4种蔬菜对硒酸盐的吸收、富集与转运特征的研究

Absorption,Bioaccumulation and Translocation of Selenium in Four Different Vegetables by Applying Selenate

用盆栽试验研究了不同含量硒酸钠对4种蔬菜(小白菜、芥菜、生菜和菠菜)生长、硒吸收及转运特征的影响,为富硒蔬菜的开发和硒污染土壤的植物修复提供理论依据。结果表明,低含量的硒酸钠态硒(<1.45mg·kg-1)可促进4种蔬菜的根和茎的生长,增加其生物量,但过量硒酸态硒(>2.04mg·kg-1)对蔬菜有明显的毒害作用。供试的4种蔬菜地上、地下部硒含量均随外源硒含量的增加显著增大(P<0.01),其中小白菜和芥菜地上硒含量是生菜和菠菜的5.8～8.5倍;4种蔬菜地下部硒含量的大小依次为芥菜>小白菜>菠菜>生菜。所有施硒处理小白菜、芥菜和生菜地上硒含量约是地下硒含量的1～2倍,菠菜地上与地下硒含量与土壤硒含量高低有关,当土壤硒含量<5.02mg·kg-1时,菠菜的地下硒含量大于地上部,当土壤中硒含量>5.02mg·kg-1时,地上部硒含量大于地下部。4种蔬菜相比较,地上部硒富集系数(BCFshoot/soi)l值的大小依次为小白菜≈芥菜>菠菜>生菜,地下部富集系数(BCFroot/soi)l值的大小依次为芥菜>小白菜>菠菜>生菜;以小白菜对硒的转运系数(TF)值最大,菠菜最小。供试的4种蔬菜中,小白菜因具有较高的将六价硒从地下转运到地上的能力,且拥有较高的地上生物量,可作为富硒蔬菜和硒污染土壤修复植物。

Pot experiment was carried out to study effects of different levels of selenate applicated to soil on selenium absorption and translocation in four vegetables（pak choi,mustard,lettuce and spinach）.The objective of the study was to provide the theoretical basis for selecting vegetables which have higher capacity for selenium enrichment and phytoremediation of soil contaminated by selenium.The results showed that lower selenate supply rates（1.45 mg·kg-1） stimulated the growth of four vegetables,but higher selenate supply rates（2.04 mg·kg-1） exerted toxic effects on vegetables.Selenium concentrations in shoots and roots of four vegetables increased with the increasing of selenate levels in soil（P0.01）.Among four tested vegetables,selenium concentrations within pak choi and mustard shoots were 5.8~8.5 times greater than those within lettuce and spinach.The selenium concentrations in roots of the four vegetables showed the follows sequence：mustardpak choispinachlettuce.For different treatments with selenate application rates,selenium concentrations in shoot were 1~2 times greater than those in roots of pak choi,mustard and lettuce.Selenium concentrations in shoot and root of spinach were related to selenate application rates in soil.When selenate application rates in soil were less than 5.02 mg·kg-1,selenium concentrations in root of spinach were larger than those in shoot,while selenate application rates in soil were more than 5.02 mg·kg-1,selenium concentrations in shoot of spinach were larger than those in roots.BCFshoot/soil（Ratio of selenium concentrations in shoot to selenate application rates to soil） of shoots of four vegetables showed the follows order：pak choi≈mustardspinachlettuce,and that sequence of roots was as：pak choi mustardspinachlettuce.Overall comparison results illustrated that,pak choi had the greatest level of TF（BCFshoot/soil/BCFroot/soil）,while that of spinach showed the smallest.Thus,pak choi was the most suitable species among four tested vegetables to eliminate soil selenium contamination because of its relatively larger biomass and better selenium translocation capacity.