05.02.2020
Comparing biostimulants to optimise root formation/branching

Vegetative propagation is utilised in many agricultural and horticultural industries as it is fast, relatively simple, and has the benefit of maintaining desirable genetic traits. With root development rate as the major limiting factor in vegetative propagation, and the recent growing interest in organic/non-hormonal plant growth methods – there is a high demand for biostimulant-based propagation methods.

Nutrifield R&D has once again teamed up with RMIT University to test the root-promoting effects of the regarded biostimulant complex Root Nectar®, and the biostimulant willow bark extract, on vegetative cuttings from lavender and Chrysanthemum. These findings were published in the journal Scientia Horticulturae, and titled “Willow bark extract and the biostimulant complex Root Nectar® increase propagation efficiency in chrysanthemum and lavender cuttings”.

Vegetative cuttings were propagated in aeroponic misting units and scored daily to monitor root development. Scoring was done using a novel adaptation to the established BBCH (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) numerical scale wherein cuttings without roots were scored 00, cuttings with adventitious roots were scored 05, and cuttings with branched roots were scored 06. Treatment efficacy was assessed by comparing the average number of days taken to reach either BBCH = 05 (adventitious roots), or BBCH = 06 (branched roots), compared with a negative control, water.

It was found that 1 ml/L Root Nectar® treatment significantly decreased the time taken to induce adventitious root formation and root branching in both chrysanthemum and lavender cuttings. Root Nectar® treatment reduced the time taken to achieved adventitious root formation in chrysanthemum by 1.9 days (15.5% faster) and in lavender by 6.8 days (33.8% faster). Additionally, Root Nectar® treatment reduced the time taken to achieve root branching in chrysanthemum by 4 days (22.1% faster) and in lavender by 10 days (36.2% faster).

By contrast to Root Nectar®, treatment with willow bark extract had varied results when applied to either chrysanthemum or lavender cuttings. In this study, 4 concentrations of willow bark extract were tested and while none of the 4 doses had a statistically significant effect on adventitious root formation in chrysanthemum, all 4 doses had equally significant effects in lavender. The lowest dose of willow bark extract (1.06 μL/L) achieved adventitious root formation in lavender in 7.3 less days (37.7% faster). Furthermore, 1.06 μL/L was the only concentration to significantly increase the rate of root branching in chrysanthemum, and it was equal best for achieving root branching in lavender. 1.06 μL/L reduced the time taken to achieve root branching in chrysanthemum by 4.5 days (12.8% faster) and in lavender by 12 days (43.4% faster).

These findings support the use of biostimulants, and in particular the biostimulant complex Root Nectar®, for the propagation of agricultural crops such as lavender and chrysanthemum. Interestingly, the varied responses from chrysanthemum and lavender to the biostimulant willow bark extract, highlight the need for species-specific research, to identify optimal dosages and thereby maximise the biostimulants beneficial effects.

The complete results of this study were published in the journal Scientia Horticulturae, which can be found here: https://doi.org/10.1016/j.scienta.2019.109108 – the title page has been copied in below.

Go check out our previous write up on our presentation at the industrial hemp seminar in Wodonga: https://www.nutrifield.com.au/research-development/aiha-industrial-hemp-seminar-in-wodonga/