Realization of Polyamines' Effect on the State of Pea Stomata with the Involvement of Calcium and Components of Lipid Signaling

Polyamines are stress plant metabolites with a wide range of physiological effects. Their effect on functioning of the stomatal apparatus of plants remains poorly understood. The aim of the study was to use inhibitory analysis to investigate the possible participation of different calcium pools and lipid signaling components in the implementation of the effect of putrescine and spermine on stomatal aperture of pea leaves (Pisum sativum L.). It was shown that the epidermis incubation in the presence of both polyamines within the concentration range of 0.25-5 mM caused a decrease in the stomatal aperture. This effect was observed within 1 h after the start of incubation and was most pronounced after 2.5 h exposure in a medium containing 1 mM putrescine or spermine. In the presence of the calcium channel blocker LaCl3, the effect of polyamines on the state of stomata was weak; also it was partially neutralized by the extracellular calcium chelator EGTA; however, polyamines' effects were completely eliminated by the phospholipase C inhibitor neomycin. The effect of putrescine and spermine on the stomatal aperture was not detected with the presence of n-butanol, an inhibitor of phospholipase D-dependent phosphatidic acid formation, but not with its inactive isomer 2-butanol. The obtained results point to the possible role of calcium entry into cytosol from intracellular compartments, and the importance of signaling intermediates formed with the participation of phospholipases C and D in the implementation of the stomatal effects of polyamines.

Automated summary

Polyamines have a significant impact on stomatal aperture in plants, possibly involving calcium channels, phospholipases C and D signaling pathways.