Vol. 4, Issue 3 (2019)
Reproductive ecology of the dioecious and chamaechorous littoral spinegrass, Spinifex littoreus (Burm.f.) Merr. (Poaceae)
Author(s): AJ Solomon Raju, K Venkata Ramana, S Sravan Kumar, T Suneetha
Abstract: Spinifex littoreus is an essential constituent of coastal sand dune ecosystem. It forms separate colonies of male and pistillate plants characterizing dioecious sexual system. The flowering occurs during October-January but within this period, male plants begin flowering two weeks early to pistillate plants. The florets are born in inflorescence, each consisting of several spikelets which vary in number between male and pistillate spikelets. Further, individual spikelets of male plants produce several florets while those of pistillate plants produce characteristically a single floret. In pistillate florets, the anthers are rudimentary, indehiscent and sterile while female sex is perfectly functional. The stamens and stigmas positioned at the apex of the florets are completely exposed, the position of which facilitating pollen flow from male plants to pistillate plants with pollination as an end result. Anemophily is the rule in this plant as insect foraging activity is completely absent which is attributed to lack of floret attraction, lack of nectar and low nutrition value of pollen. Fruit set did not exceed 16% which is attributed to low nutrient availability and alkaline sandy soils. Chamaedorea is the mode of fruit dispersal and it is applicable only to Infructescence of pistillate plants. Infructescence buried by sand germinate and produce new plants. The plant also propagates through vegetative mode through stolon formation. It is an effective sand binder, stabilizes the sand dune and hence is useful in coastal green belt development.