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Cannabis Indoor Growing Conditions, Management Practices, and Post-Harvest Treatment: A Review

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Cannabis has attracted a new wave of research attention as an herbal medicine. To deliver compliant, uniform, and safe cannabis medicine, growers should optimize growing environments on a site-specific basis. Considering that environmental factors are interconnected, changes in a factor prompts adjustment of other factors. This paper reviews existing work that considers indoor growing conditions (light, temperature, CO2 concentration, humidity, growing media, and nutrient supply), management practices (irrigation, fertilization, pruning & training, and harvest timing), and post-harvest treatment (drying and storage) for cannabis indoor production.
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... Finally, as concluded in the review of medical cannabis indoor cultivation factors and practices by Jin et al. [44], due to a large number of variables, harvest time is subjective and not possible to be determined generally for cannabis plants, thus, the necessity to be examined on a case-by-case basis. Additionally, the available details on pruning techniques -including topping and the removal of side shoots-are limited. ...
... As cited in the introduction section, the source of variation for biomass accumulation and inflorescence yield are manifold and continually being reported in the literature. Factors as genotype, pot size, fertilization scheme, plant density, light intensity, indoor growing conditions, the duration of flowering period and management practices were reviewed by Jin et al. [44] and Backer et al. [55]. Authors cite that pruning can enhance yield by maximizing light interception, optimizing nutrient allocation and by creating more air circulation [44]. ...
... Factors as genotype, pot size, fertilization scheme, plant density, light intensity, indoor growing conditions, the duration of flowering period and management practices were reviewed by Jin et al. [44] and Backer et al. [55]. Authors cite that pruning can enhance yield by maximizing light interception, optimizing nutrient allocation and by creating more air circulation [44]. Calculated inflorescence yields per area for each PT-L (226.1 g·m −2 ), C (234.7 g·m −2 ) and T (266.4 g·m −2 )-are comparable to results found by Knight et al. [56] (274.8 g·m −2 ) and yields reported in other studies [51]. ...
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The definition of optimum harvest and pruning interventions are important factors varying inflorescence yield and cannabinoid composition. This study investigated the impact of (i) harvest time (HT) and (ii) pruning techniques (PT) on plant biomass accumulation, CBD and CBDA-concentrations and total CBD yield of a chemotype III medical cannabis genotype under indoor cultivation. The experiment consisted of four HTs between 5 and 11 weeks of flowering and three PTs-apical cut (T); removal of side shoots (L) and control (C), not pruned plants. Results showed that inflorescence dry weight increased continuously, while the total CBD concentration did not differ significantly over time. For the studied genotype, optimum harvest time defined by highest total CBD yield was found at 9 weeks of flowering. Total CBD-concentration of inflorescences in different fractions of the plant’s height was significantly higher in the top (9.9%) in comparison with mid (8.2%) and low (7.7%) fractions. The T plants produced significantly higher dry weight of inflorescences and leaves than L and C. Total CBD yield of inflorescences for PTs were significantly different among pruned groups, but do not differ from the control group. However, a trend for higher yields was observed (T > C > L).
... There is a significant difference in the potency, quality and content of cannabinoids and terpenes between unripe and ripe buds [26,49,50]. When the bud is ripe, it is the best time to harvest Cannabis [50]. ...
... There is a significant difference in the potency, quality and content of cannabinoids and terpenes between unripe and ripe buds [26,49,50]. When the bud is ripe, it is the best time to harvest Cannabis [50]. Therefore, daily bud inspections and extra time to harvest will feature multiple harvesting sessions to ensure the finest harvest and best quality to process medicinal Cannabis [49]. ...
... Most growers and commercial processors predicate the product is dry based on texture and crispness, while having only 11% w/w of moisture [76,91]. Any change in drying conditions may cause decarboxylation of acidic cannabinoids, loss of terpenes and reduced product quality [50]. Studies by ElSohly, Radwan, Gul, Chandra and Galal [44] and Taschwer and Schmid [45] found that the best way to avoid poor drying problems via a selection of a drying techniques depended on the strain's chemical profile, drying behavior and the end product requirements. ...
