低磷胁迫下不同番茄品种苗期根系生理适应性研究

采用液培方法研究了不同番茄品种在低磷胁迫下根系及生理学的适应特征。结果表明：低磷胁迫导致植株根，冠比增加．不同番茄品种的磷营养效率的差异主要表现在磷的吸收能力，而不是磷素分配和利用率。低磷胁迫下，耐低磷番茄品种的侧根平均长度要高于低磷敏感品种；不同番茄品种在低磷胁迫下酸性磷酸酶活性上升幅度存在显著差异，随着磷胁迫强度的增强，耐低磷品种的酸性磷酸酶的上升幅度高于低磷敏感品种；耐低磷番茄品种在低磷胁迫下具有小的Km和Cmin，说明这两个指标是番茄在磷胁迫下较为敏感的生理指标。

Physiological Adaptability of Seedling Root System of Tomato Cutivars under Low-phosphorus Stress

The mechanism of morphological and physiological plasticity of seedling root system of tomato cutivars under low-phosphrus stress were studied with solution culture. Results showed that low-phosphorus stress restricted shoot growth, wher but stimulated root growth. The different phosphorus efficiency of tomato cultivars attributed to phosphorus uptake ability, not the different distribution of phosphorus and utilization ability. Under low-phosphorus, stress, the average length of lateral roots of low-phosphorus-tolerant tomato cultivar was longer than that of low-phosphorus-sensitive tomato cultivars; the acid phosphatasc activities of different cultivars rised significantly and the increment range of acid phosphatase activity of low-phosphorus-tolerant tomato cultivar was higher than that of low-phosphorus-sensitive tomato cultivars. Low Km and Cmin were characterized by low-phosphrus-tolerant tomato cuhivar under low-phosphorus stress.