Seed traits and their correlates in Indian tropical trees

Abstract

There exists a huge diversity in seed traits among the plant species. Ecological consequences of such variations are manifold and often vary between floras, habitats and taxonomic groups. Very few ecological studies concerned with seed traits have been done in Indian flora. Functional relationships of seed traits with plant traits like germination percentage, germination rate, dispersal, seedling establishment / survival, viability, etc. in Indian plants and especially in tropical trees have not been sufficiently investigated and evidence for any association remains equivocal in most cases. To find possible correlates of seed traits in Indian tropical tree species, we collected seeds/fruits of 80 tropical tree species from Bhimashankar in Western Ghats, Pune and Pakke Wildlife sanctuary (Arunachal Pradesh). Fruit and seed traits, which include fruit mass, fruit dimensions, number of seeds per fruit, seed mass and seed dimensions were measured. Germination assays and seedling establishment experiments were carried out in the laboratory. Data for dispersal mode, fruit type, month of dispersal, fruit maturation time, plant height, plant habit, habitat type and leaf habit were obtained from secondary sources. Interactions of these traits with seed / fruit / diaspore traits and among themselves were investigated. Diaspore mass was found to be associated with dispersal mode, fruit type and season of dispersal. Dispersal mode was associated with both fruit type and season of dispersal. Seed mass was associated with plant height, plant habit and habitat type. Leaf habit had no significant effect on seed size. Seed mass was positively correlated with seedling growth rate. However, no significant correlation was observed between fruit mass and fruiting duration, seed mass and germination percentage, and seed mass and seedling survival.