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盐胁迫对大花四照花种子萌发与幼苗生长的影响

花匠小妙招
2024-11-09 16:30

摘要： 目的

探究盐胁迫对大花四照花种子萌发及幼苗生长的影响，为大花四照花在滨海地区的推广提供理论依据。

方法

对大花四照花种子采取两种预处理：T1处理为用清水配制500 mg/L的GA3浸泡3 d,并进行低温层积；T2处理用4种浓度盐溶液（质量分数分别为0.20%、0.30%、0.40%和0.45%）配制的500 mg/L GA3浸泡3 d,低温层积。层积2个月后进行发芽、幼苗形态和生理指标测定。发芽基质（沙）和水分管理:T1处理种子分别采用5个盐浓度水平[0(CK)、0.20%.0.30%.0.40%和0.45%]进行处理，而T2处理种子则采用与预处理相一致的盐浓度水平。

结果

盐胁迫极显著降低了大花四照花种子的发芽率（GR)、发芽势（GE）、发芽指数（GI)和成苗率，并且使其盐害率极显著上升（P<0.01）o相对于T1处理,T2处理对各指标的影响更大，尤其当盐溶液质量分数≥0.3%时，各处理水平的GI在2个处理间差异显著。盐胁迫对幼苗生长指标的影响主要体现在苗高上，其次是根长、相对含水量、鲜质量和干质量。同时，丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性和脯氨酸（Pro）含量均随着盐浓度的上升而显著增加，而可溶性糖（SSC）含量在盐溶液质量分数为0.40%时达到最高，然后开始下降；盐胁迫对K+含量的影响显著（P<0.05），且随着盐浓度的增加而下降，但对Na+含量的影响不显著。

结论

盐胁迫抑制了大花四照花种子的发芽，加盐预处理加剧了抑制作用，而且显著地影响了幼苗的生长指标、生理指标和对离子的吸收。综合来看，大花四照花种子和幼苗可在0.30%的盐胁迫条件下正常萌发和生长，因此可作为滨海地区潜在的候选观赏树种，但需要进一步的试验性栽培来验证。

关键词: 大花四照花, 盐胁迫, 种子, 发芽指标, 生化指标

Abstract: Objective

The purpose of this study was to demonstrate the effects of salt stress on seed germination and seedling growth of Corios florida, to provide a basis for its potential application in coastal areas.

Method

The seeds of C.florida in pretreatment 1 (T1) were soaked with 500 mg/L gibberellin acid (GA3) , which was prepared with water. The seeds of pretreatment 2 (T2) were soaked with 500 mg/L gibberellin acid (GA3), which was prepared with four concentrations of salt solution(0.20%, 0.30%, 0.40% and 0.45%) .All the seeds were soaked for three days, followed by moist chilling for two months, then the germination testing, measurements of seedling growth and biochemical indexes were carried out. Germinating substrate (sand) and water management were as follows： five salt concentrations [0(CK), 0.20%, 0.30%, 0.40% and 0.45%] were used in T1 treatment seeds, while the corresponding to pretreatment salt concentrations were used in T2 treatment seeds.

Result

Salt stress extremely significantly decreased the germination rate and germination energy. Moreover, the effect of salt stress in T2 was considerably greater than that in T1； especially, germination indexs of salt concentrations ≥0.30% were significantly different between T1 and T2. The effects of salt stress on seedling indexes are mainly reflected in seedling height, followed by root length, relative water content, fresh weight, and dry weight. Furthermore, malondialdehyde content, superoxide dismutase activity, and proline content increased significantly with increasing salt concentration, whereas soluble sugar content was the highest at a salt concentration of 0.40%. K+ content in the roots significantly decreased with increasing salt concentration, but the response of Na+ content was not significant (P<0.05).

Conclusion

Salt stress inhibited the germination of C. florida seeds, and pre?treatment with salt enhanced the inhibition. Moreover, the growth indicators, biochemical indicators, and ion absorption of seedlings significantly differed with increasing salt concentration. Comprehensively, seed germination and seedling growth of C. florida were normal under a salt concentration of 0.30%. Thus, C. florida is a candidate species for ornamental use in salt?rich coastal areas, but further field cultivation is needed before extensive application.

Key words: Cornus florida, salt stress, seed, germination index, biochemical parameters

中图分类号:

S718.3