盐胁迫对红叶石楠‘红罗宾’幼苗生长与光合生理的影响

Effects of salt stress on the growth and photosynthetic physiology in the seedlings of Photinia glabra×P.fraseri 'Red Robin'

以红叶石楠‘红罗宾’幼苗为试验材料,用不同浓度的NaCl处理,测定了处理后的植株叶片的光合作用参数、超氧化物歧化酶(SOD)活性和丙二醛(MDA)、钠离子(Na+)含量。结果表明,植株在低浓度NaCl(≤0.7%)胁迫下,幼苗叶片的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间二氧化碳浓度(Ci)和叶片中的Na+浓度均呈现先升后降的趋势,而SOD活性则不断上升,幼苗生长未受到显著影响;植株在高浓度NaCl(≥1.0%)胁迫下,幼苗叶片的Pn、Tr、Gs均呈现出不断下降的趋势,Ci和叶片中Na+含量不断上升,SOD活性先升后降,幼苗叶片萎蔫凋落,甚至死亡,而幼苗MDA含量在各种处理下均没有明显规律性变化。

Seedlings of Photinia glabra×P.fraseri ＇Red Robin＇ were treated with different concentrations of NaCl to determine their photosynthesis,superoxide dismutase activity and content of malondialdehyde and sodium cations under salt stress.In the treatment of low NaCl concentration（≤0.7%）,the net photosynthetic rate（Pn）,transpiration rate（Tr）,stomatal conductance（Gs）,concentration of intercellular CO2（Ci） and Na＋ in the seedlings tended to increase,followed by decrease,but the activity of superoxide dismutase kept increasing,meanwhile no significant impact was measured on growth of the seedlings.In the treatment of high NaCl concentration（≥1.0%）,Pn,Tr,Gs in the seedlings tended to keep decreasing,while Ci and the content of Na＋ kept increasing,and the activity of superoxide dismutase increased,followed by decrease,which caused the seedlings withering and dead.Nevertheless,no significant change was found in the malondialdehyde content of the seedlings in both treatments.