低钾胁迫对玉米苗期根系生长和钾吸收特性的影响

The Effects of Low Potassium Stress on Root Growth and Potassium Absorption of Maize Seedling

研究低钾胁迫对玉米苗期根系生长和钾吸收特性的影响。玉米自交系种子A(不耐低钾)和B(耐低钾)用三个钾离子浓度(5μmol/L,100μmol/L,1000μmol/L)进行液体培养,4周时将苗转入培养桶中,连续培养50天。在转入的0d、3d、10d、25d、50d天时距根尖2cm处取样,观察根部形态特征及解剖结构,对其根系活力、Imax、Km进行测定。结果表明:耐低钾品种B低钾条件下,根表形态结构上,根毛数量增加,且形成部位距根尖较近;根解剖结构上,木质部导管分化增强,并改善了疏导组织运输能力;根冠比上,长度、重量根冠比增加;根系吸收能力上,根系活力、Imax显著提高,Km显著降低。耐低钾品种从根形态结构改变及根系活跃吸收能力增强两方面协同作用适应低钾胁迫,提高钾吸收能力。

The article studied stress response on root system growth and potassium absorption of maize seedling at K^＋ deficiency. Two inbred lines of maize seed, A which sensitive to K^＋ deficiency and B which tolerant to K^＋ deficiency, were cultured in nutrient solutions of three different K^＋ concentration （5, 100, 1 000 μmol/L）. After 4 weeks, the maize seedling had been cultured, the plants were transplanted into culture barrel and then cultured for 50 days. Sampling was made near by root tip 2 cm on time（0, 3,10, 25, 50 days）, when to observed root system morphological character and dissection structure, and determined its root system vigor, Imax, Km. The results showed that under lower K^＋ concentration, root hair number of B was increased and growed near by the root tip. Xylem canal differentiation enhancive at dissection structure, and it improved transportation ability of leading organization. Root top ratio of length and weight increases, root system vigor and Imax of B obviously increased while Km obviously decreased. B improved potassium absorption through synergistic action both root system morphological character and active potassium absorbency.