NaCl胁迫对油茶幼苗生理特性的影响

Effects of NaCl Stress on Physiological Characteristics of Camellia vietnamensis Seedlings

探究NaCl胁迫对油茶幼苗生理特性的影响,为提高油茶种苗耐盐能力和耐盐栽培提供理论依据。以18月生盆栽油茶幼苗为研究材料,考察不同浓度(0、100、200、400和800 mmol/L)NaCl胁迫对其生长、质膜透性、可溶性蛋白、可溶性糖、脯氨酸、丙二醛(MDA)、SOD和POD活性及离子吸收与分配的影响,分析油茶幼苗耐盐性能。结果表明,不同NaCl浓度对油茶幼苗生长有不同的影响,较低浓度NaCl处理的油茶幼苗株高增加量、全株干质量、根冠比均增加,高浓度NaCl处理的株高增加量和全株干质量显著下降;随着NaCl浓度增加,油茶幼苗的可溶性蛋白、可溶性糖、MDA、H_(2)O_(2)含量、质膜透性和SOD、POD活性均呈增加趋势,相对含水量则呈先升高后降低的趋势。NaCl胁迫下,油茶幼苗积累了大量Na^(+),不同部位Na^(+)含量表现为叶>茎>根;根和茎中K^(+)含量呈先降低再增加趋势,叶片中K^(+)积累较高,而Ca^(2+)仅在100、200和800 mmol/L NaCl处理下的茎中含量比CK高。轻度盐胁迫(100 mmol/L NaCl)下,油茶幼苗株高增加量、全株干质量、根冠比、相对含水量、可溶性糖含量增加,叶片SOD、POD活力增强,叶片中K^(+)含量大幅提高,进而抵御盐胁迫对幼苗的伤害,维持植株的正常生长。油茶幼苗对较低浓度的NaCl胁迫有一定耐受能力。

In order to provide theoretical basis for improving salt tolerance and cultivation of Camellia vietnamensis seedlings,the effects of salt stress on physiological characteristics of C.vietnamensis seedlings were analyzed.Potted C.vietnamensis seedlings aged 18 months were treated with NaCl at different levels(0,100,200,400 and 800 mmol/L)to observe the effects of salt(NaCl)stress on the growth,plasma membrane permeability,contents of soluble protein,soluble sugar,proline and malondialdehyde(MDA),and the activities of SOD and POD as well as the absorption and distribution of ions Na,K and Ca for analysis of salt tolerance of the seedlings.The result showed that concentrations of NaCl had different effects on the growth of C.vietnamensis seedlings.The plant height,dry weight and root/shoot ratio of the seedlings increased under salt stress at lower concentration of NaCl,while the increment of plant height and dry weight of the whole plant decreased significantly under the salt stress at high concentrations of NaCl.With the increase of NaCl concentration,the contents of soluble protein,soluble sugar and MDA,plasma membrane permeability,and activities of H2O2,SOD and POD of C.vietnamensis seedlings increased,while the relative water content increased first and then decreased.Under NaCl stress a large amount of Na+was accumulated in the order of leaves>stems>roots.The content of K+in the roots and stems decreased first and then increased,and higher K^(+)was accumulated in the leaves.However,the content of Ca^(2+)in the stems was higher only in the treatments under salt stress at the NaCl concentrations of 100,200 and 800 mM than in the control(CK).Under mild NaCl stress(100 mmol/L NaCl),the increment of the plant height,dry weight of whole plant,root-shoot ratio,relative water content and soluble sugar content of C.vietnamensis seedlings were increased,the activities of SOD and POD in the leaves were enhanced,and the content of K+in the leaves was significantly increased,which resisted the injury of salt stress on the seedlings and maintained the normal growth of plants.Camellia vietnamensis seedlings have a certain tolerance to salt stress at low concentrations of NaCl.