Seed and Fruit Development in Angiosperms - Class X

Fruits are formed by the maturation of one or more ovary. Fruits contain seeds resulting from the maturation of fertilized ovules. However, maturation of seed and fruit can occur in the absence of fertilization. In fleshy fruits, the outer covering is called as pericarp. Pericarp is again made of three layers, the epicarp, which is the outermost layer; the mesocarp, which is the middle layer; and the endocarp, which is the inner layer surrounding the ovary or the seeds. 

Endosperm is the nutritive tissue for the developing embryo and the seedlings. In angiosperm, the endosperm develops from triploid primary endosperm nucleus which is formed as a result of vegetative fertilization, triple fusion or fusion of male gamete with the secondary nucleus of the central cell. Generally, endosperm divides before zygote because it will provide nourishment to the developing zygote.

Wheat is a grain, which belongs to the grass family Poaceae or Gramineae. Wheat grain is a fruit (Caryopsis) that produces a dry edible seed which is commonly known as the kernel. Wheat grain is a small edible fruit, usually hard on the outside. Corn, grain sorghum, rice, oats, and rye are other examples of grains.

For the formation of male gametophyte, 1 meiosis and 2 mitoses are required.

After fertilization, the ovule matures into seeds and ovary into fruits. The process of fertilization is unique in angiosperms because it involves syngamy between male and female gametes and triple fusion between a male gamete and a secondary nucleus. Because two fertilization events are involved, it is called as double fertilization. The second fertilization is a fusion between three haploid nucleus (two forming a diploid secondary nucleus and one haploid male nucleus). Hence the secondary fertilization event is called as Triple fusion. It gives rise to a triploid primary endosperm nucleus (PEN). PEN later on gives rise to triploid endosperm. The seed coat forms from the two integuments or outer layers of cells of the ovule, which derive from tissue from the mother plant, the inner integument forms the tegmen and the outer forms the testa. The seed coats of some monocotyledon plants, such as the grasses, are not distinct structures, but are fused with the fruit wall to form a pericarp.

Aleurone layer in the seed helps in embryo protection, utilization of stored food and storage of food. Aleurone is a protein found in protein granules of maturing seeds and tubers. The term also describes one of the two major cell types of the endosperm, the aleurone layer. The aleurone layer is the outermost layer of the endosperm, followed by the inner starchy endosperm. This layer of cells is sometimes referred to as the peripheral endosperm. It lies between the pericarp and the hyaline layer of the endosperm. Unlike the cells of the starchy endosperm, aleurone cells remain alive at maturity.
Thus, the correct answer is option D.

In hypogeal germination, epicotyl elongates and cotyledons remain underground. 
In epigeal germination, hypocotyl elongates and pushes cotyledons above the ground. 
Assertion is wrong because gram, pea and mango shows hypogeal germination.
Reason is true but it is not the right explanation for given assertion.
Thus, the correct answer is option C.

Orthodox seeds are seeds which will survive drying or freezing during ex-situ conservation. There is variation in the ability of orthodox seeds to withstand drying and storage with some seeds being more sensitive than others. Thus, some seeds are considered intermediate in their storage capability while others are fully orthodox.
Thus, the correct answer is option B.

The outer thick layer is called as testa and inner thin one as tegmen. The seed develops from the tissue, that is the integument which originally surrounds the ovule. The seed coat forms from the two integuments or outer layers of cells of the ovule, which derive from tissue from the mother plant, the inner integument forms the tegmen and the outer forms the testa. The seed coats of some mononocotyledon plants, such as the grasses, are not distinct structures, but are fused with the fruit wall to form a pericarp.
Therefore, the correct answer is option C.

In hypogeal germination, cotyledons remain underground and plumule is elongated above the ground. 
Hypocotyl is part of the stem situated below the cotyledons. If hypocotyl is the active region, then it will elongate and will bring cotyledons above the ground. But, as stated above cotyledons remain underground. 
Radicle gives rise to primary root during germination process. 
Tigellum is the main axis of embryo which protrudes out of the cotyledons and forms radicle and plumule during germination process. 
Epicotyl is part of the stem above cotyledons. During germination process, epicotyl being the active region elongates and pushes plumule above the ground and cotyledons remain underground.
Thus, the correct answer is option B.

