外源甜菜碱对苋菜抗盐性与累积重金属特性的影响

用不同盐分(0.2%、0.4%)、重金属污染土壤进行盆栽实验,研究叶面喷施不同浓度甜菜碱(GB,1、10、50 mmol·L-1)对苋菜抗盐性与重金属累积的影响.结果表明,0.4%重度盐分胁迫下,喷施50 mmol·L-1甜菜碱可大幅提高苋菜茎叶部游离脯氨酸和总游离氨基酸含量;盐分胁迫抑制了苋菜根系对Ca、Mg、K、Fe的吸收,而叶面喷施甜菜碱可显著增强对Ca、Mg、K、Fe的吸收,K/Na、Ca/Na比值随着甜菜碱剂量的增加而逐渐增大.在0.4%盐分下,喷施50 mmol·L-1甜菜碱促使根系K/Na、Ca/Na比值分别增加了40.4%、34.1%,说明盐分越高,外源甜菜碱对苋菜抗盐性更明显.盐分胁迫下,外源甜菜碱明显提高了苋菜根系重金属Cd、Cr、Pb、Cu、Zn的含量.在0.4%盐分与喷施50 mmol·L-1甜菜碱条件下,苋菜根系对各重金属的累积增幅分别为22.1%、127.1%、63.4%、61.1%、56.1%.由根系重金属与盐分离子的相关性分析可知,0.4%盐分处理后,Pb、Cr、Cu、Zn与盐分离子、重金属的吸收变化呈显著正相关(p0.01);而在0.2%盐分处理下,只有Na与Ca、Cd与Cr、Cu与Zn的吸收变化呈显著正相关(p0.01).说明盐分含量较高,外源甜菜碱对苋菜抗盐胁迫效果越明显,对必需元素及其伴随吸收的非必需重金属元素吸收增加也越明显.

Effect of exogenous glycinebetaine on the salinity tolerance and heavy metals accumulation of edible amaranth

A pot experiment was used to investigate the effect of exogenous glycinebetaine on the salt tolerance and heavy metals accumulation of edible amaranth under the soil salinity of 0.2% and 0.4% and glycinebetaine concentration of GB/1 mmol · L^-1, 10 mmol · L^-1 and 50 mmol · L^-1 spraying on foliage. Result showed that:1Under severe salt treatment, spraying 50 mmol · L^-1 glycinebetaine significantly improved the concentration of free proline and total free amino acid in the shoot of amaranth. Salinity stress depressed the absorption of Ca, Mg, K and Fe significantly, whereas the opposite effect was shown after the treatment of exogenous glycinebetaine. At the salinity of 0.4% and spraying 50 mmol · L^-1 glycinebetaine, the ratio of K and Na, Ca and Na increased by 40.4% and 34.1% in the root, respectively. This indicated that the higher soil salinity was, the more effective glycinebetaine to salinity tolerance of crop. 2After salinity treatment, exogenous glycinebetaine improved the absorption and accumulation of Cd, Cr, Pb, Cu and Zn by crop. At 0.4% salinity and 50 mmol · L^-1 glycinebetaine treatment, the concentration of Cd, Cr, Pb, Cu and Zn in root was promoted by 22.1%, 127.1%, 63.4%, 61.1% and 56.1%, respectively, comparing with the controls. 3 From the correlation analysis of salt ions and heavy metals concentrations in root, the concentrations of Pb, Cr, Cu and Zn displayed significantly positive correlation with saline ions and other heavy metals at 0.4% salinity treatment (p <0.01), while only significantly positive correlation between Na and Ca, Cd and Cr, and Cu and Zn was observed at 0.2% salinity (p <0.01). Results implied that at higher soil salinity, exogenous glycinebetaine can improve crop salinity tolerance and uptake of essential elements, thereby increasing heavy metal accumulation of crop.