油松针叶束离体培养下器官建成的解剖学研究

Anatomical Study on Organ Regeneration of Needle Fascicles of Pinus tabulaeformis Cultivated in Vitro

油松针叶束经离体培养形成幼苗的整个过程，可划分为三个阶段，即愈伤组织的起源与形成；根原基的发生和不定根的形成；芽的萌动与生长。发生在针叶束切口上的愈伤组织起源于形成层和韧皮部的薄壁细胞，经脱分化恢复分生组织的生理机能，并进行分裂活动形成愈伤组织。根原基主要是从愈伤组织内发生，属于愈伤组织生根类型。在愈伤组织内分化出来的分生组织结节和维管组织结节，经单向极性分裂活动形成根原基，并继续生长突破愈伤组织成为不定根。芽在愈伤组织出现后起动，生长锥进行缓慢的分裂活动，由扁圆形芽体变为长圆形，并形成初生叶原基与幼叶紧包生长锥。移植后芽生长迅速，长出数枚窄条状初生叶，不久即抽梢。

The development process of seedling forrnation by needle fascicle cultivated invitro may be divided into three stages:callus formation,root initiation and adventitious rootsformation,germination and development of the buds.Calluses obtained from the wound sur-face of needle fascicle may originate from cambium and parenchyma cells of phloem. Afterdedifferentiation,they change into meristematic state and undergo cell division to form callus-es. The root primordia originate from the calluses. After monopolarity cell division,the meris-tematic nodules and vascular nodules differentiated from calluses and formed root primor-dia. They grew out of the calluses and became adventitious roots,The buds were activated af-ter the formation of calluses,the apical meristem divided slowly,as the young bud becamefurther elongated, the primary leaf primordia and young leaves were consecutively formedby which the apical meristem were enclosed.After transplantation the buds developed rapidlyand then needles appeared on the branch.