盐胁迫对杨树幼苗叶片光合色素及气体交换特征的影响

以‘小胡24杨’和‘吴屯杨’为材料,研究了盐胁迫对杨树幼苗叶片光合色素及气体交换参数的影响。结果表明:短期盐处理下,2个杨树品种幼苗叶片的Chla、Chlb和Car含量都有所升高,其中,在pH值较低的盐处理下叶片光合色素的增加不明显,而pH值较高的盐处理下叶片Chla、Chlb显著增加,但pH值过高使叶片光合色素有下降趋势;气体交换参数Pn、Tr、Gs随着盐溶液pH值的升高而逐渐降低,Ls先升高后降低,Ci先降低后升高,即低pH值的盐处理下,杨树幼苗叶片光合下降的主要原因是气孔因素,而高pH值的盐处理下,叶片光合下降的主要原因是非气孔因素;相对于‘吴屯杨’,‘小胡24杨’对盐处理溶液的pH值更为敏感。

Effects of Salt Stress on Photosynthetic Pigment and Gas Exchange Characteristics of the Leaves of Populus Seedlings

'Xiaohu 24 yang' and 'Wutunyang',two poplar varieties,were used to study the effects of salt stress on the parameters related to photosynthetic pigments and gas exchanges of the leaves of Populus seedlings.It was shown that under short-term salt treatments caused the two poplar varieties to increase the chla,chlb and carotenoid contents in the leaves of their seedlings,those treatments with low pH resulting in an insignificant increases and those with high pH leading to a significant increase and those treatments with too high a pH resulting in a declining tendency in photosynthetic pigments;as the pHs of the salt concentrations increased,the parameters,Pn,Tr,Gs,gradually declined,the Ls increased initially and then declined,the Ci initial declined and then increased,i.e.,under the salt treatments with low pH,the stomatal factors were the major reasons for depressed photosynthesis in the leaves of their seedlings and under the salt treatments with high pH the non-stomatal factors were the main reasons for the lowered photosynthesis in the leaves of their seedlings;'Xiaohu 24 yang' was more sensitive to the pH of the treatment solutions than 'Wutunyang'.