1
|
Balant M, Garnatje T, Vitales D, Hidalgo O, Chitwood DH. Intra-leaf modeling of Cannabis leaflet shape produces leaf models that predict genetic and developmental identities. THE NEW PHYTOLOGIST 2024; 243:781-796. [PMID: 38757746 DOI: 10.1111/nph.19817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/28/2024] [Indexed: 05/18/2024]
Abstract
The iconic, palmately compound leaves of Cannabis have attracted significant attention in the past. However, investigations into the genetic basis of leaf shape or its connections to phytochemical composition have yielded inconclusive results. This is partly due to prominent changes in leaflet number within a single plant during development, which has so far prevented the proper use of common morphometric techniques. Here, we present a new method that overcomes the challenge of nonhomologous landmarks in palmate, pinnate, and lobed leaves, using Cannabis as an example. We model corresponding pseudo-landmarks for each leaflet as angle-radius coordinates and model them as a function of leaflet to create continuous polynomial models, bypassing the problems associated with variable number of leaflets between leaves. We analyze 341 leaves from 24 individuals from nine Cannabis accessions. Using 3591 pseudo-landmarks in modeled leaves, we accurately predict accession identity, leaflet number, and relative node number. Intra-leaf modeling offers a rapid, cost-effective means of identifying Cannabis accessions, making it a valuable tool for future taxonomic studies, cultivar recognition, and possibly chemical content analysis and sex identification, in addition to permitting the morphometric analysis of leaves in any species with variable numbers of leaflets or lobes.
Collapse
Affiliation(s)
- Manica Balant
- Institut Botànic de Barcelona, IBB (CSIC-CMCNB), Passeig del Migdia s.n., 08038, Barcelona, Spain
- Laboratori de Botànica, Unitat Associada al CSIC, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), Av. Joan XXIII 27-31, 08028, Barcelona, Spain
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
| | - Teresa Garnatje
- Institut Botànic de Barcelona, IBB (CSIC-CMCNB), Passeig del Migdia s.n., 08038, Barcelona, Spain
- Jardí Botànic Marimurtra - Fundació Carl Faust, pg. Carles Faust, 9, 17300, Blanes, Spain
| | - Daniel Vitales
- Institut Botànic de Barcelona, IBB (CSIC-CMCNB), Passeig del Migdia s.n., 08038, Barcelona, Spain
| | - Oriane Hidalgo
- Institut Botànic de Barcelona, IBB (CSIC-CMCNB), Passeig del Migdia s.n., 08038, Barcelona, Spain
- Royal Botanic Gardens, Kew, Richmond, TW9 3AE, UK
| | - Daniel H Chitwood
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
- Department of Computational Mathematics, Science & Engineering, Michigan State University, East Lansing, MI, 48824, USA
| |
Collapse
|
2
|
Hesami M, Pepe M, Jones AMP. Morphological Characterization of Cannabis sativa L. Throughout Its Complete Life Cycle. PLANTS (BASEL, SWITZERLAND) 2023; 12:3646. [PMID: 37896109 PMCID: PMC10610221 DOI: 10.3390/plants12203646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 10/29/2023]
Abstract
This study extensively characterizes the morphological characteristics, including the leaf morphology, plant structure, flower development, and trichome features throughout the entire life cycle of Cannabis sativa L. cv. White Widow. The developmental responses to photoperiodic variations were investigated from germination to mature plant senescence. The leaf morphology showed a progression of complexity, beginning with serrations in the 1st true leaves, until the emergence of nine leaflets in the 6th true leaves, followed by a distinct shift to eight, then seven leaflets with the 14th and 15th true leaves, respectively. Thereafter, the leaf complexity decreased, culminating in the emergence of a single leaflet from the 25th node. The leaf area peaked with the 12th leaves, which coincided with a change from opposite to alternate phyllotaxy. The stipule development at nodes 5 and 6 signified the vegetative phase, followed by bract and solitary flower development emerging in nodes 7-12, signifying the reproductive phase. The subsequent induction of short-day photoperiod triggered the formation of apical inflorescence. Mature flowers displayed abundant glandular trichomes on perigonal bracts, with stigma color changing from whitish-yellow to reddish-brown. A pronounced increase in trichome density was evident, particularly on the abaxial bract surface, following the onset of flowering. The trichomes exhibited simultaneous growth in stalk length and glandular head diameter and pronounced shifts in color. Hermaphroditism occurred well after the general harvest date. This comprehensive study documents the intricate photoperiod-driven morphological changes throughout the complete lifecycle of Cannabis sativa L. cv. White Widow. The developmental responses characterized provide valuable insights for industrial and research applications.
