Authors: WANG XIAO LING, ZHAO ZHONG
Abstract: This study was carried out to elucidate the relationship between seasonal variation of rooting ability and inner conditions of the cuttings of Tetraploid Locust, and to determine the optimum time for rooting. It was conducted in a glasshouse at the Experimental Nursery of the College of Forestry, North-West Agriculture and Forestry University, Yang Ling, China, during 2009. Tetraploid Locust cuttings were taken from healthy trees of 3-year-old field-grown mother-stock orchard. Cuttings (15 cm in length and 10-12 mm in diameter) were collected and planted on 15 February, 15 March, 15 May, 15 June, 15 July, and 15 August. The results obtained 2 months after each planting date showed that planting the cuttings on 15 May produced significant increases in rooting percentage compared to the other planting dates. The highest total carbohydrates concentration and carbohydrate/nitrogen (C/N) ratio were recorded in the basal parts of the stem cuttings planted on 15 May, either before planting or 35 days after planting. A positive relationship of rooting percentage was found between total carbohydrate concentration and C/N ratio. No consistent relationship was established between total nitrogen and rooting percentage. Results also showed a high and a low negative relationship of the rooting percentage of the cuttings between indole-3-acetic acid (IAA) concentration and gibberellins (GAs) concentration, respectively. In addition, 35 days after planting, a positive relationship was detected between abscisic acid (ABA) concentration and the rooting percentage. From the results obtained, 15 May may be recommended as the ideal planting date for improving the rooting and the vegetative growth of Tetraploid Locust stem cuttings compared to the other investigated planting dates.
Keywords: Carbohydrate, endogenous plant hormones, nitrogen, planting date, Tetraploid Locust
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