生姜苗期耐盐性综合评价及水通道蛋白基因表达模式分析

Comprehensive evaluation of salt tolerance in ginger at seedling stage and expression pattern of aquaporin protein

  • 摘要: 【目的】探究盐胁迫对生姜苗期形态变化及生理指标的影响,建立生姜耐盐评价体系,发掘耐盐种质资源,为生姜耐盐品种选育提供理论依据。【方法】以我国5个生姜主产区的主栽品种为试验材料,设置对照(CK)与盐胁迫(NaCl)2个处理,利用主成分分析将不同处理条件下生姜的生理生化指标等单项指标整合为3个综合指标,结合隶属函数法进行耐盐性综合评价,并分析水通道蛋白(AQP)基因在耐盐品种与敏感品种中不同的表达模式。【结果】在盐胁迫下,各生姜品种的株高、茎粗、叶片数、根系活力、叶片水势和叶片渗透势均下降。叶片的过氧化氢(H2O2)含量、丙二醛(MDA)含量和过氧化物酶(POD)活性均升高。超氧化物歧化酶(SOD)活性在贵州黄姜中显著升高(P<0.05,下同),在其他4个品种中下降。过氧化氢酶(CAT)活性在山东大姜中下降,在其他4个品种中升高。苯丙氨酸解氨酶(PAL)活性在山东大姜和竹根姜中下降,在其他3种品种中升高。相关分析结果表明,株高、茎粗和叶片数均与综合评价值(D值)呈显著正相关;叶片MDA含量、H2O2含量、水势和渗透势与D值呈负相关;根系活力与D值呈极显著正相关(P<0.01)。生姜耐盐性由强到弱排序依次为山东大姜、贵州黄姜、凤头姜、罗平小黄姜、竹根姜。8个AQP基因的表达模式分析显示,山东大姜叶片中7个AQP基因在盐胁迫处理后表达下调,根部4个AQP基因表达下调;竹根姜叶片中3个AQP基因表达下调,根部6个AQP基因表达下调。【结论】5个生姜品种苗期耐盐性评价结果表明,山东大姜耐盐性最强,竹根姜耐盐性最弱。株高、茎粗、叶片数和根系活力可作为生姜耐盐品种筛选的主要参考指标。

     

    Abstract: 【Objective】To investigate the effects of salt stress on morphological changes and physiological indexes of ginger at seedling stage,establish a salt-tolerant evaluation system for ginger,explore salt-tolerant germplasm resources, which could provide theoretical reference for the selection and breeding of salt-tolerant varieties of ginger.【Method】The main plant varieties from 5 major ginger producing areas in China were used as experimental materials,and 2 treatments, control (CK)and salt stress(NaCl),were set up. Principal component analysis was used to integrate the physiological and biochemical indexes and other individual indexes into 3 comprehensive indexes,and combined with the method of the membership function to carry out a comprehensive evaluation of salt tolerance,and to analyze the expression of the aquaporin protein(AQP)gene in the salt-tolerant varieties and the sensitive varieties.【Result】The increase in plant height,stem thickness,number of leaf,root vigour,leaf water potential and leaf osmotic potential decreased in all ginger varieties under salt stress. Hydrogen peroxide(H2O2)content,malondialdehyde(MDA)content and peroxidase(POD)activity of leaves were increased. Superoxide dismutase(SOD)activity was significantly increased in Guizhou ginger(P<0.05, the same below)but decreased in the other 4 varieties. Catalase(CAT)activity was decreased in Shandong big ginger but elevated in the other 4 varieties. Phenylalanine deaminase(PAL)activity decreased in Shandong big ginger and Zhugen ginger,but increased in the other 3 varieties. Plant height,stem diameter and number of leaf were significantly and positively correlated with the comprehensive evaluation value(D value). Leaf MDA content,H2O2 content,water potential and osmotic potential were negatively correlated with D values,root vigour was extremely significantly and positively correlated withD value(P<0.01). The salt tolerance of ginger was ranked from the strongest to the weakest as Shandong big ginger,Guizhou yellow ginger,Fengtou ginger,Luoping small yellow ginger and Zhugen ginger. Expression pattern analysis of 8 AQP genes showed that 7 AQP genes were down-regulated in Shandong big ginger leaves and 4 AQP genes were down-regulated in roots after salt stress treatment;3 AQP genes were down-regulated in leaves and 6 AQP genes were down-regulated in roots of Zhugen ginger.【Conclusion】Salt tolerance evaluation of 5 ginger varieties at seedling stage indicates that Shandong big ginger has the strongest salt tolerance and Zhugen ginger has the weakest salt tolerance. Plant height,stem diameter,number of leaf and root vigour can be the main reference indexes for screening ginger salt-tolerant varieties.

     

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