Phenotypic plasticity and ecology of three species of Podostemaceae Rich. Ex C. Agardh

Abstract

The members of Podostemaceae, commonly called river-weeds, are with very peculiar vegetative form; revealing many unique morphological, anatomical and ecological characters from other angiosperms. They undergo an annual cycle of colonization, establishment of a canopy of mature plant, and dies back when the water level drops. The annual pattern is dictated by high and low water periods. Physico-chemical analysis showed that the largest population of the species occupied an area of full sunlight. Water samples from the two study sites viz. Janiaw and Umtienger localities, both from East Khasi Hills District, Meghalaya, India, showing high pH indicated less human activities of different kind. It is also determined that the species inhabits clean rivers, thus, they serve as an indicator of clean water. They occur primarily in low nutrient condition. Further, it was also observed that dissolved oxygen is the most essential factor for successful establishment of these plants, rather than other nutrients and pH. Toxic discharge of effluents from industries and agrochemical residues are serious threat to podostemads that has unique ecological requirement.