The peanut or groundnut (Arachis hypogaea) is a species in the family Fabaceae. Peanuts can be eaten raw, used in recipes, made into oils, textile materials and peanut butter as well as many other uses. In general, peanut products are considered safe for human use, although there are insufficient studies about peanut aflatoxins and uses for cosmetics. Peanut oil is often used in cooking, because it has a mild flavour and a relatively high smoke point. Due to its high monounsaturated content, it is considered healthier than saturated oils and is resistant to rancidity.
There are several types of peanut oil including aromatic roasted peanut oil, refined peanut oil, extra virgin or cold pressed peanut oil and peanut extract.
In the United States, refined peanut oil is exempt from allergen labelling laws. This oil is obtained from seeds of Arachis hypogea. Oryza sativa is rich in carbohydrates. Cicer arietinum is rich in proteins. Hibiscus esculentus (okra) seeds does not contains fats. 
Thus, the correct answer is option A.

Cotton, seed-hair fibre (testa) of a variety of plants of the genus Gossypium, belonging to the Hibiscus or mallow, family (Malvaceae) and native to most subtropical parts of the world.
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will tend to increase the dispersion of the seeds. So, fibres of Gosssypium are out growth of testa and not out growth of pericarp, pappus hair and bast fibres. 
Therefore, the correct answer is option C.

The seeds of Abrus precatorius are much valued in native jewelry for their bright coloration. Most beans are black and red, suggesting a ladybug, though other colors are available. Jewelry-making with jequirity seeds is dangerous and there have been cases of death by a finger-prick while boring the seeds for beadwork. The seeds were traditionally used to weigh jewellery in India. Seeds of Xanthium, Calotropis and Thespesia are not used as jeweler's weight. 
Therefore, the correct answer is option B.

Cotton is a soft, fluffy staple fiber that grows in a boll or protective capsule, around the seeds of cotton plants of the genus Gossypium in the family of Malvaceae. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will tend to increase the dispersion of the seeds. Cotton is a seed hair fiber produced from epidermal seed coat. Cotton fibers are not obtained from root hairs, stem hairs or leaf. 
Therefore, the correct answer is option D.

A fertilized, fully grown and ripened ovary forms a fruit. After the process of fertilization, the ovary swells up and develops into a fruit.
Thus, the correct answer is option (C), 'Only ovary'.

Seed is the ripened ovule or mature integumented megasporangium in which outer integument convert into testa and inner integument are grown up as tegmen and after fertilization, the embryo is placed inside seed in dormant state and grow into a new plant in favorable condition.

Collar like outgrowth arising from the base of ovule and forming a sort of third integument is known as aril. It is typically coloured, hairy and fleshy structure. It is edible in some of the species of plant. It helps in pollination as the insects gets attracted by its beautiful colour.

Endosperm develops after the formation of embryo. It functions as the nutritive tissue for the growing embryo. The endosperm is found as liquid (coconut water) and solid (coconut kernel, white fluffy part of maize). The endosperm found in maize is of nuclear type. 

In the case of coconut plant, the hard shell forms the inner layer of fruit (endocarp). Inside the shell, there is a seed which is covered by a seed coat. This seed coat is brown in colour and attached to the kernel which is endosperm. The seed coat is a thin layer which is protective in nature. 

Ethylene helps fruits ripen by making them softer, through the breakdown components of the cell walls, and sweeter, through the conversion of starches to sugars. Unlike the other plant hormones, ethylene is actually a gas and is distributed through the air, not through the plant body. One of the coolest things about ethylene is that it is released in a positive feedback loop, a little bit of ethylene causes more to be released, which causes even more to be released, and so on. A benefit of this fact is that you can take an unripe fruit (a pear, plum, or peach, for example) and put it in a paper bag with riper fruit (bananas work well for this) and ethylene will accumulate, making the unripe fruit soft and sweet. Indoleacetic acid, gibberellic acid and kinetin does not triggers the ripening process. 

