Inflorescence Yield Research Articles

Cannabis Inflorescence Yield and Cannabinoid Concentration Are Not Increased With Exposure to Short-Wavelength Ultraviolet-B Radiation.

Before ultraviolet (UV) radiation can be used as a horticultural management tool in commercial Cannabis sativa (cannabis) production, the effects of UV on cannabis should be vetted scientifically. In this study we investigated the effects of UV exposure level on photosynthesis, growth, inflorescence yield, and secondary metabolite composition of two indoor-grown cannabis cultivars: ‘Low Tide’ (LT) and ‘Breaking Wave’ (BW). After growing vegetatively for 2 weeks under a canopy-level photosynthetic photon flux density (PPFD) of ≈225 μmol⋅m–2⋅s–1 in an 18-h light/6-h dark photoperiod, plants were grown for 9 weeks in a 12-h light/12-h dark “flowering” photoperiod under a canopy-level PPFD of ≈400 μmol⋅m–2⋅s–1. Supplemental UV radiation was provided daily for 3.5 h at UV photon flux densities ranging from 0.01 to 0.8 μmol⋅m–2⋅s–1 provided by light-emitting diodes (LEDs) with a peak wavelength of 287 nm (i.e., biologically-effective UV doses of 0.16 to 13 kJ⋅m–2⋅d–1). The severity of UV-induced morphology (e.g., whole-plant size and leaf size reductions, leaf malformations, and stigma browning) and physiology (e.g., reduced leaf photosynthetic rate and reduced Fv/Fm) symptoms intensified as UV exposure level increased. While the proportion of the total dry inflorescence yield that was derived from apical tissues decreased in both cultivars with increasing UV exposure level, total dry inflorescence yield only decreased in LT. The total equivalent Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) concentrations also decreased in LT inflorescences with increasing UV exposure level. While the total terpene content in inflorescences decreased with increasing UV exposure level in both cultivars, the relative concentrations of individual terpenes varied by cultivar. The present study suggests that using UV radiation as a production tool did not lead to any commercially relevant benefits to cannabis yield or inflorescence secondary metabolite composition.

Shape Matters: Plant Architecture Affects Chemical Uniformity in Large-Size Medical Cannabis Plants.

Since plant organs sense their environment locally, gradients of micro-climates in the plant shoot may induce spatial variability in the physiological state of the plant tissue and hence secondary metabolism. Therefore, plant architecture, which affects micro-climate in the shoot, may considerably affect the uniformity of cannabinoids in the Cannabis sativa plant, which has significant pharmaceutical and economic importance. Variability of micro-climates in plant shoots intensifies with the increase in plant size, largely due to an increase in inter-shoot shading. In this study, we therefore focused on the interplay between shoot architecture and the cannabinoid profile in large cannabis plants, ~2.5 m in height, with the goal to harness architecture modulation for the standardization of cannabinoid concentrations in large plants. We hypothesized that (i) a gradient of light intensity along the plants is accompanied by changes to the cannabinoid profile, and (ii) manipulations of plant architecture that increase light penetration to the plant increase cannabinoid uniformity and yield biomass. To test these hypotheses, we investigated effects of eight plant architecture manipulation treatments involving branch removals, defoliation, and pruning on plant morpho-physiology, inflorescence yield, cannabinoid profile, and uniformity. The results revealed that low cannabinoid concentrations in inflorescences at the bottom of the plants correlate with low light penetration, and that increasing light penetration by defoliation or removal of bottom branches and leaves increases cannabinoid concentrations locally and thereby through spatial uniformity, thus supporting the hypotheses. Taken together, the results reveal that shoot architectural modulation can be utilized to increase cannabinoid standardization in large cannabis plants, and that the cannabinoid profile in an inflorescence is an outcome of exogenous and endogenous factors.

