The Comparative Study On Physiological Ecology Characteristic Of Four Different Species Of Catalpa Bungei

The diurnal changes of photosynthesis of four different species of Catalpa,growing at forest research place of Chuzhou import from Henan province,about 3 years living,were measured in field in different seasons using Li-6400 photosynthetic system.The content of chlorophyll changes were determined as well.Furthermore,the effects of physiological factors(stomatal conduction,CO₂ concentration in cell clearance,etc.)and ecological factors(photosynthetic available radiation,temperature,relative humidity,etc.)on photosynthetic rate were analyzed in the paper.The results showed as following:(1)The light compensation point and saturated point are different from the four different species of Catalpa and different reasons.Total regulation showed that the Catalpa bungei is heliophilous plant,The light saturated point Changguoqiu and Catalpa fargesii are larger than Mimaohuiqiu and Guangyeqiu,The light compensation charge with the different season.Settle the obvious regulation neither.(2)For all the individuals measured,Changguoqiu,Catalpa fargesii and Mimaohuiqiu,have obvious diurnal changes in photosynthetic rate,the curves of diurnal changes inphotosynthetic rate showed double-peaked at midday in spring,summer and autumn;while Guangyeqiu showed single-peaked.Generally,the value of first peak in the curve was higher than that of second one.,and.The values of both the first peak and the valley in the curve appeared to change with season;The seasonal change of photosynthesis indicated that the photosynthesis rate for values of peak in the diurnal variation curve was earliest and the low valley is continuously time longer in spring.(3)Changguoqiu,Catalpa fargesii and Mimaohuiqiu had photosynthetic depression at midday in spring,summer and autumn;The different species of Catalpa characteristic of photosynthesis showed that the photosynthesis rate had significant relationship with the different seasonal change.(4)The seasonal change of assimilation quantity was highest in summer,then autumn, spring successively.The diurnal transpiration quantity showed Changguoqiu was lowest,showed the characteristic of barren-resistant of Changguoqiu.For season,July have the lowest diurnal transpiration efficiency.For different species of Catalpa.In the whole growth season,the transpiration efficiency showed Changguoqiu was highest. Changguoqiu in the growth of the 3 years have largest diurnal assimilation quantity and transpiration efficiency showed Changguoqiu grows the advantage more obvious.(5)Regress analysis showed that the most significant factors affecting photosynthetic diurnal changes of Changguoqiu in different season,In spring the most significant factors was Relative humidity(RH).In summer the most significant factors was stomata conduction(Cond);In autumn the most significant factors was photosynthetic avail radiate(PAR).The most significant factors affecting photosynthetic diurnal changes of Catalpa fargesii was temperature atmosphere(Ta)in spring.In summer the most significant factors was CO₂ concentration in cell clearance(Ci).In autumn the most significant factors was temperature atmosphere(Ta).The most significant factors affecting photosynthetic diurnal changes of Mimaohuiqiu was temperature atmosphere(Ta)in spring. In summer the most significant factors was CO₂ concentration in cell clearance(Ci).In autumn the most significant factors was temperature leaf(Tl),the most significant factors affecting photosynthetic diurnal changes of Guangyeqiu was photosynthetic avail radiate(PAR).In summer the most significant factors was CO₂ concentration in cell clearance(Ci).In autumn the most significant factors was temperature leaf(Tl).A multivariable regulation was build in the paper to describe the interrelation between the photosynthesis rate and the affecting factor,But the ecosystem factor and the physiology factors are not isolated,but mutually interleave,mutual influence,affect the photosynthesis together.(6)The chlorophyll contents of the different species Catalpa were the factors mostly affected the Catalpa bungei photosynthetic is very obvious.And the chlorophyll contents have obvious relativity to the different season influence.The seasonal change of chlorophyll contents was highest in summer,then autumn,spring successively;The different species Catalpa bungei chlorophyll contents Changguoqiu was highest,Catalpa fargesii was second,Mimaohuiqiu was third,Guangyeqiu was lowest.In the early grow days,the more the chlorophyll contents,the more photosynthetic rate,and chlorophyll b contents were the factors mostly affected photosynthetic rate.The variety trend that the chlorophyll a/b(Ca/Cb)is then with their dissimilarity.Affect with the season variety not greatly,three quarters have the low fluctuately;It showed that the chlorophyll b more easier affection by light,the chlorophyll b can showed that Catalpa bungei is heliophilous plant,and has high adaptability to higher light intensity,if can not reach the light of request to shine on,will affect the growth directly.