大豆根形态和根分泌物特性与磷效率

通过土培和水培试验 ,对不同大豆品种进行了根系形态及根分泌物的比较研究 结果表明 :大豆在耐低磷特性方面存在着一定的品种差异 ,其中大豆品种南雄 36号有较高的耐低磷能力 ,在低磷 (P0 )胁迫条件下其苗期整株生物量为 1 5 0g/株 ,显著高于博罗 5 8号 (0 92g/株 )和博罗 61号 (1 0 3g/株 ) 在不同磷处理下 ,大豆的根冠比、主根长、总吸收面积和活跃吸收面积有变化 ,但品种间缺乏明显一致的规律性 ,表明这些性状不一定适合作为大豆磷效率比较的特异性指标 磷胁迫时大豆总酸和H+的分泌量较正常供磷条件下高 ,其中南雄 36号在磷胁迫时总酸分泌量为 0 93μmol·g-1·h-1,显著高于博罗 5 8号 (0 60 μmol·g-1·h-1)和博罗 61号 (0 63μmol·g-1·h-1) 此外 ,南雄 36号在低磷胁迫下草酸和乳酸分泌量均显著高于另外 2个品种 ,表明该品种对活化土壤中难溶性磷有一定的遗传潜力 ,具有较高的磷效率

Characteristics on Root Morphology and Root exudation of Soybean in Relation to Phosphorus Efficiency

Soil pot and hydroponic experiments were conducted to compare root morphological features and root exudation characteristics of difference soybean Glycine max (L ) Merrill] varieties The results indicated that genetic variation existed among the tested cultivars Under low phosphorus condition, a soybean cultivar, Nanxiong 36 , had relatively higher phosphorus efficiency than the other cultivars used Under phosphorus deficiency, root shoot ratio,tap root length, root total absorbing area and active absorbing area of soybean did not show a clear pattern of variation, hence these parameters should not be considered as specific indices of phosphorus efficiency At low phosphorus availability, soybean exuded higher amount of total acid and H + than at high phosphorus availability At low phosphorus level both total acid and H +exuded by variety Nanxiong 36 were significantly higher than the other cultivars At low phosphorus level the quantity of oxalic acid exuded by soybean roots was in general higher than those at high phosphorus level The quantity of oxalic acid and lactic acid exuded by Nanxiong 36 was relatively higher, which might imply that this cultivar has the genetic potential in solubilizing unavailable phosphorus in the soil, and hence has higher phosphorus efficiency