Seed Setting Stage Research Articles

Effect of Harvesting Stages on Herbage and Essential Oil Yield of Rosemary (Rosmarinus Officinalis L.) under Northern Dry Zone of Karnataka, India

Aim: To study the effect of different phenological stages of harvesting on the yield and quality of rosemary. Study Design: Fisher’s method of ANOVA. Place and Duration of Study: Department of Plantation, Spices, Medicinal and Aromatic Crops, College of Horticulture, Bagalkot, Karnataka during rabi 2023-24. Methodology: The experiment was laid out in Randomized Complete Block Design with five replications, comprising five different stages of harvesting namely vegetative stage, flower initiation stage, fifty per cent flowering stage, full bloom stage and seed setting stage. Results: The maximum mean fresh herbage yield (589.79 g plant-1, 14.74 kg plot-1 and 13.54 t ha-1) and dry herbage yield (308.40 g plant-1, 7.71 kg plot-1 and 7.08 t ha-1) were noticed at the seed setting stage. Whereas the superior essential oil content (1.51 %) was viewed at the vegetative stage. The greater essential oil yield (129.34 kg ha-1) was observed at the full bloom stage, which was on par with the seed setting stage (127.20 kg ha-1) and fifty per cent flowering stage (118.11 kg ha-1). Conclusion: Fifty per cent flowering stage can be considered as suitable harvesting stage of rosemary under northern dry zone of Karnataka.

Integrated Management of Alternaria Leaf Spot of Cauliflower under Pot Conditions

Cauliflower is widely grown throughout the world. Alternaria leaf spot of Cauliflower caused by Alternaria brassicae is the most destructive disease at the curd stage and seed setting stage, attributed to causing 30-50% losses and in severe cases reaching up to 98% in seed crop. In the present investigation, the pathogen Alternaria brassicae was found to produce typical symptoms of the disease as small, irregular brown spots with concentric rings, also surrounded by a yellow chlorotic halo. Later on, lesions were found to coalesce forming irregular, brown to dark brown patches with concentric rings. The disease is difficult to manage alone with fungicides or bio agents or botanicals. Hence the present study was undertaken to manage the disease effectively by application of fungicides, bio agents, botanicals and their combinations. During the investigation on integrated management under sick pot conditions, the combination of T. viride + Neem + Azoxystrobin (10.81% Percent Disease Index) was found most effective with inhibition of disease by 79.02%. This was followed by T. viride + Azoxystrobin (11.63% Percent Disease Index) with inhibition of the disease by 77.40% compared to the control 51.52% Percent Disease Index.

Floral biology insights into essential oil yield and chemical composition in davana (Artemisia pallens Bess), a high-value aromatic plant of India

Floral organs are identified as the major source of essential oil production in some prime aromatic plants. The quality and quantity of the essential oil are also influenced by the floral developmental stages. The present study was undertaken in A. pallens Bess (davana) with respect to its floral biology and floral sequence in relation to the essential oil yield and its chemical constituents for industrial extraction. The findings revealed that floral (inflorescence) biomass is the primary source of essential oil yield in davana, with the highest oil yield (0.90 ml/100 g) recovered during the blooming stage, followed by herbage (stems and leaves) biomass. Furthermore, cis-davanone, the major chemical constituent of davana essential oil, was recorded at a higher percentage in the bud stage (66.36±0.60%) followed by the blooming stage (60.56±0.20%) and the seed setting stage (40.54±0.80%). These findings can be used to optimize harvest timing in order to obtain higher quality and quantity of davana essential oil.

INFLUENCES OF SOWING DATE AND HARVEST STAGE ON DRY MATTER YIELD AND FORAGE QUALITY OF QUINOA (Chenopodium quinoa Willd.)

