Study On Photosynthesis And Chlorophyll Fluorescence Characteristics Of Phoebe Bournei

Phoebe bournei, an evergreen tree belonging to family of Lauraceae, genus Phoebe, is a level two national protected plant species, which it is a precious timber and good landscaping arbor. Phoebe bournei grows slowly and its wild population decreased recently. On the other hand, it has a large market need, afforestation is an effective way to solve this problem. Research on photosynthesis, day process seasonal variations and chlorophyll fluorescence characteristics difference of 2-years-old seedlings of Phoebe bournei in of shaxian, Zhenghe, Yanping and Jian’ou areas were conducted. Phoebe bournei and other several Lauraceae plants including Phoebe zhennan, Cinnamomum bodinieri, Cinnamomum camphora, were studied by the Li-6400 analyzer photosynthesis and OS5p chlorophyll fluorescence analyzer modulation, in order to master range of photosynthetic physiological pcology adaptability, provide theoretical basis for the cultivation and conservation of Phoebe bournei.(1)Photosynthetic parameters like net photosynthetic rate (Pn), transpiration rate (Tr) and chlorophyll fluorescence parameters like actual solar energy capture efficiency (Yield), photochemical quenching coefficient (qP) had certain variations in different geographic provenances. Most of the parameter existed differences significantly in Jian’ou and Zhenghe provenance, and the parameter value of Yanping and Shaxian provenance were situated between Jian’ou and Zhenghe provenance. The results of light response and CO2 response showed that, there were some differences between Phoebe bournei provenances. Light response and CO2 response parameters value range was relatively small, the light compensation point (LCP) was low, light saturation point (LSP) was high, Phoebe bournei seedlings are more shade tolerant, but also can develop under small amount of light.(2)There were big differences on photosynthesis and chlorophyll fluorescence parameters diurnal variation of Phoebe bournei in different seasons. Photosynthesis parameters like Pn, Tr, Gs, the seasonal diurnal variation curves for "single-peak" or "bimodal", and Ci was the "U-type". The diurnal variation of Fv/Fm, Fv/Fo was "V-type", "single-peak" or "bimodal", and NPQ had no obvious diurnal variation. Yield, qP and ETR diurnal variation trends in different seasons were more close to Pn. Photosynthesis and chlorophyll fluorescence parameters generally larger in autumn, and smaller in winter, that relatively strong growth in autumn, while growth dormancy in winter.(3)There were some differences in photosynthesis and chlorophyll fluorescence parameters diurnal variation of Phoebe bournei, Phoebe zhennan, Cinnamomum bodinieri and Cinnamomum camphora. The diurnal changes curve of Pn and Ls of all species were "bimodal"; Gs diurnal variation as "single peak"of Phoebe bournei and Phoebe zhennan, and present "bimodal" in Cinnamomum bodinieri and Cinnamomum camphora; The diurnal changes curve of Ci all species were "W-type"; The "single peak" diurnal variation curve of Tr existed to Phoebe bournei, but others as "bimodal"; There were no obvious diurnal variation of WUE. Characterization diurnal photosynthetic ability parameter value of Phoebe bournei is close to Phoebe zhennan, but lower than Cinnamomum camphora and higher than Cinnamomun bodinieri. Its light and CO2 response analysis found that photosynthesis potential of Phoebe bournei was much smaller than Phoebe zhennan, Cinnamomum bodinieri and Cinnamomum camphora. Chlorophyll fluorescence parameters value of Phoebe bournei less than Phoebe zhennan and Cinnamomum camphora, but larger than Cinnamomum bodinieri.In summary, under different geographical provenance, different growing seasons and different species, different degrees of photosynthesis and chlorophyll fluorescence were observed in Phoebe bournei. Phoebe bournei seedlings was shade-tolerant and can tolerate a certain intensity of light, Jian’ou provenance photosynthetic characteristics superior to other kinds of sources; Because of its strong photosynthetic ability, autumn is the prime growing season for Phoebe bournei; Phoebe bournei Photosynthetic capacity was close with Phoebe zhennan, less than Cinnamomum camphora and higher than Cinnamomum bodinieri, far lower than Phoebe zhennan,Cinnamomum camphora and Cinnamomum bodinieri in the photosynthetic potential. This also proved the slow growth characteristics of Phoebe bournei.