杨小舟蛾取食对杨树叶片光合生理特性的影响

研究了杨小舟蛾(Micromelalopha troglodyta)取食对杨树叶片光合作用的影响,并探讨了杨树叶片受取食影响后的光合补偿机制。结果表明:杨树叶片被杨小舟蛾取食后,叶片净光合速率(Pn)日动态波动变化幅度强于对照,呈单峰型曲线,峰值出现时间在上午12:00时,比对照滞后2 h,且峰值比对照提高了16.4%。单位面积受害叶片在上午(8:00—12:00)累积同化CO2的量比对照上升了9.6%,而下午(13:00—18:00)略有下降。1天中(8:00-18:00)累积同化CO2的量两者之间差异不显著(p>0.05)。蒸腾速率(Tr)的日动态为双峰曲线,分别在上午12:00和下午15:00出现蒸腾高峰;被取食叶片蒸腾速率及日累积蒸腾耗水量明显低于对照,而水分利用效率(WUE)、光饱和点(LSP)、最大净光合速率(Pn,max)分别比对照显著提高(p<0.05);暗呼吸速率(Rd)比对照高出10.33%。表观量子效率、光补偿点(LCP)等光合指标与对照差异不明显。分析表明,杨树对杨小舟蛾的取食危害存在光合补偿的适应机制。

Photosynthesis characteristics of poplar after damaged by Micromelalopha troglodyta

The author investigated the characteristics of photosynthesis of damaged poplar leaf and discussed the photosynthesis compensation of poplar after larvae of Micromelalopha troglodyta feeding.The results showed that the diurnal variation of net photosynthetic rate(Pn) of poplar leaf appeared a single peak curve after damaged by M.troglodyta and the aptitude was much higher than that of CK.Meanwhile,the Pn peak appeared at 12:00 a.m.,which delayed two hours and the Pn peak value was 16.4 % higher than that of CK.The CO2 accumulation of damaged leaf per unit area were 9.6 % higher than that of CK at 8:00 to 12:00,and very little decrease occur at 13:00 to 18:00.However,the value of Pn accumulation had no obvious difference in the whole day(8:00-18:00) between CK and the damaged leaf(p>0.05).The diurnal change of transpiration rate(Tr) showed a double-peak curve,the peak appeared at 12:00 and 15:00.Tr and the diurnal accumulative transpiration water quality of the damaged leaf were obviously lower than those of CK.However,the water utilization efficiency(WUE),light saturation point(LSP) and maximum net photosynthetic rate(Pn,max) of the damaged leaf were significantly increased(p<0.05) compared to CK,especially the dark respiration rate(Rd) was 10.33 % higher than that of CK.But there was no significant difference in apparent quantum yield and light compensation point(LCP) between damaged leaf and CK.Our study indicated that poplar had developed a adaptive mechanism of photosynthesis compensation to the damage of M.troglodyta.