Diurnal Change Of Chlorophyll Fluorescence And Photosynthetic Characteristics Of Chionanthus Retusus

Chionanthus retusus,Oleaceae tassel tree(Chionanthus)plants,plant under state protection(category ?),is a kind of the better species of ornamental and practical capabilities.Study of different types of fringe tree photosynthetic characteristics and chlorophyll fluorescence characteristics,aims to tassel tree long seed breeding,classification,and the choice of good varieties and certain theoretical reference planting and management efficiency.We selected six types of Chionanthus retusus to measure their photosynthetic and ecophysiological characteristics and the diurnal variation of the chlorophyll fluorescence using a Portable LI-6400 Photosynthesis System and portable chlorophyll fluorescence spectrometer and a computer with data acquisition software.The results show:(1)In addition to the F0 ur types of changes in net photosynthetic rate,rendering the bimodal type other five types were unimodal type,and five types of net photosynthetic rate showed a trend of reduce the first rise,peaked at 12 o 'clock,both decreases gradually with the decrease of natural light intensity.Type 4 photosynthetic lunch break occurs when 12 o'clock.(2)It can be seen from the tassel photosynthetic light response curve along with the increase of light intensity,net photosynthetic rate rising quickly,tend to be saturated when a maximum net photosynthetic rate,light saturation point.Six types of light saturation point,respectively 1425?mol/m~2·s?1506?mol/m~2·s?1395?mol/m~2·s?1343?mol/m~2·s?1439?mol/m~2·s?1522?mol/m~2·s.(3)There are significantly differences in photosynthetic indexes among six type of Chionanthus retusus except for Gs.(4)The photochemical efficiency(Fv/Fm)biggest change of six types of Chionanthus retusus all show the law of the lower after the increase,first at 10:00-12:00 noon light intensity is higher time presents the phenomenon of photoinhibition,Fv/Fm value is low.(5 Found type showed a strong physiological activity,daily average daily average transpiration rate,photosynthetic rate,the actual photochemical efficiency indicators were greater than other five types,such as type and a has high PS ?original light energy conversion efficiency and the activity of PS potential.?(6)The actual photochemical efficiency of six types of Chionanthus retusus all reduce with the increase of Photosynthetic active radiation.,in the same condition,the actual photochemical efficiency performance as type1>type 4>type5>type2>type6>type3.