小麦/玉米苗期磷累积量对介质供磷水平反应的差异
Response of P accumulation in wheat and maize seedlings to different substrate P levels
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摘要: 小麦和玉米苗期是磷素营养的关键期和敏感期, 研究两种作物苗期对介质供磷反应, 可为合理施用磷肥提供参考。试验设缺磷对照、低磷胁迫、中等磷胁迫和正常供磷(P2O5含量分别为0、0.05 mmol·L-1、0.3 mmol·L-1和0.5 mmol·L-1) 4种磷水平, 选取小麦“小偃22号”、“兰考4号”和玉米“屯玉65号”、“户单4号”为指标作物, 用营养液培养法研究小麦、玉米苗期磷累积量对介质不同供磷水平的反应差异。结果表明, 不同介质供磷水平下, 两种作物苗期磷累积量显著不同且因作物类型、基因型、器官及测定时期不同而异。总体而言, 介质供磷后, 苗期早期生长阶段(出苗后25 d以前), 小麦的介质最佳供磷水平较玉米高; 苗期后期(出苗后40～50 d), 小麦和玉米最佳供磷水平一致。如果以低磷胁迫作为对比进行分析, 玉米苗期整株磷累积量对介质供磷的敏感性比小麦强; 从不同基因型来看: “兰考4号”对介质供磷的敏感性强于“小偃22号”, “屯玉65号”和“户单4号”基本一致。缺磷条件下小麦较玉米磷效率高, 供磷条件下玉米较小麦高; 但不同基因型间规律性较差。Abstract: Wheat (Triticum aestivum L.) and maize (Zea mays L.) are very sensitive to phosphorus at seedling stage. Two varieties of wheat (“Xiaoyan 22” and “Lankao 4”) and maize (“Tunyu 65” and “Hudan 4”) were grown in Hoagland solution under different phosphate concentrations 0, 0.05 mmol (P2O5)·L-1, 0.3 mmol (P2O5)·L-1, 0.5 mmol (P2O5)·L-1 to investigate the response of P accumulation in wheat and maize at seedling stage to P levels in substrate. The results show a significantly difference in P accumulation in two corps under different substrate P levels. Variation in P accumulation is dependent on crop genotype, organ and the measurement time. The optimal level of P in wheat substrate is higher than that in maize during early seedling stage (25 days after seed emergence). There is, however, no observable difference between the two crops during later seedling stage (40 ~ 50 days after seed emergence). When 0.05 mmol·L-1 treatment is used as the control, P accumulation in the entire plant of maize becomes more sensitive to substrate P level than in wheat. “Lankao 4” is more sensitive than “Xiaoyan 22” and there exists no observable difference between “Tunyu 65” and “Hudan 4”. P efficiency in wheat is higher than in maize under zero phosphate treatment, while the reverse is the case under phosphate treatment. There is no consistent relationship between different genotypes.
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