不同重金属胁迫对盐生草种子萌发特性的影响

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胡娜, 李葆春, 姚立蓉, 汪军成, 边秀秀, 侯静静, 司二静, 杨轲, 孟亚雄, 马小乐, 王化俊. 不同重金属胁迫对盐生草种子萌发特性的影响. 草业学报, 2019,28(6): 66-81
HU Na, LI Bao-chun, YAO Li-rong, WANG Jun-cheng, BIAN Xiu-xiu, HOU Jing-jing, SI Er-jing, YANG Ke, MENG Ya-xiong, MA Xiao-le, WANG Hua-jun. Effects of different heavy metals on the seed germination and establishment of Halogeton glomeratus . Acta Prataculturae Sinica,2019,28(6): 66-81 复制到剪切板

Doi:10.11686/cyxb2019012
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不同重金属胁迫对盐生草种子萌发特性的影响

胡娜^1,^2,^**, 李葆春^1,^3,^**, 姚立蓉^1,², 汪军成^1,², 边秀秀¹, 侯静静^1,², 司二静^1,², 杨轲^1,², 孟亚雄^1,², 马小乐^1,², 王化俊^1,^2,^*

1.甘肃省干旱生境作物学重点实验室,甘肃省作物遗传改良与种质创新重点实验室,甘肃兰州730070

2.甘肃农业大学农学院,甘肃兰州 730070

3.甘肃农业大学生命科学技术学院,甘肃兰州 730070

*通信作者 E-mail: whuajun@yahoo.com

作者简介:胡娜(1993-),女,甘肃庆阳人,在读硕士。E-mail: 2524768559@qq.com;李葆春(1971-),女,甘肃陇南人,副教授,博士。E-mail: libc@gsau.edu.cn。
**共同第一作者

收稿日期: 2019-01-03

基金项目:甘肃农业大学学科建设专项基金(GAU-XKJS-2018-082、083),国家大麦青稞产业技术体系(CARS-05-03B-03),甘肃省重大专项(17ZD2NA016)和甘肃农业大学盛彤笙创新基金(GSAU-STS-2018-33)资助

摘要

以盐生植物盐生草为材料,研究不同重金属胁迫下其种子萌发特性,探讨盐生草种子萌发期对不同重金属的耐受程度,旨在为盐生草对重金属污染土壤修复提供理论依据。以5种主要土壤重金属污染物(Cu、Zn、Ni、Cd、Pb)胁迫处理盐生草种子,对其发芽率、发芽势、株高、鲜重、干重、根系活力和离子含量进行测定,并对以上指标进行聚类分析和主成分分析。结果表明:在5种不同重金属胁迫下,低浓度处理对盐生草种子萌发影响较小,高浓度则产生抑制作用;但是其对幼苗生长指标的影响不同,其中,株高、鲜重和根系活力在低浓度Zn²⁺、Pb²⁺处理下与对照差异不显著,但在5.00 mmol·L^-1 Zn²⁺和3.00 mmol·L^-1 Pb²⁺胁迫下显著降低,以上指标均低于各重金属胁迫下对照的55%和52%;低浓度Cu²⁺、Ni²⁺、Cd²⁺显著抑制盐生草幼苗的株高、鲜重和根系活力,且分别在3.00 mmol·L^-1 Cu²⁺和Ni²⁺、0.20 mmol·L^-1 Cd²⁺胁迫下降低最为显著,株高、鲜重和根系活力均低于各金属胁迫下对照的40%、46%和53%;组织内各金属离子含量随处理浓度的升高而增大,同时在5.00 mmol·L^-1 Zn²⁺,3.00 mmol·L^-1 Pb²⁺、Cu²⁺、Ni²⁺和0.20 mmol·L^-1 Cd²⁺胁迫下升高幅度最大。聚类分析结果显示,以3.00 mmol·L^-1 Zn²⁺,1.00 mmol·L^-1 Pb²⁺、Cu²⁺、Ni²⁺ 和0.10 mmol·L^-1 Cd²⁺为结点,将各金属胁迫浓度聚为两类,并对上述结点下各指标进行主成分分析,发现在重金属Zn²⁺、Pb²⁺、Ni²⁺胁迫下,发芽指标贡献率最大,Cu²⁺、Cd²⁺胁迫下,生物量指标贡献率最大。上述结果说明,在重金属Zn²⁺浓度低于3.00 mmol·L^-1,Cu²⁺、Ni²⁺和Pb²⁺浓度低于1.00 mmol·L^-1,Cd²⁺浓度低于0.10 mmol·L^-1的处理环境下,其对盐生草种子萌发和幼苗生长的影响较小;发芽指标可首选为评价盐生草萌发期耐重金属Zn²⁺、Pb²⁺和Ni²⁺的重要参数,生物量可首选为评价盐生草萌发期耐重金属Cu²⁺和Cd²⁺的重要参数。

关键词: 土壤污染; 重金属; 盐生草; 种子萌发; 主成分分析

Effects of different heavy metals on the seed germination and establishment of Halogeton glomeratus

HU Na^1,^2,^**, LI Bao-chun^1,^3,^**, YAO Li-rong^1,², WANG Jun-cheng^1,², BIAN Xiu-xiu¹, HOU Jing-jing^1,², SI Er-jing^1,², YANG Ke^1,², MENG Ya-xiong^1,², MA Xiao-le^1,², WANG Hua-jun^1,^2,^*

1.Gansu Provincial Key Lab of Aridland Crop Science, Gansu Provincial Key Lab of Crop Improvement & Germplasm Enhancement, Lanzhou 730070, China

2.College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China

3.College of Life Sciences and Techonlogy, Gansu Agricultural University, Lanzhou 730070, China

* Corresponding author. E-mail: whuajun@yahoo.com

**These authors contributed equally to this work.

Abstract

In order to better understand the tolerance of halophyte Halogeton glomeratus to different heavy metals, this research focused on its seed germination and seedling growth when exposed to different heavy metal stresses. Indicators of seed germination and seedling growth, including the germination percentage, germination energy, plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus seeds treated with five major soil heavy metal pollutants (Cu, Zn, Ni, Cd, Pb), were measured and data analysed by cluster and principal component analyses. It was found that lower concentrations of the five different heavy metals had little effect on seed germination, while higher concentrations had an inhibitory effect. However, the effects on seedling growth index were different. The plant height, fresh weight and root activity showed no significant difference under the lower concentrations of Zn²⁺ and Pb²⁺, but showed a significant decrease under the lower concentrations of Cu²⁺, Ni²⁺ and Cd²⁺.Especially, the decrease was most obvious at 5.00 mmol·L^-1 Zn²⁺, 3.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.20 mmol·L^-1 Cd²⁺, and which is the lowest concentration of inhibition effect. The plant height, fresh weight, dry weight, root activity and ion content were lower than the control under the concentration of 5.00 mmol·L^-1 Zn²⁺, all of them showing a decrease to 55%, and which showed a decrease to 52%, 40%, 46% and 53% of the control for 3.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.20 mmol·L^-1 Cd²⁺, respectively. Furthermore, the ion contents of the plant tissue increased with increase in heavy metal concentrations, and these increases first became obvious at 5.00 mmol·L^-1 Zn²⁺, 3.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.20 mmol·L^-1 Cd²⁺. On cluster analysis, the metal stress concentrations were clustered into two categories based on 3.00 mmol·L^-1 Zn²⁺, 1.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.10 mmol·L^-1 Cd²⁺, respectively. In addition, the principal component analysis showed that germination indices are mainly affected by Zn²⁺(PCA 1), Pb²⁺ (PCA 1) and Ni²⁺(PCA 1+PCA 2) treatments, and biomass has most affected by the Cu²⁺(PCA 1+PCA 2) and Cd²⁺(PCA 1+PCA 2)treatments.These results indicated that there was little effect on seed germination and seedling growth of H. glomeratus while the heavy metal concentrations were lower than 3.00 mmol·L^-1 Zn²⁺, 1.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.10 mmol·L^-1 Cd²⁺. The germination indexes can be used for evaluating the tolerance of H. glomeratus to Zn²⁺, Pb²⁺ and Ni²⁺ during the germination period, and biomass can be used to evaluate the tolerance of H. glomeratus to Cu²⁺ and Cd²⁺.

Keyword: soil pollution; heavy metals; Halogeton glomeratus; seed germination; principal component analysis

文章图片

近年来随着城市化、工业化进程不断加快, 重金属在土壤中大量富集, 其不但破坏生态环境, 还影响植物生长发育, 进入食物链最终危害人体健康^{[1, 2]}。目前全世界约1× 10⁷ hm²的土壤遭受重金属污染, 我国受重金属污染的耕地约占总耕地面积的1/6, 由重金属污染导致的作物产量下降超过1× 10⁸ t· yr^-1, 造成经济损失达2× 10¹⁰元^{[3, 4]}。因此, 充分利用土地资源, 进行经济有效的土壤重金属污染修复, 对改善生态环境, 保证农业可持续发展和人类健康具有重要意义。

重金属是指密度大于5的金属元素, 主要包括镉(Cd)、砷(As)、铅(Pb)、铬(Cr)、汞(Hg)以及有一定毒性的铜(Cu)、锌(Zn)、镍(Ni)等^[5]。重金属污染具有富集性、不可逆性和难治理等特点, 目前国际上治理土壤重金属污染的方法主要有物理化学修复、微生物修复、植物修复和农业措施修复等^{[6, 7, 8]}。相较于其他修复方法, 植物修复法具有保护土壤微环境、耗费低、适应性强、无二次污染物等优点^[9], 因此, 通过种植绿色植物来隔离或解毒土壤重金属污染似乎有望比传统技术更经济, 更有效, 更环保。近年来, 植物修复土壤重金属污染的研究方兴未艾, 例如景天科的东南景天(Sedum alfredii)是一种已被鉴定的锌和镉超积累植物, 能在富含锌、镉、镍的土壤上正常生长^[10]。相对甜土植物, 盐生植物在进化上形成特殊的信号转导途径和离子运输调控机制^[11], 在土壤盐碱地改良、重金属污染修复等方面发挥着重要作用^[12]。

