生理整合对营养分布格局下野牛草相连分株PSII叶绿素荧光参数的影响

Effect of Physiological Integraiton on PSII Chlorophyll Fluorescence Parameters of Connected-ramet under Different Nutrient Distribution in Buchloe dactyloides

本文以匍匐茎型克隆植物野牛草的克隆分株片段为材料,研究营养分布格局和生理整合对克隆植物野牛草叶绿素荧光参数的影响。结果表明,同质营养条件下,叶绿素荧光参数Fo、Fm、Fv/Fm、ΦPSⅡ和qP在相连分株间无显著差异,姊株叶片NPQ显著高于妹株。异质营养条件下,高营养斑块居中放置时,姊株叶片Fo、Fm、Fv/Fm、ΦPSⅡ和qP显著降低,而妹株叶绿素荧光参数则显著提高;高营养斑块居基放置时,姊株Fv/Fm、ΦPSⅡ和qP略有下降,Fo和Fm无明显变化,但妹株Fo和Fm则显著提高;高营养斑块居顶放置条件下,姊株叶片Fo、Fm、Fv/Fm、ΦPSⅡ和qP均高于妹株,NPQ则显著低于妹株。这说明,在资源有限条件下,基于"成本-收益"原则,野牛草相连姊株通过维持或者自抑制其光合效率,并提高妹株光合能力来增强克隆片段对异质营养环境的适应能力。本研究为进一步揭示生理可塑性对异质生境的响应机理以及探讨生理整合对生理可塑性的修饰机制提供了重要的理论依据。

Effects of nutrient distribution on chlorophyll fluorescence parameters of the connected ramets in stoloniferous clonal plant Buchloe dactyloide were determined. Results showed that no difference in the chlorophyll fluorescence parameters including original fluorescence yield（ Fo）,maximum fluorescence yield（ Fm）,photochemical quantum yield of photosystem PSⅡ（ ΦPS Ⅱ） and the potential maximum quantum yields（ Fv/Fm） were detected in connected ramets.However,the fluorescence parameters such as Fo,Fm,Fv/Fm,ΦPS Ⅱ,and photochemical quenching（ qP） decreased in older ramets while increased in the younger ramets when the high nutrient patches placed between the connected ramets. Decreasing parameter including Fv/Fm,ΦPS Ⅱ,and（ qP） and no different parameter such as Fo,Fmwere detected in older ramet,while increasing all fluorescence parameter found in younger ramets when the high nutrient patches placed near the older ramet. And Fo,Fm,Fv/ Fm,ΦPS Ⅱ,and qP were higher in the younger ramet than that in the older ramet when the high nutrient patches placed near the younger ramet. It suggested that the physiological integration among the clonal fragments of Buchloe dactyloide might maintain or reduce the photosynthetic capacity of older sister ramets,avoid competing with younger ramets to ensure the plasticity to nutrient heterogeneity according to the＂cost-benefit＂theory.