the cellular level, and it triggers a transcriptional cascade leading to sex determination [5].

Biology investigatory project class 12 | Pdf

We know that finding a Biology Investigatory project is the hardest part of a science fair project for class 12, and sometimes it just takes a little help to focus on what kinds of topics would interest you. To help you find a Biology Investigatory project idea that are interesting to you, you can select any of the categories below under the heading of EXPERIMENTS, you will find dozens of interesting experiments.

High school science covers a variety of topics in Biology like Microbiology, Zoology, Botany, Biotechnology project ideas, Ecology, meteorology etc. Therefore, nothing is forbidden when it comes to choosing a Biology project topics for class 12! These ideas would be suitable for most of the high school curriculum. When reviewing the list, remember that you can make any of these ideas more complex by changing variables and comparing results.

You may be guided by your teacher for your choice of topic. The more original or new the project is, the better it would be. But it must be realistic in terms of the time available and at a level attained in the higher secondary biology. You must review the available literature to find out what type of work has been done. This will help you to reject some of the alternatives, and possibly cause you to modify others. It may also be the source of new ideas. By doing these investigatory projects you will gain experience of research besides providing opportunity for learning skills such as photography, electronics, etc.

It is not uncommon for school students to find suitable topics for research projects . The range of options is wide, because there are as many scientific fields as there are different research fields. From the following topics student will be able to choose something for himself:

Effect of sugar concentration on transfer of water molecules across a semi-permeable membrane

Effect of temperature on Vitamin C concentration in Solanum lycopersicum
How does altering temperature affect the concentration of Vitamin C in Solanum lycopersicum as measured by a solution with 2,6-Dichlorophenol Indophenol?
Background information
Vitamin C refers to ascorbic acid and its salts. It is essential nutrient for humans as it is not synthesized by the body. Vitamin C acts as a cofactor in many enzymatic reactions, most notable of which is the synthesis of collagen. Consequently, lack of Vitamin C leads to the disease called scurvy.
Vitamin C is present in present in plants (such as strawberries, oranges, and in tomatoes) and in most animal meat (specifically the liver). However, the Vitamin C content in these foods is proportionate to the time and temperature they are stored or cooked at. This because oxidation occurs: 2 ascorbic acid + O2 2 dehydroascorbate + 2 H2O
The rate of this reaction increases with temperature. It is also further increased as fruits such as tomatoes have an enzyme called L-ascorbate oxidase which catalyzes the previous chemical reaction.
Nature of titration used: 2,6-Dichlorophenol Indophenol is a blue redox dye. When it is reduced by ascorbic acid, it turns colourless:
DCPIP (blue) + ascorbic acid→ DCPIPH2 (colorless) + dehydroascorbic acid
This reaction occurs in a 1:1 ratio ie 1 molecule of DCPIP reacts with 1 molecule of ascorbic acid.
Vitamin C content in tomatoes: According to the USDA, tomatoes have 13.7 mg of Vitamin C per 100 grams.
I expect the volume of tomato solution needed to titrate the DCPIP to increase with temperature. This is because I predict Vitamin C oxidation to increase with temperature and thus Vitamin C content of the tomato will be inversely proportional to temperature. I expect the Vitamin C will decrease fairly constantly with temperature as the denaturing of the L-ascorbate oxidase will be compensated by the large increase in kinetic activity of particles.
Independent Variable:
Temperature to which tomato juice sample was heated: 20 °C, 40 °C, 60 °C, 80 °C, 100 °C.
These temperatures were obtained by heating all the tomato juice samples in a water bath and removing them as they reached the desired temperature.
Dependent Variable:
Volume of tomato solution required to neutralize 0.5 cm3 2,6-Dichlorophenol Indophenol (DCPIP). DCPIP becomes colorless when it is reduced. Thus, when all of the molecules of DCPIP are reduced by ascorbic acid, there is a visible color change. From this data, I then calculated the amount of Vitamin C (g) in 100 cm3 of the solution.
Control Variables Effect if left uncontrolled How it was controlled
Type of tomato Using different tomato cultivars or tomatoes at different ripeness would alter the amount of Vitamin C in the tomato solution. This would pose a problem when comparing it to literature values. I used tomatoes connected to the same vine, ensuring that the tomatoes came from the same plant and are of the same cultivar. These were all red and ripe.
Conditions under which tomatoes were stored after purchase. Storing tomatoes under sun and heat decreases their Vitamin C content. If tomatoes were stored at temperatures above 20 °C, it would also make the first set of results meaningless as the tomatoes had already been heated above that temperature. I purchased these tomatoes from an outdoor market. As it was winter time the temperature was well below 20 °C. Then they were stored in a refrigerator.
However, I do not know if these tomatoes were stored at higher temperatures before purchase.
Turbidity of tomato juice Greater turbidity would cause end point determination in titration to be more difficult. Solution had to be homogeneous so all trials had same amount of Vitamin C. I crushed the tomatoes into purée and I added water to dilute it. Then I filtered the juice to remove solid material. I did all the solution at once so that all the solutions used had the same level of turbidity. The solution was red/ orange so the endpoint was decided not when the solution was colorless but when it was the original red/ orange color.
Light intensity in room The endpoint was determined using my eyesight, which is subjective to light intensity. Lower light intensity would cause solution to appear darker thus I would titrate more tomato solution. I did the titration in the same room on the same day and at equal distance to window.
Temperature at which titration took place Temperatures alters the kinetic energy of particles, causing the reaction between DCPIP and ascorbic acid to occur at different rates. Therefore, titre would alter. Heated tomato juice was let to cool down to 20 °C. Temperature was measure using a temperature probe ±0.1°C .
Time over which tomato solution was heated Duration of heating affects overall oxidation. Longer time periods causes greater amounts of oxidation to take place, decreasing the ascorbic acid content.

