硅对锰胁迫下水稻吸收矿质元素的影响

揭示Mn胁迫下硅对水稻中营养元素的影响特点,可为减轻水稻锰毒害提供理论依据.因此,本文通过水培试验,利用两个对Mn耐性不同的水稻品种,研究施Si(1.5 mmol·L-1)对Mn(2 mmol·L-1)胁迫下水稻营养元素的影响.同时,采用同步辐射X射线荧光(SRXRF)分析了营养元素的分布特点,以及各元素分布之间的相互关系.结果显示,高锰胁迫下,耐性品种叶片和根系的Mn含量都显著高于敏感品种.高锰胁迫抑制了敏感品种K元素从根部向叶片的转移,而降低了耐性品种的根部吸收K元素的能力.高锰胁迫下,施硅处理增加了敏感品种叶片中K、Fe和Zn的相对含量;可显著增加耐性品种叶片中K和Zn的相对含量,显著降低其Ca和Fe的相对含量.高锰胁迫下施硅可以促进敏感品种K元素的转运,促进耐性品种Zn元素转运.Si对耐性品种各元素含量保持相对平衡具有重要作用.水稻体内的锰大部分是硫酸锰,高锰胁迫下施硅不改变水稻植株体内的锰形态.

Silicon-mediated mineral elements in rice(Oryza sativa L.) under excess manganese stress

The aim of the paper was to study the mechanism of how silicon mediates nutrient in rice (Oryza sativa L.) grown under excess manganese (Mn) stress. Two rice varieties that differ in Mn tolerance were cultured in nutrient solution to study the effects of Si (1.5 mmol·L^-1) on nutrient elemental status in rice under excess Mn stress (2 mmol·L^-1). The distribution of elements in roots and leaves in rice was determined with X-ray synchrotron radiation XRF. The results showed that Mn concentration in foliage and roots at the high Mn level was much greater in Mn-tolerant cultivar than in the Mn-sensitive cultivar. In cv. XXY, a sensitive cultivar, treated with high-Mn resulted in a restriction of K root-to-shoot transport, whereas K uptake from the solution to roots was depressed in cv. ZLY, a tolerant cultivar. In the Mn-sensitive cultivar, supply with Si significantly increased the relative contents of K, Fe and Zn in foliage under high-Mn stress compared with the Si-untreated plants. In the tolerant cultivar, supplying with Si significantly increased the relative contents of K and Zn in foliage under high-Mn stress, but considerably decreased the relative contents of Ca and Fe compared with the Si-untreated plants. In contrast, supplying with Si considerably decreased the relative content of K in the roots of Mn-sensitive cultivar, but significantly increased in foliage under high-Mn stress. This suggests that Si can promote K transport from roots to shoots under high-Mn stress in cv. XXY and promote Zn transport from roots to shoots in cv. ZLY. This indicates that Si plays an important role in keeping the relative balance between elements in Mn-tolerant cultivar. Manganese sulfate is the most form in rice. Under high-Mn stress, Si addition did not change manganese form in rice.