Studies On The Heat And Freezing Resistance Of Hedge Plant In Guiyang

Hedge is an important manifestation of gardens. The temperature stress has affected its ecological efficiency and landscape extremely, even led to death. This article take the 9 kinds of common hedge plants which grow above 3 years barely inGuiyang city as experimental materials to be delt with about 12 hours in high (30℃,35℃, 40℃, 45℃), low temperature(0℃,-5℃, -10℃, -15℃).With the aim of providing scientific theory foundation for selecting and cultivating of hedge plants in Guiyang, Seven physiological and biochemical indexes (electrical conductivity> souluble protein, soluble sugar, proline, superoxide dismutase, Peroxidase, Malondialdehyde ) of nine hedge plants were determined in the experiment. The main research results are following: 1.The research of heat resistance:(1) By increasing of the temperature the relative conductivity of hedge plants are increasing and will be increased sharply at some degree, the temperature is 35℃ most of time. But the relative conductivity of the heat resistance variety keeps lower and its increase tends to flat.(2) The content of soluble protein shows its trend down first and up later and the soluble sugar at contrary as the increasing of the temperature .The content of proline shows up-down-up.(3 ) In the experiment the SOD active change shows up-down-up. The POD active change shows up-down, and the MDA is increasing all the time.(4) Seven physiological and biochemical indexes of nine hedge plants were treated by using principal component analysis ,The result shows: the abillity of heat-tolerant : Loropetalum chinense var. rubrum Yieh > Mahonia fortunei (Lindl.) Fedde > Ligustrum quihoui Carr. > Pyracantha fortuneana(Maxim).Li. > Jasminum nudiflorum Hance. > Serissa serissoides ( DC. ) Druce > Buxus sinica Var.Parvifolia .M.Cheng. > Nandina domestica Thunb. > Aucuba japonica Variegata., L. chinense and M. fortunei are heat-tolerant, but N. domestica , A. japonica are'nt.2 The research of freezing resistance(1) In this experiment the relative conductions of all varieties are increased as the decreasing of the temperature. The relative conductions will increase sharply at -5℃. But the realative conductions of those varieties with strong cold resistance are lower.(2) As the decreasing of the temperature, t the content of soluble protein shows up-down-up and down-up ;the soluble sugar shows its trend down first and up later; the change trend of praline is flat in former phase and has sharply increasing finally.