Studies On Diurnal Variation Characteristics And Differences Of Photosynthesis And Chlorophyll Fluorescence Of Five Sympodial Bamboo Species

In this paper,,diurnal variation of photosynthesis physiology and chlorophyll fluoresce nee targeted Dendrocalamus latiflorus,Bambusa oldhami,Bambusa boniopsis,Bambusa ventric osa and Bambusa chungii were studied.The correlation between net photosynthetic rate and other indicators,the response of net photosynthetic rate to light intensity and CO2 were also esplained.The investigation of photosynthetic characteristics and difference of the five symp odial bamboo species can provide a.theoretical basis for the ntroduction,cultivation and scie ntific forest management of bamboo.The results were as follows:1.There are two peaks in diurnal changes of net photosynthetic rates(A),stomatal con ductance(Gs),transpiration rates(E)of five sympodial bamboo species,and the diurnal change sof internal CO2 concentration are "W" type.The "midday depression" phenomenon are evi dent because net photosynthetic rates at 13:00 were at the least.But the time of net phot osynthetic rates peaks all appear is different.The first peaks of Bambusa chungii,Bambus a oldhami,Dendrocalamus latiflorus appeared at 10:00,but Bambusa ventricosa and Bambus a boniopsis are at 12:00.The second peaks all appeared at 16:00 and significantly lower t han the first peak.The maximum net photosynthetic rate are:Dendrocalamus latiflorus(14.89)>Bambusa oldhami(6.53)>Bambusa boniopsis(5.19)>Bambusa ventricosa(4.85)>Bambusa c hungii(3.86?mol·m-2·s-1),which are 1.40,1.29,1.06,1.28,1.32 times the first peak.2.By variance analysis there was significant variance in the means of relative chloro phyll content,and diurnal net photosynthetic rate,stomatal conductance and transpiration rat e among five sympodial Bamboo species except internal CO2 concentration.The means of diurnal net photosynthetic rate,stomatal conductance and transpiration rate are 2.31-7.91?mol·m-2·s-1,0.03-0.08?mol·m-2·s-1,0.71-1.67?mol·m-2·s-1.Net photosynthetic rate and stomata 1 conductance of Dendrocalamus latiflorus are significantly higher than the rest bamboo sp ecies.Transpiration rate of Dendrocalamus latiflorus and Bambusa oldhami are significantl y higher than the rest three bamboo species.The correlation coefficient between relative c hlorophyll content,and net photosynthetic rate is 0.856,which explained a significant positiv e correlation between them.3.LCP and LSP of five sympodial Bamboo species are:Dendrocalamus latiflorus(22.327 and 1736.070),Bambusa oldhami(22.603 and 1437.045),Bambusa chungii(23.431 andl315,392),Bambusa ventricosa(17.844 and 1347.947),Bambusa boniopsis(8.791 and 1043.636?mo l·m-2·s-1)?CCP and CSP are:Dendrocalamus latiflorus(32.324 and 1592.440),Bambusa oldha mi(30.319 and 1428.581),Bambusa chungii(28.227 and 1227.030),Bambusa ventricosa(23.342 and 1292.779),Bambusa boniopsis(20.567 and 1154.332?mol·mol-1).The LCP,LSP,CCP and CSP of Dendrocalamus latiflorusare relatively higher,Bambusa boniopsis are the minimu m,which explained that Dendrocalamus latiflorus adapt to high light intensity and high CO 2 concentration,and Bambusa boniopsis adapt to low light intensity and low CO2Concentrati on.4.Correlation analysis towards net photosynthetic rate and various environmental factor s and physiological traits show that:there are significant positive correlations between net p hotosynthetic rate(A)and light intensity(PAR),stomatal conductance(Gs),transpiration rate(E),a negative correlations between net photosynthetic rate(A)and internal CO2 concentration.The correlation coefficient are.4.75,0.981,0.938 and-0.552.In addition,T and T1 were als o significantly correlated to A.PAR is the main environmental factor affecting net photosy nthetic rate,and Gs is the most vita;physiological factors.5.All bamboo species Fv/Fm and Fm are higher in the morning and afternoon,lower at noon indicating that they occurred photoinhibition Variance analysis showed that there a te significant variance in chlorophyll fluorescence parameters.Fo,Fv/Fm and Fm of Den drocalamus latiflorus are higher than others indicating that it has a high energy makeup ef ficiency and a relatively strong photosynthetic activity.Throughout the diurnal ehanges,Fv/Fm,qP,qN and ETR of Dendrocalamus latiflorus and Bambusa oldhami are relative higher showing that they can minimize the degree of photoinhibtion through increasing sunshine dissipated and be more adapted to the environment than others.6.By principal component analysis to all indicators,comarehensive principal componen t scores are:Dendrocalamus latiflorus(3?534),Bambusa oldhami(1.351),Bambusa chungii(-0.746),Bambusa ventricosa(-0.779),Bambusa boniopsis(-3.359).They can be divided into threeclus ters:the first is Dendrocalamus latiflorus andBambusa oldhami,he second is Bambusa chu ngii and Bambusa ventricosa,the last is Bambusa boniops.