种子在不同重金属胁迫状况下的萌发特性以及萌发期对不同重金属的耐性程度直接影响着植株的生长发育, 因此, 植物的早期生长阶段是决定重金属对植物毒性作用的重要指标。当植物体内重金属过量、超过某一临界值, 会对植物产生胁迫作用, 导致其体内代谢紊乱, 生长发育受到抑制, 研究表明, Zn²⁺对紫花苜蓿(Medicago sativa)种子萌发和幼苗生长具有“ 低促高抑” 的毒物刺激效应, 且对幼苗根生长的抑制程度大于幼苗芽的生长^[13]。Cu²⁺导致野生赖草(Leymus secalinus)胚芽中MDA含量升高, 对胚芽产生损害作用^[14]。高浓度 Cd²⁺、Zn²⁺ 对烟草(Nicotiana tabacum)种子造成氧化损伤, 使其抗氧化酶活性降低, 代谢紊乱^[15]。禾本科植物在高浓度Cu²⁺、Cd²⁺ 和 Pb²⁺ 胁迫下出现“ 无根苗” ^[16]。

盐生植物盐生草(Halogeton glomeratus), 隶属藜科(Chenopodiaceae)盐生草属(Halogeton), 是一年生草本植物。为干旱、半干旱区广布的荒漠物种, 主要生长于蒙古、中亚及我国西北旱区等地^{[17, 18]}, 地上多分枝的肉质化茎、叶组织具有耐盐抗旱、富集重金属等特性。本实验室前期研究表明, 盐生草通过将盐分区隔在液泡内而具有较强的耐盐特性, 其不但在盐渍地生长良好, 且为金属矿区优势种群^{[19, 20]}, 是理想的进行土壤重金属污染修复的野生资源, 但关于盐生草萌发期对不同重金属的耐性还未知。鉴于此, 本研究从修复重金属污染土壤角度出发, 以我国西北旱区特色盐生植物盐生草为材料, 模拟土壤重金属污染, 对盐生草种子进行不同类型及浓度的重金属胁迫, 研究其在不同重金属胁迫下的种子萌发及幼苗生长特性, 并结合聚类分析和主成分分析, 探索其萌发期对不同重金属的耐受性以及各指标的相对贡献率, 以期进一步提高盐生草利用价值, 并为重金属污染土壤改良提供理论依据。

1 材料与方法

1.1 试验材料

试验于2018年7-9月在甘肃农业大学甘肃省干旱生境作物学重点实验室麦类遗传育种实验室进行, 供试材料为2017年采集于甘肃省民勤县戈壁滩的盐生草种子, 千粒重为0.38 g, 室温干燥保存。

1.2 供试试剂

硫酸铜(CuSO₄· 5H₂O)、硫酸锌(ZnSO₄· 7H₂O)、氯化镍(NiCl₂· 6H₂O)、硫酸镉(Cd₃O₁₂S₃· 8H₂O)、氯化铅(PbCl₂), 次氯酸钠溶液(NaOCl, 有效氯≥ 8.0%), 2, 3, 5-三苯基四唑氯化物(2, 3, 5-Triphenyl-2H-tetrazolium chloride, TTC), 乙酸乙酯, 95%、75%乙醇, 所用试剂均为分析纯试剂。

1.3 试验方法

1.3.1 浓度设置前期对盐生草种子进行萌发预试验, 根据萌发情况筛选不同重金属浓度梯度, 最终设定浓度梯度分别为:Cu²⁺(0.00, 0.10, 0.30, 0.50, 1.00, 3.00, 5.00, 10.00, 20.00, 30.00, 50.00, 100.00 mmol· L^-1); Zn²⁺和 Ni²⁺(0.00, 0.10, 0.30, 0.50, 1.00, 3.00, 5.00, 10.00, 20.00, 30.00, 50.00 mmol· L^-1); Cd²⁺(0.00, 0.05, 0.10, 0.20, 0.40, 0.60, 0.80, 1.00, 1.50, 2.00, 2.50, 3.00, 4.00 mmol· L^-1); Pb²⁺(0.00, 0.10, 0.30, 0.50, 1.00, 3.00, 5.00, 8.00, 10.00 mmol· L^-1)。用蒸馏水进行上述溶液配制。

1.3.2 种子消毒选取适量均匀一致饱满的种子于2 mL离心管中, 用75%酒精准确消毒30 s, 蒸馏水清洗3次, 再用质量体积分数为2%的次氯酸钠溶液反复颠倒清洗1.5 min后, 用蒸馏水清洗4次, 再于离心管中吸入2 mL蒸馏水, 迅速倒于经灭菌的含有两层滤纸的玻璃培养皿中, 待用^[21]。

1.3.3 萌发试验选取经高压灭菌的含有2层定性滤纸(90 mm)的玻璃培养皿作为盐生草种子的发芽床, 移液枪吸取5 mL不同浓度的重金属溶液于上述培养皿中, 用消毒的镊子挑取处理后的盐生草种子, 将其整齐排列在上述培养皿中, 每盘培养皿60粒种子, 每个处理5次生物学重复, 以蒸馏水为对照, 记号笔标记, 封口膜封口。将培养皿置于12 h光照/12 h黑暗, 温度25 ℃, 光照强度4000 Lx, 相对湿度80%的环境下进行萌发试验^[22]。

1.3.4 发芽指标测定以种子露白为标准^[18], 按7 d发芽率, 3 d发芽势进行发芽种子数统计, 计算种子发芽率、发芽势。计算公式如下:

发芽率=(露白种子粒数/供试种子粒数)× 100%(7 d)

发芽势=(露白种子粒数/供试种子粒数)× 100%(3 d)

1.3.5 株高扫描用WinRHIZO图像扫描仪对生长7 d的幼苗进行株高扫描, 每盘培养皿随机选取6株幼苗, 平均值作为株高指标。

1.3.6 生物量测定以每盘培养皿为一个单位, 将所有发芽种子于蒸馏水中轻轻漂洗数秒钟, 以除去幼苗表面黏附的多余重金属离子, 后将幼苗置于干净的定性滤纸上, 待水分吸干后测量鲜重(fresh weight, FW), 然后将幼苗装入信封袋, 置于60 ℃ 烘箱中, 3 d后用1/10000分析天平进行干重(dry weight, DW)称量。

1.3.7 根系活力测定将新鲜植株(0.2 g)浸泡于2.5 mL的100 mmol· L^-1 磷酸钾缓冲液(pH 7.0)和2.5 mL 的0.4% TTC中, 黑暗下于25 ℃温浴13 h, 除去TTC溶液, 用5 mL蒸馏水洗涤根系, 将减少的TTC用5 mL 95%乙醇代替在60 ℃下提取30 min, 并在485 nm处读取吸光度^[23]。

1.3.8 重金属含量测定以各重金属的不同处理浓度为一个单位, 将发芽幼苗放入干净研钵中, 将其研至粉末状, 装入PCR管, 用原子吸收分光光度法^[24]进行不同重金属离子含量测定。

1.4 数据处理

运用Genstat 19th Edition(64 bit)软件进行单因素方差分析(ANOVA), 采用Duncan’ s多重比较的方法统计处理间差异显著性(P< 0.05), 所有结果由平均值± 标准误(means± standard error)表示; 通过SPSS 20.0进行聚类分析和主成分分析。

2 结果与分析

2.1 Cu²⁺对盐生草种子萌发及幼苗生长的影响

低浓度Cu²⁺对盐生草种子的发芽率和发芽势无明显影响, 高浓度则产生抑制作用(表1)。发芽率在3.00 mmol· L^-1 Cu²⁺胁迫下显著低于对照(P< 0.05), 而发芽势在Cu²⁺≥ 1.00 mmol· L^-1 时较对照显著降低(P< 0.05), 二者均在最大胁迫浓度(100.00 mmol· L^-1)下达到最低值, 此时发芽率为81.67%, 较对照降低11.64%, 发芽势为77.50%, 较对照降低15.25%。

表1 Cu²⁺ 、Zn²⁺、Ni²⁺对盐生草种子萌发的影响 Table 1 Effects of Cu²⁺, Zn²⁺, Ni²⁺ on the seed germination of H. glomeratus (%)

对生长7 d的盐生草幼苗进行株高、干鲜重、根系活力和组织内离子含量测定, 发现随处理浓度的升高, 株高、干鲜重和根系活力均呈降低趋势, 组织内Cu²⁺含量呈上升趋势。其中, 低浓度Cu²⁺(0.10 mmol· L^-1)对株高和鲜重抑制作用显著(P< 0.05), 当Cu²⁺浓度为3.00 mmol· L^-1时, 株高和鲜重分别较对照降低78.24%和79.03%(图1a, b); 低浓度Cu²⁺(0.10~1.00 mmol· L^-1)处理对幼苗干重无显著影响(P> 0.05), 高浓度Cu²⁺(3.00~100.00 mmol· L^-1)则产生抑制作用(图1b); 根系活力呈现与株高、鲜重相同的趋势, 即随处理浓度的升高先迅速降低后趋于稳定, 在3.00 mmol· L^-1 Cu²⁺胁迫下仅为对照的18.02%(图1c); 在低浓度Cu²⁺(0.10~1.00 mmol· L^-1)胁迫下, 组织内Cu²⁺含量保持较低水平, 而3.00 mmol· L^-1 Cu²⁺处理下迅速上升至15.67 g· kg^-1, 在30.00 mmol· L^-1时达到最大值(图1d), 说明在重金属Cu²⁺胁迫下, 各指标的降低与组织内Cu²⁺含量有一定的相关性。

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图1 Cu²⁺对盐生草株高、鲜重、干重、根系活力及离子含量的影响
a:不同浓度Cu²⁺胁迫处理对幼苗株高影响; b:鲜重(FW)、干重(DW); c:根系活力; d:组织内Cu²⁺含量。各指标均由平均值± 标准误(SE)表示, 每组数据5次生物学重复(n=5), 同一指标不同小写字母表示差异显著(P< 0.05), 下同。a:the effects of different concentrations of Cu²⁺ stress on plant height; b:fresh weight (FW) and dry weight (DW); c:root activity; d: the Cu²⁺ content in tissues. The values are presented as means± standard error (SE), five biological repeats per group of data (n=5). The bars represent the SE. Bars with the same letter are not significantly different, P< 0.05, the same below.Fig.1 Effect of Cu²⁺ on the plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus

