不同品种甜瓜种子萌发对NO3-胁迫的响应及耐盐性评价

目的]分析不同品种甜瓜种子在NO3-胁迫条件下的发芽性状及耐盐性,为甜瓜耐盐品种资源的筛选、改良和利用提供理论依据.方法]以IVF117、ZY20、IVF198、RX8、FT7和CL 6个甜瓜品种为试材,通过培养皿发芽试验,分析不同浓度NO3-胁迫对其种子萌发、芽苗性状、渗透调节和根系活力等指标的影响,利用隶属函数法综合评价不同品种的耐盐性.结果]低浓度(67.0 mmol/L)NO3-胁迫对各品种甜瓜种子发芽率、发芽指数及芽苗主胚根长、下胚轴长、胚根鲜重、水含量、相对电解质渗漏率、根系活力及耐盐指数等指标的影响较小,高浓度(201.0 mmol/L)NO3-胁迫对各指标的抑制作用明显增强;不同浓度NO3-胁迫处理的甜瓜种子胚轴粗度及胚根干重差异不显著(P>0.05).IVF117和ZY20种子的NO3-胁迫半致死浓度(LC50)较高,分别为229.36和182.57 mmol/L,CL的LC50最小,为124.34 mmol/L.耐盐性综合评价结果表明,IVF117和ZY20对NO3-胁迫的耐受性较强,IVF198、RX8和FT7对NO3-胁迫的耐受性中等,CL对NO3-胁迫较敏感.结论]IVF117和ZY20为耐盐性甜瓜品种,可在NO3-盐渍化区域种植,且可作为优异耐盐甜瓜基因种源利用;IVF198、RX8和FT7耐盐性中等,CL耐盐性较弱,有待在生产中进行耐盐性改良.

Response of different melon varieties seed germination to NO3- stress and their salt tolerance evaluation

Objective]In this study,the germination characteristics and salt tolerance of melon seeds of different varieties under NO3-stress were analyzed to provide reference for screening,improving and utilizing salt tolerant melon varieties.Method]Six melon varieties IVF117,ZY20,IVF198,RX8,FT7 and CL were used as the experiment materials. Effects of NO3- stress at various concentrations on seed germination ,germination characteristics ,osmotic adjustment and root activity of different melon varieties were investigated. Then salt tolerance of these varieties was evaluated by membership function method.Result]Low concentration NO3-stress(67.0 mmol/L)had little influence on germination rate,germi-nation index,main radicle length,hypocotyl length,radical fresh weight,water content,relative electrolyte leakage rate, root activity and salt stress index. However,the inhibiting effect to the indexes were obviously enhanced under high concen-tration NO3-stress(201.0 mmol/L). There were no significant difference(P>0.05)in hypocotyls coarseness and radical dry weight under NO3-stress of different concentrations. Median lethal concentrations(LC50)of IVF117 and ZY20 seeds were 229.36 and 182.57 mmol/L respectively,higher than the others;but LC50 of CL was the lowest(124.34 mmol/L). Compre-hensive evaluation on salt tolerance showed that NO3- tolerance of IVF117 and ZY20 were strong,and that of IVF198, RX8 and FT7 were moderate,but CL was sensitive to NO3-stress.Conclusion]IVF117 and ZY20 are salt tolerant melon varieties,which can be planted in NO3-saline area and be used as sources of excellent salt tolerant genes. IVF198,RX8 and FT7 are moderately salt tolerant,and CL is sensitive to salt stress,which needs salt tolerance improvement in cultivation.