Research On Plant Function Groups Of Quercus Variabilis Forest And The Dynamic Mechanism At Funiu Mountain Natural Reserve

The experiments were carried out in the southern slopes'Baotianman and northern slopes'Baiyun mountain of Funiu Mountain Natural Reserve.We had community investigation on May.2006 and Nov.2006. The method of vegetation ecology of Braun-Blanquet approach was adopted in this paper to invest the type features of the study area's main forest ecosystem.Investigation index including: tree layer's coverage,species,individual number,tree height,clear bole height,crown height,crown width,basal diameter,DBH and so on;and also shrub layer's coverage,species,individual number,tree height,crown height,basal diameter and herb layer's coverage,species,individual number,heigh,crown width,basal diameter(tuft size).It also invested the community's age structure and the degree of human impact and so on. We divided them into different plant function groups according to the interspecific association of the dominant species and the similarities and differences in differentaltitude gradient. We determine one sample plot of 400㎡ per 100m in the representative mountain that have Quercus variabilis forest. And determine the dominant species that all the levels of Quercus variabilis forest plant functional groups need to measure.From May.2007 to Oct.2007,we used Licor-6400 portable photosynthesis system and FMS portable Hansatech Flurescence Monitoring System to measure the physiological ecology characteristic above.The research shows the results as follows:In northern slopes'Baiyun mountain,under 1000 metres,the absolute dominant species is Quercus variabilis,and the large accompanying species is Quercus aliena;in southern slopes'Baotianman, under 1200 metres, Quercus variabilis is basically dominant species around 1200m,there are more Quercus Glandulifera.From all the mountain body, the dominant constructing community plant is Quercus variabilis under 1000m,the distribution of Quercus Glandulifera is in a parabolic curve patten according to elevation. Based on this result, we set 8 plots in Baotianman, 5 in Baiyun mountain, and the total is 13.In this paper, through the chlorophyll content comparion about the same dominant species in the same slope plot, and also the chlorophyll content comparion about the mixed forest plots of Quercus variabilis forest and other Quercus forest, we found out that the content of chlorophyll in dominant species leaves is not only effected by its own biological characteristics,but also by environmental factors.The level of the content of chlorophyll in dominant species leaves is the basis that the plants capture light quantum and have photosynthesis, it is one of the indexes that can reflect the plants'latent photosynthetic capacity,but in reality, the photosynthetic rate is effected by mangy other factors.Fom the daily course comparison ofΦPSⅡabout the same dominant species in the same slope plot and the daily course comparison ofΦPSⅡabout different dominant species,we found that except for individual levels of dominant specie'daily course have the trend of increasing or decreasing or have"single peak"curve,the daily course ofΦPSⅡof each dominant specie in different levels have"V"curve,that means it is high in the morning and in the evening,and it is low in the midday and afternoon.The fluorescence of dominant species leaves is decreasing at noon shows that efficiency of light energy conversion at noon is decreasing and further to explain photo inhibition.As to different dominant species, the numeric whose fluorescence parameters is high play a leading role in the community.That is because only when the fluorescence parametersΦPSⅡis increasing,it is possible to transform the light energy absorbed into chemical energy,and to improve the transmission speed of photosyntheticel ectronic,and formed more ATP and ENDPH,and support enough energy and reducing power for carbon assimilation.Through the related analyse,the relatinship between photosynthetic rate Pn and photosynthetically active radiation PARi is very significant.And through the related analyse about the relatinship betwe- en photosynthetic rate Pn and other impact factor such as photosynthetic physiology,find out that photosynthetic rate Pn has a close relationship with physiological factors(Cond,Ci Trmmol),and ecological factors.It shows that photosynthesis is not only affected by light,but also have the joint influence and restriction by many physiological factors and external ecological factors.