为进一步明确盐生草幼苗对重金属Cu²⁺的耐性程度, 对以上种子萌发和幼苗生长指标进行聚类分析, 得出在欧式距离为15时, 将Cu²⁺处理下的12个浓度梯度聚为两类, 其中以0.00~1.00 mmol· L^-1为第Ⅰ 类, 3.00~100.00 mmol· L^-1为第Ⅱ 类(图2); 对1.00 mmol· L^-1 Cu²⁺处理下的各指标进行主成分分析(表2), 提取了2个主成分, 主成分1贡献率为62.73%, 主成分2贡献率为37.27%, 累计贡献率达100.00%, 其中主成分1在鲜重上具有最高载荷(0.99), 其次是根系活力(0.97), 主成分2在株高上具有最高载荷(0.95), 考虑主成分1的贡献率约为主成分2贡献率的2倍, 因此生物量可首选为评价盐生草萌发期耐重金属Cu²⁺的重要参数。

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	图2 不同浓度Cu²⁺对盐生草影响的聚类分析Fig.2 Cluster analysis of the effects of different concentrations of Cu²⁺ on H. glomeratus

表2 不同重金属对盐生草影响的主成分分析 Table 2 Principal components of the effects of different heavy metals on H. glomeratus

2.2 Zn²⁺对盐生草种子萌发及幼苗生长的影响

在Zn²⁺胁迫下, 盐生草种子发芽率和发芽势随重金属浓度的升高呈现先缓慢上升而后降低的趋势, 均在0.30 mmol· L^-1时达到最大值, 分别为93.93%和93.44%, 但与对照差异不显著(P> 0.05)(表1); 在不同浓度的Zn²⁺胁迫下, 盐生草种子发芽率较高, 且差异不显著(P> 0.05), 分布在93.93%~89.23%, 与低浓度Zn²⁺(0.30 mmol· L^-1)处理相比, 发芽势在Zn²⁺浓度高于10.00 mmol· L^-1时受到显著性抑制(P< 0.05), 且于50.00 mmol· L^-1 Zn²⁺胁迫下抑制效果最明显, 发芽势为84.69%, 相比0.30 mmol· L^-1 Zn²⁺处理降低8.75%。

Zn²⁺对盐生草幼苗生长影响较小, 各指标在低浓度Zn²⁺胁迫下与对照差异不显著(P> 0.05), 高浓度则产生明显抑制作用, 其中, 株高、鲜重和根系活力均于0.50 mmol· L^-1 Zn²⁺时开始显著低于对照(P< 0.05), 当Zn²⁺浓度为1.00 mmol· L^-1时, 上述指标分别降低为对照的68.34%、76.66%和80.52%, 3.00 mmol· L^-1 Zn²⁺处理下为对照的44.04%、54.29%和59.10%, 而干重受其影响小, 仅在最大Zn²⁺浓度(50.00 mmol· L^-1)下显著低于对照(P< 0.05)(图3a, b, c); 通过测定离子含量, 发现组织内Zn²⁺含量随处理浓度的升高呈上升趋势, 1.00 mmol· L^-1 Zn²⁺胁迫下其体内Zn²⁺含量为3.31 g· kg^-1, 3 mmol· L^-1 Zn²⁺胁迫下显著升高, 后呈直线上升趋势(图3d)。

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图3 Zn²⁺对盐生草株高、鲜重、干重、根系活力及离子含量的影响
a:不同浓度Zn²⁺胁迫处理对幼苗株高影响; b:鲜重(FW)、干重(DW); c:根系活力; d:组织内Zn²⁺含量。a:the effects of different concentrations of Zn²⁺ stress on plant height; b:fresh weight (FW) and dry weight (DW); c:root activity; d:the Zn²⁺ content in tissues.Fig.3 Effect of Zn²⁺ on the plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus

对以上数据进行聚类分析, 发现在欧式距离为20时将Zn²⁺处理下的不同浓度聚为两类, 以0.00~3.00 mmol· L^-1为第Ⅰ 类, 5.00~50.00 mmol· L^-1为第Ⅱ 类(图4), 说明盐生草幼苗在一定浓度的Zn²⁺胁迫下可以正常生长, 但当Zn²⁺≥ 5.00 mmol· L^-1 时, 植株生长受到影响; 对3.00 mmol· L^-1 Zn²⁺处理下的各指标进行主成分分析, 结果显示提取了1个主成分, 其特征值为5.58, 贡献率高达92.95%, 在发芽势和发芽率上具有最高载荷, 均为0.99(表2), 可见发芽势和发芽率可首选为评价盐生草萌发期耐重金属Zn²⁺的重要参数。

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	图4 不同浓度Zn²⁺对盐生草影响的聚类分析Fig.4 Cluster analysis of the effects of different concentrations of Zn²⁺ on H. glomeratus

2.3 Ni²⁺对盐生草种子萌发及幼苗生长的影响

发芽率、发芽势在整个Ni²⁺处理浓度范围内均低于对照, 但低浓度胁迫下与对照差异均不显著(P> 0.05), 仅在高浓度时产生抑制作用(表1)。发芽率仅在Ni²⁺胁迫浓度≥ 10.00 mmol· L^-1 时与对照差异显著(P< 0.05), 后处理间无明显差异; 而发芽势在3.00 mmol· L^-1 Ni²⁺ 处理下显著低于对照(P< 0.05), 后随处理浓度的升高缓慢降低, 当Ni²⁺浓度为50.00 mmol· L^-1 时, 发芽势为83.70%, 相比对照降低9.44%。由此可知, 重金属 Ni²⁺ 对盐生草种子萌发影响较小, 在整个胁迫浓度下均保持较高的发芽势和发芽率, 种子活力较高。

Ni²⁺对株高、干鲜重和根系活力均有明显抑制作用, 随处理浓度的升高先显著降低后趋于平缓(图5a, b, c)。在0.10~1.00 mmol· L^-1 Ni²⁺ 处理下, 株高从对照的91.13% 降低至66.43%, 鲜重从对照的84.09%降低至52.40%, 株高和鲜重均在3.00 mmol· L^-1 Ni²⁺下降低最为显著(P< 0.05), 分别为对照的33.18%和26.97%, 后处理间差异不显著(P> 0.05); 干重在0.50 mmol· L^-1 Ni²⁺ 处理下较对照显著降低(P< 0.05), 之后无明显变化; 根系活力随Ni²⁺浓度的升高呈降低趋势, 在1.00和3.00 mmol· L^-1 Ni²⁺ 处理下分别为对照的71.66%和46.30%; 组织内 Ni²⁺ 含量在低浓度(0.10~1.00 mmol· L^-1 Ni²⁺)处理下相对较低, 且增加缓慢, 3.00 mmol· L^-1 Ni²⁺ 胁迫下急速上升至11.92 g· kg^-1, 约为1.00 mmol· L^-1 Ni²⁺ 处理下的4倍, 后随处理浓度的增大缓慢升高(图5d)。

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图5 Ni²⁺对盐生草株高、鲜重、干重、根系活力及离子含量的影响
a:不同浓度Ni²⁺胁迫处理对幼苗株高影响; b:鲜重(FW)、干重(DW); c:根系活力; d:组织内Ni²⁺含量。a:the effects of different concentrations of Ni²⁺ stress on plant height; b:fresh weight (FW) and dry weight (DW); c:root activity; d:the Ni²⁺ content in tissues.Fig.5 Effect of Ni²⁺ on the plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus

聚类分析结果显示, 在欧式距离为15时, 将Ni²⁺处理下的11个浓度梯度聚为两类, 0.00~1.00 mmol· L^-1为第Ⅰ 类, 3.00~50.00 mmol· L^-1为第Ⅱ 类(图6), 说明当Ni²⁺浓度≥ 3.00 mmol· L^-1 时会严重影响盐生草种子萌发和幼苗的正常生长; 对1.00 mmol· L^-1 Ni²⁺处理下的各指标进行主成分分析, 提取了2个主成分, 主成分1特征值为4.36, 贡献率为72.60%, 其在发芽势上具有最大载荷, 主成分2特征值为1.64, 贡献率为27.40%, 累计贡献率达100.00%, 其在发芽率上具有最高载荷(表2), 而发芽势和发芽率均属于种子萌发指标, 所以在重金属Ni²⁺胁迫下, 种子萌发越整齐, 萌发数越多, 则表现为对其耐性越强。

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	图6 不同浓度Ni²⁺对盐生草影响的聚类分析Fig.6 Cluster analysis of the effects of different concentrations of Ni²⁺ on H. glomeratus

2.4 Cd²⁺对盐生草种子萌发及幼苗生长的影响

由表3可知, Cd²⁺对盐生草种子发芽率、发芽势有不同程度的影响, 其中, 发芽率在低浓度(0.05~0.10 mmol· L^-1 Cd²⁺)时略高于对照, 但差异不显著(P> 0.05), 当Cd²⁺≥ 1.00 mmol· L^-1时, 发芽率显著降低, 其中在4.00 mmol· L^-1 Cd²⁺胁迫下达最低, 为86.02%, 较对照降低6.49%, 发芽势在0.20 mmol· L^-1 Cd²⁺ 处理下较对照显著降低(P< 0.05), 后处理间差异不显著, 在最大浓度(4.00 mmol· L^-1 Cd²⁺)时达最低, 为84.33%, 较对照降低7.95%; 说明重金属Cd²⁺在一定程度上抑制了盐生草种子活力, 使其萌发率降低。

表3 Cd²⁺和Pb²⁺对盐生草种子萌发的影响 Table 3 Effects of Cd²⁺ and Pb²⁺ on the seed germination of H. glomeratus (%)

