不同水稻品种对NaCl胁迫的生理响应及耐盐性评价

Physiological Response and Salt Tolerance Evaluation of Different Rice(Oryza sativa L.)Cultivars under NaCl Stress

土壤盐渍化是限制作物生长的重要因素之一,培育水稻耐盐新品种,对扩大水稻种植面积具有重要意义。为探究不同品种水稻幼苗的生长及生理的变化趋势,明确不同水稻品种苗期耐盐性强弱,以5个水稻品种为试验材料,采用水培方式研究不同浓度NaCl(0、70、140 mmol/L)处理对水稻苗期生长及相关生理指标的影响,并利用主成分分析及隶属函数法进行综合评价其耐盐性。结果表明,盐胁迫下,盐分对各水稻品种的根长、根表面积、根体积、根尖数及根平均直径总体上起抑制作用,其中‘HH11’和‘日本晴’的根系生长指标值变化较小,‘9311’和‘JX99’的根长、根体积、根表面积、根尖数均受到显著抑制,‘HD961’平均根尖数最多。随着NaCl浓度增大,各品种株高、根系活力总体呈逐渐下降趋势,叶绿素总含量、相对电导率、丙二醛含量、脯氨酸含量、根系Na^(+)/K^(+)总体呈上升趋势,而根系Na^(+)、K^(+)含量呈先升高后减少的趋势。其中,盐胁迫下‘9311’和‘JX99’相对电导率、脯氨酸含量增幅最大,‘日本晴’和‘HH11’的丙二醛含量、根系Na^(+)/K^(+)增幅最小,‘日本晴’的株高下降率最小,‘HH11’的根系活力下降率最小。主成分分析表明,3个相互独立的综合指标解释了盐胁迫下16个单项指标94.23%的变化,其中根长、根体积、根尖数、叶绿素总量、丙二醛含量、电导率可作为评价水稻苗期耐盐性的主要作用因子,K^(+)、Na^(+)/K^(+)、株高可作为评价水稻苗期耐盐性的次要作用因子。隶属函数结果分析表明,5个水稻品种耐盐性由强到弱依次为‘HH11’>‘HD961’>‘日本晴’>‘9311’>‘JX99’。

Soil salinization is one of the important factors limiting crop growth.Cultivating new salt-tolerant rice varie-ties is of great significance to expand rice planting area.In order to explore the change trend of growth and physiology of different varieties of rice seedlings and clarify the salt tolerance of different rice varieties at seedling stage,five rice varieties were used as the experimental materials.The effects of different concentrations of NaCl(0 mmol/L,70 mmol/L,140 mmol/L)on the growth and related physiological indexes were studied at rice seedlings using hydroponic method.The principal component analysis and membership function method were used to comprehensively evaluate the salt tolerance of five rice seedlings.The results showed that under salt stress,salt inhibited the root length,root surface area,root volume,root tip number and root mean diameter of all rice varieties in general.The root growth index values of‘HH11’and‘Nipponbare’changed little.The root length,root volume,root surface area and root tip number of‘9311’and‘JX99’were significantly inhibited.The average root tip number of‘HD961’was the largest among the five rice varieties.With the increase of NaCl concentration,the plant height and root activity of each variety showed a gradual downward trend,and the total chlorophyll content,relative conductivity,MDA content,proline content and Na^(+)/K^(+)of root showed an overall upward trend,and the root Na^(+)and K^(+)contents showed a trend of first increase and then decrease.Among them,the relative electrical conductivity and proline content of‘9311’and‘JX99’increased the most,the MDA and root Na^(+)/K^(+)of‘Nipponbare’and‘HH11’increased the least,the plant height of Nipponbare decreased the least,and the root activity of‘HH11’decreased the least under salt stress.Principal component analysis showed that three independent comprehensive indexes explained 94.23%of the changes of 16 single indexes under salt stress.Among them,root length,root volume,root tip number,total chlorophyll content,malondialdehyde content and electrical conductivity could be used as the main factors to evaluate salt tolerance at seedling stage,and K^(+),Na^(+)/K^(+)and plant height could be used as the sec-ondary factors to evaluate salt tolerance at seedling stage.The results of membership function analysis showed that the salt tolerance of the five rice varieties from strong to weak was‘HH11’>‘HD961’>‘Nipponbare’>‘9311’>‘JX99’.