Study On Photosynthetic Characteristics And Stress Resistance Of Four Variety Of Aster Novae-angliae

Aster novae-angliae L. is a perennial herb.In this article, one-year old of four variety of Aster novae-angliae L. (cv.Barr's Pink,cv.Andenken an Alma Potschke,cv.Herbstschnee,cv.Purple Dome)was used as materials to study systematically its pgysiological and ecological properties of photosynthesis,drought resistent and heat resistance in natural environment.The main results were as follows:(1) The Photopic Adaptation of four variety of Aster novae-angliae L.is wide .The capacity of light accommodation register as Purple Dome> Herbstschnee > Barr's Pink > Andenken an Alma Potschke. By comparison of apparent quantum yield,the light percent conversion register as Herbstschnee > Andenken an Alma Potschke > Purple Dome> Barr's Pink. By comparison of dark respiriration rate, the liveness of leaf register as Andenken an Alma Potschke> Purple Dome> Herbstschnee >Barr's Pink.The four variety of Aster novae-angliae L.have obvious diurnal changes in photosynthetic rate,the curves of diurnal changes inphotosynthetic rate show single-peaked at midday in spring and autumn,and double-peaked at midday in summer. It is earlier in spring than in summer when the peak value comes.Generally, the values of both the four variety of Aster novae-angliae L, Purple Dome is higher than the others.During the growing season, the diurnal fluctuation regularity in the four variety of Aster novae-angliae L. is uniform. The value of firat peak in the curve was higer than that of second one in summer,and the net photosynthetic rate from high to low are summer ,autumn,spring.Regress analysis showed that the influencing factors of photosynthetic diual of Aster novae-angliae L changes in different season, the most significant factors was stomata conduction in spring; and CO2 concentration in cell clearance In summerI; and transpiration rate in autumn. The most significant factors of photosynthetic diural of the four variety of Aster novae-angliae L.in different seasons is distinct.In a word ,the affecting factors of physiological is above entironment.It is not isolated but mutual that they affect the photosynthesis of plants together.(2)According to the drought resistance experiment which makes the plant under lasting drought pressure without any watering until the upper-side die away,with the analyses of leaf water potential, parameter and biochemic parameters,the sequence of drought resistance of four four variety of Aster novae-angliae L. are made, and the mechanism of drought resistance are discussed. the water potential of four variety of Aster novae-angliae L. decreased with reduction of soil water content and had significantly positive correlation with soil relative water content, the water potential of drought-resistant variety reduced slowly.The relative electric conductivity,the MDA content,the activities of SOD and POD can be used to sequence the plants'drought resistance.Based on the analyses,the ability to drought resistance from strong to weak are: Barr's Pink, Andenken an Alma Potschke, Herbstschnee, Purple Dome.(3)According to the heat resistance experiment which makes the plant under high temperature, with the analyses of parameter and biochemic parameters, the sequence of heat resistance of four four variety of Aster novae-angliae L. are made. The relative electric conductivity,the MDA content,the activities of SOD can be used to sequence the plants'drought resistance. the ability to hest resistance from strong to weak are: Andenken an Alma Potschke, Purple Dome ,Barr's Pink, Herbstschnee.