A Physiological Study On Lespedeza In Drought And Salt Stresses

This thesis studies on the introduction of lespedeza resistant seed selection and theculture physiology, the resistant problem in produce practice also be included. The multiple physiological characteristics are studied to evaluate the endurance of nine provanences of lespedeza in drought- and salt-stess conditions. 9 provanences of lespedeza are selected from the 22 collect provanences taking the climatic condition, altitude and alkaline land into full consideration. The 9 provanences selected as follow: 5 L.bicolor Turczs which are from America, Japan, inner Mongolia, Liao ning, and He nan province of China, 2 L.cuneata G. Don d.L.hedysaroides which are from America and He nan province, 1 (L.formosa(Vog.) Koehne k.L. Thunber and 1 L.cyrtobotrya Miq both from America.The main contrasts will be the influence of different provanences to the stresses, which is achieved by the experiments on 2 kind of experimental materials, germination and individual plant, according to the physiological stresses designs of drought- and salt-resistance.The test indexes include germination parameters, individual's water traits and photosynthesis response parameters, osmotic adjustment materials variety, cell membrane penetration parameters and AOS. The abilities of resistance to stresses of the selected 9 provanences are studied and evaluated comprehensively and the resistance difference in physiological and biochemical traits also explained deeply through testing these indexes. The results are found as follow:A. Generally, Lespedeza is a kind of plant adapting the severity light, so PAR would not be a negative factor for its photosynthesis and the effects of CO2 to Lespedeza is bigger than PAR. Lespedeza belongs to the C3 plant and could be the elfin woodland.B. According to Doutht Index, the drought-resistance abilities are ordered as: L.formosa(Vog.) Koehne k.L. Thunber (America), L.formosa(Vog.) Koehne k.L. Thunber (America), L.cuneata G. Don d.L.hedysaroides (America), L.cyrtobotrya Miq. (America), L.cuneata G. Don d.L.hedysaroides, L.bicolor Turcz. (Henan), L.bicolor Turcz.(Inner mongolia), L.bicolor Turcz.(Japan), L.bicolor Turcz. (America), L.bicolor Turcz. (Liaoning).C. The ability of seeds germination in salt condition order by the comprehensive appraisal index as follows: L.bicolor Turcz.(Henan), L.bicolor Turcz.(Liaoning), L.bicolor Turcz.(Inner mongolia), L.cyrtobotrya Miq. (America) , L.formosa(Vog.) Koehne k.L. Thunber (America), L.bicolor Turcz.(Japan), L.cuneata G. Don d.L.hedysaroides (Henan), L.bicolor Turcz.(America), L.cuneata G. Don d.L.hedysaroides (America); but seed treat with PEG6000 couldn't germination in osmotic stress experiment.D. The ability of stresses resistance order by the comprehensive appraisal index as follows: in drought condition: L.cyrtobotrya Miq. (America)> L.bicolor Turcz.(Inner mongolia)> L.cuneata G. Don d.L.hedysaroides (Henan)> L.bicolor Turcz.(America)> L.bicolor Turcz.(Japan)> L.bicolor Turcz.(Henan)> L.cuneata G. Don d.L.hedysaroides (America)= L.bicolor Turcz.(Liaoning)> L.formosa(Vog.) Koehne k.L. Thunber (America); in salt condition: L.cyrtobotrya Miq. (America)> L.formosa(Vog.) Koehne k.L. Thunber (America)=L.bicolor Turcz. (Henan)= L.bicolor Turcz. (America)> L.bicolor Turcz.(Japan)> L.cuneata G. Don d.L.hedysaroides (Henan)> L.bicolor Turcz.(Inner mongolia)= L.bicolor Turcz.(Liaoning)> L.cuneata G. Don d.L.hedysaroides (America);E.The result shows that each tree species has their own drought resistance characteristics and the drought resistances are correlated and indicated by specific key traits. The ability to stresses-resistance is a complicated quantity characteristic, which is effected by kinds of factors, and it need a comprehensive evaluation relating diversified indexes not only one index which will be far enough to evaluate the intensity of abilities to stresses accurately.