31 Years NEET Previous Year Questions: Sexual Reproduction In Flowering Plants - 1

• The tapetum is a specialised layer of nutritive cells found within the anther of flowering plants, where it is located between the sporangenous tissue and the anther wall.
• Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.

• Lilium is an angiosperm plant, in which male gametophyte is 3 celled and most reduced gametophyte as compared to Funaria (bryophyte). 
• As we proceed from Thallophyta to angiosperms, there is a reduction in the gametophytic generation they become more and more dependent on sporophyte.
• In each of the plant groups that succeeded bryophytes, the gametophyte became less and less prominent. 
• In angiosperms like Lilium, the male gametophyte (pollen - grain) is highly reduced and is only a 3 celled structure.

• 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. It resembles transfer cells meant for short distance movement of metabolites.
• It is responsible for the absorption of food from the nucleus.

• Transfer of pollen from an anther of one flower to a stigma of another flower on the same plant is called as geitonogamy.
• Although geitonogamy is functionally cross-pollination involving a pollinating agent, genetically it is similar to autogamy since the pollen grains come from the same plant. 
• Cleistogamy or automatic self-pollination describes the trait of certain plants to propagate by using non-opening, self-pollinating flowers.
• Especially well known in peanuts, peas, and beans. 

Honey is made by nectar and pollens. Bees collect pollen and nectar in the spring when most flowers and plants are in bloom. They collect them in their stomach but an hour, the nector mixes with the proteins and enzymes produced by bees, which convert nectar into honey. 

The hilum is a scar found on the seed coat through which the developing seeds are attached to the fruit. 

Nectar and pollen grains are the usual floral rewards which the animal pollinators get. 

The synergid cell wall forms a highly thickened structure called the filiform apparatus at the micropylar end, consisting of numerous finger-like projections into the synergid cytoplasm. It is believed to play a major role in pollen tube guidance and reception.

Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.

 Pollen grains of other species are not compactable and do not germinate on the stigma of the flower of different species.

So, the correct option is 'Pollen grains of many species can germinate on the stigma of a flower, but one pollen tube of the same species grow into the style'.