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Which one of the following statements is correct?
A. Hard outer layer of pollen is called intine.
B. Sporogenous tissue is haploid.
C. Endothelium produces the microspores.
D. Tapetum nourishes the developing pollen.

Last updated date: 21st Jun 2024
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Hint: There are pollen grains representing the male gametophyte. These are normally spherical structures measuring approximately 25-50 micrometers in diameter. Mitotically, the pollen grain splits into two cells, a vegetative cell, and a generative cell.

Complete answer: Statement A: Intine is considered the inner wall of the pollen grain. The exine is a hard-outer layer composed of sporopollenin (one of the most resistant organic materials known) is present. As it can withstand high temperatures, strong acids, and alkali, the exine layer is safe. When pollinated by biotic/abiotic agents, it is difficult for the pollen grains to remain covered and sealed from dangerous environments, it shows an interesting array of taxonomically relevant designs and patterns. It has noticeable apertures named germ-pores where there is no sporopollenin. While intine is the inner wall that consists of cellulose and pectin, which is thin and continuous. There is a plasma membrane covering the cytoplasm of the pollen grain.
Statement B: The tissue that is sporogenous is diploid. To form microspore tetrads, it undergoes meiotic splitting. cells perform mitosis in another's primary Sporogenous layer (PSL) and develop a mass of diploid sporogenous tissue which further produces microspore mother cells (MMC). These moreover differentiate to form haploid microspores of pollen grains through meiosis.
Statement C: The wall around the microsporangium is endothecium, which provides protection and helps to release the pollen in the dehiscence of the anther.
Statement D: The inner core microsporangium layer is the tapetum. Tapetum nourishes pollen grains that grow. The outer three wall layers perform the defense role and help release the pollen in another dehiscence. The tapetum is the innermost wall layer. The developing pollen grains are nourished by it. Tapetum cells have a thick cytoplasm and normally have more than one nucleus.
Hence, the correct answer is option D, i.e., Tapetum nourishes the developing pollen.

Note: In some individuals, pollen grains of many species (particularly anemophilous plants) cause serious allergies and bronchial conditions, often contributing to chronic respiratory disorders such as asthma and bronchitis. Pollen grains are nutrient-rich. They improve the success of athletes.