Seasonal Changes In Physiology And Biochemical Index Of Some Evergreen And Deciduous Broad-leaved Species In A Montane Forest Of Mao’ Er Mountain, Guangxi

This research was carried out to investigate the Seasonal changes about the activity of such protective enzymes as SOD、CAT、POD and so on, the content of ascorbate (AsA, DAsA)、 glutathione (GSH, GSSG)、soluble sugar、Pto、soluble protein、MDA and chlorophyll content, photosyntheticrate(Pn)、transpiration rate(Tr、stomatal conductance (Gs)、carbon dioxide between cells (Ci) of three evergreen broad-leaved species and three deciduous broad-leaved species in Guangxi Mao’er Mountain. The major results are summarized as follows:Plants are influenced by many factors from spring to winter. Under the impact of a series factors, seasonal Changes are indicated on Physiology and Biochemical Index of the six species.1. Their changes of three deciduous broad-leaved species’leaves in spring and summer were similar with the activity of such protective enzymes as SOD、 POD、CAT and so on, and the content of MDA、soluble sugar, it is showed that in order to get used to outside environment they have much the same accommodation mechanism.In spring, SOD、POD activity and soluble sugar content、soluble protein content、MDA content were comparatively high. In summer, CAT、GR activity and ASA content、GSH content were comparatively high, but MDA content was lower than before.Based on these results, we may infer that the decrease of MDA content was mainly related to the increase of CAT、GR activity and ASA conten、GSH content.2. But the above Physiological Indexes of evergreen broad-leaved species have differeces on the seasonal changes, the results suggested that to adapt to environment they have different accommodation mechanism. Seasonal changes of MDA content in three types of evergreen broad-leaved species are almost the same. The changes tendency of MDA content appeared to have a decline trend after an initial ascent, and MDA content was obviously higher in autumn.Based on these results,we may infer that the increase of MDA content was mainly related to the decrease of CAT、GR activity.3. Activities of SOD、POD、 CAT and GR, and AsA conten、GSH content in three types of evergreen broad-leaved species are higher at low temperature in winter.It is an important guarantee for the security of plant overwintering.In addition, the low temperature condition also increase the content of osmotic adjustment.The content of soluble sugar、soluble protein are higher in three types of evergreen broad-leaved species, the results of these studies have the same results of other workers.But the content of Pro is lower,this is likely to adapt to adversity, and may be a manifestation of cell structure and function by injury.The reason needs further study.4. ASA and GSH are major Synthetic antioxidants and ROS scavengers in plants. Seasonal changes of AsA content and GSH content in six types of broad-leaved species are almost the same. The results suggested that Synergistic Inhibition of antioxidant compounds on preventing from the injury of outside bad surroundings and scavenging the active oxygen.5. By comparing seasonal changes of evergreen broad-leaved species and deciduous broad-leaved species, the result showed that the two species adopted different antioxidation strategies.With relatively short lifetime, deciduous broad-leaved species, leaves adopted highly garrison antioxidation strategies.But the leaves of evergreen broad-leaved species live longer, so they adopted a relatively longstanding garrison antioxidation strategies to ensure safety through winter. In spring and summer, Activities of SOD、 CAT、GR, and AsA conten、GSH content and soluble protein content in three types of deciduous broad-leaved species are higher than evergreen broad-leaved species, It was generally acknowledged that plant which has higher resistance has higher activity. Based on these reaches,it can be concluded that deciduous broad-leaved species have stronger Antioxidative Ability than evergreen broad-leaved species.6. The seasonal changes of net photosynthetic rate of evergreen broad-leaved species had the order of summer> autumn> spring> winter, deciduous broad-leaved species had the order of summer> spring. The higher net photosynthetic rate(Pn) of deciduous broad-leaved species, as of Acer davidii,than its accompanying species,such evergreen broad-leaved species as Schima argentea, indicated that higher photosynthetic capacity mad it in a favourable position to get dominating status for occupying the community.7. The seasonal changes of transpiration rate of evergreen broad-leaved species had the order of summer> spring> autumn>winter, deciduous broad-leaved species had the order of summer> spring. Generally speaking, transpiration rate of deciduous broad-leaved species was higher.8. Meanwhile, for the6species of plants, the net photosynthetic rate were positive related to the stomatal conductance, correlated with intercellular CO2concentration (Ci). It was found that the changes of Pn was related to stomatic factors.9. The seasonal changes of Chlorophyll Content of evergreen broad-leaved species had the order of summer> autumn> spring> winter, deciduous broad-leaved species had the order of summer> spring. For the same plant, chlorophyll content has some relation with photosynthesize rate. Because of different Genetic among among6species, chlorophyll content can not reflect the photosynthetic rate. For Schima argentea,when the highest Pn occurred but the chlorophyll content were lowest.