Increasing the resistance of the drug calendula to abiotic environmental factors

Currently, medicinal plant growing is one of the promising areas of activity of agricultural enterprises in the Russian Federation. This area has a high economic potential. The deterioration of the general ecological situation, the instability of weather conditions have a negative impact on the growth and development of medicinal crops, leading to a decrease in plant resistance to stress factors and the inability to fully realize their potential with cultivated varieties. Plant growth regulators are one of the most promising groups of pesticides, the advantages of which are that they are harmless, environmentally friendly and highly effective at low consumption rates of biologically active substances of polyfunctional action. Exogenous use of growth regulators makes it possible to activate physiological and biochemical processes, regulate individual stages of morphogenesis, in order to mobilize the potential of the plant organism, aimed at overcoming unfavorable environmental conditions by plants, increasing their resistance to harmful organisms and ensuring optimal productivity. On the territory of the collection nursery of the Middle Volga branch of the FSBI VILAR in 2018-2020, an experiment was carried out in order to study the effect of growth regulators and micronutrient fertilizers Zircon, Epin-extra, Ferovit and Siliplant, on the resistance of plants to unfavorable growing conditions, increasing the yield of inflorescences and seeds of calendula officinalis. Ferovit turned out to be the best result of application in the raw material areas for three years of research in the prevailing weather conditions. The average yield of raw materials of air-dried inflorescences was 2.10 t / ha, which is 0.45 t / ha more than the control variant. On seed plots, the best indicators were obtained with the use of Siliplant micronutrient fertilizer 1.25 t / ha, which is 0.2 t / ha more than the option without the use of drugs.

Modeling of mineral elements uptake and localization in cabbage inflorescence (Brassica oleracea var. capitata) grown on sugar mill pressmud-amended soils.

Sugar mill pressmud is highly considered and used as a supplement to improve soil fertility and crop yield, especially in India. This study investigated the growth and yield performance of cultivated cabbage (Brassica oleracea var. capitata) on sugar mill pressmud amended soil. Pot experiments were performed using various pressmud amendment rates (0, 50, 100, and 150g/kg soil) to study the fertilization impact on cabbage inflorescence yield (g) and size (diameter: cm). Moreover, mineral element (Cd, Cr, Cu, Fe, Mn, and Zn) accumulation in the cabbage inflorescence was also studied using a modified polynomial non-linear model. Results showed that the sugar mill pressmud had significantly (p < 0.05) higher nutrient elements which induced their concentration in the soil after mixing. Also, the highest yield (849.25 ± 7.47g), size (15.10 ± 1.50cm diameter), and dry weight (42.13g) of cabbage inflorescence were attained using 100g/kg pressmud treatment with a maximum significant (p < 0.05) accumulation of mineral elements. However, the highest accumulation of mineral elements was observed in the outer zones (Z1 and Z2) of leafy inflorescence as compared to inner zones (Z3 and Z4), respectively. The mineral elements in both outer and inner zones of cabbage followed an order of Fe > Mn > Zn > Cu > Cr > Zn. Furthermore, the developed modified polynomial quadratic model precisely predicted the total mineral element uptake (mg dwt.) by cabbage inflorescence. The models had good fitness as described by the coefficient of determination (R2 > 0.992) values. This study suggested that sugar mill pressmud was a promising resource for cabbage cultivation, and the developed models were helpful in the precise prediction of mineral elements accumulated byits inflorescence.

СОЗДАНИЕ СОРТА ШАЛФЕЯ МУСКАТНОГО С ИСПОЛЬЗОВАНИЕМ МЕТОДОВ КЛЕТОЧНОЙ ИНЖЕНЕРИИ. 2. ИЗУЧЕНИЕ РАСТЕНИЙ-РЕГЕНЕРАНТОВ НА ЭТАПАХ СЕЛЕКЦИОННОГО ПРОЦЕССА