Boiling tubes were heated together in the same water bath so that equal heat was applied. The solutions were then removed as they reached the required temperature ensuring that each consecutive sample was heated for the same time as the previous sample plus whatever time it for the next temperature to be reached. Although, I did not heat all the solutions for the same time, this was the greatest level of control that could have been done using lab apparatus. Once heated, they were placed in a beaker of water at 14 °C ±0.1°C to cool down quickly.
Volume of 1% DCPIP solution in test tube Greater volume of DCPIP would require greater quantities of tomato juice to be titrated for neutralization to occur. I fixed this volume at 0.5 cm3 for all of the trials.
Concentration of DCPIP and tomato solution Using different concentrations at each trial would alter the amount of volume needed for titration endpoint to be reached. Concentration of DCPIP was maintained at 1% and the tomato solution was made using 750 g of tomato and 250 cm3 of water.
Control Variables Effect if left uncontrolled How it was controlled
Rate at which tomato juice was added with burette The redox reaction requires time. Greater rate of addition would decrease the time allowed for reaction to occur. As a result, more tomato juice would be added. I fixed the rate to a steady stream of drops. I used the same burette and I marked the degree of opening on the burette so it would remain constant.
Amount of mixing during titration Mixing during the titration increases the kinetic energy of the particles, increasing the rate of reaction and decreasing the volume of tomato solution needed. No stirring would not produce accurate results as the reactants would not become in contact as easily as they would rely on diffusion. I mixed the solution of test tube using a steady movement of my hand throughout the trials for all of the trials. I realize that this is inaccurate. However, I did not have access to a magnetic stirrer.
2 cm3 glass pipette ±0.006 cm3
50 cm3 burette ±0.05 cm3
1000 cm3 beaker
5 boiling tubes
50 cm3 graduated cylinder ± 1 cm3
Filter paper
Data logger thermometer probe ±0.1°C
Digital balance ± 0.01 g
How it was made Uncertainty
1% DCPIP (2,6-Dichlorophenol Indophenol) solution It was produced by technician Unknown as it was produced by technician
75% Tomato solution Grind fresh tomatoes into a purée.
Measure 750.00 g of tomato purée using digital balance.
Measure 250 g of water using digital balance
Filter solution with filter paper Uncertainty of digital balance ±0.01 g
Uncertainty of Tomato purée: ±0.01 g
Uncertainty of Water: ±0.01 g
Overall uncertainty of Tomato solution:
(±0.02 g )/(1000 g)=±0.002 %
Heating of tomato solutions
Check room is at 20 °C ±0.1°C with thermometer probe.
Transfer 50 cm3 of tomato solution using a 50 cm3 graduated cylinder into five boiling tubes.
Set one of the boiling tubes aside.
Combine 300 cm3 of water and 50 g of salt (NaCl) in a 500 cm3 beaker
Place 4 boiling tubes in beaker and heat with a Bunsen burner.
Place a thermometer in each boiling tube.
Remove the first boiling tubes when the thermometer reads 40°C ±1°C. Then place the boiling tube in the cold water bath until the thermometer reads 20 °C ±1°C.
Repeat step 7 as the boiling tubes respectively reach 60°C, 80°C, and 100°C.
Check room is at 20 °C ±1°C with thermometer.
Transfer 0.5 cm3 of DCPIP using a 2 cm3 glass pipette into a test tube.
Decant 50 cm3 of the tomato solution heated to 20 °C solution into burette.
Titrate DCPIP into test tube using a burette ±0.1 cm3 until DCPIP loses dark blue color and becomes red/orange like original tomato solution.
Repeat steps 1-4 to obtain 5 trials.
Repeat step 1-5 using tomato solution heated to 40 °C, 60 °C, 80 °C and 100 °C.
Quantitative data
Table 1 to show the volume of tomato juice, which has been heated to different temperatures, needed to neutralize 0.5 cm3 of DCPIP in a titration
Temperature to which tomato solution was heated ±1 °C Start point of volume of tomato solution
±0.1 cm3 (1 DP) End point of volume of tomato solution
±0.1 cm3 (1 DP) Titre of tomato solution
±0.1 cm3 (1 DP) Average ±0.1 cm3 (1 DP) Standard deviation ±0.1 cm3 (1 DP)
20 Trial 1 0.0 4.2 4.2 5.0 0.8
Trial 2 11.5 17.6 6.1
Trial 3 17.6 23.0 5.4
Trial 4 23.0 27.8 4.8
Trial 5 35.0 39.5 4.5
40 Trial 1 13.0 18.6 5.6 6.3 0.6
Trial 2 18.6 24.8 6.2
Trial 3 24.8 31.5 6.7
Trial 4 31.5 37.4 5.9
Trial 5 37.4 44.5 7.1
60 Trial 1 14.0 19.8 5.8 6.5 0.7
Trial 2 19.8 26.7 6.9
Trial 3 26.7 33.2 6.5
Trial 4 33.2 39.2 6.0
Trial 5 39.2 46.7 7.5
80 Trial 1 13.8 21.0 7.2 7.4 0.9
Trial 2 21.0 27.8 6.8
Trial 3 27.8 34.1 6.3
Trial 4 34.1 42.5 8.4
Trial 5 41.5 49.8 8.3
100 Trial 1 11.1 18.6 7.5 7.7 0.3
Trial 2 18.6 26.7 8.1
Trial 3 26.7 34.0 7.3
Trial 4 34.0 41.7 7.7
Trial 5 41.7 49.5 7.8