Parthenogenesis is a type of asexual reproduction in which the offspring develops from unfertilized eggs. It is particularly common among arthropods and can also be found in some species of fish, amphibians, birds and reptiles, but not in mammals. 

Ovary get transformed into fruit post fertilisation. Outer layer of ovary becomes the outer layer of fruit along with ovules converting into seeds.

Ovules form into seeds in the mature fruit post fertilisation (transformed ovary). Their different arrangements can be seen in fruits such as pea, orange etc.

In almost all angiosperms, double fertilisation takes place where a triploid endosperm is formed. In a few cases, it is non - endospermous where the entire endosperm is consumed during the development of embryo.

Endosperm of angiosperm results when the secondary nuclei which is diploid fuses with the second sperm entering the apparatus, which is haploid in nature.

Water lotus (Nelumbo  nucifera) have an unusually long period of viable germination. Even if, a seed is in the ideal condition of germination, it might remain dormant for decades. They show self-preservation and resistance to germination. 

The ovary is converted into fruit after the formation of an embryo and protects the seed in angiosperms.

A. Seed in many members of the Euphorbiaceae, such as castor, the soft outgrowth capping the hard seed is formed by proliferation of the cells at the tip of the outer integument called caruncle. It is rich in starch and sugars.

B. Cotyledons-  They  are thin, semi-transparent and oval in outline in castor. They have palmate venation. The middle costa or rib is more prominent and bears a few lateral veins.

C. Funiculus- It is a stalk like structure which attaches the ovule to the placenta.

D. Inner integument- It forms the tegman, inner covering of seed.

So, the correct answer is ‘Outer Integument’.

Cardamoms are ripe and dried fruits of  Elettaria cardamomum, commonly called green or true cardamoms. They are called the 'queen of spices' because of the aroma and taste. 

Double fertilization process is observed in angiosperms in which syngamy takes place in the beginning. After syngamy the pollen tubes releases two male gametes, one fuses with the nucleus of egg cell and the other with the central cell and forms primary endosperm nucleus (PEN). The process is called as triple fusion as endosperm is triploid in nature.

In some seeds, the nucellus persists after fertilization and is referred to as perisperm (e.g., in black pepper and beet).

Fruit is a seed-bearing structure in flowering plants formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate seeds.  A fruit results from maturation of one or more flowers, and the gynoecium of the flower forms all or part of the fruit. The outer, often edible layer, is the pericarp, formed from the ovary and surrounding the seeds, although in some species other tissues contribute to or from the edible portion. The pericarp may be described in three layers from outer to inner, the epicarp, mesocarp and endocarp. 

Plumed seeds occur in Calotropis. The seeds are compressed, broadly ovoid, with a tufted micropylar coma of long silky hair. The crown of the hair on the seeds favouring anemochory give the plumed appearance.

Upon fertilization while ovule develops into seed. Pericarp develops from carpel. The pericarp is typically made up of three distinct layers, the epicarp, which is the outermost layer, the mesocarp, which is the middle layer and the endocarp, which is the inner layer surrounding the ovary or the seeds. In a citrus fruit, the epicarp and mesocarp make up the peel.
Therefore, the correct answer is option C.

Nelumbo nucifera, also known as Indian lotus, sacred lotus, bean of India, or simply lotus, is one of two species of aquatic plant in the family Nelumbonaceae. This plant is an aquatic perennial. Under favourable circumstances, its seeds may remain viable for many years, with the oldest recorded lotus germination being from that of seeds 1,300 years old recovered from a dry lake bed. 