Clary sage (Salvia sclarea L.) is a widely demanded essential oil plant. The products of its processing are used in medicine, perfumery and cosmetics, food industry, paint and varnish production. The main breeding tasks are to develop cultivars that combine high yield and quality of essential oil, resistant to abiotic and biotic stresses. All clary sage cultivars registered in the ‘State register of breeding achievements allowed for use’ Russian Federation were obtained on the basis of traditional methods. The initial breeding material of S. sclarea was obtained at the FSBSI “Research Institute of Agriculture of Crimea” using methods of cell engineering (induction of somaclones from callus cultures, obtaining hybrids in embryoculture and cell selection for resistance to osmotic stress). The aim of this work was to study the main economic and morphometric parameters of clary sage samples created using various biotechnological methods at the main stages of the breeding process. As a material for research, we used samples obtained in vitro using three biotechnological methods – regenerants (R2-R3) from calli of ‘C-785’ and ‘Taigan’ cultivars, obtained in isolated embryo culture hybrids (Salvia sclarea L. x S. grandiflora Etling.) and forms selected in embryoculture on a selective medium with an osmotic (mannitol or NaCl). When studying 10 sage samples (seed progeny of regenerants) in the breeding nursery (2012–2014), three that exceeded the control cultivar ‘Taigan’ in terms of basic economic characteristics were identified. The collection of essential oil from them was 1.2-1.4 times higher than in the control. In the nursery of competitive variety trials (2016–2019), when studying three samples (No. R3-1-6, 226-08 and 1-01), No. R3-1-6 was selected for a number of indicators. This sample is seed progeny of regenerant obtained by the induction of morphogenesis from callus. A characteristic feature of this sample was an increase in the number of lateral shoots per inflorescence by 41.1 %, which contributed to an increase in the mass of inflorescences. By the yield of inflorescences (162.0 c/ha) and the collection of essential oil (51.5 kg/ha), No. R3-1-6 exceeded control by 24.9 % and 43.9 %, respectively. The patent on the new clary sage cultivar ‘Selinzh’ (No. R3-1-6), in the creation of which the method of cell engineering was used for the first time, was received.

Productivity of medicinal raw materials by different genotypes of Matricia chammomila L. is affected with pre-sowing radiation exposure of seeds

One of the key tasks of modern pharmacology is complete and diverse use of natural raw materials - microorganisms and plants. So, different approaches of metabolism redirection were applied. Studying of plant protective reactions indicated a possibility to use various stress factors for the metabolism reorientation. One of the most effective approaches is to use ionizing and UV-C exposure. Thus, there is a shift in metabolic processes towards the formation of secondary metabolism substances with antioxidant, anticancer, immunomodulatory and anti-inflammatory effects. Biotechnological use of radiation exposure is based on the systemicity of radiobiological reactions, including protective and adaptive reactions in non-exposed organs («abscopal effect») and even in non-exposed organisms that are found in the same environment as exposed ones («by stander effect»). The products synthesized in these structures are some medicine materials and directly used by human. Radiation exposure affects developing, blocking of primary and secondary metabolism, so must be improved the selection of varieties with initial high productivity of medicinal raw materials, the choice of exposure and optimal doses inducing an increasing yield of the target metabolite and do not reduce the yield of medicinal raw materials. Effect of UV-C and X-ray pre-sowing exposure of seeds to the productivity of inflorescence formation of eight genotypes of Matricia chammomila L. was studied. There were indicated genotypes with increasing yield of inflorescence only under one or two exposure types and the variety with stimulation of flowering under UV-C exposure and absence of the marker under X-ray one.

Cannabis Yield, Potency, and Leaf Photosynthesis Respond Differently to Increasing Light Levels in an Indoor Environment.

Since the recent legalization of medical and recreational use of cannabis (Cannabis sativa) in many regions worldwide, there has been high demand for research to improve yield and quality. With the paucity of scientific literature on the topic, this study investigated the relationships between light intensity (LI) and photosynthesis, inflorescence yield, and inflorescence quality of cannabis grown in an indoor environment. After growing vegetatively for 2 weeks under a canopy-level photosynthetic photon flux density (PPFD) of ≈425 μmol·m−2·s−1 and an 18-h light/6-h dark photoperiod, plants were grown for 12 weeks in a 12-h light/12-h dark “flowering” photoperiod under canopy-level PPFDs ranging from 120 to 1,800 μmol·m−2·s−1 provided by light emitting diodes. Leaf light response curves varied both with localized (i.e., leaf-level) PPFD and temporally, throughout the flowering cycle. Therefore, it was concluded that the leaf light response is not a reliable predictor of whole-plant responses to LI, particularly crop yield. This may be especially evident given that dry inflorescence yield increased linearly with increasing canopy-level PPFD up to 1,800 μmol·m−2·s−1, while leaf-level photosynthesis saturated well-below 1,800 μmol·m−2·s−1. The density of the apical inflorescence and harvest index also increased linearly with increasing LI, resulting in higher-quality marketable tissues and less superfluous tissue to dispose of. There were no LI treatment effects on cannabinoid potency, while there were minor LI treatment effects on terpene potency. Commercial cannabis growers can use these light response models to determine the optimum LI for their production environment to achieve the best economic return; balancing input costs with the commercial value of their cannabis products.

