ANALYSIS OF DNA RESTITUTION IN COTYLEDONARY TISSUE OF GOSSYPIUM BARBADENSE L. DURING GERMINATION.

摘要

DNA repair in Gossypium barbadense L. cotyledonary tissue was examined in vivo during early germination. DNA strand breaks were initiated by applying ethyl methanesulfonate (EMS) during seed imbibition. Strand rejoining was monitored through a period of EMS induced DNS synthesis by means of velocity sedimentation analysis. There was an absence of DNA molecular weight increase as disclosed by the sedimentation profiles. It is presumed velocity sedimentation evaluation was insensitive for detecting in vivo restoration of cotyledonous DNA strand breaks. The altered DNA synthesis response perceived within treated seedling cotyledons perhaps reflects, but does not establish the operation of a cellular mutagenic repair system.;EMS induced morphological mutant cotton plants arising during the course of this investigation were cytologically identified as possessing duplicate-deficient chromosomes.