The Effect of TIBA and NPA on Shoot Regeneration of Cannabis sativa L. Epicotyl Explants

Mariola Dreger,Milena Szalata

doi:10.3390/agronomy12010104

Abstract

Industrial hemp (Cannabis sativa L., family Cannabaceae) is a multi-purpose crop, used in the production of food, nutraceuticals, cosmetics and medicines. Therefore, development of new varieties with specific chemical profiles is necessary. In vitro culture methods could be complementary to conventional breeding and a useful tool for large-scale propagation. Strong apical dominance is considered as one of the factors contributing to the recalcitrance of industrial hemp in shoot proliferation. In this study, we tested the polar transport inhibitors N-1-naphtylphtalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) to enhance shoot regeneration as the result of suppression of apical dominance and to develop in vitro protocols for Diana, Finola and Fedora 17 cultivars. Shoot tips derived from epicotyls were cultivated on Murashige and Skoog medium (MS) supplemented with meta-topolin (mT) and NPA, and also thidiazuron (TDZ) with a combination of TIBA and NPA. The results showed that the combination of TDZ with NPA (1–5 mg L−1) and TDZ with TIBA (0.5–2.5 mg L−1) increased the response of explants and the multiplication rate, but the effect was genotype-dependent and malformations were observed. To optimize the developed protocol, a two-step procedure with shortened time of exposure to inhibitors and reduced concentrations of them was applied. Shoots were rooted on media containing indole-3-butyric acid (IBA) and then successfully acclimatized. The obtained results will be useful in micropropagation of recalcitrant industrial hemp varieties.

Highlights

Industrial hemp (Cannabis sativa L., family Cannabaceae) is a multi-purpose crop used for the production of fiber, seeds, oil, essential oil, composites, drugs, supplements, cosmetics, etc. [1,2,3]
This study demonstrated for the first time that polar auxin transport inhibitors used for suppression of apical dominance could be effective in shoot organogenesis in industrial hemp cultivars
We replaced the physical method by use of the auxin polar flow inhibitors naphtylphtalamic acid (NPA) and triiodobenzoic acid (TIBA)

Summary

Introduction

Industrial hemp (Cannabis sativa L., family Cannabaceae) is a multi-purpose crop used for the production of fiber, seeds, oil, essential oil, composites, drugs, supplements, cosmetics, etc. [1,2,3]. Considering that the demand for standardized plant material has been constantly increasing, development of new or improved varieties with a specific chemical profile is necessary. Knowledge, and breeding techniques are required to design and develop new hemp varieties with specific features. In this respect, plant in vitro cultures and clonal propagation techniques can be useful for large-scale propagation of the selected elite clones [4,5]. Plant in vitro cultures and clonal propagation techniques can be useful for large-scale propagation of the selected elite clones [4,5] It may enable shortening the time of the breeding process and/or large-scale production of homogeneous plant material. Cultivar- and genotypedependent responses of explants and the low regeneration rate are the main limitations for hemp in vitro propagation

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Conclusion