Nitrogen supply affects cannabinoid and terpenoid profile in medical cannabis (Cannabis sativa L.)

Secondary metabolism in plants is considerably affected by environmental factors including mineral nutrition. Nitrogen is a key plant nutrient, known to affect primary and secondary metabolism in plants, that its effect on the cannabis plants' chemical profile is not known. To evaluate the hypothesis that N supply affects the cannabinoid and terpenoid profile, we studied the impact of N application on chemical and functional-physiology phenotyping in medical cannabis at the flowering stage. The plants were grown under five N treatments of 30, 80, 160, 240, and 320 mg L−1 (ppm) under environmentally controlled conditions. The results revealed that N supply affects cannabinoid and terpenoid metabolism, supporting the hypothesis. The concentrations of most cannabinoids and terpenoids tested were highest under the deficient concentration of 30 mg L−1 N and declined with the elevation of N supply. The concentrations of the two main cannabinoids, tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA), decreased by 69% and 63%, respectively, with the increase in N supply from 30 to 320 mg L−1 N. Plant development and function were restricted under inputs lower than 160 mg L−1 N, demonstrating N deficiency. The morpho-physiological state of the plants was optimal at supply rates of 160–320 mg L−1 N. Inflorescence yield reflected the plant physiological state, increasing with the increase in N supply up to 160 mg L−1 N, and was unaffected by further increase in N. These results of the functional and chemical characterizations suggest that high N supply has adverse effects on the production of secondary compounds in cannabis, while it promotes growth and biomass production. Hence, N supply may serve for the regulation of the cannabinoid and terpenoid profiles, or for increasing plant yield, according to the desired production scheme. Taken together, the results reveal that the optimal N level for yield quantity, that allows also a relatively high secondary metabolites content, is 160 mg L−1 N. Finally, the present study provides a better understanding of the impact of N on 'drug-type' medical cannabis physiology, and takes us one step closer to the optimization of medical cannabis cultivation.

Aspects of applying the method of chemical mutagenesis to develop cultivars of Calendula officinalis L

Background. The need for continuous breeding practice to develop new varieties of Calendula officinalisL. is induced by the accumulation of low-grade morphotypes in the already existing cultivars as a result of crosspollination.Materials and methods. Seeds selected from high-yielding biotypes of cv. ‘Kalta’ were treated with various mutagens for 18 hours, using 1000 seeds for each option. The mutation rate in the M1 generation and seed quality were determined, and plant viability was assessed under field conditions. Plant height, number of branches, number of leaves, number of inflorescences per plant, inflorescence diameter, number of ray floret rows, and weight of one inflorescence were measured in the mass flowering phase. The yield of raw materials (fresh and air-dry biomass of inflorescences) was calculated for each harvest and for the total amount of all 7 harvests during the flowering period.Results.The mutagens DES 0,05% and DMS 0,08% turned outthe most effective for developing new source material. None of the plants produced seeds after treatment with nitrosomethyl urea (NMU0.02% ), and only one plant produced seeds after treatment with NMU 0.04% . As a result of a long-term breeding process (2009–2016), new varieties were developed on the basis of mutant generations M2–M3 : cvs. ‘Zolotoe more’ and ‘Rajskij sad’, both exceeding cv. ‘Kalta’ in the yield of inflorescences by 39 and 30%, seed yield by 48 and 49%, total extractives by 13.8 and 21.3%, and total flavonoids by 29.9% and 43.3%, respectively.Conclusion.New cultivars of C. officinalis, ‘Zolotoe more’ and ‘Rajskij sad’, were developed in accordance with the mutation breeding scheme that employed methods of chemical mutagenesis, with expanded selection of plants altered in their morphological characteristics, productivity and content of bioactive compounds in the first mutant generation and assessment of uniformity, distinctness and stability in the second and subsequent generations.