Cd²⁺胁迫下, 株高和干鲜重随处理浓度的升高而降低, 低浓度Cd²⁺(0.05~0.10 mmol· L^-1)显著(P< 0.05)抑制了幼苗生长和生物量的积累, 0.20 mmol· L^-1 Cd²⁺ 处理下抑制效果最明显, 株高、鲜重、干重分别较对照降低47.01%, 65.04%和39.52%, 后随处理浓度的升高, 株高和鲜重有不同程度的降低, 但干重在不同水平间差异不显著(P> 0.05), 与种子发芽指标相比, 幼苗生长对重金属Cd²⁺的浓度更敏感(图7a, b)。对根系活力测定发现, 低浓度处理下幼苗根系仍保持较高活力, 0.20 mmol· L^-1 Cd²⁺胁迫下迅速降低为对照的一半(49.26%), 后随处理浓度的升高而降低(图7c); 组织内Cd²⁺含量在低浓度(0.05~0.10 mmol· L^-1)胁迫下相对较低, 0.20 mmol· L^-1 Cd²⁺处理下迅速升高至3.78 g· kg^-1, 后以剂量依赖性方式增大, 当处理浓度≥ 2.00 mmol· L^-1 时组织内Cd²⁺含量缓慢降低趋于稳定(图7d), 说明盐生草对Cd²⁺具有一定耐性, 且能富集一定浓度的Cd²⁺于体内。

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图7 Cd²⁺对盐生草株高、鲜重、干重、根系活力及离子含量的影响
a:不同浓度Cd²⁺胁迫处理对幼苗株高影响; b:鲜重(FW)、干重(DW); c:根系活力; d:组织内Cd²⁺含量。a:the effects of different concentrations of Cd²⁺ stress on plant height; b:fresh weight (FW) and dry weight (DW); c:root activity; d:the Cd²⁺ content in tissues.Fig.7 Effect of Cd²⁺ on the plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus

对以上指标进行聚类分析, 发现在欧式距离为15时将Cd²⁺处理下的浓度聚为两类, 0.00~0.10 mmol· L^-1为第Ⅰ 类, 0.20~4.00 mmol· L^-1为第Ⅱ 类(图8), 说明盐生草幼苗在Cd²⁺浓度≤ 0.10 mmol· L^-1 时能维持正常生长, 高于此浓度则植株生长代谢受阻, 进一步对0.10 mmol· L^-1 Cd²⁺处理下的萌发指标和幼苗生长指标进行主成分分析, 提取了2个主成分, 主成分1贡献率为56.59%, 在发芽势和干重上具有较高载荷, 主成分2贡献率为43.41%, 在鲜重上载荷最高, 两者累计贡献率为100.00%(表2), 说明在0.10 mmol· L^-1 Cd²⁺胁迫下, 种子萌发越整齐, 生物量积累越多, 则表现为对重金属Cd²⁺耐性越强。

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	图8 不同浓度Cd²⁺对盐生草影响的聚类分析Fig.8 Cluster analysis of the effects of different concentrations of Cd²⁺ on H. glomeratus

2.5 Pb²⁺对盐生草种子萌发及幼苗生长的影响

Pb²⁺胁迫下, 盐生草种子发芽率和发芽势随处理浓度的升高呈先升高后降低的趋势, 0.10~1.00 mmol· L^-1 Pb²⁺处理下, 发芽率和发芽势略高于对照, 但差异不显著(P> 0.05), 均在1.00 mmol· L^-1 Pb²⁺胁迫下达到最大值94.82%, 分别较对照增加2.54%和3.67%, 3.00 mmol· L^-1 Pb²⁺处理下显著降低(P< 0.05), 后随处理浓度的升高, 各处理间差异不显著(P> 0.05)(表3)。由此可见, 一定浓度的Pb²⁺更有利于盐生草种子萌发。

在Pb²⁺胁迫下, 株高、干鲜重和根系活力随处理浓度的升高先平稳变化后显著降低(P< 0.05)。其中, 株高、干重和根系活力在0.10 mmol· L^-1 Pb²⁺ 处理下达到最大值, 鲜重在0.50 mmol· L^-1 Pb²⁺处理下达到最大值, 1.00 mmol· L^-1 Pb²⁺处理下, 株高、根系活力分别为对照的70.60%和89.15%(图9a, c), 而干鲜重和对照差异不显著(P> 0.05), 但在3.00 mmol· L^-1 Pb²⁺胁迫下时各指标均显著降低(P< 0.05), 株高、鲜重和根系活力分别为对照的42.25%、53.58%和50.22%, 此时组织内Pb²⁺含量也迅速升高(图9d), 相比较而言, 根系活力对高浓度Pb²⁺更敏感, 可能是因为环境中过多的Pb²⁺首先富集在植物根部, 对其造成严重毒害, 导致根系活力迅速降低, 从而进一步影响其他生理代谢, 最终影响植物生长。

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图9 Pb²⁺对盐生草株高、鲜重、干重、根系活力及离子含量的影响
a:不同浓度Pb²⁺胁迫处理对幼苗株高影响; b:鲜重(FW)、干重(DW); c:根系活力; d:组织内Pb²⁺含量。a:the effects of different concentrations of Pb²⁺ stress on plant height; b:fresh weight (FW) and dry weight (DW); c:root activity; d:the Pb²⁺ content in tissues.Fig.9 Effect of Pb²⁺ on the plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus

根据盐生草萌发和幼苗生长指标, 对以上处理浓度进行聚类分析, 发现在欧式距离为15时, 将其聚为两类, 以0.00~1.00 mmol· L^-1为第Ⅰ 类, 以3.00~10.00 mmol· L^-1为第Ⅱ 类(图10), 说明盐生草幼苗在一定浓度Pb²⁺胁迫下能保持正常生长, 浓度过高幼苗生长则受到显著抑制; 进一步对1.00 mmol· L^-1 Pb²⁺处理下的各指标进行主成分分析, 发现提取了1个主成分, 其特征值为5.76, 贡献率高达92.93%, 其中发芽势和发芽率载荷最高(表2), 说明发芽势和发芽率可作为评价盐生草萌发期耐重金属Pb²⁺的重要参数。

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	图10 不同浓度Pb²⁺对盐生草影响的聚类分析Fig.10 Cluster analysis of the effects of different concentrations of Pb²⁺ on H. glomeratus

3 讨论

Cu作为植物所必需的微量元素之一, 植物体内Cu²⁺含量过多、过少都会对植物生长产生影响, 过少会影响植物体内多种氧化还原反应和光合电子传递, 过多则会对植物产生铜盐毒害, 导致植株生长缓慢, 甚至枯萎死亡^[25]。本研究结果表明, 低浓度Cu²⁺对盐生草种子萌发影响较小, 高浓度则产生抑制作用, 这与 Zhou等^[26]研究结果一致。株高、干鲜重和根系活力均随Cu²⁺处理浓度的升高而降低, 且于3.00 mmol· L^-1时降低最为显著, 各幼苗生长指标均低于对照的40%, 同时组织内Cu²⁺含量在低浓度胁迫下相对较低, 3.00 mmol· L^-1 Cu²⁺胁迫下则迅速升高, 这可能是因为溶液中Cu²⁺最先接触植物根部, 致使根尖细胞分裂速度减慢, 达到某一临界值时对植物根系产生严重毒害, 导致其活力降低, 从而严重抑制幼苗生长和生物量积累^[27]。聚类分析和主成分分析表明, 盐生草在Cu²⁺≥ 3.00 mmol· L^-1胁迫下生长受到严重抑制, 生物量可首选为评价盐生草萌发期耐重金属Cu²⁺的重要参数。

Zn是植物生长发育必需的微量营养元素, 在维持和稳定生物膜功能完整性, 保证叶绿素的形成以及6大类功能酶(氧化还原酶、转移酶、水解酶、裂解酶、异构酶和合成酶)活性等方面发挥着重要作用^[28]。研究表明, 植物体内一定浓度的Zn²⁺对植物生长发育有促进作用, 当超过某一临界值时便会对植物产生毒害, 主要体现在萌发受阻, 生长抑制, 光合、呼吸作用减弱等方面^[29]。本研究中, 在低浓度Zn²⁺胁迫下, 盐生草种子发芽率、发芽势、株高、干鲜重和根系活力均高于对照, 高浓度则产生抑制作用, 这与陈俊任等^[30]研究结果相似。萌发和幼苗生长指标在5.00 mmol· L^-1 Zn²⁺处理下均低于对照的55%, 同时组织内Zn²⁺含量在此时也显著升高, 说明各指标的降低与组织内Zn²⁺含量有一定相关性, 可能是体内过多的Zn²⁺破坏了植物代谢平衡, 导致生长受阻。聚类分析和主成分分析结果表明, 盐生草在Zn²⁺≥ 5.00 mmol· L^-1胁迫下无法正常生长, 发芽指标可首选为评价盐生草萌发期耐重金属 Zn²⁺ 的重要参数。值得注意的是, 与Ni²⁺和Cu²⁺相比, 各萌发指标和幼苗生长指标在Zn²⁺胁迫下最高, 其次是Ni²⁺和Cu²⁺, 说明盐生草对这3种金属的耐性顺序为:Zn²⁺> Ni²⁺> Cu²⁺, 有研究证明, 相比其他金属, Zn²⁺对植物的毒害作用最弱^{[30, 31]}, 这可能是因为Zn²⁺参与多种代谢途径, 植物对Zn²⁺的需求量大于其他微量元素, 此外, 金属的价态不同也会导致其对植物的毒害强度不同, 高浓度Se能显著抑制烟草的农艺性状, 且Se(VI)抑制效果大于Se(IV), 同时烟草体内Se(VI)积累量明显高于Se(IV)^[32]。

Ni对植物新陈代谢起着重要作用, 研究发现, Ni²⁺毒害会严重抑制植物侧根的形成及生长, 影响其对水分和养分的吸收, 进一步引起植物生理代谢失调^[33]。本研究中, 发芽率和发芽势在低浓度Ni²⁺(0.00~1.00 mmol· L^-1)处理下与对照差异不显著, 高浓度时受到显著抑制作用, 这与龚磊等^[34]的研究结果一致。株高、鲜重和根系活力随处理浓度的增大而降低, 在3.00 mmol· L^-1 Ni²⁺处理下差异最显著, 各指标均低于对照的46%, 同时, 组织内Ni²⁺含量在此胁迫浓度下升高幅度最大, 结合聚类分析和主成分分析结果, 推测盐生草幼苗在 Ni²⁺≥ 3.00 mmol· L^-1胁迫下无法正常生长, 发芽指标可首选为评价盐生草萌发期耐重金属Ni²⁺的重要参数。

