盐胁迫环境下不同抗盐性小麦品种幼苗长势和内源激素的变化

采用两种浓度NaCl溶液,对不同抗盐性小麦品种德抗961(抗盐性强)和泰山9818(抗盐性弱)萌发期幼苗进行胁迫处理,观察其幼苗长势和内源激素含量变化.结果表明,盐胁迫抑制小麦幼苗生长,抗盐性弱的泰山9818受抑制较重.苗、根ABA含量随盐胁迫浓度增加而提高,泰山9818的增幅高于德抗961.苗、根IAA含量随盐胁迫浓度增加而降低,但德抗961的IAA含量高于泰山9818,说明盐胁迫下抗盐性强的品种具有较高IAA合成量.2品种GA3含量变化因盐胁迫浓度而异.在低盐胁迫下抗盐性强的品种苗中GA3含量提高以适应盐胁迫利于苗的生长,在高盐胁迫下2品种GA3含量降低.盐胁迫使苗中ZR含量增加,且德抗961的苗中ZR含量高于泰山9818,而根中ZR含量则前者低,说明盐胁迫下抗盐性强的品种可迅速将根部合成的ZR向苗中转移,促进苗的生长.2品种IAA/ABA、GA3/ABA比值随盐胁迫浓度增加和时间延长而下降,德抗961 IAA/ABA比值大于泰山9818.在盐胁迫下,抗盐性强的品种协调自身激素平衡的能力较强可能是其生长受抑制较小的重要原因.

Responses of seedling growth and endogenous hormone contents in different wheat cultivars to salt stress

Salt stressis a main factor restricting the growth and grain yield of wheat grown in the salinized soils.Understanding the mechanism of salt resistance of wheat cultivars is of importance to wheat production and breeding.The endogenous hormones contents and their balance have close link to growth and development in wheat plant.However,limited knowledge exists on the relationship between endogenous hormone and salt resistance of wheat subject to salt stress.The objective of this research,therefore,is to determine the responses of endogenous hormone contents and their balance to salt stress in two wheat cultivars contrasting in salt resistance.The results will help to recognize the mechanism of salt resistance and to offer valuable information in salt resistance breeding of wheat.The experiment was conducted with two wheat cultivars,DK961(salt-resistant) and TS9818(salt-sensitive).The seeds of each cultivar ware water-cultivated in three salt concentrations,0(CK),100(S100) mmol/LNaCl,and 200(S200) mmol/LNaCl.The seedlings of each treatment were sampled after having been cultivated for 5,7,9,11,and 13 d,respectively,for determining the growth and endogenous hormone contents of seedlings.The results showed that salt stress had obviously inhibitory effects on seedlings growth,especially,of TS9818.ABA contents of the seedlings increased with salt concentration and the increased magnitude due to salt stress in TS9818 were markedly higher than those in DK961.Salt stress caused the decrease of IAA contents of seedlings in both cultivars.However,the comparison of two cultivars showed that IAA contents of seedlings in DK961were over those in TS9818 under salt stress environment,indicating that the salt-resistant cultivar has a higher potential to synthesize IAA for adapting salt stress.GA3 content of seedlings of both cultivars varied with salt concentration.The increased GA3 contents in shoots of salt-resistant cultivar DK961was found under the lower salt stress of 100 mmol/LNaCl,which was beneficial to the seedling growth.However,the GA3 contents declined significantly in seedlings of both cultivars grown in the higher salt stress of 200 mmol/LNaCl.The contents ZR in shoot of both cultivars rose as the salt concentration increased,and ZR content in shoot of DK961was higher than that in TS9818,and the latter had a higher ZR content in root than the former.Based on the results above,we considered that salt stress stimulated the translation of ZR from root to shoot for maintaining seedling growth under salt stress environment.The ratios of IAA to ABA and GA3to ABA showed dropping trend with increased salt concentration and the prolongation of salt stress duration in both cultivars.However,the ratios of IAA to ABA in DK961were higher than those in TS9818 subject to salt stress.Those results mentioned above suggested that salt resistant cultivar has stronger ability to regulate endogenous hormone contents of seedlings for adapting salt stress,which was an important reason why seedlings growth of salt resistant cultivar was less inhibited than salt-sensitive cultivar by salt stress.