Lehstuhl für Bodenschutz und Rekultivierung, Brandenburgische Technische Universität, Postfach 10 13 44, D-0313, Cottbus, Germany; and.
Am J Bot. 2000 Aug;87(8):1081-90.
The objective of this work was to determine whether radial oxygen loss (ROL) from roots of Typha domingensis and Cladium jamaicense creates an internal oxygen deficiency or, conversely, indicates adequate internal aeration and leakage of excess oxygen to the rhizosphere. Methylene blue in agar was used to visualize the pattern of ROL from roots, and oxidation of a titanium-citrate solution was used to quantify rates of oxygen leakage. Typha's roots had a higher porosity than Cladium's and responded to flooding treatment by increasing cortical air space, particularly near the root tips. A greater oxygen release, which occurred along the subapical root axis, and an increase in rhizosphere redox potential (E(h)) over time were associated with the well-developed aerenchyma system in Typha. Typha roots, regardless of oxygen release pattern, showed low or undetectable alcohol dehydrogenase (ADH) activity or ethanol concentrations, indicating that ROL did not cause internal deficiencies. Cladium roots also released oxygen, but this loss primarily occurred at the root tips and was accompanied by increased root ADH activity and ethanol concentrations. These results support the hypothesis that oxygen release by Cladium is accompanied by internal deficiencies of oxygen sufficient to stimulate alcoholic fermentation and helps explain Cladium's lesser flood tolerance in comparison with Typha.
本研究旨在确定香蒲（Typha domingensis）和卵穗苔草（Cladium jamaicense）的根是否会因径向耗氧（ROL）而导致内部缺氧，或者相反，这表明内部有充足的通气并将过量氧气漏到根际。使用琼脂中的亚甲基蓝来可视化根的 ROL 模式，并用氧化钛-柠檬酸盐溶液来定量氧泄漏速率。香蒲的根比卵穗苔草根具有更高的孔隙率，并且对淹水处理的反应是增加皮层气腔，特别是在根尖附近。随着时间的推移，沿亚根尖轴发生更大的氧气释放，以及根际氧化还原电位（E(h)）的增加，与香蒲发达的通气组织有关。无论 ROL 模式如何，香蒲根的表现出低或无法检测到的醇脱氢酶（ADH）活性或乙醇浓度，这表明 ROL 不会导致内部缺氧。卵穗苔草根也会释放氧气，但这种损失主要发生在根尖，并伴随着根 ADH 活性和乙醇浓度的增加。这些结果支持了这样一种假设，即卵穗苔草根的氧气释放伴随着足够的内部缺氧，足以刺激酒精发酵，并有助于解释与香蒲相比，卵穗苔草的耐淹水能力较差。