在所有重金属中, Cd是最受关注的元素之一, 在大量关于Cd毒性的研究中, 已报道Cd²⁺对不同物种的毒性最大。本研究中, 低浓度Cd²⁺延缓盐生草种子萌发, 高浓度则产生抑制作用, 可能是因为Cd²⁺抑制种子内储藏淀粉和蛋白质的分解, 从而影响种子萌发所需的物质和能量, 致使种子萌发受阻^[35]。植物受Cd²⁺毒害时, 线粒体和叶绿体受到破坏, 导致呼吸、光合作用减弱, 叶片发黄, 生物量下降^[36]。本研究中, 盐生草幼苗在0.00~0.10 mmol· L^-1 Cd²⁺胁迫下能维持正常生长, 0.20 mmol· L^-1处理下, 株高、鲜重和根系活力均迅速降低, 同时Cd²⁺含量也急速升高, 这说明盐生草幼苗在Cd²⁺≥ 0.20 mmol· L^-1时生长严重受阻, 而强耐Cd²⁺植物柳枝稷(Panicum virgatum)在0.01 mmol· L^-1 Cd²⁺胁迫下便受到显著抑制^[37], 说明盐生草对Cd²⁺的耐性更强, 这可能是因为盐生草长期在干旱、半干旱环境下生长, 其体内形成特殊的重金属离子解毒机制, 存在与重金属转运相关的基因。聚类和主成分分析结果表明, 生物量可首选为评价盐生草萌发期耐重金属Cd²⁺的重要参数。

Pb是植物非必需元素, 其在植物体内的过量积累不但会对植株产生毒害, 进入食物链还会对人体的多个器官和系统造成损伤, 是人类可能的致癌物质^[38]。本研究中, 在低浓度Pb²⁺胁迫下, 盐生草种子发芽率、发芽势、株高、干鲜重和根系活力略高于对照, 高浓度处理下则显著降低, 且在3.00 mmol· L^-1 Pb²⁺处理下各指标显著低于对照的52%, 组织内 Pb²⁺ 含量也在低浓度胁迫下相对较低, 3.00 mmol· L^-1 Pb²⁺胁迫下显著升高, 并具有浓度效应, 这说明盐生草对重金属Pb²⁺具有一定耐性, 而低浓度下出现升高可能是植物对生长环境变化时产生的一种应激反应, 但这种刺激作用受到浓度的限制^[39]。聚类和主成分分析结果表明, 盐生草在Pb²⁺≥ 3.00 mmol· L^-1时无法正常生长, 发芽指标可首选为评价盐生草萌发期耐重金属Pb²⁺的重要参数。

在以上5种不同重金属胁迫下, 与种子萌发相比, 幼苗生长对重金属浓度更敏感, 这可能是因为在充足的氧气和适宜的温度环境下, 水分是种子萌发的另一重要因素, 健康种子得到足够的水分便能迅速发芽, 并且种皮对种胚具有一定的保护作用, 研究发现, 被重金属处理过的种子, 经蒸馏水洗涤后其发芽率高于未洗涤的种子, 说明种皮表面对重金属离子具有一定的黏附作用, 可以适当减少进入种胚的金属离子^[40]。幼苗是植株生长最脆弱的时期, 其抗逆能力最弱, 种子萌发后, 胚芽和胚根极易受金属离子毒害^[40], 少量的金属离子胁迫便能使胚芽和胚根生长能力减弱, 进一步使幼苗生长受阻, 这便导致即使在逆境中种子能正常萌发, 也不能成苗。

4 结论

盐生草种子萌发和幼苗生长指标随着重金属胁迫浓度的提高而呈现出不同程度的下降趋势, 其中, 在重金属Zn²⁺浓度低于3.00 mmol· L^-1, Cu²⁺、Ni²⁺和Pb²⁺浓度低于1.00 mmol· L^-1, Cd²⁺浓度低于0.10 mmol· L^-1的处理环境下, 其对盐生草种子萌发和幼苗生长的影响较小; 发芽指标可首选为评价盐生草萌发期耐重金属 Zn²⁺、Pb²⁺和Ni²⁺的重要参数, 生物量可首选为评价盐生草萌发期耐重金属Cu²⁺和Cd²⁺的重要参数。本研究在一定程度上揭示了盐生草萌发期对重金属Cu、Zn、Ni、Cd、Pb的耐性程度, 为土壤重金属污染修复提供了参考依据, 但关于其耐重金属胁迫的生理和分子机制需要进一步研究。

The authors have declared that no competing interests exist.

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[36]	Cen H M, Peng L L, Yang X, et al. Effects of Cd²⁺ on the seed germination and seedling growth of Cynodon dactylon and Eremochloa ophiuroides. Acta Prataculturae Sinica, 2015, 24(5): 100-107. 岑画梦, 彭玲莉, 杨雪, 等. Cd²⁺对狗牙根、假俭草种子萌发及幼苗生长的影响. 草业学报, 2015, 24(5): 100-107. [本文引用:1]
[37]	Hu B Y, Fang Z G, Lou L Q, et al. *Comprehensive evaluation of cadmium tolerance of 14 switchgrass ( Panicum uirgatum) cultivars in the seedling stage. Acta Prataculturae Sinica, 2019, 28(1): 27-36. 胡冰钰, 方志刚, 娄来清, 等. 14份柳枝稷种质资源苗期耐镉性综合评价*. 草业学报, 2019, 28(1): 27-36. [本文引用:1]
[38]	Xu Y M, Wang C Q, Wu J X, et al. Effects of Mn²⁺ and Pb²⁺ on seed germination and seedling growth of Elymus nutans. Acta Prataculturae Sinica, 2018, 27(3): 194-200. 徐雅梅, 王传旗, 武俊喜, 等. Mn²⁺、Pb²⁺ 对野生垂穗披碱草种子萌发与幼苗生长的影响. 草业学报, 2018, 27(3): 194-200. [本文引用:1]
[39]	Duan D C, Yu M G, Shi J Y. Research advances in uptake, translocation, accumulation and detoxification of Pb in plants. Chinese Journal of Applied Ecology, 2014, 25(1): 287-296. 段德超, 于明革, 施积炎. 植物对铅的吸收、转运、累积和解毒机制研究进展. 应用生态学报, 2014, 25(1): 287-296. [本文引用:1]
[40]	Maryam M S, Bilal H A, Nisar A, et al. Toxic effects of heavy metals (Cd, Cr and Pb) on seed germination and growth and DPPH-scavening activity in Brassica rapa var. turnip. Toxicology and Industrial Health, 2014, 30(3): 238-249. [本文引用:2]

2018

0.0

... 近年来随着城市化、工业化进程不断加快,重金属在土壤中大量富集,其不但破坏生态环境,还影响植物生长发育,进入食物链最终危害人体健康^[1,2] ...

2018

0.0

... 近年来随着城市化、工业化进程不断加快,重金属在土壤中大量富集,其不但破坏生态环境,还影响植物生长发育,进入食物链最终危害人体健康^[1,2] ...

2017

0.0

... 10¹⁰元^[3,4] ...

2018

0.0

... 10¹⁰元^[3,4] ...

2018

0.0

... 重金属是指密度大于5的金属元素,主要包括镉(Cd)、砷(As)、铅(Pb)、铬(Cr)、汞(Hg)以及有一定毒性的铜(Cu)、锌(Zn)、镍(Ni)等^[5] ...

2018

0.0

... 重金属污染具有富集性、不可逆性和难治理等特点,目前国际上治理土壤重金属污染的方法主要有物理化学修复、微生物修复、植物修复和农业措施修复等^[6,7,8] ...

2018

0.0

2018

0.0

2016

0.0

... 相较于其他修复方法,植物修复法具有保护土壤微环境、耗费低、适应性强、无二次污染物等优点^[9],因此,通过种植绿色植物来隔离或解毒土壤重金属污染似乎有望比传统技术更经济,更有效,更环保 ...

2008

0.0

. 2008, 19(4):838-844

Effects of dissolved organic matter derived from hyperaccumulator Sedun alfredii Hance rhizosphere on Zn adsorption and desorption in soil

超积累植物东南景天根际可溶性有机质对土壤锌吸附解吸的影响

Li T Q , Zhu E , Yang X E

李廷强, 朱恩, 杨肖娥

1 Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education， College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029, China; 2 Shanghai Agricultural Technology Extension and Service Center, Shanghai 201103, China

The study with pot experiment and simulation test showed that after planted hyperaccumulator Sedum alfredii Hance on mining soil, the water soluble Zn and NH 4 OAc extractable Zn in rhizosphere were decreased obviously, while the available Zn in nonrhizosphere had less change. The pH value of rhizosphere soil was decreased by 0.3 units, whereas the organic matter and dissolved organic matter (DOM) contents were increased by 13.6% and 20.9%, respectively, compared with the soil without S. alfredii . The effects of DOM from S. alfredii rhizosphere on Zn absorption and desorption varied with the kinds of test soils. After the addition of rhizosphere DOM, the maximal absorption capacity ( X m ) of mining soil, quaternary red clay soil, and fluaviomarine yellow loamy soil was reduced by 17.8%, 21.9% and 27.7%, respectively, whereas the addition of nonrhizosphere DOM had no effects on Zn absorption. The Zn desorption in the three soils, especially in fluavio-marine yellow loamy soil, was promoted by the addition of rhizosphere DOM. It was indicated that the DOM from S. alfredii rhizosphere could reduce the maximal absorption capacity and accelerate the desorption of adsorbed Zn, and thus, increase the Zn mobility and bioavailability.

采用盆栽和模拟试验研究了锌超积累植物东南景天根际土壤可溶性有机质(DOM)对土壤锌吸附解吸的影响.结果表明: 采用矿山土壤种植锌超积累植物东南景天后，根际土壤水溶性锌和乙酸铵提取态锌含量显著降低，而非根际土壤有效锌无明显变化.与不种植东南景天的对照土壤相比，根际土壤pH值降低了0.3个单位，有机质和DOM含量分别提高13.6%和20.9%.东南景天根际DOM对土壤锌吸附解吸的影响方式和程度与土壤类型有关.与对照DOM相比，在矿山土、黄筋泥和黄松土中，添加根际DOM使锌的最大吸附量( X m )分别降低了17.8%、21.9%和27.7%，而非根际DOM对锌的最大吸附量没有影响.在3种供试土壤中添加根际DOM促进了锌的解吸，其中以黄松土最明显.东南景天根际DOM能降低土壤锌吸附容量，减少土壤对锌的吸附，促进吸附态锌的解吸，从而提高了根际锌的生物有效性.

