Chen Mingxue

Using iron fertilizer to control Cd accumulation in rice plants: A new promising technology

Effects of two kinds of iron fertilizer, FeSO4 and EDTA·Na2Fe were studied on cadmium accumulation in rice plants with two rice genotypes, Zhongzao 22 and Zhongjiazao 02, with soil culture systems. The results showed that application of iron fertilizers could hardly make adverse effects on plant growth and rice grain yield. Soil application of EDTA·Na2Fe significantly reduced the Cd accumulation in rice roots, shoots and rice grain. Cd concentration in white rice of both rice genotypes in the treatment of soil application of EDTA·Na2Fe was much lower than 0.2 mg/kg, the maximal Cd permission concentration in cereal crop foods in State standard. However, soil application of FeSO4 or foliar application of FeSO4 or EDTA·Na2Fe resulted in the significant increase of Cd accumulation in rice plants including rice grain compared with the control. The results also showed iron fertilizers increased the concentration of iron, copper and manganese element in rice grain and also affected zinc concentration in plants. It may be a new promising way to regulate Cd accumulation in rice grain in rice production through soil application of EDTA·Na2Fe fertilizers to maintain higher content of available iron and ferrous iron in soils.

Effect of Triazophos Degradation on Chlorophyll Content in Rice (Oryza sativa L.)and Their Correlation Study

Field experiments were conducted to study the effect of triazophos degradation on chlorophyll content,and the correlation between triazophos degradation ratio and change ratio of chlorophyll content in leaves of two rice varieties(Nei2you6,Xiushui09),which were treated with triazophos at two concentrations(2 250 mL hm-2 and 4 500 mL hm-2) at previously ripening stage.The results showed that triazophos affected chlorophyll content and its effect increased with the increasing of triazophos concentration.The time effect of triazophos on chlorophyll content was different between Nei2you6(20 d) and Xiushui09(20 d).Triazophos caused significant variation in chlorophyll content between the two varieties with time.The chlorophyll content of the two varieties treated with triazophos did not statistically show significant difference against CK(P0.05) after spraying triazophos.During the period from day 3 to 14 after spraying,the chlorophyll content decreased in Nei2you6,but increased in Xiushui09 compared with the CK(P0.05) respectively.The chlorophyll content in Nei2you6 and Xiushui09 did not change significantly and increased significantly compared with CK(P0.05) at day 21 after triazophos was sprayed.Generally,triazophos degradation ratio was correlated with change ratio of chlorophyll content,but the correlation was significantly different between the two varieties,that is,negative correlation existed for Nei2you6 and positive for Xiushui09.