31 Years NEET Previous Year Questions: Sexual Reproduction in Flowering Plants - 3 - NEET MCQ

Scutellum is the modified cotyledon observed in a grain of wheat or maize. It lies between embryo and the endosperm.

Geitonogamy is the process of transfer of pollen grains from the anther to the stigma of another flower of the same plant. Example, maize.

Apomixis is an asexual type of reproduction in which the plant embryos grow from egg cells without being fertilized by pollen-the male part of the plant. In citrus, apomictic embryos arise from maternal sporophytic tissue like nucellus and integuments in ovule. This type of embryony is called adventive embryony.

Option (a)

Filiform apparatus helps in the entry of pollen tube into a synergid in ovule. Filiform apparatus is in form of finger like projection comprising a core of micro fibrils enclosed in a sheath. The filiform apparatus resembles transfer cells" meant for short distance movement of metabolites. The filiform apparatus responsible for the absorption of food from the nucleus.

Unisexuality of flowers prevents. autogamy, but not geitonogamy. In self fertilisation , the male and female gametes are derived from the same individual. Among plants, self fertilization also called autogamy is common in many cultivated species, eg., wheat and oats. However, self fertilization is a form of inbreeding and does not allow for the mixing of genetic material; if it occurs over a number of generations it will result in offspring being less vigorous and productive than those resulting from cross fertilization. 

In pea, endosperm is consumed by developing embryo in the seed. The endosperm is completely absorbed by the growing embryo and the food reserve gets stored in the cotyledons. Such seeds are called non endospermic or exalbuminous.

The egg cell is one of the haploid cell of egg apparatus present in the micropylar end of embryo sac in seeded plants. It is also cal led oosphere and represents the single female gamete of the embryo sac. Antipodal cells are the haploid cells, usually three in number, present in embryo sac at the opposite end of micropyle. Their function is unknown and at fertilization, they may disintegrate or multiply and enlarge.

Generative cell which is a  cell of the male gametophyte or pollen grain in seed plants that divides to give rise directly or indirectly two sperms.

In a dicot plant general arrangement of nuclei in the embryosac is that 3 nuclei in 3 cells of egg apparatus (one egg cell & 2 synergids) at micropylar end and 2 polar nuclei in almost middle region and 3 nuclei in the form of antipodals at the distal end from micropyle, towards nucellus. So total nuclei 3 + 2 + 3.

After entering the ovule, the pollen tube is attracted towards the micropylar end of the embryosac. The attractants are secreted by synergids or help cells. The pollen tube pierces one of the two synergids and bursts open into it. The synergid is simultaneously destroyed.

In flowering plants, archesporium cells undergo periclinal (transverse) division to form outer primary parietal layer and inner sporogenous cells. Primary parietal wall after few more periclinal divisions form anther wall and sporogenous cells give rise to sporogenous tissue.