温度和水分及盐分胁迫对银沙槐种子萌发的影响

利用控制实验研究了温度、湿度、干旱和盐分胁迫等生态因子对银沙槐种子萌发的影响,以探索银沙槐种子对各种生态因子的适应性。结果显示:(1)银沙槐种子在20℃、25℃恒温和15℃/25℃、20℃/30℃、10℃/20℃变温环境中的发芽率较高且无显著差异,其在20℃恒温、15℃/25℃、20℃/30℃变温条件下的发芽指数较高,但差异不显著。(2)土壤含水量在1%～5%之间,各水分处理间种子发芽率差异显著(P<0.05),而在5%～25%间种子发芽率变化不显著。(3)盐胁迫和水分胁迫对银沙槐种子的萌发均有明显的抑制作用,可显著降低种子萌发率(P<0.05);种子发芽指数和活力指数均随渗透势和NaCl浓度增大而显著减小(P<0.05);恢复萌发率随渗透势和NaCl浓度的增加而显著增加(P<0.05)。研究发现,银沙槐种子萌发最适温度为20℃恒温和15℃/25℃变温,最适土壤含水量为10%～25%;种子萌发对盐分和干旱胁迫表现出不同程度的耐受性,萌发过程中主导抑制因素为渗透胁迫,离子毒害作用甚微;银沙槐种子休眠机制和萌发特征表现出它对生境的良好适应性。

Seed Germination of Ammodendron argenteum under Temperature,Drought and Salt Stress

The adaptability of Ammodendron argenteum seed to ecological factors was studied by the effects of different temperature,humidity,drought and salt stress on the germination characteristics.The results showed that:Compared 20℃ and 25℃constant temperatures with 15℃/25℃,20℃/30℃,10℃/20℃ alterante temperatures,germination rate had no significant difference(P>0.05),germination indexes also had no difference among 20℃ and 15℃/25℃,20℃/30℃(P>0.05).Germination rate had significant difference under the soil moisture content among 1%~5%(P<0.05),while changed just a little under the soil moisture content among 5%～25%(P>0.05).Germination index(GI) and vigour index(VI) decreased with increasement of PEG-6000 potential and NaCl consistency(P<0.05);Renewed germination increased with increasement of PEG-6000 potential and NaCl consistency(P<0.05).The optimum constant and alterante temperature for seeds germination were 20℃ and 15℃/25℃,the optimum soil moisture content was 10%~25%;To some extent,seed germination showed certain tolerance to salt and drought stress,the research found that osmosis stress was the dominant restrain factor and ionic toxic action was less than it.The seed dormancy mechanism and germination characteristics improve its fitness on ecological distribution and habitat.