Vivipary is a condition where plants produce seeds which germinate before they detach from the parent. 
Xerophytes are terrestrial plants which have adapted to survive in environment with little water, like desert or ice covered region. Seeds of such plants are modified to require more water before germination, so to make sure that there is sufficient supply of water for seedling survival. Hence, xerophytes do not show vivipary. 
Hydrophytes are plants which are adapted to survive in aquatic conditions.
Such plants show reproductive adaptation-
1. Production of buoyant seeds which can float on high flooded water and delay germination process.
2. Plants grow quickly after germination and form an extended shoot on water surface. 
Therefore, hydrophytes do not show vivipary. 
Epiphytes are plants which are not rooted in soil but grows on bodies of other plants. But they are not parasites, they produce their own food. Epiphytes show reproductive adaptations as,
1. They produce colorful flowers to attract many pollinators.
2. They also produce strong nectar to lure pollinators.
3. After pollination they produce large number of small seeds which can be dispersed by wind.
But epiphytes do not show vivipary.
Mangroves are various types of trees of medium height which are found in saline coastal habitat. Vivipary is a type of reproductive adaptation shown by mangroves. Mangroves show adaptation to survive in harsh, unstable, dynamic environment, low oxygen and varying salinity of soils. The salinity of the surrounding water and soil damage the seeds. The unstable flood can destroy the seeds. In such environment, if seeds are dispersed in water then their chances of survival are very less. Therefore, mangroves show vivipary.
Therefore, the correct answer is option C.

Many seeds are insensitive to light, but in a number of species, germination is stimulated or inhibited by exposure to continuous or short periods of illumination. So stimulated are many grasses, lettuce, fireweed, peppergrass, mullein, evening primrose, yellow dock, loosestrife, and Chinese lantern plant. Corn, the smaller cereals, and many legumes, such as beans and clover, germinate as well in light as in darkness.
Inhibition by light is found in chive, garlic, and several other species of the lily family, jimsonweed, fennel flower. Sometimes, imbibed (wet) seeds that do not germinate at all in darkness may be fully promoted by only a few seconds or minutes of exposure to white light or to karrikin. The best-studied case of this type, and one that is a milestone in plant physiology, concerns seeds of the Grand Rapids variety of lettuce, which is stimulated to germination by red light (wavelength about 660 nanometres) but inhibited by far-red light (wavelength about 730 nanometres). Red light inhibits stem elongation and lateral root formation but stimulates leaf expansion, chloroplast development, red flower coloration, and spore germination. Such stimulation by red light can be reversed by exposure to far-red light. So, red light is most effective in seed germination compared to green, blue and far red light. 
Therefore, the correct answer is option C.

Tetrazolium salt stains all living tissue in the seed embryo red. Thus, enabling trained analysts to determine the seeds viability or otherwise. The tetrazolium test is used to give a quick estimate of germination potential. The result of a tetrazolium test will generally predict the germination test result closely, however the tetrazolium test will not detect certain types of abnormalities nor will it give any indication of disease levels, chemical damage or dormancy. The viability of a seed is tested by tetrazolium salts. The viable seeds when respire reduce the colourless tetradyes into highly coloured compounds, i.e. 2, 3, 5 triphenyltetrazolium chloride is reduced to triphenylformazon which is red in colour. 
Therefore, the correct answer is option B.

Seed hairs of Gossypium are purely cellulosic and of commercial importance. Fibres grow from the seed coat to form a boll of cotton lint. The boll is a protective fruit and when the plant is grown commercially, it is stripped from the seed by ginning and the lint is then processed into cotton fibre. Cotton is a soft, fluffy staple fibre that grows in a boll or protective capsule, around the seeds of cotton plants of the genus Gossypium in the family of Malvaceae. The fibre is almost pure cellulose. So, pure cellulose is obtained from seed hairs and not from root hairs, stem hairs and leaf hairs. 
Thus, the correct answer is option D.

The plant is best known for its seeds, which are used as beads and in percussion instruments and which are toxic due to the presence of abrin. The plant is native to India and grows in tropical and subtropical areas of the world where it has been introduced. It has a tendency to become weedy and invasive where it has been introduced.
The seeds of Abrus precatorius are much valued in native jewellery for their bright colouration. Most beans are black and red, suggesting a ladybug, though other colours are available. Jewellery-making with jequirity seeds is dangerous and there have been cases of death by a finger-prick while boring the seeds for beadwork.
In Trinidad in the West Indies, the brightly coloured seeds are strung into bracelets and worn around the wrist or ankle to ward off jumbies or evil spirits and mal-yeux-, the evil eye. The Tamils use Abrus seeds of different colours. The red variety with black eye is the most common, but there are black, white and green varieties as well.
The seeds of Abrus precatorius are very consistent in weight. Formerly, Indians used these seeds to weigh gold using a measure called as Ratti, where 8 Ratti = 1 Masha. 12 Masha = 1 Tola (11.6 Grams). So, Abrus precatorius plant's seeds are used as jeweller's weight and not of Cajanus cajan (pigeon pea), Lens culinaris (lentil) and Glycine max (soya bean). 
Thus, the correct answer is option D.

