施磷对开割橡胶树根系生长发育的影响

摘要

Under medium-cultured condition of bagasse, the rubber tree root was treated with 0, 250, 500, 1 000, 2 000, 4 000, 8 000 mg/kg of P, to investigate the responses of root growth at different phosphorus supplying levels. Results indicated that the tested root traits responded positively to phosphorus concentration, the roots amount, total length of roots and surface area of roots was 297.4%, 246.0%, 210% of that of the CK, respectively, and diameter per unit of the root was 0.008 cm/d. When the phosphorus concentration was 500 mg/kg, the elongation rate was 0.68 cm/d, which was 51% more than that of the CK. But the traits showed negative responses when the phosphorus concentration was at 8 000 mg/kg. After rubber roots measurement, data disposal and simulated with computer, we could see that the roots configuration were transforming in dichotomous branches -dichotomous herringbone branches-herringbone branchesas phosphorus concentration increased. These effects indicated that phosphorus had an important modulation function to the rubber roots.%以甘蔗渣为介质,设计0、250、500、1 000、2 000、4 000、8 000 mg/kg等7个供磷浓度,研究磷肥供应对橡胶树根系生长的影响.结果表明,在1 000 mg/kg供磷处理下,橡胶树吸收根数量、总长度、根表面积分别为对照的297.4％、246.0％、210％,平均直径增加达到0.008cm/d,促进效应达极显著水平；500 mg/kg供磷处理下吸收根伸长速度为0.68cm/d,比对照增加了51％；最高浓度8 000 mg/kg供磷处理对胶树吸收根生长发育各项指标表现出负效应；通过测定吸收根发生量、行根直径、长度、生长速度、表面积等参数变化,可以发现局部根系构型随施磷浓度增加在二分枝型、分枝鲱骨型、鲱骨型三者之间转换,说明橡胶树根系构型对磷丰缺具有适应性变化.