外源铬胁迫下施磷对小白菜生长和铬吸收的影响

Effects of phosphorus fertilizer application on pakehoi growth and Cr uptake under exogenous Cr stress

采用土培盆栽试验和室内分析相结合的方法研究了塿土外源Cr(Ⅲ)添加和施磷对小白菜植株和土壤Cr形态的影响.结果表明:外源Cr添加使小白菜植株鲜质量、干质量、含水率和叶片SPAD值显著降低,使塿土土壤水溶态Cr、交换态Cr和全Cr含量显著增加,土壤速效磷含量显著下降.外源Cr胁迫下,小白菜植株鲜质量、干质量、含水率和叶片SPAD值随磷肥用量增加而显著增加;磷肥施用量大于33mg/kg后,小白菜植株全Cr含量明显下降.外源Cr胁迫下,土壤水溶态Cr含量随施磷量增加逐渐减小,施磷量高于33mg/kg后,含量趋于稳定;土壤交换态Cr则表现出先减小,然后又逐渐增加的趋势,施磷量在11mg/kg和33mg/kg时其含量最低.磷肥施用可以降低土壤活性Cr含量,削弱Cr对叶片合成叶绿素的毒害作用,减少小白菜植株对Cr的吸收,有效促进小白菜植株生长.

Effects of application of exogenous Cr（Ⅲ）and phosphorus fertilizer on pakehoi growth and soil Cr form were studied by the pot experiment combining with lab analysis.The results showed that fresh weight,dry weight and water content of pakehoi plant,the SPAD value of leaf,and soil available P significantly reduced.Soil water soluble Cr,exchangeable Cr and total Cr significantly increased by the application of exogenous Cr.The fresh weight,dry weight,and water content of pakchoi plant,the SPAD values of pakchoi leaves significantly increased with the increasing of P fertilizer application rates under exogenous Cr stress.Cr uptake of Pakchoi plant reduced by P application,and the total Cr concentration of pakchoi plant significantly declined after the P application was more than 33mg/kg under exogenous Cr stress.Soil water soluble Cr decreased gradually with the increasing of P fertilizer application rates,and kept stable after theP application rate was more than 33 mg/kg under exogenous Cr stress.Soil exchangeable Cr decreased first,and then increased with the increasing of P fertilizer application rates,which was the lowest under the P application of 11mg/kg and 33mg/kg.P fertilizer application could reduce the soil available Cr,weaken the toxic action of Cr to chlorophyll synthesis of leaves,decrease the Cr uptake of pakchoi plant,and promote the growth of pakchoi plant effectively.