| Soil copper (Cu) concentration is one of the evaluation criterions on soil environmental quality. Because of fast development of industry and the widespread application of herbicides and pesticides containing Cu, the area of Cu-contaminated soil is extending every year, and soil Cu concentrations in agricultural soil is increasing as well. As a result, there is a growing public concern about the effect of soil Cu contamination on rice growth and development. In order to? study the dynamics of different Cu fractions in soil and the effect of soil Cu contamination on growth and development of rice, grain yield and its components, dry matter (DM) production and distribution, nitrogen absorption and efficiency, Cu absorption and transport of two Indica rice Aizizhan and Liangyoupeijiu, a soil culture experiment was conducted with 3 levels of soil Cu treatment(CK, no Cu supply, 30.13 mg kg-1; 200 mg kg-1; 400 mg kg-1)in 2006 under mimic-field conditions. The results were expected to provide guidelines in cultivation strategies for area with Cu-contaminated soil. The main results are:1. The content of exchangeable Cu in surface soil was decreasing with time. The content of exchangable Cu in the 200 mg kg-1 soil Cu treatment in the year 2006, 2007, 2008 and 2009 was 1.9, 1.5, 1.3 and 0.8 mg kg-1, respectively, 400 mg kg-1 was 3.7, 2.2, 1.9 and 1.6 mg kg-1, respectively. The content of carbonates-bound Cu befor transplant was significantly lower than that after harvest in each season (befor transplant: June, after harvest: October); In general, the content of Fe-Mn oxides-bound Cu increased with time untill June 2009, then a significant decrease occurred in October 2009 after the rice were harvest; The content of organic matter-bound Cu showed a decrease trend with time untill June 2009, then there was a significant increase in october 2009.2.Compared with the control, both soil Cu treatments prolonged phonological development of rice with heading delayed by ca. 0.7 and 2.3 days and maturity by 1.3 and 4.5 days, at soil Cu concentrations of 200 and 400 mg kg-1, respectively. There was a significant Cu×cultivar interaction for heading and maturation stage, but no significant interaction between Cu and year was detected for the above parameters.3.The influence of soil Cu treatments on plant height ,number of leaves on the main stem and illering number were decreaseing after increasing with growth period (the time of maximum difference: 200 mg kg-1 after transplant 14, 21, 21 d , percentage to CK: 91%, 98%,80%; 400 mg kg-1 after transplant 21, 21, 21 d , percentage to CK: 85%, 96%,58%), the influence on the value SPAD of the function leaves was decreaseing with growth period (the time of maximum difference: 200 and 400 mg kg-1 soil Cu treatments: after transplant 14, 14 d , percentage to CK: 90%,83%); The impact of 400 mg kg-1 Cu treatment was greater than that of 200 mg kg-1, and tere were varying degree effect from year to year: year 2007>2008>2009.4. Averaged across all cultivars tested of three years, both 200 and 400 mg kg-1 soil Cu treatment reduced grain yield by 5% and 13% , the latter reach a significant level. No Cu×cultivar interaction was detected on grain yield, while there was a significant interactive effects between Cu and year for grain yield: 200 mg kg-1 soil Cu treatment reduced the grain yield of 2007 and 2008 by 15% and 6% , increased the grain yield of 2009 by 10%; 400 mg kg-1 soil Cu treatment reduced the grain yield of 2007 and 2008 by 20% and 17% , increased the grain yield of 2009 by 1% .400 mg kg-1 soil Cu treatment decreased the number of panicles per unit area and the number of spikelets per panicle by 7% and 7%, while little effect was found on seed setting rate and 1000-grain weight. No Cu×cultivar interaction was detected on the yield components, while there was a significant interaction between Cu and year for all yield components except for the number of panicles per unit area.5. 200 mg kg-1 soil Cu treatment had no effects on dry matter production and distribution. Averaged across all cultivars tested, 400 mg kg-1 soil Cu treatment reduced plant dry weight at maturation by 15% (P<0.01), decreased the proportion of leaf to the whole plant weight by 6% (P<0.05), increased dry matter distribution ratio in panicle by 3% (P<0.05), while no effect was found on dry matter distribution ratio in root and stem. With the exception of the proportion of leaf to the whole plant weight, no Cu×cultivar interaction was detected for dry matter production and distribution; There was a significant interaction between Cu and year for plant dry weight: the magnitude of the decrease with soil Cu concentration was in the order of 2007> 2008>2009. In contrast, no interaction between Cu and year was observed for dry matter distribution ratios.6. 200 mg kg-1 soil Cu treatment had no effects on N concentration, absorption, distribution and efficiency; Averaged across all cultivars tested, 400 mg kg-1 soil Cu treatment significantly reduced N accumulation in plant and N allocation proportion of leaf by 18% and 13%, respectively, while significantly increased N allocation proportion of spike and nitrogen harvest index all by 4%, no effect was found on other N concentration, absorption, distribution and efficiency. No Cu×cultivar interaction was detected for the above parameters, while there was a significant interaction between Cu and year for the above parameters(except for allocation proportion of leaf and spike, nitrogen harvest index ).7. Averaged across all cultivars tested, 200 mg kg-1 soil Cu treatment significantly increased Cu content, absorption, allocation proportion of root, allocation proportion of stem by 228%, 206%, 81% and 41%, respectively, 400 mg kg-1 soil Cu treatment significantly increased the above parameters by 424%, 343%, 106% and 60%, respectively; 200 mg kg-1 soil Cu treatment significantly decreased Cu, leaf and spike by 48% and 43%, respectively, 400 mg kg-1 soil Cu treatment significantly decreased the above parameters by 62% and 60%, respectively. There was a significant interaction between Cu and cultivar for the above parameters(except for allocation proportion of stem and spike), and a significant interaction between Cu and year was detected for the above parameters(except for allocation proportion of leaf ). |
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