High Temperature On The Photosynthetic Ecophysiological Characteristics Of Four Alien Invasive Plants In South China

Temperature is one of the key external factors that affect the growth of the plants.It plays a role in the whole process of plants growing.At present,the main symbol of the global warming is the average temperature rise and more and more extreme temperature events,which is continue to bring negative or potential effection to the global ecosystem and biodiversity including some invasive plants distribution and diffusion.In our study,four commonly found invasive plants in South China--Wedelia trilobata,Alernanthera philoxeroides,Ipomoea cairica and Bidens alba--were chosen to be compared with their native plants including W.chinensis,A.sessilis,I.aquatica and B.pilosa.In three temperature settings(normal: 28 ? / 23 ?,high: 30 ? / 25 ?,very high: 40 ? /35 ?),we investigated the difference on growth and photosynthetic characteristics of the plants.The main results are as follows:(1) Under three temperature teatments,W.trilobata biomass were significantly higher than that of W.chinensis.The maximum net photosynthetic rate of Pmax showed in the environment under normal and high temperature W.trilobata is higher than W.chinensis;the W.trilobata light saturation point(LSP)and the maximum fluorescence yield(Fv/Fm)and the actual fluorescence yield(Yield)at each temperature is higher than W.chinensis.Compared with normal temperature,the W.chinensis in high temperature and extreme high temperature treatment,the chlorophyll content decreased by 6.02%,14.46%,W.chinensis decreased by 29.68%,44.17%.(2)Under the condition of normal temperature,total biomass of A.philoxeroides was significantly higher than that of A.sessilis,after warming treatment,the total biomass was lower than A.sessilis.In normal temperature and high temperature treatment,A.philoxeroides and A.sessilis and there was no significant difference in Pmax,LSP,but in extreme high temperature the level of Pmax,LSP was significantly higher than that of A.philoxeroides.(3) At normal temperature and high temperature conditions,I.cairica had no advantage in total biomass and in extreme temperature conditions,there was no significantly different between I.cairica and I.aquatica.I.cairica Fv/Fm and Yield in high temperature and extreme high temperatures was lower than the I.aquatica,but in warming,the level of I.cairica Pmax LSP was higher than I.aquatica.Compared with normal temperature,at high temperature and extreme high temperature treatment,the chlorophyll content decreased by 27.74%,32.90%,water spinach decreased by 27.09%,46.11%.(4) In the three temperature,there was obvious advantages between the total biomass of B.alba and B.pilosa.Under the normal temperature condition,the level of Pmax,LSP,Fv/Fm,Yield were significantly higher than that of B.pilosa.Under the condition of high temperature Pmax,Fv/Fm,Yield slightly higher than the B.pilosa.At extreme high temperature,there was no significant differences in Pmax,LSP,but the white B.alba Yield is significantly higher than that of B.pilosa.Conclusion: In this experiment,only the W.trilobata and B alba showed obvious advantages compared with the control.In warm temperature condition the A.philoxeroides was weak than A.sessilis.The I.cairica is inhibited under the warm temperature condition,but photosynthetic ability was stronger than I.aquatica.