Tag: growth and development in plants

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.