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作 者 ：张 楠1,杨雪芹2,曹德昌3,李景文1*,井家林1,吕 爽1,夏延国1

期 刊 ：西北植物学报 2013年 4期 页码：771~779

关键词：胡杨；幼苗；根系；生长；木质化；

Keywords:Populus euphratica, seedling, root, growth, lignification,

摘 要 ：以当年生胡杨幼苗为材料,通过不同水平的水分和养分单因素控制盆栽试验,探讨土壤水肥因子对当年生胡杨幼苗生长权衡和木质化的影响,以明确胡杨生长过程中以及种子更新困难的原因和机理。结果表明:（1）当年生胡杨幼苗生长权衡主要体现在生物量的分配策略上,而主根长/高度没有显著差异。（2）在连续给水处理下,干旱胁迫使幼苗根冠比显著增加,土壤含水量15%处理的根冠比较含水量20%和30%处理分别显著增加了75%和93%;但干旱胁迫抑制了生物量的积累,含水量10%处理下生物量比15%、20%和30%处理分别显著减小53.4%、89.2%、78.6%;在断续给水处理下,随着干旱程度的增加幼苗根冠比显著增加,土壤含水量15%处理的根冠比较含水量20%和30%处理分别显著增加34%和38%;连续给水和断续给水两类干旱胁迫均能明显增加幼苗根系木质化程度。（3）土壤施加氮磷均显著增加幼苗根冠比和木质化,但过量的氮肥抑制根系生物量的积累。可见,胡杨幼苗对于水肥条件胁迫敏感性与生长权衡能力是胡杨林种子更新与种群维持的关键环节,调整立地土壤水肥环境对当年生胡杨幼苗的生长定居有重要的作用。

Abstract:By setting up a controlled-experiment with soil water content and fertilizer,the seedling were analyzed to investigated the effects of environment on the trade-off and lignification and to understand the reasons and mechanism of the seedling and the seed regeneration.The results showed that:(1)Populus euphratica seedling’s growth of trade-off was mainly reflected in biomass distribution strategy.However,the main root length to height ratio was not significantly different.(2)Under continuous water treatment,drought stress increased root to shoot ratio.The root to shoot ratio of the 15% water content level increased by about 75% and 93% of those under 20% and 30% water content levels.But drought stress decreased biomass,for example,the biomass of 10% water content level decreased by about 53.4%,89.2%,78.6% than other levels.With intermittent water treatment,drought stress also increased root to shoot ratio.The root to shoot ratio of the 15% water content level increased by about 34% and 38% of those under 20% and 30% water content levels.In addition,drought resistance can also impact lignification with both water treatments.(3)Applied nitrogen and phosphorus could improve root to shoot ratio and lignification significantly,but excessive nitrogen decreased biomass.The sensitivity of P.euphratica seedlings to water and fertilizer conditions and the growth weighed ability are key factors to create seeds and maintain population.Therefore,the soil water and fertilizer conditions play an important role for the seed germination and seedling growth of P.euphratica.

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