Yield and Quality of Inflorescences in the Zantedeschia albomaculata (Hook.) Baill. ‘Albomaculata’ after the Treatment with AMF and GA3

This study was conducted to assess the influence of gibberellic acid (GA3) and arbuscular mycorrhizal fungi (AMF) on the flowering and quality of Zantedeschia albomaculata (Hook.) Baill ‘Albomaculata’ plants. Before planting, the rhizomes were soaked in water or an aqueous solution of GA3 at a concentration of 150 mg dm−3 for 30 min. A mixture of AMF was applied to the rhizomes a week after planting. The AMF treatment increased the yield of inflorescences of the ‘Albomaculata’ cultivar by 100%. AMF and GA3 had a favourable effect on the quality of inflorescences, expressed by the length of peduncles, whereas AMF individually positively affected the length of the spathes. AMF and GA3 had no effect on the level of macroelements in calla lily leaves, with the exception of calcium (Ca). The leaves of mycorrhized plants had a high content of sodium (Na) and micronutrients, except for iron (Fe). The results of the study showed that GA3 could be replaced by mycorrhizal inoculation when applied to Zantedeschia plants.

Light matters: Effect of light spectra on cannabinoid profile and plant development of medical cannabis (Cannabis sativa L.)

Light is a key factor affecting plant growth, metabolism and function. Metabolic processes in plants are sensitive to the ratio of Blue:Red light, and there is an increasing awareness that the response to the ratio of these monochromatic lights may vary under exposure to a wider range of the spectrum, such as white light. Due to the potential for regulation of the therapeutic chemical profile and plant development, this issue is of growing interest for the cannabis (Cannabis sativa L.) industry that uses photosynthetic light extensively. Cannabis is a medicinal plant treasured for its secondary metabolites, especially cannabinoids, the unique biologically active compounds in the plant that are considered to be affected by light spectra. In this study we evaluated the hypothesis that the ratio of Blue:Red light affects cannabinoid metabolism, and that plant growth and secondary metabolism is intensified under a full spectrum with similar Blue:Red ratio. Our results point to several spectra specific reactions and some cultivar dependent responses to light spectrum. i. Yield quantity: The highest inflorescence yields were obtained when the spectrum was restricted to the red and blue range at the ratio of 1:1, and in two of the three varieties tested a ratio of 1:4 Blue:Red light had similar results. White light with Blue:Red ratio of 1:1 had the lowest yield. ii. The chemical profile was also affected by the light spectrum, and CBGA, the primary cannabinoid and a precursor for most other cannabinoids, demonstrated the highest response. CBGA accumulation was stimulated by blue-rich light as compared with far-red rich HPS light. The major cannabinoids CBDA, THCA and CBCA were also affected by light quality, and the response was cultivar specific and less pronounced than for CBGA. iii. Plant morphology: Blue light was most inductive for maintaining compact plants, more so than Red:Far-Red ratio. Our results repute the hypothesis that full spectrum improves inflorescence yield compared with Blue:Red light, but support the hypothesis that light spectrum influences plant development and the cannabinoid profile, which could be used to fine-tune cannabis and cannabinoid production.

Effect of Colonization of Trichoderma harzianum on Growth Development and CBD Content of Hemp (Cannabis sativa L.).

Trichoderma harzianum, as a natural endophytic biocontrol agent, can ameliorate plant development, nutrient uptake, and resistance to biotic and abiotic stresses. This study aimed to investigate the effect of Trichoderma harzianum inoculation on agronomical and quality characteristics of two monoecious hemp (Cannabis sativa L.) varieties, Fedora 17 and Felina. A greenhouse pot experiment was conducted in a completely randomized design of two treatments of Trichoderma harzianum with a low and high dose of the fungus (T1 and T2). The significance of differences between treatments was estimated by using a Fisher’s test with a significance level p = 0.05. The root density of both varieties was significantly affected by treatments, and higher values were recorded in Fedora 17 (2.32 mm cm−3). The Arbuscular Mycorrhizal Fungi (AMF) colonization of the root system and the soil emission of CO2 were higher after the inoculation of Trichoderma harzianum. The highest values of plant height and dry weight were noticed for T2, especially in variety Felina. Trichoderma harzianum positively influenced characteristics of inflorescences such as their number, fresh weight moisture, and compactness in both varieties, while the dry weight, length, and dry yield of inflorescences were not improved. Finally, the fertigation of Trichoderma harzianum in hemp plants was beneficial by increasing the cannabidiol (CBD) content, especially in T2 treatment (4 × 1012 CFU kg−1).

