Study On Physiological Ecology Of Five Lianas In Tiantong Evergreen Broad-leaved Forest, ZheJiang

Using portable photosynthesis system HCM—1000,main physioecological in dices of 5 vines (Ampelopsis cantoniensis,Stauntonia leucantha, Morinda umbell ate, Hedera nepalexsis var sinensis, Dalbergia millettii) in evergreen broad-leaved forest of Tiantong National Forest Park,Zhejiang Province were measured in controll ed situations of the lab as:light compensation point(LCP),light saturation point(LSP) and in natural environment of Dynamics of leaf photosynthetic rate,transpiration rate.Daily variations of net photosynthetic rate(Pn),photosynthetic active radiation (PAR),C02 concentration (CO_2abs),environment temperature(Text),relative humidity (RH), transpiration rate.Multi-linear regression equations of Pn to ecological and physiological factors (PAR, CO_2abs, Text, RH) were set up.Importances of the factors were arrayed according to partial coefficients in corresponding equations. Variations of those physioecological indices were analyzed for 2 aspects between species ,between seasons.①Dynamics of leaf photosynthetic rate,transpiration rate and seasonal change of leaf photosynthetic rate , transpiration rate are mainly represented as the difference of fluctuation intensity,amplitude and appearance time of peak of all variation types. Seasonal change of photosynthetic capacity is related with growth rhythm closely. In different seasons, Pn is higher in autumn than summer and spring, but Tr of Hedera nepalexsis var sinensis, Dalbergia millettii, Ampelopsis cantoniensis is higher in summer than autumn and spring.②Statistical results show that environment temperature is main influencing factors of leaf photosynthetic rate to five species in the whole growth season;next is Relative humidity.③There are intrinsic different in the photosynthetic capacities of the various growth forms of vines which inhabit subtropical forest.The adventitious-root cli mbers(e.s.Hedera nepalexsis var.sinensis)(reproductive stem) have the highest m-aximum photosynthetic rates of all species(5.42μmolm^-2.s(-1)).The twining vine Morinda umbellate and Stauntonia leucantha is better-adapted to low light con-ditions,with a low light compensation point.Results suggest physiological adapat ability of vines to light environments may be related to climbing mechanics.④For photosynthetic characters:Pn of the five species is accordingly high in evergreen broad-leaved trees,which Hedera nepalexsis var.sinensis(reproductive stem)(HSR)>Hedera nepalexsis var.sinensis(climbing stem)(HSC)>Stauntonia leuc antha(Sh)>Hedera nepalexsis van sinensis(stolon stem)(HSS)>Ampelopsis canton iensis{AC)>Morinda umbellate(MU)> Dalbergia militia(DM). LSP:HSR>HSC>AC>DM>HSS>SL>MU;And for LCP:DM>AC>SL>HSC>HSR> HSS>MU;So the tolerance of shading:MU>HSS>HSR>HSC>SL>AC>DM; Transration rate: HSC>AC>HSR>DM>HSS>MU>SL;Five species are ordered separately according to photosynthetic rate,transpir ation rate.On the basis of transration rate and photosynthetic rate,species are cl-ssified into:High photosynthetic rate and high transration rate:HSR,HSC;Middle photosynthetic rate and high transration rate:AC;Middle photosynthetic rate and middle transration rate:HSS;Middle photosynthetic rate and low transration rate: SL;Low photosynthetic rate and middle transration rate:DM;Low photosynthetic rate and low transration rate: MU...