Sexual Reproduction in Flowering Plants Test - 96

• Seeds that possess a special food storage tissue called as the endosperm are said to be albuminous and those which have no such tissue for storage are said to be ex-albuminous or non-endospermic. 
• When germination of seed takes place then food is used by the embryo whether it is stored in endosperm or in the cotyledon. 
• Epigeal germination implies that the cotyledons are pushed above ground. The hypocotyl (part of the stem below the cotyledon) grows, while the epicotyl (part of the stem above the cotyledon) stays the same length. In this way, the hypocotyl pushes the cotyledon upward. 
• Hypogeal germination implies that the cotyledons stay below the ground. The epicotyl grows, while the hypocotyl stays the same length. In this way, the epicotyl pushes the plumule above the ground. 
  

• A population whose members reproduce asexually is called apomictic. They reproduce by a special mechanism called apomixis. 
• Apomixis is the formation of seeds without syngamy and meiosis. Although seeds, in general, are the products of fertilization, a few flowering plants such as Asteraceae and grasses, have evolved this special mechanism. 
• An apomixis is a form of asexual reproduction that mimics sexual reproduction. It includes abnormal sexual reproduction in which egg or other cells like synergids and antipodals develop into an embryo without fertilization and meiosis.

So, the correct answer is option B.

Flowers with too many stamens to count are said to have indefinite stamens. Such condition is not observed in cucurbitaceae family. 
Syngenesious stamens are united by their anthers only, filaments remaining free. This condition is not present in flowers of cucurbiotaceae family. 
Monadelphous stamens are united by their filaments and anthers remain free. Such condition is not observed in cucurbitaceae family.
Synandrous stamens are united at their anthers as well as filaments. This condition is a characteristic feature of flowers of family cucurbitaceae. 

Indefinite number of stamens are characteristic of the family Malvaceae. The characteristic feature of family Malvaceae is monadelphous androecium. The flowers of Malvaceae are commonly borne in definite or indefinite axillary inflorescences, which are often reduced to a single flower, but may also be cauliflorous, oppositifolious or terminal. They often bear supernumerary bracts. They can be unisexual or bisexual and are generally actinomorphic, often associated with conspicuous bracts, forming an epicalyx. They generally have five valvate sepals, most frequently basally connate with five imbricate petals. The stamens are five to numerous and connate at least at their bases but often forming a tube around the pistils. The pistils are composed of two to many connate carpels. The ovary is superior, with axial placentation, with capitate or lobed stigma. The flowers have nectaries made of many tightly packed glandular hairs, usually positioned on the sepals.
Therefore, the correct answer is option C.

Some plants show spontaneous to and fro movements of their leaflets. Such movements are observed in many plants. They are generally driven by temperature, touch, light, humidity, chemicals, etc. Desmodium, which is also called as Indian telegraph plant consists of two lateral leaflets and terminal leaflets.
Leaflets of Desmodium oscillates autonomously depending upon the temperature. Such oscillations are believed to be due to rhythmic swelling and shrinking of motor cells located in the pulvinus leaflet base. This movement of leaflets is similar to telegraphic signals.
Hence, it is also called as Indian telegraph plant. Desmodium, Indian telegraph plant belongs to family Papilionaceae as it possesses legumes, brightly colored papilionaceous flowers.

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.

Cotton taken for commercial purpose is a soft, fluffy staple fibre growing in a boll from trichomes on the seed coat of the plants of the genus Gossypium  of the family Malvaceae. The cotton fibre is pure cellulose and under natural conditions, these bolls tend to increase the dispersal of the seeds.
Thus, the correct answer is option B.

Didynamous stamens is a condition in which stamens occur in two pairs as one long pair and one shorter pair. 
Diplostemonous is a condition in which stamens are arranged in two whorls as inner whorl opposite to petals and outer whorl alternating with petals.
Tetradynamous is condition of stamens where 6 stamens are present of which 4 are longer than the other 2.

In gymnosperms, the endosperm is haploid in nature. Whereas, in angiosperms there is a characteristic double fertilization, where a triploid endosperm as well as a diploid zygote is formed. In angiosperms, a diploid polar secondary nuclei fuses with male gamete forming triploid endosperm, serves the role of providing nourishment to the developing embryo.

The members of the family Solanaceae are an economically important family of flowering plants and consists of about 98 genera and some 2,700 species. Few of the characteristics features of the family include- stamens-generally 5 and epipetalous, the gynoecium is bicarpellary, syncarpous, bilocular or tetralocular due to presence of pseudo septum. the ovary is superior and obliquely placed, the fruit is a berry or capsule.