菠菜和小白菜对核素锶的吸附与富集作用

Spinach and Chinese cabbage on the uptake and accumulation of strontium

目的:研究菠菜和小白菜对核素锶(Sr)的吸附与富集作用,探索核素锶从土壤到植物中的转移过程和特征,寻找核素锶在土壤-植物系统中的迁移规律。方法:选用稳定性核素^(88)Sr代替放射性核素^(90)Sr进行室内盆栽种植菠菜和小白菜。试验共分6个组即5个试验组和1个对照组,每组设3个平行样。试验组分别为盆栽土壤中锶元素本底浓度的1.5、2.0、2.5、3.0和3.5倍,其含量分别为318.67、478.00、637.33、796.67、956.00 mg/kg。对照组土壤在避光通风处自然风干,捣碎过30目筛后直接应用。试验期间定期浇灌去离子水。在种植的第30天取样,分别剪取植株地上(茎、叶)部分和地下根部,烘干、粉碎、消化后定容至10 mL。采用电感耦合等离子体发射光谱法(ICP-AES)检测两种蔬菜和土壤中核素锶、钙和铁的含量,并计算两种蔬菜中锶与钙、铁元素之间的相关性及对锶的富集率(CR)。结果:经不同浓度核素锶处理后,与对照组相比,两种蔬菜中核素锶的含量除了低浓度组(318.67 mg/kg)外,其他各组均显著升高,且随着浓度增加而增加(P<0.05),高浓度组(796.67和956.00 mg/kg)中菠菜锶含量显著高于小白菜(P<0.05);小白菜茎叶部分锶含量与钙元素含量呈负相关(r=-0.198),菠菜根部锶含量与铁亦呈负相关(r=-0.271),其余均为正相关关系;两种蔬菜对核素锶的富集率,除了菠菜低浓度组(318.67 mg/kg)和小白菜低浓度组(318.67和478.00 mg/kg)外,其他各组与对照组相比均显著升高,差异均有统计学意义(P<0.05);两种蔬菜之间富集率相比,在高浓度组(796.67和956.00 mg/kg)中菠菜对锶的富集率显著高于小白菜(P<0.05)。结论:菠菜和小白菜对稳定性核素锶均有较强的富集和吸附作用,且高浓度组的菠菜对锶的富集率显著高于小白菜。

OBJECTIVE：We studied spinach and Chinese cabbage on the uptake and accumulation of strontium,explore the transfer process and characteristics of strontium from soil to plant,looking for migration of strontium in soil-plant system.METHODS：We chose stable nuclide ^88Sr instead of ^90Sr and used potted plants of spinach and Chinese cabbage in greenhouse.There were 5 experimental groups and a control group,each of which had three parallel samples.Strontium in the experimental groups contained in the potting soil concentrations of 1.5 times,2.0times,2.5 times,3.0 times,3.5 times,equivalent to strontium in soil of 318.67,478.00,637.33,796.67,956.00mg/kg,respectively.The soil of the control group was natural air drying in shade,being mashed before being sifted by the30 specifications sieve and was used directly.During the experiment,we irrigated the plants with deionized water.When the plants grow 30 days after seeding,we collected the stem and leaf on the ground and roots underground.After drying,crushing and digestion,it was set suspended in 10 mL solvent.All the strontium concentrations in the plants and the soil were measured with the inductively coupled plasma atomic emission spectrometry（ICP-AES） in this experiment,and the strontium concentration ratio（CR） of the two vegetables was calculated.The accumulation characteristics of strontium in soil-plant system was studied.RESULTS：The strontium content in plant rose with increasing concentration in soil.The CR values of two vegetables,except for the low concentration group（318.67mg/kg）,showed significant differences（P〈0.05） compared with the control group.The CR values of the high concentration group of spinach（697.67 and 956.00 mg/kg） were significantly higher than that of strontium in Chinese cabbage（P〈0.05）.Strontium and calcium contents of Chinese cabbage stems and leaves,and spinach root strontium and iron contents showed a negative correlation,and the rest had positive correlations.The concentration rate of strontium of the two kinds of vegetables,except for the spinach low concentration group（318.67 mg/kg） and Chinese cabbage low concentration groups（318.67 and 478.00 mg/kg）,other groups were significantly increased compared with the control group（P〈0.05）.Between the two kinds of vegetables,strontium concentration rate of high concentration group of spinach（796.67 and956.00 mg/kg） was significantly higher than Chinese cabbage（P〈0.05）.CONCLUSION：Spinach and Chinese cabbage showed great uptake and accumulation of stable strontium.The CR values of strontium in the high concentration group of spinach were significantly higher than that of Chinese cabbage.