不同耐性大白菜苗期根系形态对低钾胁迫的响应

以耐低钾大白菜品种德丰1号和不耐低钾大白菜品种丰抗70为试材,采用水培试验研究了不同耐性大白菜苗期干物质积累及根系形态参数对低钾胁迫的响应。结果表明:低钾(0.3mmol·L-1)胁迫下,丰抗70根干质量、植株干质量及根冠比显著降低,德丰1号无明显变化;德丰1号细根(Φ≤0.2mm)根长、根表面积及细根表面积占根系总表面积的比例显著增加,丰抗70无明显变化。说明耐低钾大白菜品种在低钾胁迫下其细根根长和根表面积增加,有效提高了细根表面积所占比例,增强了耐低钾能力。

Response of Chinese Cabbage Seedling’s Root Morphology with Different Tolerance to Potassium Deficiency

Taking Chinese cabbage〔 Brassica campestris L. ssp. pekinensis（Lour）Olsson〕cultivars‘Defeng No.1’（tolerance to low potassium）and‘Fengkang 70’（sensitive to low potassium）as experimental material，studies the response made by dry matter accumulation during seedling stage and root system parameter of Chinese cabbage with different tolerance to potassium deficiency through hydroponics experiment．The results showed that under potassium deficiency（0.3 mmol·L^-1），the root dry weight，plant dry weight，and root to shoot ratio in‘Fengkang 70’declined significantly，while there were no marked changes in‘Defeng No.1’．On the other hand，the length and surface area of thin roots（Φ ≤ 0.2 mm）and the proportion between thin root surface area and total root system surface area were significantly increased in‘Defeng No.1’，while there were no changes detected in‘Fengkang 70’．All these results indicated that under low potassium stress，the increase of thin root length and surface area of Chinese cabbage cultivar with low potassium tolerance might increase the propotion of thin root length and its surface area，thus strengthen its tolerance to potassium deficiency．