Sample calculation:
Using the data from the 5 trials of tomato solution heated to 20 °C:
Average titre of tomato solution:(4.2 〖cm〗^3+6.1〖cm〗^3+5.4〖cm〗^3+4.8〖cm〗^3+4.5〖cm〗^3)/5=5.0〖cm〗^3
Standard deviation: σ=√(((4.2-5.0)^(2 ) 〖+(6.1-5.0)〗^2 〖+(5.4-5.0)〗^2 〖+(4.8-5.0)〗^2+(4.5-5.0)^2 )/5)= 0.75828≈0.8 cm3 (1 DP)
Qualitative Data:
Temperature to which tomato solution was heated (°C) Observations during heating Observations during titration
20 – End point was red/orange. However, there was still a faint tint from DCPIP. Furthermore, after some time, the solution darkened again.
40 Colour of tomato juice did not change. Bubbles were not produced.
60 Colour of tomato solution did not change. Some bubbles were produced in the water of the water bath.
80 More bubbles were produced in the water of the water bath. Slight darkening of tomato solution.
100 The tomato solution turned brown and produced foam. Water in beaker boiled.
Processed data
Although the following are chemical calculations, they allow me to understand the significance of my biology experiment:
I know from my background information that 1 mol of DCPIP reacts with 1 mol of Vitamin C. Since I know the concentration of DCPIP, I can calculate the mol of DCPIP that reacted and thus the mol of Vitamin C in every tomato solution.
1% DCPIP solution suggests there is 1 g DCPIP per 100 g of water. Thus,
1/100g=x/0.5g→x=0.005 g DCPIP in 0.5 cm3 of 1% solution

