盐胁迫对杂交酸模叶片光合活性的抑制作用

以杂交酸模(Rumex K-1)为试材,研究了不同浓度(100～300 mmol·L^-1) KCl和NaCl胁迫对杂交酸模幼苗叶片光合活性及渗透调节的影响.结果表明：200 mmol·L^-1浓度的NaCl对杂交酸模幼苗叶片光合活性的抑制作用大于KCl；当浓度增大到300 mmol·L^-1时，KCl对杂交酸模叶片光合活性的抑制作用显著大于NaCl.300 mmol·L^-1 KCl和NaCl处理植株的叶片水势分别为-0.93 MPa和-1.05 MPa，渗透势分别为-1.43 MPa和-1.10 MPa,说明KCl对杂交酸模植株过多的伤害不是渗透胁迫造成的；经过300 mmol·L^-1KCl胁迫后，杂交酸模叶片中Na⁺含量急剧降到对照植株的11.4％，而补充25 mmol·L^-1 NaCl可以明显缓解KCl对杂交酸模光合活性的伤害，说明Na⁺的亏缺和高浓度K⁺的积聚可能是导致高浓度KCl对杂交酸模光合活性的伤害比NaCl更严重的主要原因.

Inhibition effects of salt stress on photosynthetic activity of Rumex K-1.

With Rumex K-1 seedlings as test materials, this paper studied the effects of different concentration (100 -300 mmol·L^-1) NaCl and KCl on their leaf photosynthetic activity and osmotic adjustment. The results showed that at the concentration of 200 mmol·L^-1, NaCl had greater inhibition effect on the leaf photosynthetic activity than KCl, but at 300 mmol·L^-1, the inhibition effect of KCl was much greater than NaCl. After treated with 300 mmol·L^-1 of KCl and NaCl, the leaf water potential was -0.93 MPa and -1.05 MPa, and the osmotic potential was -1.43 MPa and -1.10 MPa, respectively, indicating that the increased damage caused by 300 mmol·L^-1 of KCl was not from osmotic stress. Under the stress of 300 mmol KCl·L^-1, the leaf Na⁺ concentration decreased by 88.6%, compared with the control, while the supplement of 25mmol NaCl·L^-1 could obviously alleviate the damage of KCl on leaf photosynthesis, which proved that the deficit of Na⁺ and the accumulation of K⁺ in Rumex K-1 leaves could be responsible to the enhanced damage caused by 300 mmol·L^-1 of KCl.