水分胁迫对新疆准东地区钠猪毛菜的生活史对策的影响

Effects of water stress on life history strategy of Salsola nitraria in Zhundong,Xinjiang

水是制约干旱区植物生长的关键性限制因子。选取新疆准东干旱荒漠地区优势物种钠猪毛菜为研究对象,通过田间控制试验方法研究分析不同水分梯度对钠猪毛菜生长策略的影响,为新疆准东地区大规模露天矿区植被重建工作提供参考。结果表明:1)在不同生长时期,水分胁迫对钠猪毛菜的生物量分配具有显著影响,根冠比随胁迫程度增加而增加,地上生物量较地下生物量减少程度较快;2)应用模糊数学的隶属函数分析法,依此对钠猪毛菜生长状况进行评价,评价结果为幼苗期、生长期、繁殖期生长情况最优分别为5、10 d及对照组;3)钠猪毛菜各个生长阶段含水率差异显著,表现为幼苗期>生长期>繁殖期,且都随胁迫增加而降低;4)钠猪毛菜C、N含量在幼苗期、营养生长期、繁殖期差异显著,P含量差异不显著,N∶P在幼苗期、营养生长期均小于14,繁殖期大于16;5)钠猪毛菜在幼苗期和营养生长期偏向于地下权衡,在繁殖期的低胁迫下偏向于地上权衡,高胁迫下偏向于地下权衡。钠猪毛菜在幼苗期和生长期对水分胁迫具有相似的生存对策,繁殖期在低胁迫时生存对策与幼苗期、生长期相一致,而在高胁迫时恰好相反。

In arid areas,water is the key factor limiting plant growth.In this study,we determined the effects of water deficit on Salsola nitraria,the dominant species in the arid desert area of Zhundong,Xinjiang.The results of this field experiment will provide a reference for vegetation reconstruction in large open-pit mining areas in this region.The results showed that,at different growth stages,water deficit had a significant impact on biomass allocation in S.nitraria.The root∶shoot ratio increased with increasing severity of water deficit,and the aboveground biomass decreased faster than did the underground biomass.We used a membership function analysis of fuzzy mathematics to analyze the growth status of S.nitraria.The water content of S.nitraria differed significantly among different growth stages,and was highest at the seedling stage,followed by the growth stage,and then the reproductive stage.The water content of S.nitraria decreased with increasing severity of water deficit.The contents of carbon and nitrogen,but not phosphorus,in S.nitraria differed significantly among the seedling,vegetative growth,and reproductive stages.The nitrogen:phosphorus ratio was less than 14 at the seedling and vegetative growth stages but more than 16 at the reproductive stage.The results indicated that there is an energy trade-off favoring below-ground parts over above-ground parts at the seedling stage and vegetative growth stages.At the reproductive stage,the trade-off favors above-ground parts under low stress and below-ground parts under high stress.S.nitraria under drought stress has similar survival strategies at the seedling stage and growth stage.Under low stress,the survival strategy of S.nitraria at the reproductive stage is consistent with that at the seedling and growth stages,while under high stress,its survival strategy is different at the reproductive stage.