不同芹菜品种镉吸收和运转差异研究

Differences of celery cultivars in cadmium absorption and accumulation

【目的】研究镉胁迫下芹菜生长、镉吸收和向上运转品种间差异,为筛选镉低积累型芹菜品种减少镉对人体的危害提供依据。【方法】以10个芹菜品种为试材进行基质无土栽培试验,基质为蛭石,营养液采用1/2华南农业大学叶菜类营养液配方,以只浇灌营养液的处理作为对照,浇灌含15 mg/L氯化镉(CdCl2)的营养液为Cd胁迫处理;每3 d浇灌一次,每次浇灌0.2 L,累计浇灌15次,每盆Cd施用量为45 mg。移栽45 d后,测定生长指标与根、叶柄和叶片Cd含量。计算相对生长量(relative growth yield,RGY)和转运系数(translocation factor,TF),并筛选出高、低Cd积累品种。分别对高、低Cd积累品种进行穴盘基育苗,14d后采用华南农业大学叶菜类营养液配方进行营养液栽培,21 d后利用非损伤微测技术(non-invasive micro-test technology,NMT)测定根系分生区、伸长区和根毛区Cd^(2+)离子流速。【结果】与非Cd胁迫相比,Cd胁迫使‘速生四季西芹王’、文图拉西芹’、‘四季小香芹’、‘实心香芹’、‘雪白芹菜’地下部受到显著抑制,对地上部无显著影响;Cd胁迫促进了‘四季小香芹’地上部生长;而‘种都金黄芹菜’、‘红芹’、‘鲍芹’地上部受到显著抑制,对地下部则无显著影响;‘马家沟芹菜’和‘速生香芹’地上部和地下部均生长均受到抑制。食用器官叶柄中Cd含量以‘种都金黄芹菜’和‘雪白芹菜’最高;‘速生香芹’和‘实心香芹’最低。地上部Cd含量高的‘种都金黄芹菜’和‘雪白芹菜’对Cd转运能力也最高;Cd含量低的‘速生香芹’对Cd转运能力也最低。在根系成熟区(根毛区),‘种都金黄芹菜’较‘速生香芹’有更高Cd^(2+)离子流速。【结论】Cd胁迫下,芹菜不同品种生长、Cd吸收、转运和积累存在显著差异。‘四季小香芹’、‘速生四季西芹王’、‘文图拉芹菜’、‘实心香芹’和‘雪白芹菜’较为耐镉;而‘种都金黄芹菜’、‘红芹’、‘鲍芹’、‘马家沟芹菜’和‘速生香芹’对镉敏感。‘雪白芹菜’和‘种都金黄芹菜’为高Cd积累型,‘实心香芹’和‘速生香芹’为低Cd积累型,其中‘实心香芹’表现为低Cd含量和高生长量。高Cd积累型芹菜较低Cd积累型芹菜有更强Cd^(2+)吸收能力和Cd转运能力,根部Cd^(2+)流速可用于低积累品种的快速筛选。

【Objectives】Crop cultivars are different in Cd absorption and up translocation.Studying the differences and the suitable index will support the selection of suitable cultivars,though which to minimize the Cd content and provide safe crop productions.【Methods】Ten celery cultivars were chosen as materials for a hydroponic culture experiment with substrates of vermiculite.The 1/2 South China Agricultural University leafy nutrient solution was used as a control,and treatment solution containing 15 mg/L of cadmium chloride(CdCl2)were prepared at the base of control solution.0.2 L of solution was watered every 3 days for each pot during 45 days’growth of celeries,with a total input of Cd 45 mg/pot.The growth index and Cd content in roots,petioles and leaves of celeries were determined;the relative growth yield(RGY)and translocation factor(TF)was calculated,and celeries with different Cd-accumulation levels could be identified.The high-and low-Cd accumulation cultivars were selected and grown in plug trays.The seedlings were watered with the nutrient solution until 14 days,then watered with Cd-containing solution as before.After 21 days’treatment,the Cd2+flow rate in root meristem,elongation zone and root hair zone was determined using Non-invasive Micro-test Technology(NMT).【Results】The growth and Cd accumulation in shoots and roots of celeries were significantly different under the Cd stress.The for cultivar‘Sushengsiji xiqinwang’,‘Wentula xiqin’,‘Siji xiaoxiangqin’,‘Shixin xiangqin’and‘Xuebai qincai’,their root growth were significantly reduced but their shoots were not by Cd stress,and the shoot growth of‘Siji xiao xiangqin’was even promoted;For cultivar‘Zhongdujinhuang qincai’,‘Hongqin’and‘Baoqin’,in contrast,their shoot growth were significantly reduced but their roots were not by Cd stress;While for cultivar‘Majiagou qincai’and‘Susheng xiangqin’,both the root and shoot growth significantly reduced by Cd stress.The Cd concentrations in leaf stalks,the edible organ,were higher in‘Zhongdujinhuang qincai’and‘Xuebai qincai’,and those were lower in‘Susheng xiangqin’and‘Shixin qincai’.The higher Cd concentration in leaf stalks represented higher capacity of Cd transportation.The Cd2+flux rate in root hair zone of‘Zhongdujinhuang qincai’was greater than that of‘Susheng xiangqin’.【Conclusions】There are significant differences in growth,Cd absorption,transportation and accumulation among celery cultivars under Cd stress.‘Sijixiao xiangqin’,‘Sushengsijixi qinwang’,‘Wentula qincai’,‘Shixin xiangqin’and‘Xuebai qincai’are tolerance cultivars,and‘Zhongdujinhuang qincai’,‘Hongqini’,‘Baoqin’,‘Majiagou qincai’and‘Susheng xiangqini’are sensitive cultivars to Cd stress.‘Xuebai qincai’and‘Zhongdujinhuang qincai’are high Cd accumulation cultivars,where as‘Shixin xiangqin’and‘Susheng xiangqin’are low Cd accumulation ones.‘Shixinxiangqin’shows low Cd accumulation and high growth.Cultivars with high Cd concentration in shoots have strong capacities of Cd absorption in roots and transportation from roots to shoots.The Cd2+flux rate in roots could be used to rapid screen low Cd transport and accumulation celery cultivars.