Study On The Physio-ecological Responses Of Paeonia Suffruticosa 'Hongdan Lan' Under Drought Stress

With three-year-old potted Paeonia suffruticosa 'Hongdan Lan' as material, effect of drought stress on physiological and ecological characteristics of Paeonia suffruticosa 'Hongdan Lan' were investigated. The soil water content was artificially controlled by the way of weighting. It was aimed to seek the adaptable mechanism to drought stress and provide reference for water management of potted Paeonia suffrulicosa'Hongdan Lan'. Meanwhile, it provided theoretical basis and technical support of pivotal technique system. The main results are as follows:(1) With the increase of drought stress, the size of tree height, crown width, area of a terminal leaf and the petiole length declined gradually. At the same time, the size of flower (the diameter and the height of flowers) had been significantly reduced. The growth of annual branch of Paeonia suffrulicosa 'Hongdan Lan' were restrained under drought stress, which showed significant downtrend. The length of florescence increased gradually with the increase of drought stress. The drought stress had significant effect on the content of anthocyanin and the order of the anthocyanin contents was LS>CK>HS>MS.(2) In the late period of drought, the diurnal changes in net photosynthetic rate, transpiration rate, stomatal conductance presented a single-peak curve and peak point occurred at 10:00. Drought stresses had reduced the intercellular CO2 concentration (Ci) significantly, while the stomatal limitation values and the water utilization efficiency (WUE) had been increased following the strengthening drought stresses. With the process of drought stress, the Chla, Chlb and total Chl content increased first and then decreased to rise again. With the increase of drought stress, the Car content increased gradually. The energy conversion of PS Hand potential activities of PS II descended as the degree of soil drought increasing. Meanwhile, there was a same tendency in profile change of Fv/Fm and Fv/Fo and the differences between various treatments were significant.(3) RWC had descended as the degree of drought stress increasing. With the degree and process of drought stress, the content of proline, soluble sugar and soluble protein went up gradually. The order of ascended range was MS>HS>LS. Especially in MS and HS, the content of protein accumulated rapidly. With the extension of drought stress, the SOD activity increased first, then decreased, and then rise again. The SOD activity in LS, MS and HS was higher than that in CK. At the same time, the CAT activity had a similar trend with the SOD activity. With the degree and extension of drought stress, the content of MDA increased gradually.