Cd、Cu、Pb处理下增施氮对巨桉生长和光合特性的影响

EFFECTS OF NITROGEN SUPPLEMENT ON PHOTOSYNTHETIC CHARACTERISTIC AND GROWTH RATE OF Eucalyptus Grandis UNDER THREE KIND OF HEAVY METAL STRESS

为验证氮在植物解除重金属毒害中的积极作用和生理机制,本试验对巨桉(Eucalyptus grandis)幼苗在3种重金属(Cd、Cu和Pb)处理下增施氮肥的生长和光合生理效应进行研究。结果表明:Cd2+、Cu2+和Pb2+处理下,巨桉植株的叶绿素含量、光合作用、PSⅡ原初光化学反应量子产率等均显著低于对照植株;而在重金属处理的同时增施氮肥,则能显著促进植株生长,提高叶绿素含量,增强光合作用和PSⅡ原初光化学反应量子产率。由此说明,氮在植物对重金属的解毒中起到重要作用,增施氮肥可缓解重金属对植物的毒害,提高叶绿素含量和光合速率。

In order to clarify the physiological effect of nitrogen on plant exposed to metals,Eucalyptus grandis was used as exprimental material to study the responses of growth and photosynthesis to the heavy metals（Cd2＋、Pb2＋ and Cu2＋） and nitrogen addition.Results showed that（1） chlorophyll content,photosynthesis rate,and quantum yields of PSⅡ of the plants exposed to heavy metals all significantly decreased when compared to the controls;（2） nitrogen addition could increase content of chlorophyll a（Chl a） and chlorophyll b（Chl b）,photosynthesis rate,and PSⅡquantum yields of plants under stress of heavy metals.The above results indicated that nitrogen played an important role in detoxification of heavy metals,and could alleviate the toxic effect of heavy metals,which could increase content of chlorophyll and photosynthesis in plants.