To find the moles one divides the mass by the molar mass : moles=mass/(molar mass)
Mr of DCPIP: 268.1 g mol-1
moles of DCPIP which reacted in the titration=(0.005 g)/(268.1 g 〖mol〗^(-1) )=1.865 x 10-5 mol
Thus, 1.865 x 10-5 mol Vitamin C also reacted in the titration.
To find mass of Vitamin C which reacted in the titration I use the formula:
mass reacted= Mr (vitamin C) x mol (of vitamin C reacted)
Mr of Vitamin C: 176.12
1.865 ×〖10〗^(-5) mol ×176.1 g mol〖 g〗^(-1)= 0.00328 g

The following is a sample calculation for trial 1 of the 20°C solution to explain how the g of Vitamin C in 100 g of pure tomato heated to 20 °C was obtained. I chose 100 grams as it is the standard amount used in the food industry allowing me to compare my results to literature values.
Titre: 4.2 cm3
Therefore there were 0.00328 g Vitamin C in 4.2 cm3 of 75% tomato solution.
To find g of Vitamin C in 100 cm3 of 75% tomato solution:
(0.00328 g)/(4.2 〖cm〗^3 )=x/(100 〖cm〗^3 )→x= 0.078 ≈ 0.08 g (2 DP)

75% tomato solution refers to the % of tomato mass in the solution. In order to obtain a ratio of mass/ volume just as the g of vitamin C in 100 cm3, I calculated the density of the tomato solution. Tomato puree has a density of 1.12 g per cm3 and water has a density of 1 g per cm3. 100 g of 75% tomato solution consists of 75g tomato puree and 25 g water:
├ █(75 g of tomato puree would occupy (75.00 g)/(1.12 g cm^(-3) )=66.96 cm^[email protected] g of water has a volume of 25 〖cm〗^[email protected])>25+66.96=91.96 〖cm〗^(3 ) is the volume of 100 g of 75% tomato solution
Therefore, (75 g)/(91.96 〖cm〗^3 ) is the ratio of tomato mass to volume of solution.

To find the grams of Vitamin C in 100 g of pure tomato, I divided the g of vitamin C in 100 cm3 of the 75% solution by the ratio of tomato to volume of the 75% solution:
0.078 g/(75 g)/(91.96 〖cm〗^3 ) = 0.09563 g ≈ 0.10 g ±0.01g (2 DP) of Vitamin C in 100 grams of solution.

