Studies On Ecophysiological Characteristics Of Drought Resistance In Caryopteris Mongholica Bunge

The drought-resistant species, Caryopteris mongholica Bunge, was taken as the material in the studies. The mechanism of drought resistance was investigated in the sight of ecophysiological on the six provenance level. The main results of research are as followings:1. Under the water stress, the growth of six Caryopteris mongholica Bunge provenance is inhibited, the ability of water reservation was affected, photosynthesis ability has been suppressed due to stomatal restriction.The relative growth, total biomass, leaf weight ratio, Specific leaf mass, leaf/stem ratio, LDW/SA, LAI/SA, SML, number of branches, Succulence Index, leaf water proportion, crown water proportion, water relative content in leaves, water potential, Pn, Ci, Gs, E, LUE, car, Fv/Fm and NPQ show a decline with the increase of water stress, while root weight ratio, Root/Crown ratio, root water proportion, the water saturated deficit, relative electrical conductivity rate, Ls, WUE and qL rises. CUE and chla/b increased then reduced with the increase of drought stress.2. At different water gradients, the index of relative growth, total biomass, Root/Crown ratio, SML, root weight ratio, leaf weight ratio, number of branches, Specific leaf mass, Succulence Index, leaf water proportion, crown water proportion, root water proportion, relative electrical conductivity rate, water relative content in leaves, the water saturated deficit, water potential, Pn, Ci, Gs, E, Ls, WUE, CUE, LUE, Fv/Fm and Fv/F0 of Caryopteris mongholica Bunge is significantly different.3. The index of relative growth, total biomass, Root/Crown ratio, SML, root weight ratio, leaf weight ratio, number of branches, Specific leaf mass, Succulence Index, leaf water proportion, crown water proportion, root water proportion, relative electrical conductivity rate, water potential, Ci, Gs, E, Ls, WUE, CUE, chla, chlb, car, chl, chl/car, Fv/Fm, Fv/F0, NPQ and qL of six provenances of Caryopteris mongholica Bunge is significantly different. 4. The drought-resistant abilities of the six provenances were listed by total biomass in descending order as follows:NY>SY>NT>GM>NE>XT.The ability of water reservation of the six provenances were listed by subordinate function method in descending order as follows: NT>NY>SY>XT>GM>NE.The photosynthesis ability of the six provenances were listed by subordinate function method in descending order as follows:NT>SY>NY>XT>GM>NE. The drought-resistant abilities of the six provenances were contrasted and compared through principal components analysis, the order as follows: NT>NY>SY>GM>NE>XT.On the basis of field investigation of physiological indices, the NT is best in water deficit among six provenances.So, the provenance of Inner Mongolia TUZUOQI (NT) is the strongest drought-resistance among six provenances, and it could be the best choice for planting in the arid region.