低磷胁迫下云南松幼苗的生物量及其分配

对云南松幼苗进行低磷胁迫的实验表明:不同磷处理水平下云南松幼苗的总生物量、茎叶生物量和株高在处理间的差异极为显著;随着培养液磷浓度的降低,云南松幼苗茎叶生物量和总生物量下降,株高降低,侧芽数减少;总生物量与茎叶生物量之间存在极显著的相关关系和线性回归关系,总生物量随培养液磷浓度的降低而下降主要是由茎叶生物量随培养液磷浓度的降低而下降引起的。低磷胁迫下云南松幼苗的根系生物量并没有随培养液磷浓度的降低而明显减少,根系生物量保持在比较高的水平,低磷胁迫下的云南松幼苗主要以降低茎叶生物量为代价来提高根冠比并保持根系生物量在比较高的水平来维持整个生命。实验还表明,在培养液磷浓度0.03125~0.00781mmol·L-1之间或附近,存在着一个云南松幼苗对低磷忍耐的临界值。

Biomass and its allocation of Pinus yunnanensis seedlings under phosphorus deficiency

The results in this paper showed that there were significant differences in total biomass,root biomass and plant height between treatments of Pinus yunnanensis seedlings under different phosphorus supplies. As phosphorus supplies decreased,total biomass, root biomass,plant height as well as the number of bud of P.yunnanensis seedlings decreased. A significant positive correlation and a linear regression were borne between total biomass and shoot biomass. The total biomass decreased in accordance with the phosphorus supplies mainly coming from shoot biomass. The study showed that no obvious decrease happened on root biomass as phosphorus supplies decreased, and so the root biomass maintained at a relatively higher level,and P.yunnanensis seedlings under phosphorus deficiency ensured their livelihood by increasing root/shoot ratio and maintaining root biomass at a relatively higher level at a cost of decreasing shoot biomass. It also made clear that there may be a critical content of phosphorus around or from 0.031 25 to 0.007 81 mmol·L~ -1 for P.yunnanensis seedlings to tolerate phosphorus deficiency.