不同钾水平对钾饥饿墨兰碳水化合物和蛋白质含量的影响

墨兰（Ｃｙｍｂｉｄｉｕｍｓｉｎｅｎｓｅ（Ａｎｄｒ．）Ｗｉｌｌｄ）植株经过钾饥饿后，无上栽培于不同钾浓度的培养液中．随着钾浓度的升高（５ｍｍｏｌ／Ｌ），体内可溶性糖、淀粉、纤维素和蛋白质含量比对照分别增加１２５、１１７、１２７和４１％，而还原糖和游离氨基酸含量则比对照分别下降４４％和２４％．假球茎是贮藏还原糖、可溶性糖、淀粉、游离氨基酸和蛋白质的主要器官，叶片是纤维素最多的器官．钾供应充足时，叶片丙酮酸激酶活性明显加强（比对照强１５倍），而硝酸还原酶活性也加强（比对照强０．８倍）．本文对钾促进墨兰生长发育和抗病等原因加以讨论．并初步提出诊断墨兰体内钾状况的三种生理指标．

INFUENCE OF DIFFERENT POTTASSIVM LEVELS ON CONTENTS OF CARBOHYDRATE PROTEIN IN CYMBIDIUM SINENSE FOLLOWING POTASSIUM STARVATION

Cymbidium sinense(Anar)Willd. plants were cultured hydloponically in culture solution at different K levels following K starvation. The contents of Carbohydrate and protein as well as some enzymes activities in various growth periods had been measured. With increasing K concentration, the contents of soluble suber, starch, cellulose and protein in plants treated with 5 mrnol/L KC1 were inerased by 125, 117, 127 and 41% respectively than those of the control. However, these KC1 treated plants had reduced by 44 and 24% in the contents of reducing sugar and free amino acid respectively than those in the control. Pseudocorm was the major organ for storing reducing sugar, soluble sugar, starch,protein and free amino acid, but cellulose mainly diStributed in leaf. When K was sufficient to plant requirement, the activity of pyruvate kinase in leaf iucreased by 15 times as against the control, and nitrate reductase was also about 1. 8 times the activity of the control. The possible reason for K promoting growth, development and disease resistance in C. sinense was discussed. And, three methods of Preliminary physiological diagnosis for K nutrition in this Plant were also suggested.