摘要
为揭示互花米草对遮荫和刈割处理的光合响应机制,本研究测定了不同组合处理(0％遮荫+不刈割、0％遮荫+刈割、30％遮荫+不刈割、30％遮荫+刈割、50％遮荫+不刈割、50％遮荫+刈割、70％遮荫+不刈割、70％遮荫+刈割、90％遮荫+不刈割、90％遮荫+刈割)互花米草的日均光合速率、最大净光合速率、光补偿点、暗呼吸速率、叶绿素a、叶绿素b及类胡萝卜素等7项指标.结果表明:遮荫极显著抑制了互花米草的日均光合速率(P＜0.01),随遮荫强度增加,日均光合速率下降,而叶绿素a及类胡萝卜素含量则正好相反,随遮荫强度增加而显著增加(P＜0.01);刈割处理极显著抑制了互花米草的日均光合速率、叶绿素a、叶绿素b及类胡萝卜素含量(P＜0.01);遮荫-刈割交互处理对互花米草光补偿点影响显著(P＜0.05),但对其他指标影响不显著.主成分分析得出,90％遮荫+不刈割处理下对互花米草光合作用抑制最强.
Abstract
To reveal the photosynthetic response mechanism of Spartina alterniflora to shading and mowing,we in-vestigated the effects of different treatments(0％shading+no mowing,0％shading+mowing,30％shading+no mowing,30％shading+mowing,50％shading+no mowing,50％shading+mowing,70％shading+no mow-ing,70％shading+mowing,90％shading+no mowing,90％shading+mowing)on the photosynthetic charac-teristics of S.alterniflora.Seven photosynthesis-related indices were measured,including daily average photosyn-thetic rate,maximum net photosynthetic rate,light compensation point,dark respiration rate,chlorophyll a,chlo-rophyll b,and carotenoids.The results showed that shading significantly inhibited daily average photosynthetic rate(P＜0.01),which decreased with increasing shading intensity.The contents of chlorophyll a and carotenoids in-creased significantly with increasing shading intensity(P＜0.01).Mowing significantly inhibited daily average pho-tosynthetic rate,chlorophyll a,chlorophyll b,and carotenoid content(P＜0.01).Shading and mowing interacted to affect light compensation point of S.alterniflora(P＜0.05),but did not affect other indices.Principal component analysis revealed that the combination treatment of 90％shading and no mowing exhibited the strongest inhibition on photosynthetic activities of S.alterniflora.
维普
万方数据