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The traditional Cannabis plant as a medicinal crop has been explored for many thousands of years. The Cannabis industry is rapidly growing; therefore, optimising drying methods and producing high-quality medical products have been a hot topic in recent years. We systemically analysed the current literature and drew a critical summary of the drying methods implemented thus far to preserve the quality of bioactive compounds from medicinal Cannabis. Different drying techniques have been one of the focal points during the post-harvesting operations, as drying preserves these Cannabis products with increased shelf life. We followed or even highlighted the most popular methods used. Drying methods have advanced from traditional hot air and oven drying methods to microwave-assisted hot air drying or freeze-drying. In this review, traditional and modern drying technologies are reviewed. Each technology will have different pros and cons of its own. Moreover, this review outlines the quality of the Cannabis plant component harvested plays a major role in drying efficiency and preserving the chemical constituents. The emergence of medical Cannabis, and cannabinoid research requires optimal post-harvesting processes for different Cannabis strains. We proposed the most suitable method for drying medicinal Cannabis to produce consistent, reliable and potent medicinal Cannabis. In addition, drying temperature, rate of drying, mode and storage conditions after drying influenced the Cannabis component retention and quality
... As heat is the main agent for the decarboxylation of cannabinoids, the appropriate drying temperature and conditions are very important to obtain good quality product with a maintained amount of THC, CBD, or other cannabinoids. The inflorescence of raw cannabis contains around 78 to 80% moisture, which needs to be reduced for safe storage and production of readyto-use dry products [28,29]. Researchers are trying to identify suitable drying technology, which can replace the existing hang-drying practice. ...
... It can also result in an increase in the level of THC and CBN by completing the decarboxylation process, as well as extending the storability by limiting fungal growth [29]. According to Jin et al. [28], maintaining a temperature of 18 • C and an RH of 60% for a period of 2 weeks, with the opening of the lid after 6 h, is the best curing condition. Although curing is one of the most significant postharvest operations, it has been overlooked and is not investigated properly. ...
Article
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In recent years, cannabis (Cannabis sativa L.) has been legalized by many countries for production, processing, and use considering its tremendous medical and industrial applications. Cannabis contains more than a hundred biomolecules (cannabinoids) which have the potentiality to cure different chronic diseases. After harvesting, cannabis undergoes different postharvest operations including drying, curing, storage, etc. Presently, the cannabis industry relies on different traditional postharvest operations, which may result in an inconsistent quality of products. In this review, we aimed to describe the biosynthesis process of major cannabinoids, postharvest operations used by the cannabis industry, and the consequences of postharvest operations on the cannabinoid profile. As drying is the most important post-harvest operation of cannabis, the attributes associated with drying (water activity, equilibrium moisture content, sorption isotherms, etc.) and the significance of novel pre-treatments (microwave heating, cold plasma, ultrasound, pulse electric, irradiation, etc.) for improvement of the process are thoroughly discussed. Additionally, other operations, such as trimming, curing, packaging and storage, are discussed, and the effect of the different postharvest operations on the cannabinoid yield is summarized. A critical investigation of the factors involved in each postharvest operation is indeed key for obtaining quality products and for the sustainable development of the cannabis industry.
... The quality and quantity of plant chemical metabolites are influenced by many environmental factors: temperature, light, moisture, soil nutrients, ozone depletion due to carbon dioxide concentrations, and biotic stress (Ncube et al. 2012;Prince et al. 2018). Agronomic factors have been presented in the scientific literature that determines the yield potential and quality for specific end-use applications Jin et al. 2019). The sowing density of 30 seeds/m2 influences the production of bigger flowers culminating in higher yields of polyphenols and terpenes. ...
... In addition, the crop prefers warm and sunny weather (Petrack 2021). To maximize cannabis yields and obtain quality crops and products, the process entails regulating the growing conditions and management practices (Jin et al. 2019). A research gap needs to be addressed about the growing conditions of cannabis in Africa since most of its cultivation is outdoors. ...
... Furthermore, in vitro cannabis production allows the elimination of biotic contamination factors while contributing genetically and physiologically uniform, miniaturized specimens to improve replicability. Although certain plants do not flower in vitro, many cannabis cultivars develop floral organs under short-day conditions [34,35], which is also observed in vitro [36], further extending the applicability of these protocols with cannabis to assess additional light-mediated physiological responses and secondary metabolism. With expected trends emerging from both experiments, assessing and validating specific suppositions relating to the nature of plant responses as directed by different growth conditions using the methods presented exemplifies their value. ...