The g of Vitamin C per 100 cm3 of the solutions in each trial are summarized in the table on the next page:
Table 2 to show the calculated amount of Vitamin C in 100 cm3 of the 100% solution. It also includes the average value along with the standard deviation, standard error and 2 standard error. The values shown are rounded to two decimal places as this was the precision of the balance used. However, as this level of precision does not allow one to appreciate the differences in standard deviation or standard error, I added a table in the appendix with the values to 4 decimal places.
Temperature to which tomato solution was heated ±1 °C
Mass of Vitamin C (g) in 100 cm3 of pure solution
±0.01 g (2 DP) Average grams of Vitamin C in 100 g of solution pure solution
±0.01g (2 DP) standard deviation
(2 DP) standard error
(2 DP) 2 standard error
±0.01g (2 DP)

Trial 1 0.10 0.08 0.01 0.01 0.01
Trial 2 0.07
Trial 3 0.07
Trial 4 0.08
Trial 5 0.09

Trial 1 0.07 0.06 0.01 0.00 0.01
Trial 2 0.06
Trial 3 0.06
Trial 4 0.07
Trial 5 0.06

Trial 1 0.07 0.06 0.01 0.00 0.01
Trial 2 0.06
Trial 3 0.06
Trial 4 0.07
Trial 5 0.05

Trial 1 0.06 0.06 0.01 0.00 0.01
Trial 2 0.06
Trial 3 0.06
Trial 4 0.05
Trial 5 0.05

Trial 1 0.05 0.05 0.00 0.00 0.00
Trial 2 0.05
Trial 3 0.06
Trial 4 0.05
Trial 5 0.05

Sample calculation:
Using the data from the 5 trials of tomato solution heated to 20 °C:
Average g of Vitamin C in 100 g of solution: (∑▒x)/N:(0.09858 g+0.0659g+0.0745g+0.0838g+0.0894g)/5=0.0819g≈0.08 g
Standard deviation: σ=√((∑▒〖(X-X ̅)〗^2 )/N) σ=√(((0.0958-0.0819)^(2 ) 〖+(0.0659-0.0819)〗^2 〖+(0.0745-0.0819)〗^2 〖+(0.0838-0.0819)〗^2+(0.0894-0.0819)^2 )/5)=0.0118≈0.01 (2 DP)
Standard error:(0.0118)/√5 =0.0053≈0.01 (2 DP) 2 standard error : 0.0053x 2=0.0106≈0.01
Graph 1 showing the mass of Vitamin C in pure tomato heated to different temperatures with error bars representing 2 standard error
The curve of best fit in this graph shows a negative correlation between the temperature to which the tomato solution was heated and g of Vitamin C per 100 g of tomato in the solution. The error bars represent 2 standard errors, thus there is 95% chance that the true values lie within the bars.
Qualitative data:
My qualitative data did not indicate a change in the amount of Vitamin C. Nonetheless, the darkening of the color of the tomato solution could be due to the fact that the red carotenoids in tomato degrade at high temperatures.
Quantitative Data:

My quanititative data saw an increasing volume of tomato solution react with DCPIP as the temperature increased. As vitamin C and DCPIP react in a 1:1 ratio, an increasing volume per the same amount of DCPIP signified that vitamin C concentration decreased with increasing temperature. Thus my hypothesis that ‘Vitamin C content of the tomato will be inversely proportional to temperature’ was supported

