Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii:the impact of citric acid and tartaric acid

The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metallic element tolerance,translocation,and accumulation in plants.The impact of exogenous organic acids on cadmium(Cd) uptake and translocation in the zinc(Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study.By the addition of organic acids,short-term(2 h) root uptake of 109 Cd increased significantly,and higher 109 Cd contents in roots and shoots were noted 24 h after uptake,when compared to controls.About 85% of the 109 Cd taken up was distributed to the shoots in plants with citric acid(CA) treatments,as compared with 75% within controls.No such effect was observed for tartaric acid(TA).Reduced growth under Cd stress was significantly alleviated by low CA.Long-term application of the two organic acids both resulted in elevated Cd in plants,but the effects varied with exposure time and levels.The results imply that CA may be involved in the processes of Cd uptake,translocation and tolerance in S.alfredii,whereas the impact of TA is mainly on the root uptake of Cd.

东南景天叶肉细胞原生质体和液泡的分离与纯化技术（英文）

目的:在超积累植物东南景天对镉的区隔化过程中,叶肉细胞等内含大型液泡的薄壁细胞起重要作用。本文旨在建立并优化其叶肉细胞原生质体和液泡的提取和纯化技术,在技术层面上为东南景天的镉区隔化机理研究奠定基础,有助于深入探明其超积累镉的生理与分子机理。创新点:优化了东南景天叶片原生质体的提取和纯化技术,并建立了能较高效率获得膜完整性好、数量多、纯度高的液泡提取方法。方法:主要包括原生质体提取、液泡粗提和液泡纯化。原生质体提取:取东南景天叶片,切成1~2 mm的细条状后浸入经预热过的细胞裂解液中,震荡2 h后过滤,离心清洗后获得原生质体。液泡粗提:采用1-丙磺酸浓度为0.675 mmol/L的原生质体裂解液裂解原生质体,离心后获得粗提的液泡,并加入含0.8 mol/L甘露醇的液泡保护液。液泡纯化:往初提液泡的悬浮液下层加入质量体积比浓度为0.10 g/ml的Ficoll溶液,进行密度梯度离心,获取纯化的液泡。结论:细胞裂解液的预热处理可加速细胞壁降解,裂解时间设置为2 h有利于原生质体的高效提取;通过对原生质体裂解液浓度、细胞保护液浓度和梯度离心等参数的改良,可有效提取叶片细胞原生质体中的液泡。

通过锌肥和适宜的水分管理提高水稻籽粒产量及锌积累量(英文)

研究目的:在生产高度集约化体系下,研究节水灌溉措施及锌肥对水稻产量及锌积累量的影响。创新要点:目前关于干湿交替能否对水稻增产仍存在争议,对锌含量及生物有效性也鲜有报道。因此,针对这些问题,本文系统地研究影响水稻产量及品质的两大限制性因素,即锌肥和灌溉方式对稻米锌生物有效性的影响。研究方法:采用盆钵试验模拟大田锌肥及水分管理方式,两种基因型、两种锌肥种类、两种水分管理,三个重复控制误差。利用电感耦合等离子体质谱(ICP-MS)测定微量元素锌含量,以精米中植酸含量表征锌生物有效性。重要结论:干湿交替在增加了稻米产量、锌含量及积累量方面效果显著。干湿交替结合土施硫酸锌肥可以作为水稻生产体系中获得高产、高锌、高生物有效性的农艺措施。