Effects of different phosphorus fertilizers on photosynthesis and antioxidant enzyme systems of eggplant seedlings under cadmium stress
This research was conducted in order to investigate the effects of applying different phosphorus fertilizers on photosynthesis and antioxidant enzyme systems of eggplant seedlings under cadmium stress in calcareous soils,and to provide a basis for selecting a reasonable and effective phosphorus fertilizer to alleviate the toxic effects of cadmium.Four kinds of phosphorus fertilizers,including monoammonium phosphate(MAP),calcium superphosphate(SSP),diammonium phosphate(DAP)and calcium hydrogen phosphate(DCP),and four levels of phosphorus application(P 0,0.15,0.25 and 0.35 g·kg-1,which was expressed as P0,P1,P2,P3,respectively)were set up in a pot experiment using eggplant and loess-like calcareous brown soil as experimental materials under soil Cd(5 mg·kg-1 Cd)environment,and the chlorophyll,photosynthesis,malondialdehyde(MDA),superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbate peroxidase(APX)and glutathione reductase(GR)of eggplant seedling leaves were investigated.The results showed that chlorophyll was impaired in eggplant leaves under Cd stress,and chlorophyll content was increased by applying different phosphorus fertilizers,with chlorophyll a,chlorophyll b,carotenoids and total chlorophyll content increasing by 57％,120％,53％and 76％,respectively,at the P3 level of SSP phosphorus application type.All different phosphorus fertilizers significantly increased the intensity of photosynthesis and reduced Cd stress.Specifically,the net photosynthetic rate(Pn)and stomatal conductance(Gs)showed as MAP ≥ DAP ≥ SSP＞DCP,with Pn of 17.4 μmol·m-2·s-1 and Gs of 0.2 mmol·m-2·s-1 at the P3 level of MAP phosphorus application type,transpiration rate(Tr)increased by 165％compared to P0 at the P3 level of DCP phosphorus application type,and intercellular CO2 concentration(Ci)increased most significantly at the P3 level of DAP phosphorus application type,which increased by 28％compared to P0.Phosphorus fertilizer application significantly increased the activity of antioxidant enzyme systems,but different phosphorus fertilizers had different effects on enhancing the activity of antioxidant enzyme systems,with diammonium phosphate showing the most significant decrease in MDA content by 41％;monoammonium phosphate showed the most significant increase in SOD,POD and CAT activities by 43％,106％and 66％,respectively;calcium superphosphate showed the largest increase in APX and GR activities.Calcium superphosphate increased the activity of APX and GR the most,by 54％and 93％,respectively.Therefore,the application of different phosphorus fertilizers could alleviate the toxic effects of Cd stress on eggplant leaves,enhance photosynthesis and increase the effect of antioxidant enzyme activities.
cadmium stressphosphorus fertilizer typephosphorus application leveleggplantphotosynthesisantioxidant enzyme system
万方数据
维普
