Auxin, Bottom Heat, and Time of Propagation Affect the Adventitious Rooting of Leucophyllum candidum Silver Cloud

摘要

Leucophyllum candidum ‘Silver Cloud’ is a woody shrub in the Scrophulariaceae (figwort) family and is grown as an ornamental in the desert regions of the Southwestern U.S. and throughout the world in areas with similar climates. Given its popularityand ability to thrive under low-water regimes, it has become a popular part of many plant palettes. The plant is propagated from softwood cuttings to maintain the clonal integrity of the species. Leucophyllum candidum ‘Silver Cloud' is considered an elite clone of the plant and can be recalcitrant to rooting. Rooting percentages below 50% for this clone are not uncommon in commercial nurseries. Information on asexual propagation of Leucophyllum species is scarce. Nutritional status of stock plants isimportant, as rooting of cuttings was enhanced by maintaining the leaf tissue of stock plants at a level of >2% nitrogen (Simpson and Hipp, 1982). The objectives of the study presented here were to investigate the influence of the potassium salt of indole-butyric acid (K-IBA), the use of bottom heat, and the month of propagation on rooting of L. candidum 'Silver Cloud’.