Effect of Physiological Integraiton on PSⅡ Chlorophyll Fluorescence Parameters of Connected-ramet under Different Nutrient Distribution in Buchloe dactyloides
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 PS Ⅱ (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,ΦPSⅡ,and (qP) and no different parameter such as Fo,Fm were 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.