... 近年来,植物修复土壤重金属污染的研究方兴未艾,例如景天科的东南景天(Sedum alfredii)是一种已被鉴定的锌和镉超积累植物,能在富含锌、镉、镍的土壤上正常生长^[10] ...

2016

0.0

... 相对甜土植物,盐生植物在进化上形成特殊的信号转导途径和离子运输调控机制^[11],在土壤盐碱地改良、重金属污染修复等方面发挥着重要作用^[12] ...

2017

0.0

... 相对甜土植物,盐生植物在进化上形成特殊的信号转导途径和离子运输调控机制^[11],在土壤盐碱地改良、重金属污染修复等方面发挥着重要作用^[12] ...

2015

0.0

... 的毒物刺激效应,且对幼苗根生长的抑制程度大于幼苗芽的生长^[13] ...

2017

0.0

... Cu²⁺导致野生赖草(Leymus secalinus)胚芽中MDA含量升高,对胚芽产生损害作用^[14] ...

2017

0.0

... 高浓度 Cd²⁺、Zn²⁺ 对烟草(Nicotiana tabacum)种子造成氧化损伤,使其抗氧化酶活性降低,代谢紊乱^[15] ...

2018

0.0

... ^[16] ...

2015

0.0

... 为干旱、半干旱区广布的荒漠物种,主要生长于蒙古、中亚及我国西北旱区等地^[17,18],地上多分枝的肉质化茎、叶组织具有耐盐抗旱、富集重金属等特性 ...

2011

0.0

. 2011, 28(6):902-904

Improvement effect of Halogoton arachnoideus on saline-alkali soil

白茎盐生草对盐碱土壤的改良效果

Wang W , Zhang D G

王文, 张德罡

Abstract:The effect of Halogeton arachnoideus on improving saline soil was studied with two treatments (T1, naturally grown H. arachnoideus and T2, planted H. arachnoideus) and bare land as CK. The results indicated that the salt content of saline soil (soluble salt content was 0.49%) was significantly reduced by H. arachnoideus. The salt contents of T1 and T2 were reduced by 28.57% and 32.65 % after one year in the soil layer from 0 to 20 cm, respectively, but showed less change in the soil layer from 20 to 40 cm. After one growing season, the total soil salt content was reduced from11.172 t/ha to 8.738 t/ha. Accordingly, the soil pH value in the soil layer from 0 to 20 cm was reduced by 0.13 to 0.14 units. These results suggested that planting H. arachnoideus could be an effective method to improve saline soil.

摘要：在全盐含量0.49%的土壤中设置人工种植和自然生长白茎盐生草(Halogeton arachnoideus)处理，以裸地为对照，研究种植白茎盐生草对盐碱土壤的改良效果。结果表明，2个处理下的土壤全盐含量明显下降，0~20 cm土层分别下降28.57%和32.65%。对盐碱的消除效果0~20 cm土层较20~40 cm好。播种前0~20 cm土壤全盐总量约为11.172 t/hm2，1个生长季后下降为8.738 t/hm2，全盐总量下降2.434 t/hm2，即种植白茎盐生草1年可从0~20 cm土层中除去盐分2.434 t/hm2。试验前后，0~20 cm土壤pH值下降0.13～0.14，下降幅度大于20~40 cm土壤。白茎盐生草对盐分的富集降低了土壤的pH值，达到改良盐碱土壤的目的。

... 4 发芽指标测定以种子露白为标准^[18],按7 d发芽率,3 d发芽势进行发芽种子数统计,计算种子发芽率、发芽势 ...

2017

0.0

... 本实验室前期研究表明,盐生草通过将盐分区隔在液泡内而具有较强的耐盐特性,其不但在盐渍地生长良好,且为金属矿区优势种群^[19,20],是理想的进行土壤重金属污染修复的野生资源,但关于盐生草萌发期对不同重金属的耐性还未知 ...

2015

0.0

2012

0.0

... 5 min后,用蒸馏水清洗4次,再于离心管中吸入2 mL蒸馏水,迅速倒于经灭菌的含有两层滤纸的玻璃培养皿中,待用^[21] ...

2018

0.0

... 将培养皿置于12 h光照/12 h黑暗,温度25 ℃,光照强度4000 Lx,相对湿度80%的环境下进行萌发试验^[22] ...

2011

0.0

... 4% TTC中,黑暗下于25 ℃温浴13 h,除去TTC溶液,用5 mL蒸馏水洗涤根系,将减少的TTC用5 mL 95%乙醇代替在60 ℃下提取30 min,并在485 nm处读取吸光度^[23] ...

2014

0.0

. 2014, 34(4):963-972 DOI:10.5846/stxb201210091392

Ion absorption and distribution of symbiotic Reaumuria soongorica and Salsola passerina seedlings under NaCl stress

盐胁迫下荒漠共生植物红砂与珍珠的根茎叶中离子吸收与分配特征

Zhao X , Yang X J , Shi Y

赵昕, 杨小菊, 石勇

Wild C 3 plant Reaumuria soongorica and C 4 plant Salsola passerina coexist mutually in some desert habitats and form large-scale communities distributed in northwestern China. In this study we collected their seedlings from the edge of the Tengger desert. Their seedlings were subjected to salt stress together by soaked in 0, 100, 200, 300 to 400 mmol/L NaCl solutions for 10 d. We examined their water contents and main mineral ion contents changes in their roots, stems, and leaves during salt stress. The experiment results indicated that S. passerina absorbed K and inhibited Na in leaves to adapt to high salt stress as NaCl concentration increased. By on the contrary, R. soongorica absorbed Na and inhibited K. Cl in its roots continuously increased two to five times higher than that in S. passerina's roots. Ca content in S. passerina roots was two to three times higher than that in R. soongorica roots. Si content in R. soongorica roots was three to five times higher than that in S. passerina. Therefore, salt stress resistance in R. soongorica and S. passerina communities occurred via root absorption of different ions, and these ions were subsequently distributed to various organs. Based on salt ion selective absorption coefficient S Na(leaf/root)/K(leaf/root) ratio value, the two plants foliar selectivity increased K absorption and decreased Na absorption, thereby reducing salt damage on the leaves. Thus, these plants mutually benefit from each other and cooperate to promote their resistance to salt stress.

西北荒漠地区C 3 小灌木红砂（ Reaumuria soongorica ）和C 4 半灌木珍珠猪毛菜（ Salsola passerina ）在特定环境下混生在一起，分布面积广阔。以采自腾格里沙漠边缘荒漠地带的天然野生珍珠猪毛菜和红砂群落的幼苗为材料，经0、100、200、300、400mmol/L NaCl盐溶液共同胁迫10 d，检测它们的含水量、主要矿质离子在根茎叶的含量与分布，揭示二者耐盐的共生协同的离子平衡适应机制。试验结果发现，珍珠猪毛菜叶片具有“吸钾排钠的”的耐盐特征，红砂叶片具备“吸钠排钾”的特征，吸收利用无机矿质离子具备互补效应。二者耐盐Cl、Ca和Si离子吸收与累积能力存在很大差异：随着盐胁迫程度加剧，红砂的根茎叶中Cl离子含量持续增加，并且为珍珠猪毛菜的2-5倍；珍珠猪毛菜根中Ca离子含量为红砂的2-3倍，但含量变化不显著；红砂根中Si离子含量迅速降低后稳定，并且是珍珠猪毛菜根的3-5倍，其他器官变化差异较小。因此，红砂与珍珠猪毛菜的共培养盐胁迫下根中吸收的离子侧重不同，红砂以Na、Cl、Si为主，珍珠猪毛菜以K、Ca为主。随着盐胁迫的程度加强，离子选择吸收系数 S k，Na 的变化趋势降低，表明二者叶部对Na的选择性减小，K的选择性吸收积累增大，增强了它们的抗盐性，最终使叶片所受盐害减小。总之红砂与珍珠猪毛菜共生的耐盐离子稳态机制显著不同，离子吸收与分布具有互补互利的效应。

... 8 重金属含量测定以各重金属的不同处理浓度为一个单位,将发芽幼苗放入干净研钵中,将其研至粉末状,装入PCR管,用原子吸收分光光度法^[24]进行不同重金属离子含量测定 ...

2016

0.0

. 2016, 36(6):1719-1727 DOI:10.5846/stxb201408081588

Effects of Cd²⁺ and Cu²⁺ stress on the growth and photosynthetic fluorescence characteristics of Hydrilla verticillata

Cd 2+ 、Cu 2+ 胁迫对黑藻( Hydrilla verticillata )的生长及光合荧光特性的影响

Jian M F , Wang S C , Yu H P

简敏菲, 汪斯琛, 余厚平

In this study, we selected the aquatic plant Hydrilla verticillata as our specimen and cultured it in clean river sand and water in order to study the influence of five separate concentration levels of Cd 2+ or Cu 2+ on the plant. Effects of the stress on the plant were identified, and we recorded parameters such as height, biomass, chlorophyll content, and survival ratios of H. verticillata , as well as the effects of fluorescence parameters such as minimal fluorescence ( F o), maximal fluorescence ( F m), PS II maximum quantum yield ( QY max ), degree of PSⅡ reaction centers closed under stable state (1- Qp _Lss), non-photochemical quenching under stable state (NPQ_Lss), and fluorescence images of H. verticillata leaves. We also separately studied the variation characteristics of each parameter of H. verticillata under the stress of increasing Cd 2+ or Cu 2+ concentrations. We found that the height of H. verticillata decreased significantly under the different levels of pollution stress by the heavy metal Cd 2+ . This indicated that Cd 2+ pollution may damage the bundle structure of H. verticillata . There were no significant effects on the fresh weight of H. verticillata under the stress of either Cd 2+ or Cu 2+ pollution, and this may be related to the high content of free water in aquatic plants. Dry weight of H. verticillata decreased significantly when the plants were exposed to Cd 2+ or Cu 2+ pollution. Effect of Cu 2+ pollution on the dry weight of H. verticillata was far more prominent than that of Cd 2+ pollution. All chlorophyll values decreased significantly when the plants were subjected to Cd 2+ or Cu 2+ pollution, and we found that the effect of Cu 2+ pollution was greater than that of Cd 2+ pollution. This suggested that the toxicity of Cu 2+ against H. verticillata chloroplasts is greater than that of Cd 2+ . The chlorophyll fluorescence parameters ( F o, F m, and QY max ) of H. verticillata under Cd 2+ or Cd 2+ stress were significantly lower than those of the control groups; however, the values of (1- Qp _Lss) increased, and the values of NPQ_Lss first increased and then decreased as the concentrations of the heavy metals increased. The different values for the physiological parameters, fluorescence parameters, and imaging characteristics indicated that the influence of Cd 2+ on H. verticillata was greater than that of Cu 2+ when the same concentrations of the two different heavy metals were used. When Cu 2+ concentration was lower than 1 mg/L in the water environment, photosynthetic activities of H. verticillata under Cu 2+ stress were almost normal. This means that H. verticillata could be used to restore a water environment with a low Cu 2+ concentration. H. verticillata cannot survive for a long time in a water environment contaminated with Cd 2+ or if Cu 2+ concentrations reach or exceed 3 mg/L. This means that H. verticillata could be used as an indicator species for water contaminated with Cd 2+ .

