Effect of GA_3 and Tryptophane on the Growth of Rice Seedlings from Dry Nursery under the Condition of Lack of Zn~(2+)

Xu Weili et al(Engineering Centre of Plant Growth Regulator of Jiangsu Province, Huaiyin 223001)

Lack of Zn~(2+), Tryptophane, GA_3, Rice seedling from dry nursery

The effect of exogenous chemicals GA, and tryptophane(Trp) on the growth of dry cultivation rice seedlings under the condition of lack of Zn2+ was investigated by means of field tests. The results showed that under the condition of lack of Zn2+, the rice seedlings from dry nursery could not grow well. Spraying the GA, at the concentration of 5mg/L could not ef-fectively improve the seedling quality, but the obvious recovery effect of seedling growth could be obtained by spraying the Trp at the concentration of 500mg/L or spraying the mixture of GA, and Trp with respective concentration of 5mg/L and 500mg/L. Also, the increasing effect action could be found through spraying this mixture;Under the condition of rich of Zn2+(fertilizing Zn2+ to the seedling bed), spraying the GA, at the concentration of 5mg/L made the number of tillers and total roots per plant decrease obviously and no effect was observed by spraying the Trp with the concentration of 500mg/L. The re-sults indicated that:①under the condition of lack of Zn2+, the main reason for inhibition of seedling growth was the reducing the synthesis of Trp in plant and the exogenous Trp had a supplemental action. On the premise of spraying Trp, some path-ways regulated by GA3, which affected the metabolism of lAA or Trp, might exist in plant, so the increasing effect action could be gained between GA, and Trp;②under the condition of rich of Zn2+, dynamics equilibrium of endogenous plant hor-mones might be disturbed and normal growth of seedlings was damaged by spraying exogenous GA3, so that the seedling qual-ity was reduced.