Study On The Changes In Leaf And Reproductive Phenology Of Woody Plants In Eastern China

The change of global climate has more and more obvious effects on terrestrial ecosystem.The mechanical research on the response of plant phenology to temperature and other environmental factors has become an important ecological issue.Based on the phenological observation data and temperature data from 1963 to 2008,this research studied the temporal and spatial variation trend and potential mechanism of main tree species in the eastern forest of China during the leaf duration(leaf unfolding date and leaf falling date)and reproductive duration(flower bud date,flowering date and fruiting date).The main research results are as follows:1.In the terms of leaf phenology,the higher temperature sensitivity of leaf unfolding date(5.50 ± 0.22 days /?)and the significantly increased temperature in the leaf falling period(autumn,0.04 ?/year,P <0.05)led to a earlier leaf unfolding date(-0.85 days/year)and leaf falling date(-0.16 days/year),and a longer leaf duration(1.02 days per year,P < 0.05)during 1988-2008(negative value indicate advance,P <0.05).2.In the terms of reproductive phenology,the higher temperature sensitivity of flower bud date(-6.84 ± 0.50 days/ ?)and the significantly increased temperature in flowering period(summer,0.06?/year,P <0.05)led to a earlier flower bud date(0.58 days/year,P <0.05)and flowering date(0.43 days/year,P <0.05)in 1988-2008.Although the temperature increased in autumn,there was no significant change in the average the fruiting date(P > 0.05),which ultimately resulted in no significant change in the reproductive duration(P > 0.05).3.With the latitude moving northward or longitude moving eastward,the temperature in spring,summer,autumn and winter decreased significantly in 1963-2008.Therefore,the average leaf unfolding date and leaf falling date were advanced with latitude or longitude,leading to a shorted leaf duration.Additionally,the average flower bud date and flowering date were also significantly advanced,resulting to a shorted reproductive duration.Similar spatial trends of phenological period were shown during 1963-1983 and 1988-2008(P > 0.05),except the latitudial trend of the reproductive duration(a smaller decrease after 1988,P < 0.05).Our results indicated that plant leaf phenology and reproductive phenology showed a greater response after 1988.The temporal and spatial changes of plant phenology and its duration are significantly related to the temperature in the relative period.Global warming and the seasonal asymmetry in the future will show more impacts on the phenology and its duration,which ultimately play significant influences on ecosystem structure and function,as well as the diversity of ecosystem,and the interactions among animals and plants.