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This article is part of the Research Topic

Cannabis Genomics, Breeding and Production

Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.00350

Architecture and Florogenesis in Female Cannabis sativa Plants

 Ben Spitzer-Rimon1*, Shai Duchin1,  Nirit Bernstein2 and Rina Kamenetsky1
  • 1Department of Ornamental Horticulture and Biotechnology, Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Israel
  • 2Department of Environmental Physics and Irrigation, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Israel

The inflorescence is the main product of medical cannabis. Hundreds of specialized metabolites with potential bioactivity are produced and accumulated in the glandular trichomes that are highly abundant mainly on female inflorescences. Understanding the morphophysiological and genetic mechanisms governing flower and inflorescence development is therefore of high scientific and practical importance. However, in-depth investigations of cannabis florogenesis are limited. Cannabis producers and researchers consider long photoperiod to be “non-inductive” or “vegetative”, but under these growth conditions, the development of solitary flowers and bracts in shoot internodes clearly indicates that the plant cannot be defined as vegetative or non-inductive in the classical sense. Most probably, induction of solitary flowers is age-dependent and controlled by internal signals, but not by photoperiod. Short photoperiod induces intense branching, which results in the development of a compound raceme. Each inflorescence consists of condensed branchlets with the same phytomer structure as that of the larger phytomers developed under long day. Each phytomer consists of reduced leaves, bracts, one or two solitary flowers, and an axillary shoot (or inflorescence). Therefore, the effect of short photoperiod on cannabis florogenesis is not flower induction, but rather a dramatic change in shoot apex architecture to form a compound racemose inflorescence structure. An understanding of the morphophysiological characteristics of cannabis inflorescence will lay the foundation for biotechnological and physiological applications to modify architecture, and to maximize plant productivity and uniformity in medical Cannabis.

Keywords: Cannabis, Inflorescence, photoperiod, solitary flower, branching

Received: 08 Jan 2019; Accepted: 07 Mar 2019.

Edited by:

Mahmoud A. ElSohly, School of Pharmacy, University of Mississippi, United States

Reviewed by:

Joseph Colasanti, University of Guelph, Canada
David Smyth, Monash University, Australia  

Copyright: © 2019 Spitzer-Rimon, Duchin, Bernstein and Kamenetsky. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: PhD. Ben Spitzer-Rimon, Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Department of Ornamental Horticulture and Biotechnology, Rishon LeZion, Israel, benrimon@volcani.agri.gov.il