沙地盐胁迫对油莎豆幼苗生理生长影响的模拟研究

To simulate the growth and physiological responses of Cyperus esculentus seedlings to salt stress in sandy soil

为了解油莎豆(Cyperus esculentus)幼苗对沙化土地盐胁迫的生理生长适应性,本研究在温室条件下以风沙土为培养基质,采用盆栽试验对油莎豆幼苗进行不同浓度NaCl胁迫处理,分析盐胁迫30 d和50 d后油莎豆幼苗的生长、生理生化特性及Na^(+)和K^(+)平衡。结果表明:(1)盐胁迫30 d和50 d后,油莎豆幼苗地上和地下部分均在NaCl浓度≤0.5 g·kg^(-1)时生长良好,但株高明显降低;在NaCl浓度≥1.0 g·kg^(-1)时,地上及地下部干重、株高和叶面积均出现不同程度下降。(2)盐胁迫30 d时主要通过脯氨酸大量积累来减轻盐胁迫,在50 d时主要通过可溶性蛋白和可溶性糖的大量累积来提高其渗透调节能力以适应盐胁迫。(3)随NaCl浓度的增加,叶片与根系Na^(+)含量和Na^(+)/K^(+)均显著增加,说明其离子平衡遭到破坏。(4)隶属度综合评价结果表明,NaCl浓度≤0.5 g·kg^(-1)时油莎豆幼苗的综合生理生长表现没有发生明显变化,但超过1.0 g·kg^(-1)时则显著下降,这表明油莎豆幼苗具有一定的耐盐性,在沙地轻度盐胁迫条件下可以正常生长。

To investigate the growth and physiological responses of Cyperus esculentus to salt stress in wind-sand soil,a pot experiment with eolian sandy soil as the growth medium was conducted to examine the effects of different degrees of salt stress(NaCl solution)on the growth,physiological and biochemical characteristics,and the balances of Na^(+)and K^(+)in root and leaves in a greenhouse on days 30 and 50 of stress exposure.The results showed that:(1)When the NaCl concentration was≤0.5 g·kg^(-1),both the aboveground and underground dry weights of C.esculentus seedlings were significantly unaffected.However,plant height declined significantly compared with the non-stress seedlings.When Na Cl the concentration was≥1.0 g·kg^(-1),the dry weights of aboveground and underground,plant height,and leaf area decreased significantly with stress time.(2)On day 30,under salt stress,the proline content increased significantly with the NaCl concentration,but soluble and protein contents increased slightly.However,MDA content increased significantly under 0.5 g·kg^(-1)NaCl treatment and decreased significantly with increasing NaCl concentration.Under salt stress on day 50,as the NaCl concentration increased,the soluble protein content increased significantly.Then,soluble sugar content increased significantly firstly and then remained stable,while the contents of proline and MDA only increased significantly at 3.5 g·kg^(-1)NaCl.(3)The Na^(+)content and Na^(+)/K^(+)in leaves and roots increased significantly as the NaCl concentration increased,while the K^(+)content decreased significantly and then remained stable when the NaCl concentration was>1.0 g·kg^(-1).These results suggest that increased proline content at the early growth stage,while increased contents of soluble protein and sugar at the late growth stage,contribute to increasing the osmotic adjustment and waterholding capacity and decreasing the MDA content and K^(+)loss,improving the salt tolerance of C.esculentus in sandy soil.The comprehensive evaluation results showed that when the Na Cl concentration was≤0.5 g·kg^(-1),no effect of salt stress on the growth of C.esculentus seedling was found,while the plant growth was inhibited significantly when the concentration was>1.0 g·kg^(-1).