以黑藻( Hydrilla verticillata )为供试材料,采用Cd 2+ 和Cu 2+ 等两种重金属分别在5个浓度梯度水平下的河砂水培方法,研究Cd 2+ 或Cu 2+ 不同浓度胁迫对黑藻株高、生物量、成活率和叶绿素含量的影响,以及对黑藻叶片最小荧光( F o)、最大荧光( F m),PSⅡ最大量子产率( QY max ,)、稳态下的PSⅡ反应中心关闭程度(1- Qp _Lss)、稳态下的非光化学淬灭(NPQ_Lss)等光合荧光参数及其荧光成像的影响,探讨各个参数分别随镉、铜浓度递增的变化规律。研究结果表明,Cd 2+ 胁迫下黑藻的株高显著下降,说明Cd 2+ 可能对黑藻叶片的维管束结构产生伤害作用;Cd 2+ 和Cu 2+ 胁迫对黑藻鲜重均无显著影响,说明与水生植物自由水含量存在一定关系;Cd 2+ 和Cu 2+ 胁迫均使黑藻干重显著下降,其中Cu 2+ 胁迫对黑藻干重的影响更显著,说明Cu 2+ 胁迫对黑藻累积生物量的影响远大于Cd 2+ ;Cd 2+ 和Cu 2+ 胁迫下叶绿素各值均呈下降趋势,而Cu 2+ 胁迫对叶绿素的影响更大,说明Cu 2+ 对黑藻叶绿体的毒害比Cd 2+ 更大。随着Cd 2+ 或Cu 2+ 胁迫浓度梯度的增加,黑藻的叶绿素荧光参数( F o、 F m、 QY max )呈显著下降趋势,(1- Qp _Lss)呈上升趋势,而NPQ_Lss先上升后下降。黑藻在不同重金属胁迫下的生理指标、荧光参数及成像特征等方面所表现出的变化差异性,反映出同等浓度下黑藻受重金属胁迫的影响程度为:Cd 2+ 胁迫>Cu 2+ 胁迫;黑藻可以在Cu 2+ 浓度低于1 mg/L的环境下具有正常的光合活性,可推测将黑藻用于低浓度Cu污染水域的修复;在Cu 2+ 浓度达3 mg/L以上环境下黑藻即无法长时间生存,可推测黑藻可以作为Cd污染水环境的指示种。

... 3 讨论Cu作为植物所必需的微量元素之一,植物体内Cu²⁺含量过多、过少都会对植物生长产生影响,过少会影响植物体内多种氧化还原反应和光合电子传递,过多则会对植物产生铜盐毒害,导致植株生长缓慢,甚至枯萎死亡^[25] ...

2018

0.0

... 本研究结果表明,低浓度Cu²⁺对盐生草种子萌发影响较小,高浓度则产生抑制作用,这与 Zhou等^[26]研究结果一致 ...

2018

0.0

... L^-1 Cu²⁺胁迫下则迅速升高,这可能是因为溶液中Cu²⁺最先接触植物根部,致使根尖细胞分裂速度减慢,达到某一临界值时对植物根系产生严重毒害,导致其活力降低,从而严重抑制幼苗生长和生物量积累^[27] ...

2017

0.0

... Zn是植物生长发育必需的微量营养元素,在维持和稳定生物膜功能完整性,保证叶绿素的形成以及6大类功能酶(氧化还原酶、转移酶、水解酶、裂解酶、异构酶和合成酶)活性等方面发挥着重要作用^[28] ...

2014

0.0

. 2014, 31(6):1080-1086 DOI:10.11829\j.issn.1001-0629.2013-0337

Effects of three metal ions on growth and physio-biochemical response of Achnatherum inebrians

重金属胁迫对醉马草生长及生理生化指标的影响

Wang P , Zhang X X , Zhao X J

王萍, 张兴旭, 赵晓静

Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology , Lanzhou University, Lanzhou 730020, China

The effects of manganese (Mn), zinc (Zn) and iron (Fe) on growth parameters of drunken horse grass ( Achnatherum inebrians ) over an 8-week period were determined with controlled-environment experiment. Varions were also determined for anti-oxidative enzymes including catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD), proline and malonialdehyde (MDA). The results showed that the plant height, tiller number and aboveground biomass of A.inebrians decreased with the increasing concentration of Mn, Zn and Fe, which had significant differences ( P P A. inebrians increased with the increasing concentration of Mn. CAT and SOD activities significantly ( P -1 treatments and dropped dramatically under the concentrations of 2.5～7.5 mmol·L -1 treatments. Under the stress of Zn, POD activities had a peak value at 7.0 mmol·L -1 , while SOD activities maintained higher level at 14.0 mmol·L -1 treatment which had significant ( P P -1 which had significant ( P A.inebrians had strong tolerance to three heavy metal stresses, as reflected by morphological parameters and reduced ROS injury.

本研究通过比较不同浓度的Mn、Zn和Fe胁迫下醉马草( Achnatherum inebrians )的形态及生理生化指标，探讨醉马草对Mn、Zn和Fe的耐受性。结果表明，随着Mn、Zn和Fe胁迫浓度的增大，醉马草地上生物量积累、株高和分蘖数均显著降低( P P P -1 浓度范围内呈显著( P -1 浓度范围内呈显著( P -1 时达到最大，SOD活性在Zn处理14.0 mmol·L -1 时达到最大，均与其他处理差异显著( P P P -1 时达到最大，并与其他处理差异显著( P <0.05)。综上所述，重金属胁迫对醉马草幼苗生长有一定的抑制作用，同时对其生理生化指标也产生影响。

... 研究表明,植物体内一定浓度的Zn²⁺对植物生长发育有促进作用,当超过某一临界值时便会对植物产生毒害,主要体现在萌发受阻,生长抑制,光合、呼吸作用减弱等方面^[29] ...

2014

0.0

. 2014, 34(22):6501-6509 DOI:10.5846/stxb201312132944

Seed germination and metal accumulation of Moso bamboo (Phyllostachys pubescens) under heavy metal exposure

重金属胁迫对毛竹种子萌发及其富集效应的影响

Chen J R , Liu D , Wu J S

陈俊任, 柳丹, 吴家森

Along with the increase of economics, heavy metal pollution in soil directly threatens food production security, and the toxicity affects humans because of their longevity and accumulation in organs. Phytoremediation is a new technology that usually employ hyperaccumulator plants to remove pollutants from environment or to render them harmless. The biomass of hyper-accumulators discovered before are less, and as a result in actual applications the hyper-accumulators are restricted significantly. Moso bamboo ( Phyllostachy pubescens ) is not hyperacculator specie, but it has several advantages compared with hyperaccumulators. Moso bambo grows quickly, reaching maximum size within two months with an average height of 15m. In present paper the seeds of Moso bamboo are taken as test materials, the toxicity effects of four heavy metals involving Pb 2+ , Zn 2+ , Cu 2+ and Cd 2+ on seed germination and its accumulation of heavy metals were studied. The results indicated that: (1) The addition of Pb 2+ and Cd 2+ inhibited the germination rate, germination energy, germination index and vigor index of Moso bamboo seed significantly. For the low treatment level of Cu 2+ and Zn 2+ , the germination rate, germination energy, germination index and vigor index increase significantly, while the results were on the contrary for the high treatment level. When the treatment dosage reached to 1600 μmol/L, the Cd 2+ addition has strong inhibition on seed germination than other three heavy metals. (2) The addition of low levle of Pb 2 + and Zn 2+ would promote the root growth significantly, while with the stress of Cu 2+ and Cd 2+ the root morphology are inhibited. (3) The concentration of Pb 2+ , Zn 2+ , Cu 2+ and Cd 2+ in shoots of Moso bamboo reached 6810.51, 1387.77, 951.77 and 429.33mg/kg respectively after treating for 10 d. The translocation factor dimension is Zn 2+ > Cd 2+ > Pb 2+ > Cu 2+ , and the tolerance order of bamboo seedlings to heavy metal is: Zn 2+ > Pb 2+ > Cu 2+ > Cd 2+ . In summary, the results of above all would provide useful reference for soil test in future, and it also opens a new perspective for the study of phytoremediation species selection.

以毛竹种子为供试材料,研究4种重金属(Pb 2+ 、Zn 2+ 、Cu 2+ 、Cd 2+ )胁迫对毛竹种子萌发的影响,并考察重金属在毛竹幼苗各组织部分的富集情况.结果表明:(1)Pb 2+ 和Cd 2+ 对毛竹种子的发芽率、发芽势、发芽指数及活力指数有抑制作用,低浓度下Cu 2+ 和Zn 2+ 对毛竹种子的发芽势、发芽率、发芽指数等指标有促进作用,高浓度则显著抑制;当浓度达到1600μmol/L时Cd 2+ 对种子萌发的抑制效果明显强于其他3种元素;(2)选取根尖数、根表面积、根体积、根系总长4个根系形态指标发现,低浓度处理下Pb 2+ 、Zn 2+ 对根系生长有促进作用,而Cu 2+ 和Cd 2+ 起到明显的抑制作用;(3)处理10d后,种子萌发幼苗地上部对Pb 2+ 、Zn 2+ 、Cu 2+ 、Cd 2+ 的含量最高可达6810.51、1387.77、951.77、429.33 mg/kg,转移系数Zn 2+ > Cd 2+ > Pb 2+ > Cu 2+ .综上,系统揭示了毛竹种子在重金属胁迫下的萌发和富集情况,为今后的土培、大田试验提供了有益的参考,也为将毛竹作为植物修复材料加以研究开启了新的研究视角,具有重要的研究价值.

