中文摘要：

以核桃品种‘新早丰’试管嫩茎为试材，采用二步生根法诱导生根，对其试管苗不定根发生发育过程进行了解剖学研究。结果表明：核桃试管嫩茎内未发现潜伏根原基；诱导生根后，不定根原基起源于形成层，特别是髓射线正对的形成层部分，属于诱生根原基型；不定根上的侧根起源于中柱鞘细胞。核桃试管嫩茎不定根的发育过程可分为4个阶段：（1）形成层细胞分裂；（2）转变为分生组织细胞群（即根原始细胞）；（3）细胞群发育成可见的根原基；（4）根原基内细胞继续分裂分化形成根尖的外形，其内发育出维管束，并向外生长，穿过皮层，突破茎表皮。在组织培养条件下长出的不定根内部解剖构造为典型的初生构造，移栽后68d出现次生构造。另外，试管苗根毛出现与否及其发育状况受基质理化性质的影响，即生态条件可以改变组织发生及其形状。

英文摘要：

The in vitro stems of ‘Xinzaofeng＇ ,a walnut variety was induced by two-stage rooting protocol to root ,and the development of the adventitious roots of their in vitro seedlings was anatomically examined. The results showed that no dormant root primordius were founded in the in vitro tender stems of walnut after root induction,the primordia of the adventitious roots originated in the cambium ,especially the cambium part over against the pithy rays,thus then they were induced root primordia ;the lateral roots of the adventitious roots originated in the pericycle cells. The development of the adventitious roots of the in vitro stems could be divided into four stages. （1） The cambium cells divided; （2） The cells from the division transformed into cambium cell groups （root initials）; （3） The cambium cell groups developed into visible root primordia;（4） The root-tip shape formed by the continuous division of the cells in the root primordia, and vascular bundles developed inside the root tips ,which grew outward ,penetrated through the cortex and broke through the stem epidermis. The structure of the adventitious roots induced under the conditions of tissue culture was a typical primary structure and the secondary structure appeared for the first time 68 days after their transplanting. In addition ,whether the in vitro seedlings grew root hairs or not depended on chemical and physical properties of the substrate ,i. e. ,ecological conditions could decide the occurrence andshape of a tissue.