Comparison of nutrient absorption and photosynthetic characteristics between Alternanthera philoxeroides and companion species of Paspalum paspaloides under different light conditions
[Objective]This study was conducted to explore the differences in nutrient absorption and photosynthetic characteristics between the invasive plant Alternanthera philoxeroides and its local companion species Paspalum paspaloides under different light conditions.[Method]A pot experiment was conducted to investigate the effects of 5 light intensities,including 100%light intensity(L1),80%light intensity(L2),60%light intensity(L3),40%light intensity(L4),and 20%light intensity(L5),on biomass distribution,nitrogen and phosphorus absorption,chlorophyll fluorescence,and osmotic regulatory substance contents in hollow lotus grass and double spikelet barnyard grass.[Result]With the decrease of light intensity,the root biomass ratio(RMR)and root crown ratio(R/C)of A.philoxeroides and P.paspaloides both decreased continuously,while the stem biomass ratio(SMR)of the two plants first increased and then decreased.In terms of leaf biomass ratio(LMR),A.philoxeroides was the largest under L5 treatment,while P.paspaloides was the largest under L1 treatment.The nitrogen and phosphorus contents of A.philoxeroides reached their maximum values under L2 treatment,while the nitrogen and phosphorus contents of P.paspaloides showed no significant difference under L1 and L2 treatments.However,the nitrogen and phosphorus contents inside A.philoxeroides was higher than that of P.paspaloides.The chlorophyll content,maximum PSII photochemical quantum efficiency(Fv/Fm),and PSII potential activity(Fv/Fo)of the two plants showed a trend of first increasing and then decreasing with the decrease of light intensity.The net photosynthetic rate(Pn),transpiration rate(Tr),and stomatal conductance(Gs)also showed a trend of first increasing and then decreasing.The intercellular CO2 concentration(Ci)continued to increase,while the soluble sugar,soluble protein,and proline content continued to decrease.Under low light intensity(L4,L5),the chlorophyll fluorescence parameters and osmotic regulatory substance contents of A.philoxeroides were higher than that of P.paspaloides.[Conclusion]The adaptability of A.philoxeroides to low light intensity is stronger than that of P.paspaloides.The monitoring of Alternanthera philoxeroides invasion should be strengthened to prevent its competition to native species.
万方数据
维普
