| The testing ground is located in Dashan Forest Form of Zongyang County in Anhui province.The photosynthetic physiological characteristics,cold resistance and chlorophyll fluorescence of Adinandra millettii were studied.The main results are as follows.?1?Through the study on the photosynthetic physiological ecology of Adinandra millettii in different seasons,the result shows that the light utility efficiency of Adinandra millettii in spring,summer,autumn and winter are 0.914×10-2,0.839×10-2,0.862×10-2,0.696×10-2 respectively.The seedling's light-saturation point?LSP?and light-compensation point?LCP?are 1780?molm-2 s-1,17.81?molm-2 s-1;1390?molm-2 s-1,16.34?molm-2 s-1;1679?molm-2 s-1,17.52?molm-2 s-1;950?molm-2 s-1,20.88?molm-2 s-1.The variation rule of diurnal variation of net photosynthetic rate is spring?6.38?mol·m2·s1?>autumn?5.45?mol·m2·s1?>summer?5.23?mol·m2·s1?>winter?2.25?mol·m2·s1?.The net photosynthetic rate of summer and autumn present double pesks type,exists “noon break” phenomenon.The variation rule of diurnal variation of stomatal conductance is spring(0.102molm-2·s-1)>autumn(0.089molm-2·s-1)>summer(0.087molm-2·s-1)>winter(0.047molm-2·s-1).The rule of diurnal variations of transpiration rate mean value in spring,summer,autumn,winter are 2.259 mmol H2O·m-2·s-1,4.285 mmol H2O·m-2·s-1,2.954 mmol H2O·m-2·s-1,1.331 mmol H2O·m-2·s-1 respectively.Through multiple regression analysis,the resule shows that the photosynthesis of spring was positively correlated with temperature,stomatal conductance,photosynthetic active radiation,the photosynthesis of summer and autumn was negatively correlated with temperature,light intensity,which was positively correlated with air humidity,the result shows that within a certain range,increasing the temperature and photosynthetic active radiation did not increase the photosynthetic rate of Adinandra millettii.?2?Through the study on cold index of leaves in October to next March,the result shows that the semi-lethal temperature of Adinandra millettii in October to next March are-6.00?,-12.88?,-14.70?,-15.89?,-14.65?,-11.62? respectively.The leaf's soluble sugar content is in a significantly negative relation with its semi-lethal temperature in January,February,November and December.The MDA content and soluble sugar content of leaf in January are highest,October is lowest,which shows that the accumulation of photosynthetic products through the photosynthetic physiological characteristics of Adinandra millettii in October to next January,so that the soluble sugar content increases,the cold resistance of leaves gradually increase.The result shows that the trend of cold resistance for leaves in October to next March present single peak type.?3?The study on chlorophyll fluorescence of Adinandra millettii shows that highly significant differences were existed among average daily Fm,Fm?,Fv,Fm/F0,Fv/F0 in four seasons.Fm,Fm ',Fv,Fv/Fm,Fm/F0,Fv/F0 present the rule of obvious rise after first drop in summer daytime,and the lowest level in around 14:00.Fm,Fm ',Fv,Fv/Fm,Fm/F0,Fv/F0 present the rule of obvious drop after first rise in winter daytime,and the highest level in around 14:00.There is no highly significant differences in F0 between spring and autumn,which significantly lower than in summer and winter,but there is no obvious difference in summer and winter,the maximum of average daily F0 is in winter?124.80?.The daily dynamic curve of NPQ present single peak type in spring,summer and autumn,and it peaked at noon,The NPQ of winter has dropped noticeably from 8:00 to 14:00,and then rapid rise,which shows that Adinandra millettii takes full advantage of the high light energy at noon through self-regulation in winter,this is also the ability to adapt to low temperature stress of Adinandra millettii. |
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