生物多样性 ›› 2014, Vol. 22 ›› Issue (4): 458-466.DOI: 10.3724/SP.J.1003.2014.13232

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四川都江堰迁地保育的42种杜鹃属植物开花-展叶物候节律

庄平*()   

  1. 中国科学院植物研究所华西亚高山植物园, 四川都江堰 611830
  • 收稿日期:2013-10-28 接受日期:2014-02-26 出版日期:2014-07-20 发布日期:2014-07-24
  • 通讯作者: 庄平
  • 基金资助:
    四川省科技厅高山杜鹃花低海拔开发试验示范(2013NZ0031)和中国科学院战略生物资源技术支撑体系专项(CZBZX-1)

Analysis of the flowering-leafing phenorhythm of 42 Rhododendron species conserved ex situ in Dujiangyan, Sichuan Province, China

Ping Zhuang*()   

  1. West China Sub-alpine Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Dujiangyan, Sichuan 611830
  • Received:2013-10-28 Accepted:2014-02-26 Online:2014-07-20 Published:2014-07-24
  • Contact: Zhuang Ping

摘要:

目前有研究表明被子植物类群中单一的开花或展叶物候模式可能具有遗传性, 但两类物候事件的节律关系是否受遗传因素控制, 各种节律模式的形成与演化机制及其与生物系统演化的关系仍不清楚。作者对四川都江堰市迁地保育的2个海拔点的杜鹃属(Rhododendron)4亚属4组13亚组42种植物的开花-展叶节律模式进行了5年的观察研究。作者假定杜鹃属的开花-展叶节律模式为进化遗传特性, 包括先花后叶(F→L)、先花后叶部分重叠(F+L)、叶期包花期(L∈F)、先叶后花部分重叠(L+F)和先叶后花(L→F)等5种类型。同一地点不同年份以及不同地点同一物种的相关物候观察结果均显示, 尽管它们5年的物候发生时间随年度和观察点海拔不同而有波动, 但物候发生次序和开花-展叶节律模式均未见随年份而变化, 即每个物种只对应一种节律模式, 支持了上述假设。作者进一步提出了开花-展叶节律模式与物种的系统演化存在进化程度上的差异和序列关系的假设。不同节律模式的物种其区系地理以及不同海拔和分类群中的物种数量分布特征表明: (1)进化程度不同的节律模式分别对应于古老的中国-日本森林植物亚区和年轻的中国-喜玛拉雅森林植物亚区物种, 较原始的节律模式倾向于出现在中高山海拔区域, 并与杜鹃属可能起源山地的一定海拔区域构成关联, 而进化程度较高的节律模式倾向于出现在更高或更低的海拔地段; (2)节律模式的进化程度与有关亚属、组、亚组的系统位置和进化程度有一定关联; (3)节律模式的演化与生活型、叶性进化同步, 环境胁迫、生长期长度变化、光资源竞争等都可能是节律模式演化的外部动力。研究还表明, 在气候波动条件下物候事件间的发生次序比单一物候事件的时间属性更加稳定。

关键词: 开花-展叶节律, 物候学, 系统演化, Rhododendron

Abstract

Recent research suggests that the timing of flowering and leafing out are genetically controlled. It remains unknown, however, whether it is genetic or environmental factors that control the flowering-leafing phenorhythm, and whether this character can be linked to the systematic evolution of a group. In this study, the flowering-leafing phenorhythm type of 42 Rhododendron species belonging to 4 subgenera, 4 sections and 13 subsections were determined conserved ex situ at two sites with different elevations in Dujiangyan, Sichuan Province, China. The phenorhythm of the Rhododendron species was divided into five types: (1) flowering before leafing (F→L); (2) flowering ahead and covering part time of leafing (F+L); (3) leafing covers flowering (L∈F); (4) leafing ahead and covering part time of flowering (L+F); and (5) leafing before flowering (L→F). We tested the following hypotheses: flowering-leafing phenorhythm type is a heritable trait for Rhododendrons, and phenorythm is related to evolutionary processes resulting in an evolutionary sequence among the five types. The results showed that Rhododendron species at the same site or at different sites displayed only one flowering-leafing phenorhythm type that did not change throuth time, thereby supporting the hypothesis that phenorhythm is heritable. Floristic components, proportion of Rhododendron species at different elevations, and the different taxa showed that the phenorhythm type is related to the phylogenetic evolution supporting the second hypothesis. The primitive species are present at the mid- elevation range and the advanced species are present at a lower and higher range. The evolution of these phenorhythm types agree with life form and leaf trait evolution. Environmental stress, growing season length and light resource availability could be selective pressures driving phenorhythm type evolution. Overall, the results indicate that the timing sequences of phenological events are more stable than the specific timing of any single phenological event in response to climate change.

Key words: flowering-leafing phenorhythm, phenology, phylogenetic evolution, Rhododendron