不同光强下入侵植物剑叶金鸡菊与伴生种生长和光合特征研究

Study on growth and photosynthesis traits of the invasive species Coreopsis lanceolata and its co occuring species in contrasting light conditions

关键词:  剑叶金鸡菊  生长  生物量分配  光合能力  入侵性

Key words:  Coreopsis lanceolata  growth  biomass allocation  photosynthesis capacity  invasiveness

摘要:

研究了剑叶金鸡菊及其伴生植物鬼针草、羊蹄幼苗的生物量分配、生长和生理特性在不同强度的光生境中(全光照和31%光照)的响应特征，探讨了这些特征与其入侵性的关系。结果表明:(1)光强是影响剑叶金鸡菊入侵的重要环境因子，高光环境下其幼苗较高的相对生长速率(RGR)和植物单位重量的光合效率(Am)与其入侵性密切相关。遮荫下，剑叶金鸡菊的RGR、Am均降至最低，资源利用能力下降是其不能适应林下荫蔽环境的原因；(2)剑叶金鸡菊在适合生境和逆境下的可塑性反应属于专能型(master of some trades)类型，即只有在全光生境才具有最优种群扩散能力。

Abstract:

To better understand its invasion mechanism and comprehensive control，we compared the morphological and physiological traits of C.lanceolata with those of its co occurring species Bidens bipinnata and Rumex japonicus under two different irradiance treatments(full irradiance and 31% of the full irradiance)，then analyzed the correlation between those traits and invasiveness. It was found that C.lanceolata was a light favoring species，and that the high relative growth rate(RGR)and photosynthetic capacity based on mass basis(Am)contributed to improve its competitiveness under high light environment. In partly shaded conditions，the significant decrease in RGR and Am of C.lanceolata reduced its competitiveness. However，other traits related to biomass allocation and resource capture related traits，such as leaf area ratio(LAR)，stem mass ratio(SMR)，leaf mass ratio(LMR)and specific leaf area(SLA)were not always higher for C.lanceolata than for its co occurring species even under high light environment. The reaction norm of C.lanceolata to light showed a master of some trades pattern，which means that C.lanceolata could only increase population densities under favorable conditions.