混合盐碱胁迫对青山杨渗透调节物质及活性氧代谢的影响

Effects of salt-alkali stress on osmoregulation substance and active oxygen metabolism of Qingshan poplar (Populus pseudo-cathayana × P. deltoides)

为研究青山杨(Populus pseudo-cathayana×P.deltoides)对盐碱的适应能力,对青山杨2年生扦插苗进行不同盐度和碱度的28组胁迫处理.结果表明:随盐浓度增加,青山杨叶片的电解质外渗率、丙二醛和脯氨酸含量呈上升趋势,可溶性糖、SOD和POD活性先升后降.pH值升高使电解质外渗率、丙二醛和POD活性呈上升趋势,脯氨酸和可溶性糖含量先升后降,SOD活性上升趋势不明显.盐浓度低于100mmol.L-1时,随pH值升高,各项生理指标的变化不明显,SOD具有较高的活性;盐浓度在200mmol.L-1、pH8.99以上时,其电解质外渗率在50%以上,POD活性和丙二醛含量大幅度增加,脯氨酸和可溶性糖含量下降,SOD活性较低.推断盐浓度>200mmol.L-1、pH>8.99的盐碱条件不适宜青山杨的生长.

Aimed to examine -the adaptability of Qingshan poplar （Populus pseudo-cathayana × P. deltoides） to salt-alkali stress, two-year-old cutting seedlings of the poplar were treated with 28 combinations of salt-alkali stress. With increasing salt concentration, the leaf electrolyte leakage and MDA and proline contents of test seedlings all showed an increasing trend, while the leaf solu- ble sugar content and SOD and POD activities increased first but decreased afterwards. The increase of substrate pH made the electrolyte leakage, MDA content, and POD activity increased and the proline and soluble sugar contents decreased after an initial increase, but had lesser effects on the SOD activity. When the salinity was 〈 100 mmol·L^-1 and the pH was increasing, all test physiological indices had a slight change while SOD activity kept at a higher level; when the salinity was 〉 200 mmol·L^-1 and the pH was higher than 8.99, the electrolyte leakage was higher than 50%, POD activity and MDA content increased obviously, proline and soluble sugar contents declined, and SOD activity was lower. It was concluded that a salt-alkali condition with salinity 〉 200 mmol·L^-1 and pH 〉 8.99 was not appropriate to the growth of Qingshan poplar.