钾素增强干旱胁迫下草地早熟禾生理耐性的机制

Mechanism of Potassium Application for Increasing Physiological Tolerance of Kentucky Bluegrass under Drought Stress

采用不同程度的水分胁迫与5个不同钾素水平进行交互处理,以草地早熟禾品种Merit为试材,研究钾对水分胁迫下草地早熟禾生理特性及草坪质量的影响。结果表明:同一钾素浓度下,水分胁迫显著(P<0.05)降低草地早熟禾草坪质量、叶绿素含量、根系活力、抗氧化酶活性,显著(P<0.05)增加草地早熟禾电导率及丙二醛、脯氨酸、可溶性糖含量。同一水分条件下,随着钾素浓度的增加,草地早熟禾草坪质量、叶绿素含量、根系活力、脯氨酸含量、抗氧化酶活性先升高后降低,电导率、丙二醛含量先降低后升高,可溶性糖含量不断升高。在重度水分胁迫下,与0mmol/L钾处理相比,9mmol/L钾处理下Merit的POD、SOD、CAT活性分别上升了68%、35%、65%,对于缓解干旱、提高草坪耐受性和坪用质量效果最好。

The affects of physiological indexes and turf quality of Kentucky bluegrass under the interac- tion of different water gradients （25±2%, 15±2%, 5±2%） and different potassium concentrations （0mmol/L,3mmol/L, 6mmol/L, 9mmol/L, 12mmol/L） were evaluated. An introduced variety ＇ Merit＇ of Kentucky bluegrass was used in the study. The results showed that under the same potassium concentra- tion, mild and severe water stress significantly decreased the turf quality, chlorophyll content, root activi- ty and antioxidant enzyme activity （P〈0.05）, and significantly increased the electrical conductivity and malondialdehyde （MDA） in cells of Kentucky bluegrass （P〈0.05）. Under the same water condition, with the increase of potassium concentration, the quality, chlorophyll content, root activity, proline content and antioxidant enzyme activity of Kentucky bluegrass increased first and then decreased. MDA decreased first and then increased, but the soluble sugar content increased continuously during treatment period. Un- der severe water stress, the values of CAT, POD and SOD of 9mmol/L treatment were increased by 68%, 35 %and 65 %, respectively than that of 0mmol/L potassium treatment. The application of potassium at 9mmol/L concentration was the best choice to alleviate drought, and to improve turf tolerance and turf quality.