The Research Of Physiological And Biochemical Characteristics Related To Cold Resistance In Four Cupressaceae Varieties

Under the artificial low temperature stress and normal temperature fall, doimant branches of four Cupressaceae Varieties, which were Juniperus formosana ’Blue Arrow’,Platycladus orientalis ’Green oriental’ Juniperus scopulorum ’Blue Heaven’ and Platycladus oriental ’Golden oriental’ were used as test materials to evaluate their frost resistance. The content of total soluble sugar soluble protein was determined to show the effect of osmosis substances on different species. The level of chlorophyll was determined to show the Cold and frostbitten injury on photosynthetic tissue of different species. The level of SOD was determined to understand the effect of antioxidant metabolism on frost resistance. The effect of combination of factors on the frost resistance by subject function.Results showed that the value of the relative conductivity,proline (Pro) content, the soluble sugar content has been increasing as the temperature decreases. According to Logistic equation fitting, the semi-lethal low temperatures were-23.57℃,-29.7℃,-32.32℃,-38.99℃.Seven physiological indices with the processing time increases variation, relative electrical conductivity changes a little, the processing time on the plant cell membrane, osmotic substances and enzyme activity has a direct impact, but on the cold-resistance of judgment is not the key factor. Artificial temperature control and natural cooling, cold resistance physiological indexes of basically the same, But the artificial temperature change trend is more clear, more easy and rapid response of plant under low temperature stress in the stress response, and the natural cooling is more gentle, linearity, small error, both union can be accurate description of plant cold hardiness. The four Cupressaceae Varieties cold tolerance of pruning intensity as follows:Blue arrow>Blue sky>Gold Platycladus orientalis>Green Platycladus orientalis.