Sowing dates and harvest stages are very important to obtained better forage yield and quality. The goal of the study was to ascertain how the quinoa growing conditions in Marmara will be affected by the sowing dates and harvest stages. In 2018 and 2019, the experiment was conducted in an experimental field in the Agricultural Application and Research Area of Bursa Uludag University's Agriculture Faculty. The field experiment was set up using three replicates of a split-plot randomized complete blocks design. Titicaca variety of quinoa was used as a plant material in the study. Four different sowing dates (15 April, 1 May, 15 May and 1 June) were considered in the main plot and three different harvest stages (beginning of flowering, full flowering and seed setting) in the sub-plot. In this study, plant height, dry matter yield, crude protein, crude protein yield, neutral detergent fiber, acid detergent fiber, the relative feed value, and macro and micro elements were examined. The two-year findings show that sowing on May 1 produced the maximum dry matter yield (2798 kg ha-1) and crude protein yield (584 kg ha-1). In terms of harvest stages, seed setting stage came to the fore in terms of high forage (4001 kg ha-1) and crude protein yield (746 kg ha-1).

Phenological Stage Specific Variations in Chemical Compo-sition, Antioxidant and Antimicrobial Properties of the Essential Oils of Aerial Parts of Monarda didyma L. Cultivated Under Doon Valley Climatic Conditions of Uttarakhand, India

This study aims to evaluate the variations in yield of essential oil, chemical constituents, antimicrobial and antioxidant potential of Monarda didyma L. (aerial parts) at three different phenophases, namely vegetative stage, full blooming and maturity (seed setting) stages. The essential oil content ranged from 0.62-0.75% in whole aerial parts, with the highest yield in the full flowering (0.75 ± 0.042%), followed by pre flowering (0.70 ± 0.033%) and seed setting (0.62 ± 0.052%) stages. Linalool was found as the major compound followed by γ-terpinene, thymol methyl ether, p-cymene and thymol in the oils during different phenophases of plant. Linalool was maximum in vegetative (pre flowering) stage (60.15 ± 1.56%) as compared to full blooming (44.32 ± 2.55%) and seed setting (46.49 ± 1.63%) stages respectively. γ-Terpinene, the second major constituent was found to be maximum in full blooming stage (21.06 ± 3.06%) as compared to the other stages, and showed cogent variations in percent composition of γ-terpinene during different phenological stages. In thymol methyl ether content, significant variation was observed during all three phenophases of plant. The antioxidant (DPPH assay) activity showed that M. didyma oil has maximum activity at seed setting stage. The maximum antimicrobial activities in oil was active at vegetative phase of plant against bacteria and yeast i.e., Bacillus sp., E. coli, L. monocytogens, P. aeruginosa, S. aureus, C. albicans and revealed favourable values of MIC (0.5% to1% v/v) and MBC/MFC (0.5 to 2% v/v) against bacterial and yeast cultures.

The effect of deficit irrigation and fertilizer on quantitative and qualitative yield of quinoa (Chenopodium quinoa)

In order to investigate the effect of deficit irrigation and chemical fertilizers on yield and some physiological traits of quinoa an experiment was conducted in 2019 as split plot based on a randomized complete block design in two locations (Mashhad and Neishabour). Irrigation included, I0: full irrigation, I1: no irrigation at emergence stage, I2: no irrigation at stem elongation stage, I3: no irrigation at flowering stage, I4: no irrigation at seed setting stage. Fertilizer treatments included control (no fertilizer application); chemical fertilizer application according to local practices; manure application of 10 tons; and manure application of 20 tons per hectare. In general, seed yield, percentage of protein and seed oil in Mashhad was higher than in Neishabour. I2 treatment had the least negative effect on relative leaf water content. Application of chemical fertilizers, 10 tons and 20 tons of animal manure increased the percent of seed protein by 1.43, 1.66 and 2.37 compared to the control, respectively. The highest percentage of seed oil (5.91%) was obtained for treatment I2 in Mashhad and the lowest percentage of seed oil (4.18%) was obtained for treatment I4 in Neishabour. The lowest seed yield due to I1 treatment was observed in Neishabour and the highest seed yield was related to I0 treatment with 20 tons of manure and was observed in Mashhad. The results showed that the yield and water stress tolerance potential of quinoa can be modified by irrigation, fertilizer source and location.

