Studies On Physiological Reaction Of Ramie (Boehmeria Nivea L.) Under Low Potassium Stress

In this research, two ramie varieties that tolerance to low potassium and two ramie varieties that intolerance to low potassium were selected to as experiment materials. Pot experiment and analysis methods were conducted to study any kinds of adaptive reaction from morphology to physiology in ramie under low potassium stress systematically, and discussed the possibility of physiological diagnosis index of potassium deficiency in ramie under low potassium stress. Main results were as follows:1. External symptom of potassium deficiency in ramie was obvious under low potassium stress. The growth of ramie was stunted, and the plant height lowered apparently. The old leaves expressed symptom first generally, it turned yellow along outer margin of leaf, and turned brown further and withered to shed off finally. The symptom of potassium deficiency of varieties that intolerance to low potassium was deeper than varieties that tolerance to low potassium. In the meanwhile, the percentage of radish root in the fresh root weight declined, the percentage of rootlet in the fresh root weight increased, and the plant fresh weight reduced. On the contrary, the proportion (fresh weight) of the underground part and the aerial part increased.2. The contents of endogenous hormone in ramie varied apparently under low potassium stress, contents IAA and iPAS contents went down, but ABA and GAi/3 contents went up. In the meanwhile, the ratio of leaf ABA to root ABA contents, the ratio of iPAS to ABA contents in root declined apparently. The ratio of ABA to IAA contents in leaf, and the ratio of IAA to iPAS content in leaf of varieties that intolerance to low potassium increased apparently. The ratio of leaf iPAS to root iPAS contents declined in early growing period, and increased in middle and behind growing period, but the ratio of ABA to GAi/3 contents in leaf declined in early and middle growing period, and increased in behind growing period apparently.3. Potassium contents in aerial part of ramie went down apparently under low potassium stress. The fluctuation range of potassium contents in bone of ramie was biggest. The effect of low potassium stress on potassium contents in behind growing period was larger than in early and middle growing period.4. Put contents in leaf of ramie increased apparently under low potassium stress. The increasing proportion of Put was larger apparently than lowing proportion of potassium contents. In the meanwhile, the ratio of ABA to Put contents in leaf also went down.5. In a word, it may serve as hormone signal by the ABA contents in root of ramie under low potassium stress, regard as physiology diagnose index of potassium deficiency by Put contents in leaf.