RESPONSE OF Calendula officinalis L. PLANTS TO AQUEOUS ACTIVE DRY YEAST APPLICATION TYPE AND RATE IN SANDY SOILS

The present work was carried out during two successive seasons of 2017/2018 and 2018/2019 at the Experimental Farm of El-Qassassein Horticultural Research Station, Ismailia Governorate, to study the effect of active dry yeast aqueous solution rates (2, 4, 6 and 8 g/L.) with two application types (soil drench and foliar spray) each solely or in combination to obtain the pest growth, good production of flowers yield and the highest chemical composition of Calendula officinalis L. plants, under sandy soil conditions. The active dry yeast levels were applied three times starting from 1 st Dec. with 21 days interval between them. The flower heads were collected manually in 13 flower picking times starting from 1st Feb. with one-week intervals between them. The treatment of 4 g/L. active yeast solution in both soil drench and foliar spray and their interaction gave the highest plant height, number of branches/plant, fresh and dry weights of herb/plant, number of inflorescences/plant, fresh and dry weights of inflorescences and ray flowers (g)/plant, dry yield of inflorescences, ray flowers (kg)/fed. and total carotenoids content, during the two seasons. The interaction treatment of 4 g/L. soil drench + 4 g/L. foliar spray yielded 86.8 and 85.4 % of total productivity/year of dry weight of inflorescences (g)/plant, and 85.3 and 84.0 % of total productivity/year of dry weight of ray flowers (g)/plant from the 6th to 13th flower picking times, during the two seasons, respectively.

The Supplementary irrigation and drying method affect the yield and essential oil content and composition of lavender (lavandula angustifolia mill.) flowers

This paper presents the results of a study conducted over the period 2016–2017 which was designed to determine to what extent crop irrigation and raw material drying process determine the content and composition of lavender essential oil. In cultivation with irrigation, a higher yield of fresh and yield of air-dried inflorescences was obtained compared to cultivation without irrigation. The use of supplementary irrigation in lavender crops contributed to an increased amount of essential oil (EO) compared to plants without irrigation. The main components of the essential oil were Linalyl acetate, Linalool, and E-Caryophyllene. In EO obtained from plants cultivated with irrigation, the share of oxygenated monoterpenes (OM) was higher and the share of hydrogenated monoterpenes (HM) was lower than in the oil from plants without irrigation. The EO content in lavender flowers dried at a temperature of 30°C was twice higher than in those dried in natural conditions. In 2016 in which the air temperatures were high and a greater number of sunshine hours was recorded in July and August, plants accumulated more EO than in 2017. Study shows that there are prospects for practical application of crop irrigation in lavender cultivation and of raw material preservation method in order to modify EO content and chemical composition.

Response of medical cannabis (Cannabis sativa L.) genotypes to P supply under long photoperiod: Functional phenotyping and the ionome

Phosphorus (P) is an essential macronutrient required for many central metabolic processes, and is therefore a major factor governing plant development, structure and function. Cannabis is a short-day plant that its' development progression involves a vegetative growth phase under long photoperiod, followed by a reproductive phase under a short photoperiod. The reproductive inflorescence yield potential in cannabis is therefore largely dependent on the morphology and physiological condition of the plants at the vegetative phase. Due to legal restrictions, there is lack of science-based knowledge about cannabis plant science, including mineral nutrition. The present study therefore focused on P nutrition of plants at the vegetative growth phase under long photoperiod. The plants were cultivated in pots in a controlled environment and subjected to 5 levels of P (5, 15, 30, 60, 90 mg L−1). We investigated impact on the ionome, physiological and morphological traits, uptake of nutrients into the plant, translocation to the shoot, and distribution in the plant organs for 2 medicinal cannabis genotypes. Plant biomass production, photosynthesis rate, stomatal conductance, transpiration rate and intercellular CO2 at the vegetative growth phase exceled under 30 mg L−1 P supply. Uptake and translocation of nutrients from root to the shoot was highly influenced by the P treatment. Under excess P supply, most of the plant P accumulated in the roots, and translocation to the shoot was inhibited. Uptake of Mg into the plants, and its' translocation to the shoot was inhibited by P deficiency in both cultivars, and was enhanced by increased P supply. Calcium uptake was increased by P application but translocation to the shoot was inhibited. Zinc retention in roots under P deficiency was found in both varieties. Our results suggest a wide optimum range for P in medicinal cannabis at the vegetative growth stage, with a minimum requirement of 15 mg L−1 P and a recommended application of 30 mg L−1. The functional physiology and ionome profiling revealed genotypic variability in P sensitivity.

