Photosynthetic Diversity in Indian Grass Flora

Abstract

Plants following C3 and C4 pathways of photosynthesis respond differently to environmental variables such as temperature and precipitation. The C3 and C4 plants therefore, comprise specific groups which can help predict species response to climatic changes. Grasses alone account for nearly half of the known C4 species and half of the grass species are estimated to follow C4 photosynthesis. Indian grass flora has about 250 genera and 1,250 odd species, 55 % of which are of C4 type. The C4 tribe Andropogoneae, exclusively of NADP-malic enzyme (NADP-ME) sub-type, alone represents 50 % of the Indian C4 grasses. NADP-ME grasses exhibit high moisture affinity and constitute more than three-fourth of the Indian C4 grasses. The greater representation of NADP-ME species in the Indian grass flora could be attributed to the onset of Indian monsoons during the late Miocene, when the main adaptive radiation in grasses took place, the world over.