Sulpholipid reflects plant resistance to stress-factor action.

The results of studying the behaviour of sulphoquinovosyldiacylglycerol (SQDG) during environmental-factor action are discussed. Low-temperature action caused SQDG accumulation in 1-year-old shoot bark of resistant apple varieties, and was especially striking in the Siberia apple, a variety of extreme hardiness. Another unfavourable factor, high temperature, induced SQDG accumulation in leaves and chloroplasts of drought-resistant plants while in sensitive plants a decrease in its content took place. Water deficit caused the same effect. SQDG increase was also observed in field experiments with artificial irrigation in the drought region of Ukraine, at the stages of stooling and milk ripeness. Besides, SQDG accumulation was observed in wheat plants infected by Puccinia graminis and kidney bean plants infected by tobacco mosaic and potato x viruses. But lead supplied at various concentrations caused an SQDG decrease in wheat seedling leaves and roots. The reasons for these phenomena seemed to be mainly the stabilization of the photosynthetic processes, particularly ATP synthesis and light-harvesting complex II functioning, but signal function also cannot be excluded.