不同紫花苜蓿品种在均匀与不均匀盐胁迫下的耐盐性评价

Evaluation of salt tolerance in different alfalfa varieties under uniform and non-uniform salt stress

土壤中的盐分分布通常存在空间异质性,单株植物的根系区域土壤盐分变化较大。而目前关于植物品种耐盐性的评价都是在均匀的盐胁迫下进行的,研究不均匀盐胁迫下植物品种的耐盐性更接近自然盐分状况,可以为耐盐品种的选育提供重要的参考依据。选取6个紫花苜蓿品种作为研究对象,通过分根装置在均匀(100/100、200/200mmol·L-1 NaCl)盐胁迫和不均匀(0/200mmol·L-1 NaCl)盐胁迫下分别测定植株生长速率、地上生物量、地下生物量、水分吸收、电导率、丙二醛(MDA)、叶绿素(Chl)、脯氨酸(Pro)含量等指标,对各紫花苜蓿品种进行耐盐性比较;并通过隶属函数法对6个紫花苜蓿品种各盐分浓度下的耐盐性进行综合评价。结果表明,不论在哪种盐胁迫(均匀、不均匀)处理下,各紫花苜蓿品种均表现为生长速率下降,地上、地下生物量降低,水分吸收和叶绿素含量减少,膜透性、MDA和Pro含量增加,盐胁迫抑制了植物生长,且各指标存在品种差异。通过综合评价,均匀和不均匀盐胁迫下各品种的耐盐性不同,在均匀盐胁迫(100/100和200/200mmol·L-1 NaCl)处理下各品种的耐盐性为中苜一号>WL354HQ>WL343HQ>WL353LH>阿尔冈金>WL298HQ,而在不均匀盐胁迫(0/200mmol·L-1 NaCl)处理下则为中苜一号>WL354HQ>WL298HQ>WL343HQ>WL353LH>阿尔冈金。中苜一号在不同盐胁迫处理下均表现出较高的耐盐性,而阿尔冈金耐盐性较差,WL298HQ在均匀与不均匀盐胁迫下的耐盐性差异较大,其他品种的耐盐性居中。

Soil salinity is rarely spatially uniform under field conditions;it varies greatly in the single plant rhizosphere.While many previous studies have assessed the effects of uniform salt stress on different plant varieties,much less is known about plant salt tolerance under non-uniform salt stress,which more closely resembles field salt conditions.The salt tolerance of six varieties of alfalfa were assessed at uniform salt stress(100,200mmol·L-1NaCl)and non-uniform salt stress(0/200mmol·L-1NaCl)by using a split-root system.The plant growth rate,aboveground biomass,belowground biomass,water uptake,electric conductivity,malondialdehyde(MDA),chlorophyll(Chl)and proline(Pro)contents were measured.The membership function method was utilized to assess salt tolerance.Our results showed both uniform salt stress and non-uniform salt stress significantly decreased growth rate,above/below-ground biomass,water uptake,and chlorophyll content,while membrane permeability,malondialdehyde and proline increased at high salt stress.Varieties differed in their response to salt stress.The salt tolerance of each cultivar at uniform salt stress of100and200mmol·L-1NaCl was Zhongmu No.1>WL354HQ>WL343HQ>WL353LH>Algonquin>WL298HQ,non-uniform salt stress of0/200mmol·L-1NaCl was Zhongmu No.1>WL354HQ>WL298HQ>WL343HQ>WL353LH>Algonquin.Zhongmu No.1appeared to be the most tolerant cultivar to different salinity,whereas Algonquin had a lower salt tolerance.WL298HQ under uniform and non-uniform salt stress varied greatly while other cultivars showed a moderate salt tolerance.