盐胁迫对肯氏南洋杉幼苗生长及离子分布的影响  

Effects of salt stress on growth and ion distribution of Araucaria cunninghamii seedlings

作　　者：梁育勤[1] LIANG Yuqin(Xiamen Botanical Garden,Xiamen 361003,China)

机构地区：[1]厦门市园林植物园,福建厦门361003

出　　处：《厦门大学学报（自然科学版）》2023年第1期144-150,I0002-I0005,共11页Journal of Xiamen University：Natural Science

基　　金：厦门市科学技术局社会指导性项目(3502Z20214ZD4002)。

摘　　要：盐胁迫抑制植物的生长,影响植物组织的离子分布,且不同浓度的盐溶液对植物的生长影响存在差异.为研究肯氏南洋杉(Araucaria cunninghamii)在滨海盐碱地的生长适应性,探讨其耐盐机制,对肯氏南洋杉幼苗进行盐胁迫试验.肯氏南洋杉种子在非盐胁迫条件下萌发,用1/2 Hoagland营养液培养1年后,设置6个NaCl质量分数(0,0.7%,1.4%,2.1%,2.8%和3.5%)进行盐胁迫试验,胁迫第30天统计其盐害情况,并测定其生物量及K^(+)、Na^(+)、Cl^(-)3种离子在根、茎、叶中的含量.研究表明:当NaCl质量分数为1.4%时肯氏南洋杉幼苗尚能正常生长,其耐盐阈值范围为2.1%~2.8%;盐胁迫时,肯氏南洋杉幼苗发生盐害的症状为叶片枯焦、枝条枯萎,发黄的面积从叶尖扩散到整个叶片,从枝条先端弥漫到枝条基部,从下层枝条发展到上层枝条.肯氏南洋杉幼苗的耐盐策略主要是:通过根部限制盐分进入植物体内,并将进入植物体内的盐分分隔到特定区域(Na^(+)主要贮存于茎,Cl^(-)主要运往叶),从而减轻盐分对功能器官或组织的伤害,同时积极向叶片运输K^(+),提高K^(+)、Na^(+)质量比以减缓盐分对其生理代谢的伤害.综上,肯氏南洋杉在我国南方滨海地区土壤盐质量分数不超过1.4%的环境下可以获得较好的绿化效果.Salt stress inhibits plant growth and affects ion distribution in plant tissues.Different concentrations of salt solution have different effects on plant growth.In order to study the growth adaptability of Araucaria cunninghamii in coastal saline-alkali land and explore its salt tolerance mechanism,salt stress experiment was carried out on A.cunninghamii seedlings.The seeds of A.cunninghamii germinated under non-salt stress.After one year of cultivation with 1/2 Hoagland nutrient solution,six NaCl mass fractions(0,0.7%,1.4%,2.1%,2.8%and 3.5%)were set for salt stress experiment.The damage of A.cunninghamii seedlings was calculated after 30 d salt stress.The biomass and contents of K^(+),Na^(+)and Cl^(-)three ions in roots,stems and leaves were also determined.The results showed that with a NaCl mass fraction of 1.4%,the seedlings could grow normally,and their salt tolerance threshold was between 2.1%and 2.8%.Under salt stress,the symptoms of salt damage included scorched leaves and withered branches,and the yellow area spread from the leaf tip to the whole leaf,from the tip to the base of branches,and from the lower to the upper branches.The salt tolerance mechanism of A.cunninghamii seedlings is mainly to limit the salt entering the plant through the root,and to separate the salt into specific areas(Na^(+)mainly stored in the stem,Cl^(-)mainly transported to the leaf),so as to reduce the damage of salt to functional organs or tissues,while actively transporting K^(+)to the leaf and increasing K^(+)/Na^(+)mass ratio to slow down the damage of salt to its physiological metabolism.It can be concluded that A.cunninghamii in the coastal area of South China with the soil salt mass fraction of less than 1.4%can obtain a good greening effect.

关 键 词：盐胁迫 肯氏南洋杉幼苗 生长 离子分布 

分 类 号：Q945.78[生物学—植物学]