Submitted to: International Plant Propagators Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2000
Publication Date: 12/1/2000
Citation: Scagel, C.F. 2000. Regulating root growth in ericaceous plant propagation. International Plant Propagators Proceedings. 49:589-593.
Interpretive Summary: A strong, healthy root system is extremely important for the vegetative propagation of woody nursery crops and during transplant of container and bareroot crops. When roots do not grow or function optimally, plant productivity declines, plants are more susceptible to disease, insect, and weed problems, and the cost of production increases. Maintaining optimal conditions for the initiation and growth of roots at all stages in propagation can not only increase the efficiency of nutrient and water uptake, but also increase overall crop growth and survival. In two separate studies we investigated the relationship between tissue composition of several different ericaceous plants, plant growth, and rooting of cuttings. We have found cultivar-specific differences in optimum nitrogen concentrations for adventitious rooting while rooting increases linearly with increasing stem protein content. We have also found that altering media components, fertilizer formulations, or mycorrhizal fungi changes tissue protein levels and may potentially offer growers methods of influencing adventitious rooting of cuttings.
Technical Abstract: The control of adventitious rooting is complex and involves regulation by several different compounds, which vary during stages of root development. Regulation of rooting involves the interaction between carbohydrates, nitrogen compounds, enzymes, and hormones. In two separate studies we investigated the relationship between tissue composition of several different ericaceous plants, plant growth, and rooting of cuttings. There is little available information describing hormonal and nutritional changes that occur in ericaceous plants during vegetative propagation or during container production. We tested several cultivars of different ericaceous plants and found cultivar-specific differences in optimum nitrogen concentrations for adventitious rooting. Root initiation in cuttings also increased with increasing stem protein content. This suggests that although nitrogen plays an important role in adventitious rooting of cuttings, the proportion of nitrogen as proteins may be equally important. Cultural methods that change tissue protein levels and may potentially influence adventitious rooting include altering media composition by addition of coconut fiber (coir), using organic fertilizers, or optimizing growing conditions for using mycorrhizal fungi.