I used my titration results to calculate the g of vitamin C per 100 g of pure tomato pure. These chemical calculations indicated that the pure tomato heated to 20 °C had 0.08 g per 100 g whilst tomato heated to 100 °C had 0.05 g per 100g. That constitutes a 33% decrease in Vitamin C content.
Plotting the data in a graph shows that there is an overall decreasing trend throughout the 5 trials. However, whilst I hypothesized that the ‘Vitamin C will decrease fairly constantly with temperature as the denaturing of the L-ascorbate oxidase will be compensated by the large increase in kinetic activity of particles’, in the graph obtained is not linear one can observe the most significant decrease in Vitamin C content is between 20 °C and 40 °C and after that, there is no significant difference between 40 °C to 60 °C and 80 °C to 100 °C as the error bars overlap. This could be due to the fact that the L-ascorbate oxydaze enzyme present in tomatoes, which catalyzes Vitamin C oxidation, works optimally between 20 °C and 40 °C, and denatures soon after. In fact, according to the fact file on the enzyme provided by SEKISUI ENZYMES, L-ascorbate oxydaze’s optimum temperature is 45 °C and it’s activity declines rapidly afterwards . Overall, as temperatures above 20 °C are quite common, my data would indicate that it is very important for tomatoes to be stored at a cool temperature to avoid a significant reduction in vitamin C.
The data of g of vitamin C per 100 g of tomato was not dispersed as can be seen by the 2 standard error of 0.1 cm3 for 4 of the trials. This is insignificant as the uncertainty was ±0.1 cm3. Nonetheless, the values were not accurate, this is evidenced by the fact that at 20 °C I calculated a Vitamin C content of 0.08g per 100g whilst the literature value, according to the USDA , is 0.0137 g. This is a difference of which leads to a very high percentage error of 484%. As the uncertainty of ±0.01 g is much smaller than the error of 0.07 g I can conclude that the largest errors in my experiment were systematic (such as the water) and not random. I will explain these errors further in the evaluation. Nonetheless, the predominance of systematic error lead me to conclude that the overall trend is accurate as a systematic error affects the trials equally.
The decreasing trend in my results is coherent with an experiment done by Lucia Sánchez-Moreno, published in an article called ‘Impact of high-pressure and traditional thermal processing of tomato purée on carotenoids, Vitamin C and antioxidant activity’ for The Journal of the Science of Food and Agriculture. A paper by the Federal of University of Technology in Owerri, Nigeria, called ‘Temperature Effects on Vitamin C Content in Citrus Fruits’ also found that the most significant decreases in Vitamin C content occurred between 30 °C and 40 °C and 70 °C and 80 °C. Allthough these experiment were done on citrus fruits, the nature of the ascorbic acid present is the same.

