2014年和2015年连续2年对哈密和乌恰裸果木(Gymnocarpos przewalskii)自然种群的开花物候特征进行野外定点观测,并运用相对开花振幅、开花强度和开花同步性等参数对其开花物候特征进行分析.结果表明,2个种群每年均开1次花,4月下旬到5月上旬进入始花期,开花进程基本相似,均呈单峰曲线,具有较高的开花同步性,呈现“集中大量”开花模式;在个体水平上,始花期、终花期在种群和年份间略有差异;单花持续时间在年际间是稳定的,但在种群间有所不同,即乌恰种群的单花持续时间略长于哈密种群;不同裸果木种群的开花数与结籽数间均呈极显著正相关,开花同步性指数与相对开花强度间呈显著负相关;乌恰种群的始花期与开花数间呈负相关.裸果木个体开花振幅、开花同步指数及开花模式在种群和年份间的相似性很大程度上是由其在长期的地理变迁中形成的遗传特性决定的,而始花期和开花持续时间等开花物候特征的差异主要是由环境和气象因子(海拔、气温、降水及光照)差异造成.研究结果对于探讨该属植物的繁殖生物学特性及其保护具有重要意义.%From 2014 to 2015,we investigated and compared the Hami and Wuqia populations of Gymnocarpos przewalskii in the wild,and used indices such as flowering amplitude,relative flowering intensity,synchrony index.The two populations flowered once in a year,late April to early May into flowering onset;the flowering phenology of the two populations was similar,and the plant has the characteristics of high flowering synchrony and a typical "mass flowering"pattern.At the individual level,there were significant differences both in the first flowering date and the end flowering date by population and year;the single flower longevity and mean longevities of individual flowers were similar at different years.Different populations differed:the flowering duration of a single flower of Wuqia was slightly longer than for the Hami population.We found a significant positive correlation between flower number and seed number,whereas the synchrony indices were negatively correlated with relative flowering intensity in different populations.The similarity in flowering amplitude and flowering synchrony in the two species and years of G.przewalskii may be explained by their phylogenetic relationships,whereas the differences may result from their evolutionary history in heterogeneous habitats (altitude,temperature,precipitation and light).These results can provide useful information for research on reproductive biology and conservation for the species.
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