磷酸饥饿对番茄幼苗生长状况及其磷吸收的影响

Effects of Phosphate Starvation on Growth State andPhosphorus Uptake of Tomato Seedlings

本文就磷酸饥饿对番茄幼苗生长状况及其磷吸收的影响进行了研究。结果表明，磷酸饥饿时，番茄幼苗的平均高度下降，而主根的长度却明显长于对照。磷酸饥饿初期对番茄幼苗鲜重累积影响不大，但随着饥饿的继续，受胁迫苗的鲜重累积与对照间的差异逐渐加大并且变得明显低于对照。磷酸饥饿还降低了番茄幼苗的干重累积，但对其干重累积的速率并无太大影响。磷酸饥饿使番茄幼苗Ｐｉ（Ｈ２ＰＯ－４或ＨＰＯ２－４）吸收速率显著提高。动力学分析表明，磷酸饥饿增强了磷酸透过酶对Ｐｉ的亲和力。对磷酸饥饿下的幼苗恢复供磷，则磷酸饥饿时所诱导的高亲和性Ｐｉ透过酶的亲和力会明显下降，但其下降的速度会随着恢复供磷前磷酸饥饿程度的加深而减慢。

Abstract The effects of phosphate starvation on growth state and phosphorus uptake of tomato seedlings were studied in this paper. In the studies, the seedlings were arranged to grow in complete (Pi-adequate) or Pi-depleted nutrient solution. The results revealed that, under Pi-starved conditions, the average height of the seedings decreased to a certain degree, while the main roots of the seedlings were obviously longer than those of the controls, especially under phosphate starvation for 5 and 7 d. Therefore the root / shoot ratios of the seedlings under Pi-starved conditions were also obviously higher than those of the controls. In addition, the early days of phosphate starvation had no obvious effect on the fresh weight (FW) accumulation of the seedlings, while the late days of starvation had some effect so that the fresh weight accumulation of the seedlings gradually became markedly less than the control. Phosphate starvation also decreased the dry weight (DW) accumulation of the seedlings but had little effect on the rate of the accumulation. The results in this paper also indicated that, after 7 d of phosphate