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.

An example of a seed with endosperm, perisperm, and caruncle is castor. Castor seed is the source of castor oil, which has a wide variety of uses. The seeds contain between 40% and 60% oil that is rich in triglycerides.

Cotyledons and testa respectively are edible parts in groundnut and pomegranate. A cotyledon is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. Testa is often thick or hard outer coat of a seed.

The fig (Syconus) is an aggregate fr uit, consisting of numerous seed-like pericarps inclosed within a hollow, fleshy receptacle where the flowers were attached. This fruit developed from hypanthodium inflorescence.

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. 

The fleshy receptacle of syconus of fig encloses a number of Achenes. Achene is the thin dry pericarp is free from seed except at one point. The fruit develops from a monocarpellary pistil having superior unilocular and ovuled ovary. 

Dry indehiscent single-seeded fruit formed from bicarpellary syncarpous inferior ovary is cypsela. Cypsela is also called inferior, false or pseudocarpic achene, the thin friut wall (developed from peri carp and thalamus)is attached to the seed at one point but the fruits develops from an inferior, unilocular and uniovuled ovary, e.g., sunflower, marigold. Some cypsela develop pappus for dispersal e.g. Soncus, Taraxacum.

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.

The wall of the pollen mother cell (microspore mother cell) is deposited by callose (β-1, 3-glucan). Callose plays a significant role in reproductive biology of angiosperms. It acts as a temporary wall to prevent the product of meiosis from cohesion and fusion and its dissolution results in the release of free spores.

Synergids are haploid in nature. Thus, n = 8. The aleurone layer is triploid in nature. Thus, the aleurone layer will have 3n number of chromosomes. That is 3n = 3 X8 = 24 chromosomes are present in aleurone.

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.

Vivipar y is the condition when seeds  germinate on the plant. It is an undesirable character for annual crop plants because germinated seeds can not be stored under normal conditions for the next season.

Leaves of a number of plants develop or posses adventitious buds for vegetative propagation e.g., Broyophyllum, Kalanchoe, Adiantum caudatum.

Cycads is a group of gymnosperms which have top shaped multiciliated male gametes and each mature seed of these plants contain one embryo and two cotyledons e.g., Cycas.

In Amphitropous ovule, the embryo sac becomes horse-shoe shaped and the funiculus and micropyle are close to each other.  This amphitropous ovule is seen in Alismaceae and Butomaceae families. 
So the correct option is A.

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 oogamy  male and female gametes are morphologically as well as physiologically different. Female gametes are large and non-motile. Male gametes are small but motile.

In campylotropous ovule, the body is curved but the embryosac is straight eg. Capsella. In Anatropous, the body of ovule is inverted and gets fused with funiculus along its whole length on one side (most of the angiosperms). In orthotropous condition the body of ovule lies straight and upright over the funicle. e.g. Piperaceae, Polygonaceae.

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.