Effect of Low Potassium Stress on Photosynthetic and Chlorophyll Fluorescence Parameters of Two Soybean Varieties with Different K-efficiency
In former thesis,difference of photosynthetic ability due to low K stress between two kinds of K-efficiency varieties had been reported in soybean,but the internal change and factors led to this difference hadnf been found. So in this experiment, we selected two soybean varieties with different K-efficiency as material,in order to study the effect of low potassium on chlorophyll( Chl) contents, photosynthesis characteristics and chlorophyll fluorescence parameters, so as to probing into tolerant mechanism of different K-efficient varieties on low potassium stress. The plants were grown in modified 1/2 Ho-agland's solution with two different levels of K( K0.5 and K3.0). Results showed there was no difference in Chl contents(a,b and a + b) between low potassium stress and CK for K-efficient variety,but the ratio of Chl a/b increased significantly. For K- inefficient variety, the content of Chl a and(a + b) greatly decreased in low potassium stress, and there were no change in content of Chl b and ratio of Chl a/b. Photoaynthetic rate( Pn) of K- efficient variety in low potassium level was similar to that of CK,but the CO2 concentration(Ci) in the cell and stomatal conductance( Gs) in low K level were much lower than that of CK. For K-inefficient variety,the decreases of Pn,Ci and Gs were all significant. The differences of F0,Fm,Fv/Fm and Fv/F0 between two K levels werent significant for K-efficient variety,while the changes of these parameters were significant difference for K-inefficient variety,including the change of Fv. Except for that,the ratio of energy dissipated by reaction center increased in low K stress for GD8521 ,and the ratio of transfer energy decreased at the same time, while those change of Jiunong 15 were tiny. So we can concluded that a relatively high content of Chl a ,b and( a + b) ,especially the increase of Chl a content,resulted in a high ability of photosynthesis,the effective transfer of photosynthetic electron was another factor in maintaining the ability,while the significant changes of those parameters led to decrease of photosynthesis a-bility for K-inefficiency variety.
国家科技期刊平台
NSTL
万方数据
维普