Problems that occurred during the experiment Effect these had on experiment Improvements to be made if experiment was repeated
The titration method had inaccuracies due to the fact that the end-point was hard to determine as the tomato solution was not colorless. This was a systematic error in my method as the end-point was not accurate. This can be seen by the large error compared to literature values of 484% or which is not accounted for by the small uncertainty of ±0.01 g. The tomato solution would be filtered using a less permeable filter or a centrifuge to produce a clearer solution. This would allow one to observe the color change in the DCPIP more clearly. A colorimeter could be used to obtain a more precise endpoint. A different method altogether could be used. For example, measuring the absorbance of the solution using a UV-spectroscophotometer. However, the school lab did not have this apparatus.
During my titration I tried to swirl the test tubes consistently throughout the trials. Nonetheless, as it was done with my hand, it was not controlled properly as it is subject to human error. Therefore, the amount of mixing that occurred in each trial was different. Different amounts of mixing will cause different rates of reaction. This is important as a slower rate will cause more tomato solution to be titrated in, decreasing its value for Vitamin C content. Swirling a solution increases the particles’ kinetic energy, increasing the number of successful collisions between particles. Additionally, mixing allows the two solutions to come in contact easier. If there is no mixing, the solutions will take longer to come in contact with each other as they will rely solely on diffusion. If the experiment were repeated, I would use a magnetic stirrer. As it is mechanical, it will allow the solutions in each trial to be mixed equally and thus reducing the random error in my experiment.
The DCPIP was saturated. Some solid DCPIP deposited in the flask. I assumed the fact that DCPIP was a 1% solution. However, some DCPIP had precipitated out of the solution, the actual percentage of DCPIP in the solution was slight lower. This increased the values of Vitamin C. This could account for part of the 484% percentage error compared to literature values. If the experiment were repeated I would use a more diluted DCPIP solution. This would assure that the solution was not saturated so no DCPIP was deposited on the bottom. Furthermore, this would allow solution to be more homogeneous. Additionally, with a more diluted solution I could use greater volumes in the titration. This would reduce the effect of the uncertainties. Additionally, I would do the solution myself and not rely on the lab technicians.
When calculating the mass of vitamin C, I assumed that when the solution turned colourless, all of the molecules of DCPIP had reacted. However, this could not have been the case. If not all of the molecules of DCPIP reacted then, due to my assumption that ascorbic acid and DCPIP reacted in a 1:1 ratio, a inaccurately low mass of vitamin C was calculated. However, this error is unlikely to have been significant as my calculated masses were much greater than the literature values. If the experiment were repeated I would use a different method to calculate vitamin C. Instead of using chemical mol calculations, I could have titrated the DCPIP with a known Vitamin C solution (using an ascorbic acid tablet). The known mass of Vitamin C in this Vitamin C solution will be equal to the volume of the Vitamin C in the tomato solution titrated. Consequently, I could find the masses of Vitamin C in each solution.
Problems that occurred during the experiment Effect these had on experiment Improvements to be made if experiment was repeated
In my experiment, it was necessary to dilute and filter tomato purée in order for the titration to be accurate.
However, as I was interested in knowing the Vitamin C content of 100 g of pure tomato purée in order to compare it to known values, I used the value of Vitamin C in the dilution and I divided it by the mass of tomato puree in the solution to take into account for the dilution. By doing this calculation, I assumed that the water had had no effect on the decrease in Vitamin C content. This is questionable as water is needed for Vitamin C to oxidize. Nevertheless, there was already water present in the pure tomato. Additionally, the water affected all the trials equally so it did not affect the overall trend. If the experiment were repeated I would not dilute the tomato puree in water. This would nonetheless not allow the titration method to be useful so a different method would be necessary such as the spectroscopic technique explained previously.
Further investigation:
It would be interesting to investigate what happens to Vitamin Content above 100 °C as cooking temperatures normally range between 140 °C to 165 °C due to the nature of the Maillard reactions that occur .
Additionally, it would be noteworthy to investigate the effects of long term storage at below zero temperatures compared to normal room temperatures. This is important because from my experiment I was learnt that at the lowest temperature was when most oxidation occurred. Thus, if storage at these temperatures also leads to significant levels of oxidation, maybe freezing produce should be considered in order to maintain Vitamin C content.

8.5: Fruits - Biology

The sapote fruit fly, Anastrepha serpentina (Wiedemann), sometimes called the serpentine fruit fly, is intercepted frequently in United States ports of entry in various hosts from several countries. It is an important pest species in Mexico because its larvae infest sapote, sapodilla, willowleaf lucuma, and related fruits.

Figure 1. Adult female. Drawing by Division of Plant Industry.

Synonymy (Back to Top)

Dacus serpentina Wiedemann, 1830
Leptoxys serpentina (Wiedemann), 1843
Urophora vittithorax Macquart, 1851
(Trypeta) Acrotoxa serpentina (Wiedemann), 1873
Acrotoxa serpentina (Wiedemann)

Distribution (Back to Top)

This species is one of the most widely distributed in the genus Anastrepha. Its range extends from northern Mexico south to Peru and northern Argentina, and is recorded from Trinidad, Tobago and Curaçao. It has also been trapped in southern Texas in the USA, but it is uncertain whether it has breeding populations there (Norrbom 2003).

If Anastrepha serpentina were introduced into southern Florida, it could possibly become a serious pest of the tropical fruits grown there.

Description (Back to Top)

Adult: The adult is a medium sized, dark brown fly, with pale yellow and orange-brown markings. The dorsum of the thorax is dark brown with yellow markings. The wing is 7.25&ndash8.5 mm long. Wing bands are predominantly dark brown, and the costal and S bands are rather broadly coalescent. On the wing, the hyaline areas to each side of the juncture rarely touch the vein R4+5, with no distal arm to V band. The proximal arm is slender and entirely separated from the S band. The dorsum of the abdomen is marked with dark brown, brownish yellow, and orange. Leg color varies from pale yellow to brownish yellow, or brown on one side and pale yellow on the other.

