ISHS Acta Horticulturae 517: XXV International Horticultural Congress, Part 7: Quality of Horticultural Products
RELATION BETWEEN NITROGEN AND SOLUBLE CARBOHYDRATE CONCENTRATIONS AND SUBSEQUENT ROOTING OF CHRYSANTHEMUM CUTTINGS AS INFLUENCED BY NITROGEN NUTRITION OF STOCK PLANTS AND COOL-STORAGE OF CUTTINGS |
| Authors: | U. Drüge, S. Zerche, R. Kadner |
| Keywords: | Dendranthema grandiflorum, Chrysanthemum, cuttings, nitrogen, rooting, quality, soluble carbohydrates, stock plants, storage |
| Abstract:
It is generally held that high carbon/nitrogen ratios favour rooting potential of cuttings. So it has been reported that adventitious root formation of chrysanthemum cuttings under low light conditions in climate chambers was negatively correlated with nitrogen and positively correlated with sugar contents. The objectives of the present investigation were to characterize the relations between the concentrations of total nitrogen and soluble carbohydrates in cuttings and the subsequent rooting under more favourable light conditions in a greenhouse (April - July). In two experiments in hydroponic (exp. 1) and organic substrate (exp. 2) the amount of nitrogen supplied to chrysanthemum stock plants of the cultivars 'Puma white' (exp. 1 and 2) and 'Cassa' (exp. 2) was varied in combination with an additional cool-storage of cuttings at 0.5 °C (exp. 1 and 2) and 5°C (exp. 2) for different durations (0, 2, 3, 4 weeks). In the first experiment, higher nitrogen nutrition increased the nitrogen concentrations in cuttings up to 6.8 % of their dry mass and significantly lowered the concentrations of glucose, fructose, sucrose and total soluble carbohydrates in whole cuttings. Significantly higher sucrose values were measured when cuttings were stored for two weeks. In the second experiment, the nitrogen effect on carbohydrates was found to be strongest in the case of glucose particularly in the basal stems and to be more pronounced after storage. In both experiments, root formation of cuttings was positively correlated with pre-rooting total nitrogen concentration and not limited by simultaneously lower concentrations of individual or total soluble carbohydrates in cuttings. Possible interactions between the relationships found and the light conditions during root formation of cuttings are discussed. | |
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