构树再生组织分化的比较研究

COMPARATIVE STUDIES ON DIFFERENTIATION OF REGENERATED TISSUE IN BROUSSONETIA PAPYRIFERA

构树(Broussonetia papyrifera)在剥皮后,木质部上新皮形成时,愈伤组织中先分化出许多分生组织团,进而发育成维管组织团,维管形成层与木栓形成层几乎是同时发生的。如果除去一段主干木质部,存留的树皮(韧皮部)上可较快地产生大量愈伤组织,并在未成熟韧皮部中发生维管形成层带,随后在愈伤组织中也形成维管形成层带。这两条形成层带彼此连接成扁圆内凹的一圈,各向内、外分化出木质部及韧皮部,随之形成一扁圆内凹的茎干,与上、下正常茎干连接,继续生长。其再生组织的分化要比剥皮后的提早1周左右。

This paper describes the differentiation process of regenerated tissue after ordinary girdling or after removal of a section of xylem from the stem, and the disparity in differentiation of the regenerated tissues after being differently treateds in Broussonetia papyrifera. After ordinary girdling for 3-4 weeks, new bark regenerated in the xylem. During the process of rind formation, many specks of meristematic tissue were formed in the callus, from which vascular tissue clusters were developed. In addition, the new periderm appeared almost at the same time as the new vascular cambium was seen. When a section of xylem was removed from the stem, numerous calli developed rapidly on the inner surface of the bark. Meanwhile, the vascular cambium appeared in the immature phloem. Soon after, discontinued meristematic tissue bands also occurred in the callus. These meristematic tissues then connected with each other to form a concave oblate cambial ring which developed xylem inward and phloem outward. About 2-3 weeks later, the concave oblate trunk grew lengthwisely connecting with the upper and lower portions of the normal stem. By then, the tree continued to grow. The inner surface tissue of the bark, after the xylem was removed, differentiated about one week earlier than the tissue on the surface of the xylem after girdling.