The Study On Cold-resistance And Its Mechanism Of 3 Species Of Eucalyptus Along The Coast In Zhejiang

In this study, the cultivation and growth of E.grandis, E.saligna and E.dunnii was surveyed completely along the coast in Zhejiang. 3 species of eucalyptus was treated in natural low temperature, analysing and discussing cold resistance behaves, revealing their difference on adaptability, and studying its cold resistance and resistance mechanism among physiology, photosynthesis, and biochemistry, etc, which provided scientific evidence on screening the excellent stress-resistant specie of eucalyptus and the brand-new variety, utilization and construction of eucalyptus forestry. The main results was as followed:Zhejiang was located in the southeast of china, the north edge of which eucalyptus was cultivated. Since many years of introduction and cultivation of eucalyptus, it become the chief specie of afforestation in Zhejiang province. The utilization of eucalyptus is of positive value on the appliance of protection forest by field survey. With the suitable technique fitting to eucalyptus cultivation, it has entered the stage of rapid development from seedling production to the appliance of it, that has great ecological, economical benefit with significance in landscape. In this study, the introduction and cultivation of eucalyptus was investigated in Zhejiang along the coast, describing the technical points of cultivation there, and analysing the growth performance of it among all the cultivated places, especially under the natural low temperature. It showed that three selected species of eucalyptus grew very well and behaved stronger cold hardiness in these area.By surveillance of natural low temperature of plastic greenhouse and opening field at the experimental field, combining with external morphology observation, 3 species of eucalyptus was analyzed on their growth performance. The annual E.dunnii behaved stronger cold hardiness basing on the effect of extreme low temperature at -5℃and sustained chilling. It suffered less freezing injury, but also recovered growth normally after the rise of temperature.3 different species differed in a varied way of tolerance ability in natural low temperature through kinds of physiological and biochemical index showed in their leaves. Conclusively, the order of these species on cold-hardiness is that E.dunnii>E.saligna>E.grandis. It suggested that E.dunnii should be considered as first choice on afforestation in north central of Zhejiang at the view of saplings wintering in the coastal area. Comparing the physiological index of these species in their leaves, the annual E.dunnii met the need of cold resistance by keeping lower level of cell membrane perme -ability, producing lower content of MDA, and higher activity of SOD to clear free radicals and oxide in leaves and maintain normal running of cell membrane system for further. Moreover, it sustained higher photosynthetic efficiency itself to resist cold and behaved better on anti-cold by analyzing characteristic of chlorophyll fluorescence of these eucalyptus in leaves before and after the cold current.E.grandis and E.saligna were selected as experimental materials in this part because their comprehensive behaves was much better in practical application of protection forest in south central of coastal area. Two technicals, SDS-PAGE and 2D-PAGE, were combined to isolate total protein in their leaves and get the patterns of SDS-PAGE and 2D-PAGE. The result was that natural low temperature stress did effect on protein expressions in their leaves, which differed significantly among their patterns, mainly showed the fluctuation of protein spots and shade of dyeing. It suggested that these protein spots was changed both in substance and content after suffering low temperature stress. From greenhouse to opening field, the patterns of PAGE of E.grandis and E.saligna showed several different protein spots. By contrast with E.grandis, protein in leaves of E.saligna decreased less than it, which expressed on quantity, while the up-regulation of expression showed obviously more than E.grandis had. Therefore, E.saligna behaved stronger cold hardiness than E.grandis. After analysing these differences, it was also found that these two species functioned in some kinds of varied ways responding to the low temperature stress, which was related to its characteristic. Further study would be needed on it.