Research On Photosynthesis And Ecophysiology Of Introduced And Selected Strains Of Broussonetia Papyrifera

Broussonetia papyrifera is one of forage plant belongs to Moraceae deciduous tree, which has strong adaptability and resistance to dry and barren, but also can grow in the waterside. Broussonetia papyrifera is most suit to calcareous soil , but also can growth in acid and neutral soils, grows best under sunshine and normally under shade. The Broussonetia papyrifera plants'natural distribution is very wide in basins of Chinese Yellow River, Yangtze River and Pearl River. It has vertical distribution in at least 1 600 metres in altitude in these areas, such as Qinling Mountains, the upper reaches of Yellow River and Yangtze River. Broussonetia papyrifera can unite the soil, conservate water and soil, break wind , fix sand, adsorb dust, and has strong resistance in pollution, drought weather, cold weather, so it plays an important role in cleaning air, improving the environment and the ecological balance. The Broussonetia papyrifera branches and stems are rich in fiber, leaves are rich in fiber, protein (20% 30%), amino acids, vitamins, carbohydrates, and trace elements, so it is high quality raw materials of.paper and production and domestic animal feed. The current ecological researchs on Broussonetia papyrifera are mainly in risistence to drought, salt stress, and in relationship between soil, microbes, and in community, rarely in photosynthetic physiological aspects. Based on this, this experiment did comparative study of photosynthesis of Broussonetia papyrifera different areas, to provide a theoretical basis on strains'selecting and production practices.Broussonetia papyrifera trees from different areas were selected for comparison of photosynthesis in summer, the results show that trees from Wuhan, Shantou and Jiangsu grows not so well, Pn, Gs, Ci and WUE is low, Tr is high, Pn and PAR response curves upward trend is flattering as Pn and CO₂ response curves, AQY and CE is small, the two peaks are small of Pn diurnal curves. Trees from Shandong grows at a medium level.Trees from the left six areas such as Zhanjiang, Japan, Guangxi, Guangzhou2, Guangzhou1 and Henan, grow very well in Zhanjiang area, Pn, Gs, Ci and WUE is high, Tr is low, Pn and PAR response curves upward trend is sharp as Pn and CO₂ response curves, AQY and CE is high, the two peaks are high of Pn diurnal curves. Trees from five areas such as Zhanjiang, Shandong, Japan, Guangxi and Guangzhou2, were selected to do researchs on seasonal change of photosynthesis, the results shows that photosynthetic parameters of Broussonetia papyrifera changed with the seasonal change of PAR, CO₂, TL and RHS environmental factors, the ability of photosynthesis is declined as summer>autumn> spring > winter, there is little difference between autumn and spring. Pn, Gs and Ci displayed as summer> autumn> spring> winter. Accidental higher Ci data in the autumn made there was little difference between summer, autumn and spring. Data of Tr were highest in summer, autumn and spring small, lowest in winter. Performance of WUE was higher in winter, spring and autumn, and lower in summer. AQY displayed as summer> spring> autumn> winter, there were some special data of AQY as higher in winter and spring. LSP was high in autumn, winter, spring, low in summer. LCP was high in autumn and winter, low in spring and summer. CE showed as high in summer, secondary as autumn and spring,minimum in winter. Almostly, there were light difference of CSP of almost both five strains between four seasons. CCP showed high in summer and winter, low in autumn and spring.