盐胁迫对台湾相思幼苗形态及相关生理指标的影响

Effects of salt stress on seedling morphology and related physiological indexes of Acacia confusa

为探寻台湾相思种子的耐盐情况,在其种子萌发期和幼苗期分别进行不同浓度盐胁迫试验。结果表明:低浓度NaCl胁迫可提高种子发芽率,随着NaCl浓度的增高,种子发芽势、发芽率、活力指数以及发芽指数均不同程度降低,且和对照有显著差异。通过拟合台湾相思发芽率和NaCl胁迫浓度回归曲线,发现种子萌发期台湾相思适宜的最大NaCl胁迫浓度为203.87 mmol∕L,NaCl致死浓度为383.16 mmol∕L;幼苗期台湾相思叶鲜重、茎鲜重、根鲜重、主根长、株高、地径以及叶片数等指标在NaCl胁迫下呈下降趋势,根冠比先上升后下降,植物的总根长、总根表面积、总根投影面积、总根体积、根平均直径、总根尖数、分枝数、交叉数均和NaCl浓度呈负相关,NaCl胁迫适宜的最大浓度为49.28 mmol∕L,台湾相思幼苗SOD、POD活力及MDA、PRO含量随着NaCl胁迫浓度的增加呈现先增高后降低的趋势。

In order to explore the salt tolerance of A.confusa seeds,different concentration gradients of NaCl solution were used to conduct salt stress tests during the seed germination and seedling stages.The results showed that low-concentration NaCl stress could increase the germination rate of seeds.With the increase of NaCl concentration,the germination potential,germination rate,vigor index and germination index of seeds all decreased to varying degrees,and were significantly different from the control.By fitting the regression curve of the germination rate and NaCl stress concentration of A.confusa,it was found that the optimum maximum NaCl stress concentration of A.confusa was 203.87 mmol∕L,and the lethal NaCl concentration was 383.16 mmol∕L during the germination period.During the seedling stage,leaf fresh weight,stem fresh weight,root fresh weight,main root length,plant height,ground diameter and leaf number showed a downward trend under NaCl stress;The root cap ratio first increased and then decreased;The total root length,total root surface area,total root projected area,total root volume,average root diameter,total root tip number,number of branches,and number of crossings were negatively correlated with the concentration of NaCl;The optimum maximum concentration of NaCl stress during this period was 49.28 mmol∕L;the activities of SOD,POD and the contents of MDA,PRO incrersed first and then decreased with the increase of NaCl stress concentration.