Effects of exogenous polyamines applied separately and in combination with simulated acid rain on functional activity of photosynthetic apparatus

摘要

Ten-day-old bean (Phaseolus vulgaris) seedlings were grown in a greenhouse and sprayed with 1 mmol/litre spermidine or spermine or were not sprayed. After 24 h they were treated with a cocktail of simulated acid rain (pH 5.6 and 1.8). The protectiveeffect of polyamines on the functional activity of the photosynthetic apparatus in the acid rain-treated plants was investigated. Acid rain with pH 1.8 applied separately strongly decreased photosynthetic rate, oxygen evolution and photosystem II activity. Polyamines (spermidine and spermine) applied 24 h the before the acid rain treatment partially diminished the inhibitory effect of acid rain on the photosynthetic apparatus. The protective effect of spermine was higher than that of spermidine. It issuggested that the protective action of polyamines could be explained by their polycationic nature, their ability to bind with photosynthetic membranes, resulting in conformational changes and stabilization, of the membrane and by their ability to act asfree radical scavengers.