Department of Plant Sciences, Texas A & M University, College Station.
Plant Physiol. 1966 Apr;41(4):718-24. doi: 10.1104/pp.41.4.718.
The effect of substrate manganese on tissue manganese levels and activity of the indoleacetic acid (IAA)-oxidase system of cotton (Gossypium hirsutum, L.) was investigated. A sand culture technique was used with 1, 3, 9, 27 and 81 mg manganese (MnSO(4)) per liter nutrient solution applied in various experiments.The following relationships held for both long-term (126 days) and short-term (12-14 days) exposures to manganese treatment: A) There was a direct relationship between substrate and tissue manganese. B) Only the 81 mg/liter Mn plants exhibited severe manganese toxicity symptoms. C) At the toxic level of manganese an increased IAA-oxidase activity and decreased IAA-oxidase inhibitor activity was observed. There was a direct relationship between degree of enzyme response and severity of visible symptoms. D) With the manganese toxicity plants, but none of the other treatments, extracts of the young leaves contained as much IAA-oxidase activity as extracts of much older leaves. E) Crude extracts from the plants grown with 81 mg manganese per liter solution, in contrast to those of other treatments, destroyed IAA without addition of MnCl(2) to the assay medium.A hypothesis is advanced stating that manganese toxicity symptoms in cotton are expressions of auxin deficiency caused by IAA-oxidase activity increased by the abnormal tissue levels of manganese.
研究了基质锰对棉花（Gossypium hirsutum，L.）组织锰水平和吲哚乙酸（IAA）氧化酶系统活性的影响。在各种实验中，使用了沙培技术，用 1、3、9、27 和 81 mg 锰（MnSO4）/升营养液进行处理。以下关系适用于长期（126 天）和短期（12-14 天）暴露于锰处理：A）基质和组织锰之间存在直接关系。B）只有 81 mg/l 锰处理的植物表现出严重的锰毒性症状。C）在锰的毒性水平下，观察到 IAA 氧化酶活性增加和 IAA 氧化酶抑制剂活性降低。酶反应程度与可见症状的严重程度之间存在直接关系。D）在锰毒性植物中，但在其他处理中均未观察到，幼叶提取物中的 IAA 氧化酶活性与老得多的叶片提取物中的活性相同。E）与其他处理相比，在 81 mg 锰/升溶液中生长的植物的粗提取物在测定介质中无需添加 MnCl2 即可破坏 IAA。提出了一个假设，即棉花中的锰毒性症状是由于 IAA 氧化酶活性增加导致生长素缺乏的表现，而这种活性增加是由异常的组织锰水平引起的。