Potassium and micronutrient fertilizer addition in a mock aquaponic system for drug-type Cannabis sativa L. cultivation

Cultivating drug-type Cannabis sativa L. with aquaponics could reduce mineral fertilizer use; however, its nutrient solution is often unbalanced and low in K+ and micronutrients. It is unknown if a K+ fertilizer, a micronutrient fertilizer, or both, would improve C. sativa production in aquaponic solution, as optimal K+ and micronutrient concentrations in the root zone for C. sativa during the flowering stage have not been investigated. To determine the effects of adding a K+ fertilizer and a micronutrient fertilizer to aquaponic solution for C. sativa production, we grew drug-type C. sativa in five aquaponic based solutions: aquaponic solution (control plants) (15 mg·L−1 K+); aquaponic solution with added micronutrients (Fe3+, Cu2+, Mn2+, B3+, Mo3+, and Zn2+); and aquaponic solution with added micronutrients and three K+ concentrations (75, 113, and 150 mg·L−1) during the flowering stage. To evaluate the impact of additional K+ and micronutrients on C. sativa production, we measured growth (vegetative parameters and weight), physiology (leaf gas exchange), leaf nutrition content, and yield (inflorescence weight). Adding the K+ fertilizer at 75 and 113 mg·L−1 with micronutrients to aquaponic solution increased harvest index (marketable inflorescence to shoot weight) by 16% and 22% compared with the control, respectively. Cannabis sativa dry apical inflorescence and total inflorescence yield also increased linearly with increasing K+ concentration. Alternatively, plants grown in the control (suboptimal K+ and micronutrient conditions) had no difference in growth or measured physiological parameters compared with plants with supplemented nutrients. Our study suggests that aquaponic solution mitigates low K+ concentrations from causing deficiency.

Determination of total nitrogen content in fresh leaves and leaf powder of Dendrobium orchids using near-infrared spectroscopy

Appropriate application of nitrogen (N) fertilizer promotes plant growth, inflorescence yield, and flower quality of orchids. In this study, we used the near-infrared spectroscopy (NIRS) technique to develop a prediction model of the N content in the leaf of Dendrobium orchid, which is an essential indicator for monitoring plant health. The Dendrobium orchid samples were foliar sprayed in rotation between 20N–20P–20K and 30N–10P–10K fertilizers at a frequency of once or twice a week to create a diverse amount of leaf N content. An application of water was used as the control treatment. After nine months of fertilizer treatments, 150 fresh orchid leaf samples, containing various N contents, were scanned using Fourier-transform near-infrared spectroscopy (FT-NIRS). Then the samples were dried and ground to a fine powder and were again scanned. The absorbance spectra were collected at the 12,000–4000 cm−1 (800–2500 nm) region. Total N content was determined by using the combustion method. The result showed a high proficiency in the estimation of N in leaf powder with the correlation coefficient of prediction (Rp), the root mean square error of prediction (RMSEP), and the ratio of standard deviation of reference data of prediction set to standard error of prediction (RPD) being 0.9882, 0.0637% dry weight (DW), and 6.53, respectively. The fresh leaf sample was successfully predicted with Rp, RMSEP, and RPD of 0.8874, 0.207% DW, and 2.13, respectively. Additionally, external validation confirmed the high reliability of using leaf powder since the correlation coefficient of external validation (rp) and RMSEP of the external validation achieved 0.9651 and 0.1405% DW, respectively, while the external validation of fresh leaf should be improved with rp = 0.7438 and RMSEP = 0.2652% DW. The overall results suggested that NIRS can be used for monitoring the N status in orchids, especially in leaf powder, with high accuracy.

