塔里木河下游胡杨物候特征观测

以塔里木河下游胡杨(Populus euphratica)为对象,对胡杨的开花期、展叶期、第一次展叶期、第二次展叶期、果熟期、叶黄期及落叶期等主要物候期进行观测。结果表明:胡杨各物候期中,开花期持续时间最短,3月29日至4月19日,果熟期持续时间最长,5月25日开始,10月13日结束。由于春尺蠖(Apocheima cinerarius)的危害,胡杨有"二次展叶"现象,第一次展叶期为4月4日至5月1日,第二次展叶期为5月13日至6月4日。胡杨叶黄期和落叶期相重叠,叶黄期从9月26日开始,10月28日结束,落叶期从10月11日开始,11月12日结束。胡杨长达4个多月的果熟期与河道洪水期吻合,这有利于种子的传播、萌发及幼苗扎根,促进天然胡杨林种群的更新及演替。

Study on Phenological Characters of Populus euphratica Oliv.in the Lower Reaches of the Tarim River

In this study,six phenological characters,i.e.the flowering,first foliation,second foliation,maturity,leaf coloration and defoliation of Populus euphratica Oliv.in the lower reaches of the Tarim River are observed and researched.The results show that the total phenophase of P.euphratica Oliv.form the flowering stage to the defoliation is for 229 days.Among these phenophases,the flowering stage from March 29 to April 19 is the shortest,whereas the maturity stage from May 25 to October 13 is the longest,and their durations are 21 and 141 days respectively.Because of Apocheima cinerarius pest,foliation of P.euphratica Oliv.can occur twice,the first and second foliations occur during the periods from April 4 to May 1 and from May 13 to June 4 respectively.The leaf coloration and defoliation stages occur simultaneously to some extent,they occur during the periods from September 26 to October 28 and from October 11 to November 12 respectively.The maturity stage of P.euphratica Oliv.is as long as more than 4 months,and it occurs simultaneously with flood season,which is advantageous for seed dispersal and germination,seedling rooting and promotion of the regeneration and succession of natural forests of P.euphratica Oliv.The study results also reveal that all the phenophases of P.euphratica Oliv.in the Tarim River Basin are latter than that in Minqin County of Gansu Province but earlier than that in the Turpan Basin of Xinjiang.