Abstract：
Fungicides containing manganese (Mn) applied to control plant diseases increase the concentration of Mn in soils, which may potentiate Mn toxicity in acid soils. Some species of wild grasses, such as those from the Pampa biome located in South America, or even those introduced into this biome, may possess different mechanisms of tolerance to excess Mn. The present study aimed to evaluate the subcellular distribution and physiological and biochemical responses of exotic and native grasses from the Pampa biome, cultivated in Mn excess. The experiment was conducted in nutrient solution in a greenhouse, in an entirely randomized design, bifactorial 4 × 4, consisting of four Mn concentrations (2 [control], 300, 600 and 900 μM) and four species (two exotic: Avena strigosa and Lolium multiflorum; and two native: Paspalum notatum and Paspalum plicatulum). At 27 days of exposure to the treatments, biomass and growth rates, leaf gas exchange with the environment, photosynthetic pigment concentrations of malondialdehyde and H2O2, antioxidant enzyme activities (SOD and POD), and subcellular distribution of Mn were evaluated. Most of the grasses showed high concentration of Mn in tissues, mainly, in the shoot. In the presence of 900 μM Mn, more than 80% of the absorbed Mn was compartmentalized in the cell walls and vacuoles of the cells. Compartmentalization of Mn excess into metabolically less active organelles is the main tolerance factor in grasses. Physiological and biochemical responses were stimulated in the presence of 300 μM Mn, while 900 μM Mn negatively affected biochemical-physiological responses of grasses. The species L. multiflorum was most sensitive to excess Mn, while P. notatum was the most tolerant.
摘要：
用于控制植物病害的含锰（Mn）杀菌剂会增加土壤中Mn的浓度，这可能会增强酸性土壤中锰的毒性。一些野生草，比如南美的潘帕生物群落，甚至那些被引入这个生物群落的人，可能对过量Mn具有不同的耐受机制。本研究旨在评估Pampa生物群落中外来和本地草的亚细胞分布和生理生化反应，锰过量栽培。实验是在温室营养液中进行的，在完全随机的设计中，双因子4×4，由四个锰浓度组成(2[对照]，300、600和900μM）和四个物种（两个外来物种：Avenastrigosa和黑麦草；和两个本地物种：Paspalumnotatum和Paspalumplicatulum）。在接受治疗的27天，生物量和生长速率，叶与环境的气体交换，丙二醛和H2O2的光合色素浓度，抗氧化酶活性（SOD和POD），并对Mn的亚细胞分布进行了评价。大多数草在组织中显示出高浓度的锰，主要是,在拍摄中。在900μMMn的存在下，超过80％的吸收的Mn被分隔在细胞壁和细胞的液泡中。锰过量进入代谢活性较低的细胞器是草类的主要耐受因素。在300μMMn的存在下刺激生理和生化反应，而900μMMn对草类的生化生理反应产生负面影响。多花落叶松对过量锰最敏感，而P.notatum是最宽容的。