Comparing hydroponic and aquaponic rootzones on the growth of two drug-type Cannabis sativa L. cultivars during the flowering stage

The cultivation of drug-type Cannabis sativa Lin. (C. sativa) employs a variety of rootzone systems, yet little is understood about rootzone-effects on plant physiology, inflorescence biomass, and cannabinoid potency. To determine if rootzone systems can affect C. sativa growth, physiology, and inflorescence biomass and phytochemicals, two C. sativa cultivars, colloquially known as ‘Nordle’ and ‘Sensi-Star’, were grown in three rootzone systems in a controlled environment. The three tested rootzone systems were: 1) an 11-litre pot containing a peat-based growing substrate, top fertigated with a synthetic fertilizer solution (“hydroponic”); 2) an 11-litre pot containing a peat-based growing substrate, top fertigated with aquaculture effluent solution (“aquaculture”); and 3) a 3-litre pot containing a custom made, predominantly peat-based growing substrate, with the lower portion of the roots submerged in a conventional aquaponics deep-water culture system (“aquaponics”). Throughout the experiment, plant growth (height, branch number, canopy volume), leaf-level physiological traits (e.g., chlorophyll) foliar mineral nutrition, and substrate physio-chemical properties were measured. At experimental completion, inflorescence yield (dry biomass) and potency (mass-based cannabinoid and terpene concentrations) were determined. Results revealed, significant rootzone-effects on most growth and physiological traits measured. Plants performed best in the in the hydroponic rootzone: e.g., producing 42–116% greater inflorescence biomass than the other rootzone systems. In contrast, however, Nordle plants in the aquaponics treatment had greater Δ9-tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), and the terpenes ß-pinene and limonene, relative to their congeners grown in the other rootzones investigated. Pronounced differences in substrate macro-nutrient availability and foliar nutrient content occurred among the rootzones, suggesting a potential mechanism to explain the observed growth, physiological, yield and potency responses. This work underscores the importance of the rootzone environment for the cultivation of C. sativa, specifically in indoor systems focused of medical or research production.

Impact of Different Phytohormones on Morphology, Yield and Cannabinoid Content of Cannabis sativa L.

The impact of exogenously applied plant growth regulators (PGR), 1-naphthalenaecetic acid (NAA), 6-benzylaminopurine (BAP), and a mixture of both (NAA/BAP-mix), was investigated in regard to plant height, length of axillary branches, number of internodes, biomass yield and cannabinoid content of three different phytocannabinoid-rich (PCR) Cannabis genotypes. The results showed that total plant height was significantly reduced under the application of NAA (28%), BAP (18%), and NAA/BAP-mix treated plants (15%). Axillary branch length was also significantly reduced by 58% (NAA) and 30% (NAA/BAP-mix). BAP did not significantly reduce the length of axillary branches. The number of internodes was reduced by NAA (19%), BAP (10%), and the NAA/BAP-mix (14%) compared to the untreated control. NAA application influenced the plant architecture of the tested cv. KANADA beneficially, resulting in a more compact growth habitus, while inflorescence yield (23.51 g plant−1) remained similar compared to the control (24.31 g plant−1). Inflorescence yield of v. 0.2x and cv. FED was reduced due to PGR application while cannabinoid content remained stable. Overall, the application of PGR could be used on a genotype-specific level to beneficially influence plant architecture and optimize inflorescence yield per unit area and thus cannabinoid yield, especially in the presence of space limitations under indoor cultivation.

Azolla as an Alternative of Mineral Nitrogen for Chamomile Plant (Matricaria chamomilla L.) Fertilization in Sandy Soil

Two pot experiments were carried out during the two successive seasons of 2010/2011 and 2011/ 2012 to apply mineral nitrogen and/or Azolla at different methods of addition with a reduction of mineral nitrogen fertilizer and its effect on vegetative growth, the yield of inflorescences, total phenolic concentration, antioxidant activity, nitrate and nitrite concentrations and the volatile oil concentrations and composition of chamomile inflorescences in sandy soil. Data indicated that dry Azolla (DA) treatments increased significantly plant height, number of branches/plant, shoot fresh and dry weights and number of inflorescences/plant against the rest treatments. It is clear that DA singly induced maximum growth parameters in both seasons and the reverse was true with fresh Azolla (FA) alone. It is obvious that DA achieved the highest total phenolic concentrations, antioxidant activity and volatile oil (VO) concentrations, and the opposite response was true for nitrate &amp; nitrite concentrations. Addition of 50% ammonium nitrate to 50% FA or 50% Azolla extract as foliar (spray Azolla) SA have positive effect on chemical constituents except nitrate and nitrite concentrations. It is evident that the highest chamazulene and α ̶ bisabolol oxide ̶ B were achieved with DA and the reverse was true for α ̶ bisabolol oxide ̶ A. Dry Azolla treatment alone was the most efficient one in increasing the yield production with increment in active substances of chamomile plant in sandy soil.