The Study On Cutting Propagation Techniques Of 3 Distylium Species And Physiological Response To Water Stress

Distylium species belongs to Hamamelidaceae,and have strong resistance and ornamental values,and has great application potential.In recent years,they have been more and more widely used in ecological environment improvement and urban greening.In order to probe the cutting propagation of Distylium species and physiological response mechanisms to water.3 Distylium species,Distylium racemosum,Distylium chinense and Distylium buxifolium,were used as materials,and the effects of substrates for cuttage and rooting agents concentration on rooting were studied.The water stress(drought stress,waterlogging stress)experiments was carried out by pot water control with two-year cutting seedlings as materials.The main results are as follows:1.The best substrate for the cuttings of 3 Distylium species of was V(peat):V(perlite)=3:1.There were significant differences in the survival rate and rooting rate among species.Distylium chinense was the highest,followed by Distylium buxifolium,and Distylium racemosum was the lowest.2.The optimum concentration of "Genpan" rooting agent suitable for Distylium chinense cuttings was 500 mg/L.3,The physio-chemical characters of substrates which had high gas permeability,lower electronic conductivity and weak acidity were suitable for Distylium chinense cuttings.4.Under drought stress,3 Distylium species all showed that the leaves had symptoms such as yellowing,falling and wilting,and their drought injury indexes gradually increased;the relative water contents(RWC)of leaves kept decreaing;the relative electrical conductivity(Rec),malondialdehyde(MDA)contents,and free proline(Pro)contents kept increasing;SOD activities,soluble protein(SP)and chlorophyll(Ch1).contents rise first and then decreased.5.Under waterlogging stress,3 Distylium species all showed that as the intensification of stress,the waterlogging symptoms were aggravated and waterlogging injury indexes gradually increased;RWC of leaves and Ch1 contents first decreased slowly and then sharply;Rec and MDA contents kept decreaing;SOD activities first increased sharply and then slowly;SP contents rise first and then decreased;and free proline(Pro)contents first increased slowly and then sharply.6.The correlation analysis and principal component analysis showed that 4 evaluation indexes that can be use as the drought tolerance of 3 Distylium species were identified,including drought injury index,RWC,MDA content and SP content;5 evaluation indexes that can be use as the waterlogging tolerance of 3 Distylium species were identified,including waterlogging injury index,RWC,MDA content,SOD activity and SP content.7.The value of the membership function showed that the order of drought tolerance of 3 Distylium species was from strong to weak:Distylium chinense>Distylium buxifolium>Distylium racemosum;the order of waterlogging tolerance of 3 Distylium species was from strong to weak:Distylium racemosum>Distylium buxifolium>Distylium racemosum.