Botany and Plant Science

Syngamy is the fusion of gametes, i.e., the union of nuclei of male gamete and female gamete in theprocess of reproduction. In angiosperms, generative fertilization is also called, syngamy.

Cross pollination is the transfer of pollen grains of a male flower to the stigma of female flower, which occurs either on the same plant (monoecious) or on the different plant (dioecious).

In orthotropous (atropous) ovule, the micropyle, funicle and chalaza lie in a straight line.

The movement of pollen tube towards embryo sac is chemotropism as it occurs in responce to certainchemical substances like auxin and carbohydrates.

In angiosperms, endosperm is triploid and secondary nucleus (2n) is diploid.

Unisexuality of flowers prevents autogamy (self pollination) but not geitonogamy (pollination betweenseparate male and female flowers on the same plant).

In angiosperms, one male gamete fuses with the egg to form the diploid zygote. The process is called syngamy. The other male gamete fuses with the two polar nuclei to form triploid primary endosperm nucleus. The process is called triple fusion. These two acts of fertilization constitute the process of double fertilization.

In porogamy, pollen tube enters the ovule through the micropyle. It is the most common way of the entry of pollen tube inside ovule.

Pollination by wind (anemophily) is more common amongst abiotic pollinations. It is quite common in grasses.  

In embryo sac of angiosperm, egg apparatus occurs towards micropylar pole and generally organises by two synergids and one egg cell. Egg cell has a large vacuole at its upper end and a prominent nucleus near its lower end. Synergids show a filiform apparatus attached to their upper wall. It is known to attract and guide the pollen tube. Each of the synergids has a vacuole at its lower end and the nucleus at its upper end.  

Lotus, rose, leaves and jasmine all are lighter than water and float on the surface but lotus, rose and jasmine are the flowers making the leaves as an odd option.  

The bud of the plant is the part which develops into a flower. Leaf and stem can not further develop to form another part of the plant and seed is the structure formed after the development of a flower. 

 Heterospory results in the variation in the size of spores, which results in the formation of different sized spores, larger in female reproductive structure, which in the course of evolution gets modified into egg in the ovule and the smaller sized spores get modified into pollen grains, the male gametes. This modification results in fertilisation of egg in the ovary by male gametes derived from pollen grains and ultimately formation of seed.

This option is correct because the leaflet of Oxalis exhibits hyponasty. Hyponasty is the increased growth of the lower surface of a plant part, resulting in an upward bending of the part.

This option is correct because the chemical stimuli causing the movement of antherozoids towards the egg are malic acid and sugar.