中文摘要：

沙冬青属（Ammopiptanthus）植物是我国西北荒漠区唯一的常绿阔叶灌木.作者对吐鲁番沙漠植物园迁地保护的两种沙冬青的开花物候进行了详细的比较观察,旨在探讨它们在同一生境条件下开花特性的异同点及其影响因素.主要结果如下：（1）两种植物在开花频率、花序开放顺序、开花振幅曲线及单花寿命等开花参数上相似,但在始花时间、单株花期、花序的开花数及开放持续时间与频率分布、开花振幅等参数上明显不同;（2）在个体和群体水平上,蒙古沙冬青（A.mongolicus）始花时间均比新疆沙冬青（A.nanus）早,蒙古沙冬青开花全过程为20-21 d,新疆沙冬青为13-14 d;（3）蒙古沙冬青花序的开花数比新疆沙冬青多、开放持续时间长,两者在开花数（F=17.51,P＜0.01）和持续时间（F=14.08,P＜0.01）上均存在显著差异;（4）花序上的花大多从近基部向两端开放,开花振幅呈单峰曲线,但新疆沙冬青的开花振幅较高;（5）花序开放持续期的频率分布明显不同,新疆沙冬青较蒙古沙冬青更为集中,但两者的单花寿命稳定,均在7 d左右;（6）花序上每天的开花数与其座果数呈正相关（蒙古沙冬青,r=0.885,P＜0.05;新疆沙冬青,r=0.827,P＜0.01）,但其开花数和座果数与始花时间存在不同程度的相关关系,这些特点可能与开花对传粉者的吸引以及物种本身的遗传特性有关.对上述观察结果及其影响因素的分析表明,两种植物在开花参数上所表现出的一致性可能是受系统发育限制的,而彼此间的差异可能与其进化历史及所处的环境异质性有关,是在与环境的长期适应过程中分别形成的一些可遗传的变异;而不同年份间两种沙冬青在花序的开花数及开放持续时间上表现出的差异可能与环境温度的变化有关.这些结果对于探讨该属植物的繁殖生物学特性及其保护对策具有重要意义.

英文摘要：

The genus Ammopiptanthus （Fabaceae）, a typical evergreen broadleaf shrub of the northwestern deserts of China, comprises two species： A. mongolicus and A. nanus. Both are semi-endemic and relict species in China. In order to detect the differences between the two species in flowering phenology as well as factors influencing flowering, we investigated and compared flowering in the Turpan Eremophytes Botanical Garden in 2004 and 2005. （1） The two species are similar in terms of flowering frequency, flowering order of inflorescences, flowering amplitude curves, and the mean longevity of individual flowers, but differ considerably in the onset, the flowering duration of individuals, flower number per inflorescence, mean and frequency distribution of duration, and flowering amplitude. （2） At both individual and population levels, onset was earlier and duration was longer in A. mongolicus than in A. nanus. （3） A. mongolicus bore more flowers and had longer duration of flowering than A. nanus. There were significant differences both in flower number （F=17.51, P〈0.01） and duration of inflorescences （F=14.08, P〈0.01） between the two species. （4） The flowering of both species initiated from near the base spreading to the two ends, presenting a unimodal flowering amplitude, but A. nanus had a relatively higher flowering amplitude. （5） There were obvious differences in the frequency distribution of duration of inflorescences between the two species, but the mean longevities of individual flowers were similar （about seven days）. （6） Pearson correlation analysis showed that the fruit number of an inflorescence was positively correlated with its flowering number per day（A, mongolicus,r=-0.885, P〈0.05; A. nanus, r = 0.827, P〈0.01）, while the flowering and fruit number of inflorescences per day had different correlations with onset, which may result from the different pollinators and genetic characters of the species. The results showed that the similarity in flowering paramet