不同供磷水平对云南松幼苗形态建成及根际有机酸分泌的影响

磷是植物生长所必需的重要元素.通过在不同梯度的磷营养液中对云南松(Pinus yunnanensis)幼苗217 d的培养发现,云南松根系生物量、侧根数、根部全磷含量、茎叶全磷含量随磷浓度变化而呈二次函数曲线变化.在较低磷浓度下云南松对供磷变化反映明显,但随磷浓度的增加,这种变化呈减弱趋势.在缺磷处理还导致云南松茎叶生物量减少,主根长度增加.在云南松根系分泌物中未发现有机酸的大量分泌,说明缺磷可以导致云南松体内酸环境的变化,但不是植物根际酸化的主要原因.

Effects of phosphorus supply on seedling morphology and organic acids exudation of Pinus yunnanensis

Phosphorus is a key element for plant growth.Effects of P supply on seedling growth and organic acid exudation were tested by growing Pinus yunnanensis seedlings in culture solutions with different P supply.Quadratic relationships were found between P supply and root biomass,numbers of lateral roots and P content of above-ground and under-ground body of Pinus yunnanensis seedlings.The effect was very strong when P supply was low,in contrast turned weak when P supply was high.As the time extension of P shortage,seedlings reduced their root biomass and raised the primary root length to ensure their growth.Phosphorus deficienciy causes the internal plant acid environment charge and then affect the growth of Pinus yunnanensis.However much exudation of organic acids in the root were hardly found.This indicates that the exudation of organic acids is not the major reason for pH change in root rhizosphere.