The Photo-Physiological And Biochemical Mechanism Of 4 Offorestal Trees In The Loess Plateau

In this study ,we examined all kinds of physiolocal ecology parameters and chlorophyâ…¡fluorescence of four offerestal trees(Salixbaby lomical, Robinnia pseudoscacia, Pinus tabulaeform is, Syrina pekinensis)with international advanced protable photosynthetic measuring system . We also measured the effect of elevated CO₂ concentration on their photosynthesis and chlorophyâ…¡fluorescence . Result showed that: (1) The photosynthetic and water using efficiency of Salixbaby lomical is larger than the other broad-leaved species . Salixbaby lomical has the largest light saturation point and Robinnia pseudoscacia has the shortest light compensation point . (2) The transpiration efficiency of Salixbaby lomical is higher than other's thousand time, 1ed-leavers of Pinus tabulaeform is is a main material accumulater. (3) Robinnia pseudoscacia has the shortest ETR(electron transfer rate) stabilized time and the longest qP(quenching coefficient) stabilized time among these species while the leaves move to light from darkness . these species's ETR and qP are same time to photosynthetic . (4) when the leaves move to darkness, Pinus tabulaeform is has the shortest NPQ(Non-photochemical quenching ) relaxation . PhiPS2 positively related to PhiCO₂ while the light intensity over 200μmol.m^-2.s^-1. (5) The photosynthetic, transpiration, PhiPS2 and PhiCO₂ may be improved while CO₂ concentration elevated. (6) Robinnia pseudoscacia has the most protein .Different species have different drought resistant ablities.