Physiological effects of colchicine on the male germ cells of Ginkgo biloba and Populus tomentosa × P. bolleana

ObjectivePolyploidization is an important approach to the genetic improvement of trees, colchicine inducing reproductive cells is an important method of tree polyploid induced, but there are problems such as some tree polyploid induction is difficult, and polyploidization induced quality is difficult to distinguish. Therefore, it is necessary to explore the mechanism of polyploidy induction and to find a scientific method for the preliminary discrimination of the polyploidy effect of colchicine artificially induced forest germ cells.

MethodTaking ginkgo, Populus tomentosa × P. bolleana male reproductive cells as the research object, by ninhydrin colorimetry, CBA method,tetrazolium blue method,guaiacol method and thiobarbituric acid method, their intracellular free proline (PRO) content, soluble protein (Protein) content, superoxide dismutase (SOD), peroxidase (POD) activity, malondialdehyde (MDA) content changes were determined by colchicine inducing, and then the dynamic change nodes of the physiological and biochemical indexes of the male germ cells of Ginkgo biloba and Populus tomentosa × P. bolleana under the double induction of colchicine were compared and analyzed.

ResultAfter colcine treatment, in ginkgo germ cells, proline content increased first at 12−36 hour and then decreased, soluble protein content decreased at 1−36 hour, SOD activity decreased at 12−48 hour, POD activity increased significantly at 3−36 hour, MDA content began to increase at 6 hour and peaked at 12−48 hour. In the Populus tomentosa × P. bolleana, germ cell proline content increased within 0.5−1 hour and the change trend was not obvious at the later stage, the soluble protein content decreased within 24−48 hour, the SOD activity increased significantly within 12−48 hour, the POD activity was not significantly different from the blank group, and the MDA content was similar to the blank group and the control group.

ConclusionColchicine induction had different effects on gene expression mechanism of ginkgo and Populus tomentosa × P. bolleana generative cells, and the stress on ginkgo germ cells was stronger than that on poplar. However, the change of protective enzyme of the poplar was opposite to that of ginkgo, and the SOD activity increased significantly during 12−48 hour period, while the POD activity did not change significantly. Therefore, the regulation of gene expression after damage accumulation under colchicine stress may be the main reason for the difficulty of tree germ cell polyploidy, and the influence on gene expression regulation is mainly in the late stage of colchicine stress. The results of this study will lay a foundation for exploring the regulation mechanism of gene expression during colchicine induction and provide theoretical and practical references for the preliminary identification of the difficulty of inducing polyploidy in germplasm of different trees.