Applications of vegetation indices and biostimulators to the rooting of camellia cuttings

Abstract: There are no reports on biostimulators being used to stimulate the rooting process of camellia (Camellia japonica) cuttings. The influences of vegetation indices and biostimulators on the rooting of shoot cuttings of the camellia ?Nine Bends? were determined using the reflectance spectroscopy. Six root growth parameters were recorded, 81 days after sticking cuttings. Different groups of soil-plant analysis development (SPAD) and normalized difference vegetation index (NDVI) values were used. Higher SPAD and NDVI values were found to be most effective in predicting rooting stages and percentages, whereas root number and length and dry weight could not be predicted. Indole-3-butyric acid (IBA) at a concentration of 2000 ppm alone or combined with three concentrations of thiamine (TA), ascorbic acid (AA) and catechol (CAT) were applied to cuttings of camellia. The maximum root number and dry weight were detected in TA (1000 mg?L^-1) alone and IBA+TA (800 mg?L^-1). However, IBA+AA (1000 mg?L^-1) treated cuttings showed the highest rooting stage, root number, root length, and dry weight compared to other treatments. Cuttings treated with IBA+CAT (50 or 100 mg?L^-1) produced greater root number, length, and dry weight compared to other treatments. The effects of biostimulators applied to tea stem cuttings for raising camellia plants in the nursery would offer insights into the mechanism of its action in plant conservation, and there is a need to improve propagation technology.