... 本研究中,在低浓度Zn²⁺胁迫下,盐生草种子发芽率、发芽势、株高、干鲜重和根系活力均高于对照,高浓度则产生抑制作用,这与陈俊任等^[30]研究结果相似 ...

... Cu²⁺,有研究证明,相比其他金属,Zn²⁺对植物的毒害作用最弱^[30,31],这可能是因为Zn²⁺参与多种代谢途径,植物对Zn²⁺的需求量大于其他微量元素,此外,金属的价态不同也会导致其对植物的毒害强度不同,高浓度Se能显著抑制烟草的农艺性状,且Se(VI)抑制效果大于Se(IV),同时烟草体内Se(VI)积累量明显高于Se(IV)^[32] ...

2012

0.0

2015

0.0

2017

0.0

... Ni对植物新陈代谢起着重要作用,研究发现,Ni²⁺毒害会严重抑制植物侧根的形成及生长,影响其对水分和养分的吸收,进一步引起植物生理代谢失调^[33] ...

2013

0.0

... L^-1)处理下与对照差异不显著,高浓度时受到显著抑制作用,这与龚磊等^[34]的研究结果一致 ...

2013

0.0

. 2013, 22(3):154-161 DOI:10.11686/cyxb20130320

Effects of cadmium stress on growth, biomass and nutrient accumulation and distribution of Catharanthus roseus

镉胁迫对长春花生长, 生物量及养分积累与分配的影响

Liu S L , Shi X S , Pan Y Z

刘柿良, 石新生, 潘远智

长春花是我国广泛栽培兼具园林绿化和抗癌药源等重要价值的多年生草本花卉植物。为了解镉胁迫下长春花的生长适应性和对养分的吸收和利用，采用盆栽试验研究了不同镉处理（０，５，１０，２５，５０，１００ｍｇ／ｋｇ）下长春花生长、生物量及养分（Ｃ、Ｎ、Ｐ和Ｋ）积累与分配特征。结果表明，随镉处理浓度的增加，植物各器官镉积累量升高；除叶片Ｐ积累量降低外，植物各器官生物量生产及Ｃ、Ｎ、Ｐ和Ｋ积累量均表现出先升高后降低的趋势。较高浓度镉处理（≥２５ｍｇ／ｋｇ）明显抑制了长春花的生长特性、生物量生产以及Ｃ、Ｎ、Ｐ和Ｋ的积累，显著改变了生物量及其Ｃ、Ｎ、Ｐ和Ｋ积累量的分配格局，但相对低浓度的镉处理（≤１０ｍｇ／ｋｇ）并无显著影响。一定程度上，长春花对镉具有较强的耐性，为城市园林绿化和净化重金属污染土壤提供了可能，在镉污染土壤的修复中具有一定的应用潜力。

... 本研究中,低浓度Cd²⁺延缓盐生草种子萌发,高浓度则产生抑制作用,可能是因为Cd²⁺抑制种子内储藏淀粉和蛋白质的分解,从而影响种子萌发所需的物质和能量,致使种子萌发受阻^[35] ...

2015

0.0

. 2015, 24(5):100-107 DOI:10.11686/cyxb20150512

Effects of Cd²⁺ on the seed germination and seedling growth of Cynodon dactylon and Eremochloa ophiuroides

Cd 2+ 对狗牙根、假俭草种子萌发及幼苗生长的影响

Cen H M , Peng L L , Yang X

岑画梦, 彭玲莉, 杨雪

The College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611730, China

The effect of Cd 2+ concentration on the germination and growth of Cynodon dactylon and Eremochloa ophiuroides has been studied. The results showed that the seed germination rate, germination vigor, germination index, vigor index, root length and seedling length of the two turfgrass species decreased with increases in Cd 2+ concentration. Chlorophyll content in leaves decreased slightly and the MDA contents in leaves showed a rising trend after an initial drop with increasing Cd 2+ concentration. The CAT activities of C. dactylon increased at first and then decreased with increasing concentrations. At a Cd 2+ concentration of 5.0 mg/L, CAT activities were significantly higher than that of CK, while the CAT activities of E. ophiuroides in all treatments were lower than that of CK. The POD activities of the two turfgrass species increased at first and then decreased with increasing Cd 2+ concentration, reaching its peak at 10.0 mg/L. The PPO activities of C. dactylon and E. ophiuroides were higher than CK when the concentrations were at 5.0, 10.0, 20.0 and 40.0 mg/L. With increasing Cd 2+ concentrations, the PPO activities of both species showed a declining trend following an initial rise. The two turfgrass species have a certain degree tolerance of Cd 2+ , with the tolerance of C. dactylon greater than that of E. ophiuroides . Both turfgrass species can thus be used in soils with low levels of Cd 2+ pollution.

探讨了Cd 2+ 浓度对狗牙根与假俭草种子萌发和幼苗生长的影响。结果表明,两草种种子的发芽势、发芽率、发芽指数、活力指数、根长以及幼苗长度均随Cd 2+ 浓度的升高而降低;叶片叶绿素含量随Cd 2+ 浓度的升高略有降低;叶片丙二醛(MDA)含量随Cd 2+ 浓度的升高呈先降后升趋势;狗牙根过氧化氢酶(CAT)活性随Cd 2+ 浓度升高呈先升高后降低趋势, 在5.0 mg/L时显著高于CK, 假俭草各处理浓度的CAT活性均低于CK;两草种的过氧化物酶(POD)活性随Cd 2+ 浓度的升高呈先升高后降低趋势, 并在10.0 mg/L时达到峰值;Cd 2+ 浓度在5.0,10.0,20.0,40.0 mg/L时, 狗牙根和假俭草多酚氧化酶(PPO)活性均高于CK, 两草种PPO活性随Cd 2+ 浓度的升高都呈先升高后降低趋势。两草种对Cd 2+ 均有一定的耐受能力, 狗牙根耐受能力大于假俭草, 二者均可以应用于Cd 2+ 轻度污染土壤。

... 植物受Cd²⁺毒害时,线粒体和叶绿体受到破坏,导致呼吸、光合作用减弱,叶片发黄,生物量下降^[36] ...

2019

0.0

... L^-1 Cd²⁺胁迫下便受到显著抑制^[37],说明盐生草对Cd²⁺的耐性更强,这可能是因为盐生草长期在干旱、半干旱环境下生长,其体内形成特殊的重金属离子解毒机制,存在与重金属转运相关的基因 ...

2018

0.0

... Pb是植物非必需元素,其在植物体内的过量积累不但会对植株产生毒害,进入食物链还会对人体的多个器官和系统造成损伤,是人类可能的致癌物质^[38] ...

2014

0.0

. 2014, 25(1):287-296

Research advances in uptake, translocation, accumulation and detoxification of Pb in plants

植物对铅的吸收、转运、累积和解毒机制研究进展

Duan D C , Yu M G , Shi J Y

段德超, 于明革, 施积炎

( 1 College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China;  2 Hangzhou Environmental Group Co., Ltd., Hangzhou 310022, China)

Contamination of soils by lead (Pb) is of widespread occurrence because of the industrialization, urbanization, mining, and many other anthropogenic activities. It is urgent and necessary for scientists to uncover the mechanisms of uptake, translocation, accumulation and detoxification of Pb in plants for the following two reasons. First, it helps target and regulate the key process of Pb uptake by crops and vegetables and minimize the threat of Pb introduction to the food chain. Second, it helps cultivate Pb hyperaccumulating plants that can absorb and sequester excessive amounts from contaminated soils in their biomass without incurring damage to basic metabolic functions. The purpose of this review was to summarize the research advances in uptake, translocation and accumulation of Pb in plants and address the mechanisms by which plants or plant systems detoxify Pb. The further researches on the foliar uptake, the interactions between soil components and plant cell wall, as well as the integrated technologies for phytoremediation of Pbcontaminated soils were prospected.

揭示植物对铅的吸收、转运、累积和解毒的分子机制，可以明晰农作物吸收铅的关键过程，阻控铅在粮食、蔬菜中的积累，降低重金属的食用风险；也可以阐明某些铅超积累植物的耐性与解毒机制，分离并克隆铅超积累的功能基因，培育高效的铅污染土壤修复植物.本文从铅进入植物的两个重要途径(叶片的吸附与吸收以及根系的吸收与转运)出发，系统总结讨论了植物对铅的吸收、转运、累积和分布的研究进展；采用胞外至胞内的空间顺序，分别从植物根系分泌物的解毒、细胞壁的固定和动态响应、细胞质膜的选择透过性作用、液泡的区隔化作用以及金属有机配体的螯合等方面论述植物铅耐性和解毒的分子机理，并在此基础上提出存在的问题和今后研究的重点.

... L^-1 Pb²⁺胁迫下显著升高,并具有浓度效应,这说明盐生草对重金属Pb²⁺具有一定耐性,而低浓度下出现升高可能是植物对生长环境变化时产生的一种应激反应,但这种刺激作用受到浓度的限制^[39] ...

2014

0.0

... 在以上5种不同重金属胁迫下,与种子萌发相比,幼苗生长对重金属浓度更敏感,这可能是因为在充足的氧气和适宜的温度环境下,水分是种子萌发的另一重要因素,健康种子得到足够的水分便能迅速发芽,并且种皮对种胚具有一定的保护作用,研究发现,被重金属处理过的种子,经蒸馏水洗涤后其发芽率高于未洗涤的种子,说明种皮表面对重金属离子具有一定的黏附作用,可以适当减少进入种胚的金属离子^[40] ...

... 幼苗是植株生长最脆弱的时期,其抗逆能力最弱,种子萌发后,胚芽和胚根极易受金属离子毒害^[40],少量的金属离子胁迫便能使胚芽和胚根生长能力减弱,进一步使幼苗生长受阻,这便导致即使在逆境中种子能正常萌发,也不能成苗 ...