迎红杜鹃萌蘖条不定根起源和形态发生的研究

迎红杜鹃萌蘖条经流水冲和ＡＢＴ（１号）２００ｍｇ·ｋｇ－１处理１ｈ后，扦插于粗粒蛭石中．从外部形态看，凡是插入基质中的茎段部分均有不定根的发生．从横切面上观察到，流水冲处理时间的长短对不定根起源的部位有一定的影响：处理１ｄ的插穗，不定根原基起源于髓射线与维管形成层交叉的部位；而处理３ｄ的插穗，既有起源于上述部位的不定根原基发生，同时也有起源于髓薄壁组织的不定根原基发生．在刚离体枝条中，未发现有先生不定根原基的存在．

Origin and Morphogensis of Adventitious Roots of Root Sucker in Rhododendron mucronulatum Turcz.

The root suckers in Rhododendren mucronulatum were placed in vermiculite in early July,after being watered and then having been sucked in 200mg·kg -1 ABT for 1 hour.From outward apperance,adventitious roots were formed from the cortex of the whole cutting in the vermiculite. From cross sections of stem cuttings,the different periods when the suckers were watered had a certain effect on the orgin part of adventitious roots.In the group of the suckers watered for one day,primordia of adventitious roots originated from the cross region of pith rays and vascular cambium. But in the group of the suckers watered for three days,primordia of adventitious roots originated not only from the cross region of pith rays and vascular cambium,but also from pith parenchyma.There were no root primordia preformed in the suckers just after their removal from the bush.