Influence of long-term fertilization on photosynthesis,part of protective enzyme activities in leaves and the yield of rice
In order to study the influence of long-term fertilization on photosynthesis and protective enzyme activities(superoxide dismutase,peroxidase and catalase) in leaves of rice,a long-term field experiment has been carried out in Jinxian County Institute of Red Soil in Jiangxi Province(116°20′24″N,28°15′30″E),and different experimental treatments were shown as follows.1) Zero fertilization(CK);2) Chemical fertilization alone(N,NP,NPK);3) Organic fertilization alone(M);4) Combination of chemical and organic fertilization(NPKM).The re-sults show that long-term application of fertilization,especially in NPKM treatment,increased chlorophyll content,net photosynthetic rate,protective enzyme activities in flag leaves in full heading stage of rice and the rice yield.With the development after full heading stage of rice,chlorophyll content,net photosynthetic rate,and catalase(CAT) decaeased,namely they followed a decreasing order of booting stage,full heading stage and milk stage.But the activities of superoxide dismutase(SOD) and peroxidase(POD) in full heading stage were maximum.There were significant correlations among chlorophyll content,net photosynthetic rate,part of protective enzyme activities and the rice yields in all treatments.Therefore,long-term application of fertilization,especially in NPKM treatment,was favorable to the growth and development of rice and its yield and protective enzyme activi-ties in leaves of rice efficiency in red paddy soil.