After fertilization, zygote is formed which develops embryo, which forms the future plant. The endosperm cells serve as a source of nutrition for the developing embryo. The ovule becomes the seed. The ovary becomes the fruit. In most of the plants the antipodals and synergids disintegrate before, during or immediately after fertilization. The outer and inner integuments of the ovule become the testa or the seed coat of the seed.  Petals and sepals fall off. 
Thus, the correct answer is option (A), 'Seed.'

Germination is the process by which a plant grows from a seed. A series of changes in the reproductive biology among the heterosporous plants led to the evolution of seed plants. In seed plants, the megaspore is retained in the megasporangium and the microspore is taken to a pollen chamber at the tip of this organ. The development and fertilization of gametophyte occur within a protected environment. A pattern that showcases evolution of seed is found among the vascular plants. In homosporous vascular plants (plants that produce only one type of spore) have exosporic gametophytesthat is, the gametophyte develops outside of the spore wall. In addition, these exosporic gametophytes are normally bisexual (produce both sperm and eggs). In heterosporous vascular plants (presence of both microspores and megaspores), development of gametophyte is endoscopic and gametophytes are unisex, producing either sperm or eggs.
Therefore, the correct answer is option B.

Lathyrism is a disease caused by eating seeds of species of Lathyrus (the grass pea), mainly L. sativus (the chickpea or khesari), L. cicera (flat-podded vetch) and L. clymenum (Spanish vetchling). It affects mostly people in Bangladesh, India, Pakistan, Nepal and Algeria but is sometimes found in France, Italy, Spain and Australia. This disease affects horses and cattle as well as in man.
Beta-Oxalyl-amino-L-alanine acid (BOAA), an excitatory neurotoxin and glutamate agonist, has been identified as the constituent of the chick pea responsible for the disease. BOAA appears to exert its effects through mitochondrial toxicity.
Prolonged use of seeds of Lathyrus sativus causes a debilitating disorder is not due to presence of glucodsinolates, amygdalin and cyanogenic glucosides. 
Therefore, the correct answer is option C.

Endosperm is a tissue produced inside the seeds of most flowering plants around the time of fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein.
Thus, the correct answer is option (B), 'Endosperm'.

• During fertilisation, there is a fusion of the male and the female gametes. 
• In the case of angiosperms, there is a phenomenon called as double fertilisation. 
• There is a formation of zygote and endosperm after triple fusion. The zygote gets transformed to form the embryo. 
• The ovule gets converted to seed and the ovary develops to form the fruit. the integuments form the seed coat. 

The outer and inner integument of the ovule are of dermal derivation. The endothelium develops from the inner layer of integument. It is also called as  integumentary tapetum. At maturity, it becomes about 14-cell layers thick. The middle layers give the shape of the ripe seed. 

A dormant seed contains only 10-15% of water and is essentially dehydrated. The seed has to absorb water in order to become active. Plants grow by absorbing nutrients from the soil and all the nutrients have to be in the dissolved form.
Irrigation does not always improve soil texture. Irrigation does not protect the crops from frost. Irrigation is the artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall.

A fruit is the seed-bearing structure in flowering plants (also known as angiosperms) formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate seeds. The outer, often edible layer, is the pericarp, formed from the ovary and surrounding the seeds, although in some species other tissues contribute to or form the edible portion. The pericarp may be described in three layers from outer to inner, the epicarp, mesocarp and endocarp. A fruit results from maturation of one or more flowers, and the gynoecium of the flower(s) forms all or part of the fruit