Colchicine-Induced Polyploidization Influences the Morphological, Physiological, and Biochemical Characteristics of...

Cyclocarya paliurus (Batal.) Iljinskaja is a rare and multifunctional tree species endemic to China. This study aimed to establish a feasible method for polyploid induction in C. paliurus with colchicine treatment, and the obtained polyploid plants were identified and characterized. In this study, natural diploid and tetraploid C. paliurus seedlings were treated with different concentrations and durations of colchicine to induce polyploidization. The results indicated that a colchicine concentration of 0.4% for 4 d was the most suitable induction protocol, respectively. Compared with diploid and tetraploid control plants, the induced polyploid plants were shorter and thinner. The number of compound leaves in induced polyploids were fewer, and the compound leaf areas became smaller. The stomatal density of induced polyploids decreased, but the stomata became larger and wider, with an increased number of chloroplasts in the guard cells. The induced polyploids exhibited higher levels of carotenoid, and the contents of soluble sugar, soluble starch, and soluble protein were higher than those of controls. The polyploid plants exhibited an increase in the contents of growth-inhibiting hormones (JA) and a decrease in those of growth-promoting hormones (IAA, GA₃, BR). In summary, the induced polyploids with a dwarfing effect would provide superior germplasm resources for leaf-harvesting plantation. As C. paliurus is endemic to China, our results have a rather local effect. Overall, the established polyploid induction method of C. paliurus will provide technical support for creating superior C. paliurus germplasm resources and subsequent plant breeding research.