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Supplemental sugar additives for plant tissue culture cause mixotrophic growth, compli- cating carbohydrate metabolism and photosynthetic relationships. A unique platform to test and model the photosynthetic proficiency and biomass accumulation of micropropagated plantlets was introduced and applied to Cannabis sativa L. (cannabis), an emerging crop with high economic interest. Conventional in vitro systems can hinder the photoautotrophic ability of plantlets due to low light intensity, low vapor pressure deficit, and limited CO2 availability. Though exogenous sucrose is routinely added to improve in vitro growth despite reduced photosynthetic capacity, reliance on sugar as a carbon source can also trigger negative responses that are species-dependent. By increasing photosynthetic activity in vitro, these negative consequences can likely be mitigated, facilitating the production of superior specimens with enhanced survivability. The presented methods use an open-flow/force-ventilated gas exchange system and infrared gas analysis to measure the impact of [CO2], light, and additional factors on in vitro photosynthesis. This system can be used to answer previously overlooked questions regarding the nature of in vitro plant physiology to enhance plant tissue culture and the overall understanding of in vitro processes, facilitating new research methods and idealized protocols for commercial tissue culture.
... Importantly, the composition and concentration of the different secondary metabolites are also affected by harvest time (Happyana and Kayser, 2016) and change over time postharvest as a result of different degradation routes, depending on the storage conditions and its duration (Trofin et al., 2011;Jin et al., 2019;Zamengo et al., 2019;Milay et al., 2020). The concentrations of terpenoids rapidly decline in storage due to their volatile nature (Milay et al., 2020). ...
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Medical Cannabis and its major cannabinoids (−)-trans-Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are gaining momentum for various medical purposes as their therapeutic qualities are becoming better established. However, studies regarding their efficacy are oftentimes inconclusive. This is chiefly because Cannabis is a versatile plant rather than a single drug and its effects do not depend only on the amount of THC and CBD. Hundreds of Cannabis cultivars and hybrids exist worldwide, each with a unique and distinct chemical profile. Most studies focus on THC and CBD, but these are just two of over 140 phytocannabinoids found in the plant in addition to a milieu of terpenoids, flavonoids and other compounds with potential therapeutic activities. Different plants contain a very different array of these metabolites in varying relative ratios, and it is the interplay between these molecules from the plant and the endocannabinoid system in the body that determines the ultimate therapeutic response and associated adverse effects. Here, we discuss how phytocannabinoid profiles differ between plants depending on the chemovar types, review the major factors that affect secondary metabolite accumulation in the plant including the genotype, growth conditions, processing, storage and the delivery route; and highlight how these factors make Cannabis treatment highly complex.
... Throughout the growth cycle, the plants were constantly irrigated with a solution of distilled water to which the nutrient solution was periodically added by applying the dosage recommended in the product data sheet. Furthermore, the electric conductivity and pH value of the nutrient solution were measured daily and maintained below 1.5 mS/cm and in the range 5.8-6.0 with the aid of a pH corrector [32]. After 65 days of growth at natural light (12-14 h of sunlight) and temperature, the whole plants (60 cm high and still in vegetative phase) were collected and dried in a ventilated oven at 60 • C for 3 days. ...
Article
L-Kynurenine (KYN) and kynurenic acid (KYNA) are products of the metabolism of L-tryptophan (TRP) in the central nervous system of animals, but they are not commonly found in plants. In particular, KYNA is known for its interesting pharmacological properties (anti-oxidative, anti-inflammatory, hypolipidemic, and neuroprotective), which suggest a potential functional food ingredient role. The three compounds were identified in samples of Cannabis sativa L. by means of high-performance liquid chromatography coupled to high-resolution mass spectrometry using an untargeted metabolomics approach. Their concentrations were evaluated using a targeted metabolomics method in three organs of the plant (roots, stem, and leaves) in soil at two different growth stages and in hydroponics conditions. The distribution of TRP, KYN and KYNA was found tendentially higher in leaves compared to stem and roots and changed over time. Moreover, the levels of KYNA found in this study are unprecedentedly high compared to those found so far in other plant species, suggesting that Cannabis sativa L. could be a promising alternative source of this metabolite.
