形成层活动对机械伤害诱导巴西橡胶树次生乳管分化的影响

Effect of Vascular Cambia Activity on Secondary Laticifer Differentiation Induced by Mechanical Wounding in Rubber Tree(Hevea brasiliensis Mll.Arg.)

为了进一步优化机械伤害诱导次生乳管分化的实验系统,采用实验形态学的方法,分析了形成层的季节性活动、新梢和顶芽的发育状态以及伤害程度对机械伤害诱导巴西橡胶树萌条次生乳管分化的影响。结果表明,橡胶树萌条的形成层活动具有明显的休眠期和活动高峰期。在形成层活动的高峰期,小面积的机械伤害容易诱导淡绿期和稳定期萌条分化次生乳管,而且稳定期萌条次生乳管分化程度显著大于淡绿期萌条。但在形成层活动的休眠期,小面积的机械伤害不能诱导萌条的次生乳管分化。新梢和顶芽发育状态对机械伤害诱导次生乳管分化程度的影响都与形成层的季节性活动密切相关。大面积的机械伤害抑制次生乳管分化,可能与伤害部位的形成层细胞分裂活性受抑制有关。

The effect of season changes in vascular cambia activity, development stage of new shoots and terminal buds, and intensity of mechanical wounding on secondary laticifer differentiation induced by mechanical wounding in rubber tree was investigated by means of experimental morphological techniques so as to optimize the experimental system for secondary laticifer differentiation induced by mechanical wounding. Results showed that the activity of vascular cambia of Hevea epieomic shoots undergone obviously seasonal changes. In the peak period of vascular cambial activity, secondary laticifer was easily induced by mechanical wounding with small scale in the wounded site of stem of new shoot with leaves in light green color （i.e., light green shoot） and of new shoot with leaves and terminal bud in stable state （i.e., stable shoot）. The intensity of secondary laticifer differentiation in stable shoots was much more than that in light green shoots. In dormant period of vascular cambia activity, mechanical wounding with small scale had little effect on inducing secondary laticifer differentiation. The effect of development state of both new shoots and terminal buds on the secondary laticifer differentiation induced by mechanical wounding with small scale was correlated with the seasonal changes in vascular cambia activity. On the other hand, mechanical wounding with large scale inhibited the secondary laticifer differentiation, suggesting that cell division of vascular cambia is inhibited under this condition.