Plasma Membrane H～+-ATPase Is Involved In Pollen Germination Regulation In Arabidopsis Thaliana

The regulation of pollen germination and tube growth is one of the most important questions of plant development. Active proton pump on the pollen grain membrane drives H+ efflux, hyperpolarize the membrane and triggers signaling transduction. In this paper, pharmacological and fluorescence ratio photometry was applied to investigate the effect of proton pump activator fusicoccin and inhibitor sodium vanadate on Arabidopsis pollen germination and cytosolic calcium concentration in pollen cells.The results suggest that pollen germination percentage and tube length of pollen which treated with fusicoccin is higher and longer than that of control, while pollen treated with sodium vanadate has lower germination percentage and shorter tube length compared with control.After treated by fusicoccin, most of the pollen present an increase of cytosolic calcium, while sodium vanadate lead to a main trend of decrease of cytosolic calcium. Results indicate proton pump may stimulate pollen germination and tube growth by promoting cytosolic calcium arose and calcium signaling.Heterotrimeric G proteins play an crucial role in many transmembrane signaling transductions. The G protein null mutant,G protein over-expression line and WS was used in the experiment to compare the result of diffenent genotype that response to fusicoccin and sodium vanadate. No apparent difference was observed in pollen germination,tube length and cytosolic calcium between pollens treated with fusicoccin or sodium vanadate of diffenent genotypes.This result imply heterotrimeric G proteins may be a upstream regulator of proton pump or of no direct relation to proton pump.