Technical Report
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Is medical cannabis really capable of making a difference for poor countries in terms of growth and job creation? That was the main question motivating the research whose findings are presented in this book. However, at the time the project was launched in January 2020 no one could have foreseen that the entire globe would soon be in thrall to a severe pandemic. Broadening the scope of the research to cover the entire pharmaceutical industry therefore seemed appropriate. The COVID-19 outbreak has starkly reminded us of the contribution of pharmaceutical drugs to human welfare. The present lacklustre performance of the pharmaceutical industry in some regions of the world is reflected in the way that large numbers of people are left behind, particularly in developing countries. Sub-Saharan Africa imports most of the medicines that are needed across the region, which renders local populations extremely vulnerable to disease and adversities in general. Some illnesses are peculiar to Africa, and imported pharmaceuticals may not always work there, as in the case of some COVID-19 vaccines, which are not effective against certain local variants of the virus. Medical cannabis has gained in prominence worldwide in recent years. Its use has become legal in an increasing number of advanced economies, and its market volume is projected to grow at double-digit rates in the near future. Some developing countries, in particular those negatively affected by the decline of tobacco exports, have seen a growth opportunity for their economies in the cultivation of cannabis and the production of cannabis-derived pharmaceuticals. The goal of creating new jobs and raising revenues from exports has prompted a number of sub-Saharan African countries to legalize the production of medical cannabis and the cultivation of the cannabis plant to that end. Lesotho was the very first country in Africa to grant licences for the production of medical cannabis, in 2017, and it was followed by Zimbabwe one year later. The early-mover position of these two African countries accounts for the special attention accorded to their experience in the present book. Dependent to a great extent on the capital brought by foreign investors, the activities undertaken in Lesotho and Zimbabwe to set up the necessary infrastructure for medical cannabis cultivation and production were considerably slowed down by the spread of the COVID-19 virus and by the drastic restrictive measures adopted in response. The medical cannabis industry in Africa can therefore still be said to be in its infancy.
Chapter
Artificial vision, also known as computer vision or technical vision, is the scientific discipline that includes methods to acquire, process, analyze, and understand images of the real world in order to produce numerical or symbolic information so that they can be processed by a computer. Just as humans use our eyes and brains to understand the world around us, computer vision tries to produce the same effect so that computers can perceive and understand an image or sequence of images and act as appropriate in a given situation. Applications in this discipline show its use in the monitoring and development of the maturity stages for various crops. On the other hand, the cultivation of medicinal cannabis in Colombia is taking on a significant economic and scientific interest, and due to the limited local research around this plant, it is necessary to direct efforts to study its different phenological stages that allow determining the moment of maturity optimal for harvesting. The present work proposes the future contribution of computational vision in the detection of maturity states of medicinal cannabis. In this study, two main topics are discussed: first, a review of the state of the art on the use of computer vision techniques related to the recognition of images applied to monitoring the development of various crops, and second, an elaboration of a methodological proposal for the identification of the optimal harvest time for medicinal cannabis inflorescences and the development of a computational application. Conclusions at the end of the work are raised in which the use of artificial neural networks and the creation of a database for their training stand out.
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The influence of light spectral quality on cannabis (Cannabis sativa L.) development is not well defined. It stands to reason that tailoring light quality to the specific needs of cannabis may increase bud quality, consistency, and yield. In this study, C. sativa L. ‘WP:Med (Wappa)’ plants were grown with either no supplemental subcanopy lighting (SCL) (control), or with red/blue (‘‘Red-Blue’’) or red-green-blue (‘‘RGB’’) supplemental SCL. Both Red-Blue and RGB SCL significantly increased yield and concentration of total D⁹-tetrahydrocannabinol (D⁹-THC) in bud tissue from the lower plant canopy. In the lower canopy, RGB SCL significantly increased concentrations of a-pinine and borneol, whereas both Red-Blue and RGB SCL increased concentrations of cis-nerolidol compared with the control treatment. In the upper canopy, concentrations of a-pinine, limonene, myrcene, and linalool were significantly greater with RGB SCL than the control, and cis-nerolidol concentration was significantly greater in both Red-Blue and RGB SCL treated plants relative to the control. Red-Blue SCL yielded a consistently more stable metabolome profile between the upper and lower canopy than RGB or control treated plants, which had significant variation in cannabigerolic acid (CBGA) concentrations between the upper and lower canopies. Overall, both Red-Blue and RGB SCL treatments significantly increased yield more than the control treatment, RGB SCL had the greatest impact on modifying terpene content, and Red-Blue produced a more homogenous bud cannabinoid and terpene profile throughout the canopy. These findings will help to inform growers in selecting a production light quality to best help them meet their specific production goals. © 2018, American Society for Horticultural Science. All rights reserved.