The ovipositor sheath of the female is 3.0&ndash3.9 mm long, orange-brown, rather stout basally and depressed apically. The spiracles are about 1.2 mm from its base. The ovipositor itself is 2.8&ndash3.7 mm long, with the tip slightly more than apical half minutely serrate.

Figure 2. Ovipositor tip. Drawing by Division of Plant Industry.

Larva: The mature larva is relatively large for fruit flies, 9&ndash10 mm long and 1.5 mm in diameter, with the usual elongate shape. Anterior respiratory organs have the external parts somewhat fan-shaped, but nearly flat across the top, with 17 to 19 small, thick, short tubules. For detailed larval characters, see Phillips (1946).

Anastrepha serpentina, the type of the genus, is one of a group of four species that differ noticeably in color pattern from other species in the genus. As illustrated by Stone (1942), Anastrepha anomala Stone has the wing pattern as in Anastrepha serpentina, but has a longer ovipositor and a reduced dark pattern on the pleura and abdomen.Anastrepha ornata Aldrich has the costal and V bands separated, and Anastrepha pulchra Stone has a large black spot in the disk of the wing.

Life cycle and Biology (Back to Top)

Females may oviposit up to 600 eggs in about one and a half months. Mature green fruits apparently are preferred. Females have been observed to continue oviposition over periods extending from 21 to 29 weeks under laboratory conditions.

Figure 3. Egg of the sapote fruit fly, Anastrepha serpentina, compared with other common Anastrepha species. Drawing by Division of Plant Industry.

Hosts (Back to Top)

The preferred food plants are members of the family Sapotaceae, especially star-apple, Chrysophyllum cainito, and sapodilla, Manilkara zapota. Other hosts include:

  • Annona glabra, pond-apple
  • Citrus mitis, calamondin Citrus paradisi, grapefruit Citrus sinensis, sweet orange
  • Cydonia oblonga, quince
  • Dovyalis hebecarpa, 'Ceylon gooseberry'
  • Ficus spp.
  • Malus sylvestris, European wild apple
  • Mammea americana, mammee apple
  • Mangifera indica, mango
  • Mimusops coriacea, monkey's apple
  • Persea americana, avocado
  • Pouteria lucuma, 'lucuma' Pouteria sapota, mamey sapote
  • Prunus persica, peach
  • Psidium guajava, common guava
  • Pyrus communis, European pear
  • Sideroxylon palmeri and Sideroxylon tempisque, bully trees
  • Spondias mombin, jobo or hog plum

Also, larvae have been reared experimentally from tomato, Lycopersicum esculentum.

Damage (Back to Top)

Infestations in tree-ripe fruits frequently are so high that in parts of Mexico, especially in Veracruz, growers pick the fruits green and ripen them artificially to avoid infestation. Fruits so ripened, however, are inferior to tree-ripened fruits.

Selected References (Back to Top)

  • Baker AC, Stone WE, Plummer CC, McPhail M. 1944. A review of the Mexican fruitfly and related species. U.S. Department of Agriculture Miscellaneous Publication No. 531, Washington, D.C. 155 pp.
  • Phillips VT. 1946. The biology and identification of trypetid larvae (Diptera: Trypetidae). Memoirs of the American Entomological Society 12, 161 pp.
  • Stone A. 1942. The fruit flies of the genus Anastrepha. U.S. Department of Agriculture Miscellaneous Publication No. 439, Washington, D.C. 112 pp.
  • White IM, Elson-Harris MM. 1994. Fruit flies of economic significance: Their identification and bionomics. CAB International. Oxon, UK. 601 pp.

Web Design: Don Wasik, Jane Medley
Publication Number: EENY-206
Publication Date: April 2001. Latest revision: January 2015. Reviewed April 2018.

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