钾对玉米苗期抗冷性的影响

EFFECT OF POTASSIUM ON CHILLING RESISTANCE OF MAIZE SEEDLINGS

利用玉米为材料，在砂培试验中，设置了0、1．5、3．0、15．0mmol／L4个钾水平，当玉米长至五叶期时分别进行8℃、25℃两种温度处理4天，测定了钾对玉米苗期抗冷性的影响。结果表明，在砂培条件下，适施钾肥增加了玉米地上部钾含量。低温胁迫下玉米叶片质膜离子渗透率增加，施钾有利于质膜透性保持较低水平；15．0mmol／L钾处理叶片质膜的离子渗透率仅为不施钾处理的58％。与此同时，在低温胁迫下，高钾植株叶片过氧化物酶活性降低，萎蔫率明显下降，抗冷性增强。

A sand culture experiment with 4 potassium concentration levels(0,1. 5, 3. 0and 15 mmol/L) was conducted. When the maize growing in 5 leaves, the pots were putinto growth chambers with two different temperatures(8℃ and 25℃ ) for 4 days tostudy the effect of potassium on the chilling resistanee of maize plants. The resultsindicated that application of potash fertlllzer. the potassium content of maize shoots wasincreased. After 4 days low temperature treatment, some leaves of maize began to wiltand the wilt rate of maize leaves was decreased from 73. 7% with 0 mmol/L K level to4. 5% with 15 mmol/L K level, while maize was normal growth at 25℃. The results alsoindicated that potash fertilizer decreased the activity of peroxidase and memberaneinjury of maize leaves induced by chilling stress. Therefore, appropriate application ofpotash fertilizer might improve chilling resistance of maize seedlings.