Characterization of cadmium binding, uptake, and translocation in intact seedlings of bread and durum wheat cultivars
Characterization of cadmium binding, uptake, and translocation in intact seedlings of bread and durum wheat cultivars
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DOI：
10.1104/pp.116.4.1413
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发表时间：
1998-04-01
期刊：
影响因子：
7.4
通讯作者：
Kochian, LV
中科院分区：
文献类型：
--
作者：
Hart, JJ;Welch, RM;Kochian, LV
硬粒小麦（Triticum turgidum L.）var durum）谷物对消费者和种植者带来了潜在的健康和经济问题。为了解小麦幼苗镉过量积累、根系镉吸收和木质部向地上部转运的生物学过程，和硬粒小麦品种进行了研究。全株Cd积累在面包小麦品种有点大，但这可能是因为增加质外体Cd结合。Cd-109（2+）浓度依赖性内流动力学曲线均为非饱和曲线，可分为线性和饱和曲线，饱和曲线代表载体介导的Cd跨质膜内流（米氏常数，20-40 nM;最大初始速度，26-29 nmol g（-1）鲜重h（-1）），而线性镉吸收代表细胞壁结合的Cd-109。镉转运到地上部的面包小麦品种比硬粒小麦品种，因为更大比例的根吸收的镉移动到地上部。我们的研究结果表明，过量的镉积累在硬粒小麦籽粒是不相关的幼苗根流入率或根冠转运，但可能与韧皮部介导的镉运输到籽粒。
High Cd content in durum wheat (Triticum turgidum L. var durum) grain grown in the United States and Canada presents potential health and economic problems for consumers and growers. in an effort to understand the biological processes that result in excess Cd accumulation, root Cd uptake and xylem translocation to shoots in seedlings of bread wheat (Triticum aestivum L.) and durum wheat cultivars were studied. Whole-plant Cd accumulation was somewhat greater in the bread wheat cultivar, but this was probably because of increased apoplastic Cd binding. Concentration-dependent Cd-109(2+)-influx kinetics in both cultivars were characterized by smooth, nonsaturating curves that could be dissected into linear and saturable components, The saturable component likely represented carrier-mediated Cd influx across root-cell plasma membranes (Michaelis constant, 20-40 nM; maximum initial velocity, 26-29 nmol g(-1) fresh weight h(-1)), whereas linear Cd uptake represented cell wall binding of Cd-109. Cd translocation to shoots was greater in the bread wheat cultivar than in the durum cultivar because a larger proportion of root-absorbed Cd moved to shoots. Our results indicate that excess Cd accumulation in durum wheat grain is not correlated with seedling-root influx rates or root-to-shoot translocation, but may be related to phloem-mediated Cd transport to the grain.