铊胁迫下甘蓝根系有机酸分泌特征及对铊吸收的影响

Characteristics of Organic Acid Secretion in Cabbage Roots Under Thallium Stress and Its Effect on Thallium Absorption

为促进食品安全评估,本研究采用火焰原子吸收分光光度法测定了甘蓝不同部位对重金属铊的吸收能力;并利用高效液相色谱法测定两种阴离子通道抑制剂Niflumic acid(NIF)、Phenylglyoxal(PG)添加前后的甘蓝根系有机酸分泌特征及对铊吸收量的影响,探究甘蓝富集铊的吸收机制。结果表明:甘蓝在铊胁迫下根系分泌唯一有机酸-草酸,并随处理时间延长,草酸分泌量增大;阴离子通道抑制剂NIF明显抑制甘蓝根系内部有机酸分泌量,同时明显降低甘蓝根系对铊的吸收量,进而减少地上茎叶部的铊含量。铊胁迫下甘蓝根系草酸分泌模式初步确定为延迟分泌Ⅱ型,根系有机酸含量将影响甘蓝对铊的吸收。

In order to promote food safety assessment,the absorption capacity of thallium in different parts of cabbage was determined by flame atomic absorption spectrophotometry.High performance liquid chromatography(HPLC)was used to determine the characteristics of acid secretion in cabbage roots before and after the addition of two anionic channel inhibitors,niflumic acid(NIF)and phenylglyoxal Chinese(PG),and the effects on thallium absorption,the absorption mechanism of thallium in cabbage was explored.The results showed thatthe roots system secreted the unique organic acid-oxalate under thallium stress and the amount of oxalate increased companying with the treated time.Anion channel inhibitor NIF significantly inhibited the secretion of organic acids in cabbage roots and significantly decreased thallium uptake of cabbage roots,thereby reduced thallium contents in cabbage stems and leaves.Above all,the secretion pattern of oxalate in cabbage roots under thallium stress was the delayed secretion type II,and the content of organic acid in cabbage roots would affect the uptake of thallium in cabbage.