31种木本植物开花物候与系统发育的关系

Relationship between flowering phenology and phylogeny in 31 woody plants of Urumqi,Xinjiang

植物物候通常被认为是由环境因素,如降水、温度和日照长度所决定,然而环境因素是否是物候唯一的决定因素仍然存在很大争议。谱系结构表征了植物在进化上的顺序,该发育时序是否对物候产生影响,当前仍然未知。在调查2016年春季新疆乌鲁木齐市最常见的31种木本植物的初始开花时间、败花时间和开花持续时间的基础上,通过分析植物开花物候的分布特征、开花物候在乔灌木间的差别、以及植物谱系距离与开花物候距离间的关系,试图揭示植物的开花物候和物种谱系(进化)顺序间的关系。结果表明:(1)新疆乌鲁木齐市31种木本植物的初始开花时间为4月18日±9d、败花时间为5月5日±12d、开花持续时间为(16±8)d;(2)乔木的初始开花时间和败花时间的标准差分别均低于灌木,乔木开花物候相对灌木更稳定;(3)乔木的初始开花和败花时间均显著早于灌木(P<0.05),但开花持续时间在两者间未有显著性差异(P>0.05);(3)31种木本植物间的初始开花时间距离、败花时间距离和开花持续时间距离均与物种谱系距离存在显著线性回归关系(P<0.05)。综上可知:乔灌木在垂直空间上的分化使得木本植物的开花物候在植物生活型间存在不同。对植物的开花物候,除已被证明的降水、温度和日照长度等环境因素的影响外,物种进化顺序也可能造成了它在植物种间、时间和空间上的变异。

Environmental factors, i. e. precipitation, temperature, and sunshine duration, are considered the determinate factors of variation in plant phenology. However, whether environmental factors singly affect phenological change is still unknown. Phylogenetic structure refers to a developmental sequence of plants along evolutionary time; however, there is no consensus regarding whether phylogenetic structure affects plant phenology. In this paper, the initial flowering time, falling flower times, and duration of the flowering period of 31 woody plants, were investigated in Urumqi, Xinjiang. Subsequently, the distribution pattern in flowering phenology, the differences in flowering phenology between trees and shrubs, and the regression relationships between flowering phenology and phylogenetic structure were analyzed to explain the relationship between flowering phenology and phylogeny in woody plants. The results showed that：（1） the initial flowering time, falling flower time, and the duration of the flowering period was April 18th±9 days, May 5th±12 days, and 16 days±8 days, respectively, for 31 woody plants of Urumqi; （2） standard deviations of the initial flowering time and falling flower time of trees were higher than those of shrubs, indicating that trees have a greater stability of flowering phenology than shrubs; （3） the initial flowering time and falling flower time of trees were significantly earlier than those of shrubs （P〈0.05）, whereas the duration of flowering period was not significantly different （P〉0.05）; （4） the time interval of the initial flowering time, the falling flower time, and the duration of the flowering period had a significantly positive linear relationship with the phylogenetic distances between different species （P〈0.05）. In conclusion, the differentiation between trees and shrubs in the vertical space changed the flowering phenology across plant life types. Additionally, although environmental factors change flowering phenology, phylogenetic structure also may play an important role in variation in flowering phenology among species, among biotypes, and along temporal and spatial scales.