Study on Cutting Cultivation Technology and Rooting Mechanism of Cyclocarya paliurus

Abstract

Cyclocarya paliurus is an important rare and multipurpose tree species in China. In view of the difficulty of asexual propagation of Cyclocarya paliurus, this paper explores the technical system of Cyclocarya paliurus cutting propagation from the aspects of cutting collection position and time, tannin removal pretreatment, hormone treatment, sand storage treatment, cutting matrix, environmental factors and physical factors, and discusses its internal physiological changes in the process of cutting rooting. This paper attempts to clarify the physiological characteristics of Cyclocarya paliurus in the process of cutting propagation and rooting. The results of this study can provide technical support and theoretical basis for the cuttings propagation of Cyclocarya paliurus. The results show that the rooting rate of cuttings inserted on the mixture of perlite and vermiculite is up to 32.2 %. In summer, when the middle and upper parts of branches were treated with 300 mg/L rooting powder No. 1 and GGR-6 (Green Growth Regulator-6) mixture, the rooting rate was up to 44.4 %; in winter, the rooting rate of the base of branches was 36.7 % under the same treatment. During the rooting process of Cyclocarya paliurus, a large number of nutrients such as soluble sugar, starch and soluble protein were consumed. SOD (Superoxide Dismutase), POD (Peroxidase), and PPO (Polyphenol oxidase) are closely related to cutting and rooting. High activity SOD and POD are conducive to the expansion of cuttings, and high activity SOD and PPO are conducive to improving the stress resistance of cuttings. Hormone treatment can improve the enzyme activity and make the enzyme activity change in the direction conducive to rooting. The change of endogenous hormone content in cuttings reflects the rooting ability of Cyclocarya paliurus. Substrate heating and hormone treatment can regulate the content of endogenous hormone in cuttings during the rooting process, so as to affect the rooting effect, the stable total nitrogen content in cuttings was conducive to root formation.

Insights into the Hormone-Regulating Mechanism of Adventitious Root Formation in Softwood Cuttings of Cyclocarya paliurus and Optimization of the Hormone-Based Formula for Promoting Rooting

“…Plants in the Juglandanceae family, such as C. paliurus and Carya illinoinensis, have hard-to-root characteristics in their cuttings [13,35]. In recent years, some studies have indicated that the application of suitable exogenous hormones and hormonal formulas could improve the rooting efficiency of hard-to-root tree species [13,35], but the effects of each hormone on the rooting efficiency are species-specific.…”

“…Plants in the Juglandanceae family, such as C. paliurus and Carya illinoinensis, have hard-to-root characteristics in their cuttings [13,35]. In recent years, some studies have indicated that the application of suitable exogenous hormones and hormonal formulas could improve the rooting efficiency of hard-to-root tree species [13,35], but the effects of each hormone on the rooting efficiency are species-specific. For instance, Zhang et al [35] reported that treating the base of C. illinoinensis hardwood cuttings by 0.09% NAA and 0.06% IAA could improve the rooting rate up to 82% and 80% with 8.3 and 6.8 roots per rooted cutting, respectively, whereas Guo et al [36] indicated that the highest rooting rates were only 10.5% and 23.2% after soaking the base of C. paliurus cuttings with different concentrations of NAA and IAA, respectively.…”

“…For instance, Zhang et al [35] reported that treating the base of C. illinoinensis hardwood cuttings by 0.09% NAA and 0.06% IAA could improve the rooting rate up to 82% and 80% with 8.3 and 6.8 roots per rooted cutting, respectively, whereas Guo et al [36] indicated that the highest rooting rates were only 10.5% and 23.2% after soaking the base of C. paliurus cuttings with different concentrations of NAA and IAA, respectively. Indeed, many studies on C. paliurus cutting propagation have been conducted to enhance the rooting rate [8,13,14,26,36]; however, the existing results cannot meet the requirements for a large-scale reproduction. For example, the greatest rooting rate (58.0%) for the soft C. paliurus cuttings was obtained under the treatment of a 200 mg•L −1 GGR solution, with an average root number of 7.2 per rooted cutting [26], whereas the highest rooting rate (44.1%) was achieved for the hard C. paliurus cuttings treated with the formula of IR3 and SR3 mixed powder [14].…”

“…Our previous study indicated that grafting, as a routine method of asexual propagation, is also not ideal for C. paliurus because optimum grafting survival only reached 53.5% [12]. Therefore, propagation via softwood and hardwood cuttings has been extensively investigated to find an ideal alternative grafting method as well as quickly replicate desired clones of C. paliurus [13,14]. As a hardto-root woody plant, however, the rooting rate and rooting quality of C. paliurus achieved via cutting propagation are unable to meet the requirements of large-scale production, despite the method's potential value in commercial production.…”

Transcriptomic and Non-Targeted Metabolomic Analyses Reveal Changes in Metabolic Networks during Leaf Coloration in Cyclocarya paliurus (Batalin) Iljinsk

“…Cyclocarya paliurus (Batalin) Iljinsk., a tree species found only in subtropical China, has leaves that contain health-promoting secondary metabolites, including flavonoids, triterpenoids, and phenolic acids. Thus, this tree species has a unique medicinal and health function and has great potential for commercial development [1][2][3][4]. Secondary metabolite-containing extracts from C. paliurus can improve insulin sensitivity, regulate disordered glucose and lipid metabolism, and reduce blood lipid contents and blood pressure [5].…”