Departamento de Biología Molecular, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Departamento de Ciencias Naturales, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Plant Physiol Biochem. 2018 Feb;123:8-17. doi: 10.1016/j.plaphy.2017.11.020. Epub 2017 Dec 2.
Soybean (Glycine max L.) is often cultivated in areas contaminated with arsenic (As), which negatively affects plant growth and reduces crop yield. The deleterious effects may be due, at least in part, to disturbances in the water status, as was reported for some plants exposed to heavy metals. However, to our knowledge, these mechanisms have not been studied in depth in soybean plants exposed to As. The aim of the present work was to analyze possible changes in water relations and the responses developed in soybean plants under arsenate (AsV) and arsenite (AsIII) stress. We discuss physiological and morphological aspects of the As stress response, such as root absorption rate, water content, stomatal conductance, water and osmotic potential, accumulation of compatible solutes, leaf conducting tissues and stomata characteristics. AsV and AsIII caused a significant decrease in root absorption rate, which could reduce metalloid uptake. On the other hand, water content decreased at the beginning of the treatment but was re-established after 4 and 8 d. This was correlated with a decrease in stomatal conductance and a reduction in leaf water and osmotic potential due to the accumulation of proline and soluble sugars. Besides, smaller leaf xylem vessels and abnormal stomata were observed in plants under As treatment. These mechanisms increased the plant's ability to retain water and therefore to avoid dehydration. Thus, the results of the present work contribute to the understanding of how soybean responds to As, by describing key tolerance strategies to the metalloid.
大豆（Glycine max L.）通常在砷（As）污染的地区种植，这会对植物生长和作物产量产生负面影响。这些有害影响可能至少部分归因于水势的紊乱，正如一些暴露于重金属的植物所报告的那样。然而，据我们所知，这些机制在暴露于砷的大豆植物中尚未得到深入研究。本工作的目的是分析在砷酸盐（AsV）和亚砷酸盐（AsIII）胁迫下大豆植物可能发生的水分关系变化和响应。我们讨论了砷胁迫响应的生理和形态方面，如根吸收速率、含水量、气孔导度、水势和渗透势、相容性溶质的积累、叶片导组织和气孔特征。AsV 和 AsIII 导致根吸收速率显著下降，这可能会减少金属元素的吸收。另一方面，处理开始时含水量下降，但在 4 和 8 d 后重新建立。这与气孔导度下降以及脯氨酸和可溶性糖积累导致叶片水势和渗透势下降有关。此外，在砷处理的植物中观察到较小的叶片木质部导管和异常的气孔。这些机制提高了植物保留水分的能力，从而避免了脱水。因此，本工作的结果通过描述对金属元素的关键耐受策略，有助于了解大豆对砷的响应。
