生物多样性 ›› 2015, Vol. 23 ›› Issue (1): 18-22.DOI: 10.17520/biods.2014065

• 研究报告: 植物多样性 • 上一篇    下一篇

喜旱莲子草对遮荫的可塑性反应: 入侵地与原产地种群的比较

张紫妍, 张致杰, 潘晓云*   

  1. 复旦大学生物多样性科学研究所, 生物多样性与生态工程教育部实验室, 上海 200433
  • 收稿日期:2014-03-29 修回日期:2014-10-02 出版日期:2015-01-20 发布日期:2015-05-04
  • 通讯作者: 潘晓云
  • 基金资助:

    国家自然科学基金

Phenotypic plasticity of Alternanthera philoxeroides in response to shading: introduced vs. native populations

Ziyan Zhang, Zhijie Zhang, Xiaoyun Pan*   

  1. Institute of Biodiversity Science, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Fudan University, Shanghai 200433
  • Received:2014-03-29 Revised:2014-10-02 Online:2015-01-20 Published:2015-05-04
  • Contact: Xiaoyun Pan

摘要:

表型可塑性可能在外来植物的成功入侵和随后的扩散中起到至关重要的作用。一些研究者推测喜旱莲子草(Alternanthera philoxeroides)入侵地种群可能比原产地种群对光强具有更强的可塑性反应。为了验证该假说, 我们在正常光照和遮荫(30%正常光照)条件下研究了喜旱莲子草原产地(阿根廷)和入侵地(美国)种群在形态特征和生物量分配上是否存在显著差异。结果表明: (1)喜旱莲子草对光照强度具有很强的可塑性。在遮荫处理下, 其根冠比和分枝生物量比显著降低, 而比茎长和比叶面积显著增加; (2)原产地和入侵地喜旱莲子草的总生物量和比叶面积对遮荫的可塑性没有显著差异。入侵地种群的根冠比、分枝强度和比茎长的可塑性显著小于原产地种群; (3)无论在正常或低光照条件下, 入侵地种群的根冠比(–20.8%)、分枝强度(–54.6%)、比茎长(–18.5%)和比叶面积(–8.6%)均显著低于原产地种群。这些结果表明, 喜旱莲子草对光照强度具有很强的可塑性, 这可能是该物种可以分布于从河岸带草丛到疏林灌丛等各种生境的主要原因; 从原产地到入侵地, 喜旱莲子草与耐阴性有关的性状对光照的可塑性显著降低, 可能是该物种在入侵地能够形成单优势种群的主要原因。

关键词: 生物入侵, 表型可塑性, 光照强度, 根冠比, 比叶面积, 比茎长

Abstract:

It is still debated whether invasive plants have superior functional traits or the ability to display increased phenotypic plasticity in the introduced area. We conducted common garden experiments using five native populations and five invasive populations of Alternanthera philoxeroides to look for differences in phenotypic plasticity in response to shading of functional traits between introduced and native populations. We found both native and introduced plants showed significant phenotypic plasticity in response to shading, including reduction of biomass, root / shoot ratio (RSR) and branch biomass fraction (BBF), and increasing in specific stem length (SSL) and specific leaf area (SLA). The introduced populations (from the USA) showed higher plasticity in response to shading than the native Argentina population in traits such as RSR, BBF and SSL. Introduced plants also show significant reductions in RSR (–20.8%), BBF (–54.6%), SSL (–18.5%) and SLA (–8.8%). Our results suggest that A. philoxeroides has evolved a lower plastic response to shading in its introduced range, which might contribute to the establishment of dense populations with high persistence and resistance to colonization by sympatric native species.

Key words: biological invasion, phenotypic plasticity, light intensity, root/shoot ratio, specific leaf area (SLA), specific stem length (SSL)