Submitted to: Adventitious Root Formation of Forest Trees and Horticultural Plants - From Genes to Applications
Publication Type: Book / Chapter
Publication Acceptance Date: 9/1/2008
Publication Date: N/A
Technical Abstract: Plants with roots colonized by mycorrhizal fungi are potentially more effective at nutrient and water acquisition, less susceptible to disease, and can be more productive under certain stressful environmental growing conditions than plants without mycorrhizae. Although a great deal of research has been performed on seedling responses to inoculation with mycorrhizal fungi and there is a growing body of information describing the benefits of inoculation of tissue culture plantlets ex vitro, there has been little research on how inoculation influences adventitious root (AR) formation during cutting propagation from stems or in vitro culture, especially in woody perennial plant species. The formation of ARs on stem cuttings and during in vitro culture is controlled by the action and interactions between plant growth regulators such as auxins, cytokinins, ethylene, and polyamines; nutrients such as nitrogen (N) and carbon (C); and external abiotic factors, including light, temperature, and moisture. Little research attention has been paid to the potential effects of external biotic factors, such as mycorrhizal fungi on AR formation, even though these fungi are known to produce several plant hormones and alter plant N and C status. This chapter reviews concepts associated with using mycorrhizal fungi to influence initiation and growth of ARs and describes the results of several studies assessing the influence of mycorrhizal fungi on the adventitious rooting of stem cuttings and in vitro shoots from different woody plant species. Much of the information presented has applied relevance to propagation of forest tree and horticultural crops; however, we will also summarize some of the current literature that has used these plant-fungus interactions to investigate basic mechanisms of AR formation.