Thesis
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Cannabis producers lack reliable information on the horticultural management of their crops. This thesis research was designed to improve horticultural practices for controlled environment cannabis production; topics included propagation, growing substrates, fertilization, and irrigation. To optimize the procedures for taking vegetative stem cuttings in cannabis, several factors were evaluated on how they affect rooting success and quality (Chapter Two). These included number of leaves, leaf tip removal, basal/apical position of cutting on the stock plant, and type of rooting hormone. Removing leaf tips reduced rooting success and cuttings with three fully-expanded leaves had higher rooting success and quality than those with two. Also, a 0.2% indole-3-butyric gel was more effective than a 0.2% willow extract gel to stimulate rooting and cutting position had no effect on rooting. Coir-based substrates with different physical properties were evaluated during the vegetative and flowering stage of cannabis production; optimal organic fertilizer rates were established for each substrate (Chapters Three and Four). During the vegetative stage, cannabis performed well in both tested substrates despite the ≈11% difference in container capacity (CC) between them. During the flowering stage, the substrate with lower CC increased floral dry weight (yield) and the concentration and/or yield of some cannabinoids, including THC, compared to the substrate with higher CC. The optimal organic fertilizer rate varied by substrate during the flowering stage but not during the vegetative stage; higher fertilizer rate during the flowering stage increased growth and yield but diluted some cannabinoids. Finally, the effects of controlled drought stress timing and frequency during the flowering stage were explored on floral dry weight and secondary metabolism (Chapters Five and Six). When drought was applied during week seven of the flowering stage, through gradual substrate drying over eleven days, floral concentration and content per unit growing area of major cannabinoids were increased. When drought was applied over a period of ≈8 days during week seven, cannabinoid content was similar to a well-watered control; though, dependent on drought timing, the content of some terpenoids varied. This research provided evidence-based information that can help growers improve the quality and yield of their cannabis crops.
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Cannabis sativa L. flowers are the main source of Δ-9-tetrahydrocannabinol (THC) used in medicine. One of the most important growth factors in cannabis cultivation is light; light quality, light intensity, and photoperiod play a big role in a successful growth protocol. The aim of the present study was to examine the effect of 3 different light sources on morphology and cannabinoid production. Cannabis clones were grown under 3 different light spectra, namely high-pressure sodium (HPS), AP673L (LED), and NS1 (LED). Light intensity was set to ∼450 µmol/m2/s measured from the canopy top. The photoperiod was 18L: 6D/21 days during the vegetative phase and 12L: 12D/46 days during the generative phase, respectively. At the end of the experiment, plant dry weight partition, plant height, and cannabinoid content (THC, cannabidiol [CBD], tetrahydrocannabivarin [THCV], cannabigerol [CBG]) were measured under different light treatments. The experiment was repeated twice. The 3 light treatments (HPS, NS1, AP673L) resulted in differences in cannabis plant morphology and in cannabinoid content, but not in total yield of cannabinoids. Plants under HPS treatment were taller and had more flower dry weight than those under treatments AP673L and NS1. Treatment NS1 had the highest CBG content. Treatments NS1 and AP673L had higher CBD and THC concentrations than the HPS treatment. Results were similar between experiments 1 and 2. Our results show that the plant morphology can be manipulated with the light spectrum. Furthermore, it is possible to affect the accumulation of different cannabinoids to increase the potential of medicinal grade cannabis. In conclusion, an optimized light spectrum improves the value and quality of cannabis. Current LED technology showed significant differences in growth habit and cannabinoid profile compared to the traditional HPS light source. Finally, no difference of flowering time was observed under different R:FR (i.e., the ratio between red and far-red light).
