Pollen heteromorphism in Schleichera Lour. (Sapindaceae), observed in surface soil samples from central India

Abstract

Angiosperms display striking variation of pollen morphological features within and between populations of the same species, as well as within individual plants. We describe and illustrate variation of pollen aperture number, which is called pollen heteromorphism, in Schleichera Lour. (Sapindaceae) from surface soil samples collected from central India, based on combined observations from light microscopy (LM) and confocal laser scanning microscopy (CLSM). Tri-zono-parasyncolporoidate pollen grains are, in general, known to occur in Schleichera Lour., but occasional tetra-zono-parasyncolporoidate pollen is also recorded, for the first time, from Chhattisgarh State, central India. Changes in ploidy level (diploidy/polyploidy), chromosome number, the C-value of DNA, completion of meiosis, as well as environmental factors and/or pollination ecology could be driving the occurrence of pollen heteromorphism. The present study could provide insights into the phylogeny and systematics, and has implications for pollen preservation as well.