Collapse
|
3
|
Steel L, Welling M, Ristevski N, Johnson K, Gendall A. Comparative genomics of flowering behavior in Cannabis sativa. FRONTIERS IN PLANT SCIENCE 2023; 14:1227898. [PMID: 37575928 PMCID: PMC10421669 DOI: 10.3389/fpls.2023.1227898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/03/2023] [Indexed: 08/15/2023]
Abstract
Cannabis sativa L. is a phenotypically diverse and multi-use plant used in the production of fiber, seed, oils, and a class of specialized metabolites known as phytocannabinoids. The last decade has seen a rapid increase in the licit cultivation and processing of C. sativa for medical end-use. Medical morphotypes produce highly branched compact inflorescences which support a high density of glandular trichomes, specialized epidermal hair-like structures that are the site of phytocannabinoid biosynthesis and accumulation. While there is a focus on the regulation of phytocannabinoid pathways, the genetic determinants that govern flowering time and inflorescence structure in C. sativa are less well-defined but equally important. Understanding the molecular mechanisms that underly flowering behavior is key to maximizing phytocannabinoid production. The genetic basis of flowering regulation in C. sativa has been examined using genome-wide association studies, quantitative trait loci mapping and selection analysis, although the lack of a consistent reference genome has confounded attempts to directly compare candidate loci. Here we review the existing knowledge of flowering time control in C. sativa, and, using a common reference genome, we generate an integrated map. The co-location of known and putative flowering time loci within this resource will be essential to improve the understanding of C. sativa phenology.
Collapse
Affiliation(s)
| | | | | | | | - Anthony Gendall
- Australian Research Council Research Hub for Medicinal Agriculture, La Trobe Institute for Sustainable Agriculture and Food, Department of Animal, Plant and Soil Sciences, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC, Australia
| |
Collapse
|
4
|
Ahrens A, Llewellyn D, Zheng Y. Is Twelve Hours Really the Optimum Photoperiod for Promoting Flowering in Indoor-Grown Cultivars of Cannabis sativa? PLANTS (BASEL, SWITZERLAND) 2023; 12:2605. [PMID: 37514220 PMCID: PMC10386198 DOI: 10.3390/plants12142605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/30/2023]
Abstract
Cannabis sativa ("cannabis" hereafter) is a valuable recent addition to Canada's economy with the legalization for recreational use in 2018. The vast majority of indoor cannabis cultivators use a 12-h light/12-h dark photoperiod to promote flowering. To test the hypothesis that robust flowering initiation responses can be promoted in indoor-grown cannabis cultivars under longer photoperiods, clones of ten drug-type cannabis cultivars were grown under six photoperiod treatments. All treatments were based on a standard 24-h day and included 12 h, 12.5 h, 13 h, 13.5 h, 14 h, and 15 h of light. The plants were grown in a growth chamber for 3 to 4 weeks, receiving an approximate light intensity of 360 µmol·m-2·s-1 from white LEDs. Flowering initiation, defined as the appearance of ≥3 pairs of stigmas at the apex of the primary shoot, occurred in all cultivars under all photoperiod treatments up to 14 h. Delays in flowering initiation time under 14 h vs. 12 h ranged from no delay to approximately 4 days, depending on the cultivar. Some cultivars also initiated flowering under 15 h, but floral tissues did not further develop beyond the initiation phase. Harvest metrics of some cultivars responded quadratically with increasing photoperiod, with ideal levels of key flowering parameters varying between 12 h and 13 h. These results suggest there is potential to increase yield in some indoor-grown cannabis cultivars by using longer than 12-h photoperiods during the flowering stage of production. This is attributed to the inherently higher daily light integrals. Indoor cannabis growers should investigate the photoperiod responses of their individual cultivars to determine the optimal photoperiod for producing floral biomass.
Collapse
Affiliation(s)
- Ashleigh Ahrens
- School of Environmental Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - David Llewellyn
- School of Environmental Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Youbin Zheng
- School of Environmental Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| |
Collapse
|
5
|
Effect of Explant Source on Phenotypic Changes of In Vitro Grown Cannabis Plantlets over Multiple Subcultures. BIOLOGY 2023; 12:biology12030443. [PMID: 36979133 PMCID: PMC10044989 DOI: 10.3390/biology12030443] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/06/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023]
Abstract
Drug-type cannabis is often multiplied using micropropagation methods to produce genetically uniform and disease/insect-free crops. However, micropropagated plantlets often exhibit phenotypic variation, leading to culture decline over time. In cannabis, the source of these changes remains unknown, though several factors (e.g., explant’s sources and prolonged in vitro culture) can result in such phenotypical variations. The study presented herein evaluates the effects of explant sources (i.e., nodal segments derived from the basal, near-basal, middle, and apical parts of the greenhouse-grown mother plant) over multiple subcultures (4 subcultures during 235 days) on multiplication parameters and leaf morphological traits of in vitro cannabis plantlets. While initial in vitro responses were similar among explants sourced from different regions of the plant, there were significant differences in performance over the course of multiple subcultures. Specifically, explant source and/or the number of subcultures significantly impacted plantlet height, number of nodes, and canopy surface area. The explants derived from the basal and near-basal parts of the plant resulted in the tallest shoots with the greatest number of nodes, while the explants derived from the middle and apical regions led to shorter shoots with fewer nodes. Moreover, the basal-derived explants produced cannabis plantlets with shorter but wider leaves which demonstrated the potential of such explants for in vitro rejuvenation practices with minimal culture decline. This study provides new evidence into the long-term impacts of explant source in cannabis micropropagation.
Collapse
|