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Cannabis producers, especially those with organic operations, lack reliable information on the fertilization requirements for their crops. To determine the optimal organic fertilizer rate for vegetative-stage cannabis (Cannabis sativa L.), five rates that supplied 117, 234, 351, 468, and 585 mg N/L of a liquid organic fertilizer (4.0N–1.3P– 1.7K) were applied to container-grown plants with one of two coir-based organic substrates. The trial was conducted in a walk-in growth chamber and the two substrates used were ABcann UNIMIX 1-HP with lower water-holding capacity (WHC) and ABcann UNIMIX 1 with higher WHC. No differences in growth or floral dry weight (yield) were found between the two substrates. Pooled data from both substrates showed that the highest yield was achieved at a rate that supplied 389 mg N/L (interpolated from yield-fertilizer responses) which was 1.8 times higher than that of the lowest fertilizer rate. The concentration of Δ⁹-tetrahydrocannabinol (THC) in dry floral material was maximized at a rate that supplied 418 mg N/L, and no fertilizer rate effects were observed on Δ⁹-tetrahydrocannabidiolic acid (THCA) or cannabinol (CBN). The highest yield, cannabinoid content, and plant growth were achieved around an organic fertilizer rate that supplied 389 mg N/L during the vegetative growth stage when using the two coirbased organic substrates. © 2017, American Society for Horticultural Science. All rights reserved.
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For over a century, research on cannabis has been hampered by its legal status as a narcotic. The recent legalization of cannabis for medical purposes in North America requires rigorous standardization of its phytochemical composition in the interest of consumer safety and medicinal efficacy. To utilize medicinal cannabis as a predictable medicine, it is crucial to classify hundreds of cultivars with respect to dozens of therapeutic cannabinoids and terpenes, as opposed to the current industrial or forensic classifications that only consider the primary cannabinoids tetrahydrocannabinol (THC) and cannabidiol (CBD). We have recently developed and validated analytical methods using high-pressure liquid chromatography (HPLC-DAD) to quantify cannabinoids and gas chromatography with mass spectroscopy (GC-MS) to quantify terpenes in cannabis raw material currently marketed in Canada. We classified 32 cannabis samples from two licensed producers into four clusters based on the content of 10 cannabinoids and 14 terpenes. The classification results were confirmed by cluster analysis and principal component analysis in tandem, which were distinct from those using only THC and CBD. Cannabis classification using a full spectrum of compounds will more closely meet the practical needs of cannabis applications in clinical research, insdustrial production, and patients’ self-production in Canada. As such, this holistic classification methodology will contribute to the standardization of commercially-available cannabis cultivars in support of a continuously growing market.
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The evolution of major cannabinoids and terpenes during the growth of Cannabis sativa plants was studied. In this work, seven different plants were selected: three each from chemotypes I and III and one from chemotype II. Fifty clones of each mother plant were grown indoors under controlled conditions. Every week, three plants from each variety were cut and dried, and the leaves and flowers were analyzed separately. Eight major cannabinoids were analyzed via HPLC-DAD, and 28 terpenes were quantified using GC-FID and verified via GC-MS. The chemotypes of the plants, as defined by the tetrahydrocannabinolic acid/cannabidiolic acid (THCA/CBDA) ratio, were clear from the beginning and stable during growth. The concentrations of the major cannabinoids and terpenes were determined, and different patterns were found among the chemotypes. In particular, the plants from chemotypes II and III needed more time to reach peak production of THCA, CBDA, and monoterpenes. Differences in the cannabigerolic acid development among the different chemotypes and between monoterpene and sesquiterpene evolution patterns were also observed. Plants of different chemotypes were clearly differentiated by their terpene content, and characteristic terpenes of each chemotype were identified.
Book
This is the fourth edition of an established and successful reference for plant scientists. The author has taken into consideration extensive reviews performed by colleagues and students who have touted this book as the ultimate reference for research and learning. The original structure and philosophy of the book continue in this new edition, providing a genuine synthesis of modern physicochemical and physiological thinking, while entirely updating the detailed content. Key concepts in plant physiology are developed with the use of chemistry, physics, and mathematics fundamentals. The figures and illustrations have been improved and the list of references has been expanded to reflect the author's continuing commitment to providing the most valuable learning tool in the field. This revision will ensure the reputation of Park Nobel's work as a leader in the field. * More than 40% new coverage * Incorporates student-recommended changes from the previous edition * Five brand new equations and four new tables, with updates to 24 equations and six tables * 30 new figures added with more than three-quarters of figures and legends improved * Organized so that a student has easy access to locate any biophysical phenomenon in which he or she is interested * Per-chapter key equation tables * Problems with solutions presented in the back of the book * Appendices with conversion factors, constants/coefficients, abbreviations and symbols.