NaCl胁迫对辣椒种子萌发及幼苗生长的影响

Effect of NaCl Stress on Seed Germination and Seedling Growth of Pepper

为探究辣椒(Capsicum annuum L.)种子和幼苗对盐胁迫的生理响应机制,本研究以3个不同基因型的辣椒品种为试验材料,研究不同浓度NaCl胁迫对辣椒种子萌发和幼苗生长的影响,并通过隶属函数值法对辣椒品种及不同处理阶段的耐盐性进行综合评价。结果显示,随着NaCl浓度的升高,3个辣椒品种的发芽率、发芽指数、发芽势和胚根长均呈现下降趋势,而胚芽长和鲜重则呈现先上升后下降的趋势。在NaCl浓度为200 mmol/L时,3个辣椒品种种子的萌发均受到显著抑制,表明萌发过程中辣椒种子仅可适应低于200 mmol/L NaCl的盐胁迫,200 mmol/L可作为辣椒种子耐盐性的筛选参考浓度。耐盐性综合评价表明,低盐条件下‘Wanyu’和‘Liu58’品种的耐盐性较好,而高浓度的盐胁迫下‘HJ10-1’则具有更好的耐盐性。辣椒幼苗体内的各项生理指标均对盐胁迫有响应,丙二醛(MDA)、脯氨酸(Pro)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)的含量或活性随NaCl浓度的升高而增大;过氧化物酶(POD)、叶绿素、根系长和根系面积的含量或长度则随NaCl浓度的升高呈现先升高后降低的趋势,叶绿素、根系长和根系面积的含量或长度在NaCl浓度为100 mmol/L时达到峰值,POD的活性则在NaCl浓度为200 mmol/L时达到峰值。本研究结果不仅有助于辣椒盐胁迫生理响应机制的解析,且为辣椒耐盐品种的选育提供了科学依据。

To explore the physiological response mechanism of pepper seeds and seedlings on salt stress,3 different genotype pepper varieties were identified as experimental materials,and the effect of different concentrations of NaCl stress on seed germination and growth of pepper seedlings were identified in this study.Besides,a comprehensive evaluation of salt-tolerance properties of pepper varieties and different treatment stages was performed by weighted subordinate function method.The result showed that with the increase of NaCl concentration,the germination rate,germination potential,germination index and root length of 3 pepper varieties decreased gradually,while the bud length and fresh weight appeared a trend of firstly increased and then decreased.The germination of the 3 pepper varieties was significantly inhibited at the NaCl concentration of 200 mmol/L,indicating that the pepper seeds can only be adapted to the salt stress of less than 200 mmol/L NaCl during germination,and 200 mmol/L can be used as a reference concentration for salt-tolerant screening of pepper seed.The comprehensive evaluation of salt-tolerance indicated that'Wanyu'and'Liu58'varieties show preferred salt-tolerance properties under low salt conditions,while'HJ01-1'has better salt-tolerance under high salt conditions.The physiological indicators of pepper seedlings have a response to salt stress.With the increase of NaCl concentration,the content or activity of malondialdehyde(MDA),proline(PRO),catalase(CAT),superoxide dismutase(SOD)increased,while the activity or content of peroxidase(POD),chlorophyll,root length and root area increased first and then decreased.The content or length of chlorophyll,root length and root area reached peak at NaCl concentration of 100 mmol/L,but the activity of the POD reached the peak at the NaCl concentration of 200 mmol/L.The study results not only contribute to the analysis of physiological response mechanisms under salt stress,but also provides a scientific basis for the breeding on salt-tolerance of pepper varieties.