Studies On The Physiological And Biochemical Characteristics Of Heat And Humidity Tolerant Tree Peony

Tree peony(Paeonia suffruticosa Andr.), a traditional flower in China, gets itspopularity for its rich cultivars and a wide range of colors. The cool climate is suitablefor it, but in cultivation high temperature and humidity would potentially make atremendous damage, and then there for their ornamental values are decreased andtheir appling region are limited. With the aim of providing simple and appliedmethods for the identification of tree peony's heat and humidity tolerant, and offeringscientific basis for the application of peony in high temperature and high humidityarea, six cultivars of peony were used as materials under the different temperature(25℃, 30℃, 35℃, 40℃), the different SRWC (40%, 60%, 100%), the differentrelative air moisture (80%, 90%, 95%) in this study, and physiological andbiochemical changes under heat and humidity treatment were studied.The main results were as follows:Results of the leaf physiological and biochemical changes showed that:1. Physiological and biochemical indexs of proline, protein, chlorophyll,malondialdehyde, relative water content, conductivity and super oxide dismutase,peroxidase, catalase activity were used to evaluate the heat and humidity tolerantcharacters of peony. Paeonia suffruticosa 'Rou Furong' and 'Wu Longpengsheng'was heat tolerant, 'Cang Jiao' was next, Paeonia suffruticosa 'Lu Hehong' and 'ZhiHong' were the weakest; Paeonia suffruticosa 'Cang Jiao' and 'Zhi Hong' were highsoil SRWC tolerant, Paeonia suffruticosa 'Lu Hehong' was in middle, but Paeoniasuffruticosa 'Hu Hong' wasn't. The air moisture tolerant of Paeonia suffruticosa 'RouFurong' is stronger than Paeonia sufrruticosa 'Lu Hehong'.2. Nine physiological and biochemical indexes were measured by using principalcomponent analysis and subordinative function under the temperature of 35℃. The comprehensive value of tree peony's heat tolerant was obtained and evaluated. Usingthe proline content (X₁), the malondialdehyde content(X₂), the conductivity(X₄),catalase activity(X₈) as variable established forecast regression function, the bestregressive function was founded to forecast other tree peony's heat tolerant:(D=0.515-0.00054X₁+0.000693X₂+0.001X₄-0.00069X₈).3. Nine physiological and biochemical indexes were measured by using principalcomponent analysis and subordinative function under the soil SRWC of 100%. Thecomprehensive value of SRWC tolerant was obtained and evaluated. Using theproline content (X₁), the malondialdehyde content(X₂),catalase activity(X₈) asvariable established forecast regression function, The best regressive function wasfounded to forecast other tree peony's SRWC tolerant:(D=1.947-0.00161X₁-0.00132X₂-0.00097X₈).4. Results of Duncan and subordinative function analysis showed that: solubleprotein, malondialdehyde(MDA), super oxide dismutase(SOD), Catalase(CAT),peroxidase(POD) activity and conductivity was strong to the change regularity andremarkable to difference under the heat and humidity tolerant (contain high airmoisture and soil SRWC). The effect of free proline, MDA content, conductivity,CAT activity was fairly good to identify heat tolerant of tree peony; and free prolinecontent, MDA contents, CAT activity were fairly good to identify the tree peonyhumidity tolerant.