海雀稗种质资源耐镉性评价及生理机制初步分析

海雀稗是重要的暖季型草坪草,为筛选耐镉海雀稗优质资源,本试验在海雀稗耐镉评价体系优化的基础上,对23份海雀稗种质资源进行耐镉性评价,并初步探讨了其耐镉生理机制。结果表明,低浓度镉（0.50~1.50 mmol/L）处理时,海雀稗叶片枯黄率有显著差异,镉浓度为0.50 mmol/L与1.50 mmol/L时坪用质量无显著差异,镉浓度为1.00 mmol/L与1.50 mmol/L时坪用质量无显著差异,坪用质量与枯黄率在镉浓度为1.50~2.00 mmol/L均有显著差异,高浓度镉（2.0~3.0 mmol/L）处理时枯黄率差异显著,镉浓度为2.00 mmol/L与2.50 mmol/L、2.50 mmol/L与3.00 mmol/L时坪用质量间无显著差异。以叶片枯黄率50%为标准,通过建立回归方程求得临界浓度为1.5 mmol/L。选用坪用质量较好的23份海雀稗种质资源进行耐镉性评价,结果表明1.50 mmol/L镉胁迫条件下,不同材料之间耐镉能力差异明显,USA17-2、USA17-30、USA17-37、USA17-41和USA17-45相对坪用质量高,枯黄率低于45.00%,对镉耐性强;USA17-22、USA17-24、USA17-42、HN17-35和US17-47相对坪用质量低,最高枯黄率达到83.33%,对镉耐性最弱。通过对耐镉能力极端资源的脯氨酸及叶绿素含量测定发现,镉胁迫后耐镉海雀稗中脯氨酸和叶绿素含量显著高于镉敏感型海雀稗,推测维持高的脯氨酸和叶绿素含量是海雀稗耐镉的重要生理机制。本研究结果为选育优良耐镉海雀稗品种提供参考。

Evaluation of Cadmium Tolerance and Preliminary Analysis on Physiological Mechanism of Germplasm Resources of Paspalum vaginatum Sw.

Paspalum vaginatum Sw is an important turfgrass resource.Based on the optimization of the cadmium tolerance evaluation system of P.vaginatum Sw,this experiment evaluated the cadmium tolerance of 23 P.vaginatum Sw germplasm resources,and preliminarily explored the physiological mechanism of cadmium tolerance.Under low concentration(0.50~1.50 mmol/L)treatment,there was a significant difference in the leaf firing percentage,but there was no significant difference in turf quality between 1.00~1.50 mmol/L,and high concentration(2.00~3.00 mmol/L)showed a significant difference in the leaf firing percentage,but there was no significant difference in turf quality between 2.00~2.50 mmol/L,and no significant difference 2.50~3.00 mmol/L.Based on the 50%leaf firing percentage as the standard,the critical concentration was found to be 1.5 mmol/L by establishing equation of linear regression.The cadmium tolerance of 23 P.vaginatum Sw germplasm resources was evaluated under the condition of 1.50 mmol/L cadmium stress.The results showed that different germplasm resources had significant differences.The turf quality of USA17-2,USA17-30,USA17-37,USA17-41 and USA17-45 was high,the leaf firing percentage was lower than 45.00%,the cadmium tolerance was the strongest.The turf quality of USA17-22,USA17-24,USA17-42,HN17-35 and US17-47 was relatively low,and the leaf firing percentage was 83.33%,the cadmium tolerance was the weakest.Through the determination of proline and chlorophyll content of extreme resources for cadmium tolerance,the content of proline and chlorophyll in cadmium-tolarence P.vaginatum Sw after cadmium stress was significantly higher than that of cadmium-sensitive P.vaginatum Sw.It is speculated that maintaining high proline and chlorophyll content was an important physiological mechanism of cadmium tolerance in P.vaginatum Sw.The results would provide a basis for the selection of excellent cadmium-tolarence P.vaginatum Sw varieties.