盐胁迫下3种海滨植物形态和生理响应特征及耐盐性差异

Morphological and Physiological Response and Salt-tolerance Differences of Three Coastal Plants under Salt Stress

[目的]研究盐胁迫条件下3种海滨植物的生理生态动态响应特征及其耐盐性差异,为盐碱地绿化树种筛选提供科学依据。[方法]以2年生中山杉、小叶榕和海滨木槿幼苗为材料进行为期56 d的盆栽试验,设置3个盐分梯度对其生长和形态、抗氧化酶系统以及渗透调节系统等指标的动态变化特征进行比较,并通过主成分分析来明确3种植物在耐盐性上的差异。[结果]短期盐胁迫(14 d)对3种植物存活率、叶形和叶色影响较小,但长期盐胁迫(56 d)对小叶榕产生较大影响,盐胁迫下3种植物固定枝条相对生长率动态特征差异明显。3种植物叶片超氧化物歧化酶(SOD)活性随着盐处理时间增加而呈现降低趋势,过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性先增加后降低,丙二醛(MDA)含量呈现总体降低趋势。盐胁迫下3种植物叶片可溶性糖和可溶性蛋白含量均呈现先减少后增加的趋势,叶片相对电导率则随着盐浓度增加而显著提高。盐处理时间和物种的交互作用对SOD和POD活性以及MDA含量有显著影响,3种植物耐盐性主成分有明显差异,表明它们不同的耐盐响应特征。[结论]3种植物的生态生理响应特征表明盐处理对小叶榕影响最大,中山杉次之,对海滨木槿影响最小,因此海滨木槿和中山杉有优先作为我国东部沿海地区盐碱地绿化树种的潜力。

[Objective]To study the dynamic physio-ecological response and salt tolerance differences of plants under salt stress to select proper greening species in saline-alkali areas. [Method]Pot experiment was conducted with2-year-old seedlings of Taxodium hybrid ‘Zhongshanshan＇,Ficus microcarpa and Hibiscus hamabo,and three salt gradients were set to compare the dynamic characteristics of seedling growth and morphology,antioxidant enzyme system and osmoregulation system,and the principal component analysis（PCA） was conducted to determine the differences of salt tolerance among the three species. [Result]Short-term salt stress（14 d） showed little influence on the survival rate,leaf shape and leaf color of the three species,but long-term salt stress（56 d） showed a signifi-cant effect on F. microcarpa,and the dynamic characteristics of comparative branch lengths differed obviously under salt stress. With increasing salt treatment time,leaf SOD activities of the three species showed a decreasing trend,the POD and APX activities increased at first and then decreased,and the MDA contents showed a general decreasing trend. The leaf soluble sugar and soluble protein contents of the three species decreased at first and then increased under salt stress,and the leaf comparative conductance increased significantly with the increase of salt concentration. The interaction of salt treatment time and species had significant effects on leaf SOD,POD activities and MDA contents. Principal components of salt tolerance in three species were distinct,indicating their different tolerance response characteristics. [Conclusion] The eco-physiological response characteristics of the three species show that the salt treatment has the greatest impact on F. microcarpa and less impact on A. hybrid and H. hamabo,consequently,H. hamabo and A. hybrid can be potentially prioritized as greening species in saline areas in Eastern China.