Genome-wide analysis of the C2H2 zinc finger protein gene family and its response to salt stress in ginseng, Panax ginseng Meyer

The C2H2 zinc finger protein (C2H2-ZFP) gene family plays important roles in response to environmental stresses and several other biological processes in plants. Ginseng is a precious medicinal herb cultivated in Asia and North America. However, little is known about the C2H2-ZFP gene family and its functions in ginseng. Here, we identified 115 C2H2-ZFP genes from ginseng, defined as the PgZFP gene family. It was clustered into five groups and featured with eight conserved motifs, with each gene containing one to six of them. The family genes are categorized into 17 gene ontology subcategories and have numerous regulatory elements responsive to a variety of biological process, suggesting their functional differentiation. The 115 PgZFP genes were spliced into 228 transcripts at seed setting stage and varied dramatically in expression across tissues, developmental stages, and genotypes, but they form a co-expression network, suggesting their functional correlation. Furthermore, four genes, PgZFP31, PgZFP78-01, PgZFP38, and PgZFP39-01, were identified from the gene family that were actively involved in plant response to salt stress. These results provide new knowledge on origin, differentiation, evolution, and function of the PgZFP gene family and new gene resources for C2H2-ZFP gene research and application in ginseng and other plant species.

Differential regulation of flower transpiration during abiotic stress in annual plants.

Summary Heat waves occurring during droughts can have a devastating impact on yield, especially if they happen during the flowering and seed set stages of the crop cycle. Global warming and climate change are driving an alarming increase in the frequency and intensity of combined drought and heat stress episodes, critically threatening global food security.Because high temperature is detrimental to reproductive processes, essential for plant yield, we measured the inner temperature, transpiration, sepal stomatal aperture, hormone concentrations and transcriptomic response of closed soybean flowers developing on plants subjected to a combination of drought and heat stress.Here, we report that, during a combination of drought and heat stress, soybean plants prioritize transpiration through flowers over transpiration through leaves by opening their flower stomata, while keeping their leaf stomata closed. This acclimation strategy, termed ‘differential transpiration’, lowers flower inner temperature by about 2–3°C, protecting reproductive processes at the expense of vegetative tissues.Manipulating stomatal regulation, stomatal size and/or stomatal density of flowers could serve as a viable strategy to enhance the yield of different crops and mitigate some of the current and future impacts of global warming and climate change on agriculture.

Chemical Composition, Antioxidant and Antimicrobial Potential of the Essential Oils from Aerial Parts of Tagetes patula L. at Different Phenological Stages

The current study aims at determining the variability in composition, antibacterial and antioxidant properties of the essential oils extracted from aerial parts of Tagetes patula at different phenological stages of plant growth i.e., the vegetative, full blooming and seed setting stages. The maximum average yield of hydrodistilled essential oils was obtained as 0.083 ± 0.003% (seed setting), 0.068±0.007% (full flowering) and 0.059±0.005% (pre flowering). (Z)-β-ocimene was found to be most abundant compound of essential oil of T. patula, and α-terpinolene, piperitenone, limonene and propanedinitrile, dicyclohexyl were found as major compounds in oil extracted at different phenological stages of plant. Contribution of (Z)-β-Ocimene was highest in full flowering stage (18.27±3.14%) as compared to other two stages where its amount ranged from 12.03-17.17 %. α-Terpinolene the second major component was found highest in the pre-flowering stage (13.86±1.15%) compared to other stages. Significant variation was observed in the percent content of piperitenone during all three phenological stages The antioxidant (DPPH radical scavenging) assay showed that T. patula oils have maximum activity at the pre-flowering stage. Antibacterial activities of the essential oils were observed at the pre-flowering stage against different bacteria; i.e., Bacillus sp., Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus and exhibited promising values of MIC (0.125 % v/v -0.5 % v/v) and MBC (0.25 v/v to 1% v/v) against bacterial cultures.

Variation in Phenolic Compounds and Antioxidant Activity of Various Organs of African Cabbage (Cleome gynandra L.) Accessions at Different Growth Stages.

The presence of nutritional and health-benefiting compounds has increased awareness of orphan leafy vegetables such as Cleome gynandra (CG), whose phytochemicals vary among accessions and organs during growth. This study investigated the polyphenol accumulation and antioxidant activities (AOA) of eight CG accessions from the vegetative stage to the seed set stage. Plants were separated into leaves and stem (LS), flowers, and silique organs, and extracts were analyzed for total phenolic content (TPC), total flavonoid content (TFC), rutin and astragalin content, and AOA using 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). There were significant interaction effects of growth stages and accessions that contributed to changes in compounds content and AOA. TPC accumulated in plant generative parts, whereas flavonoids accumulated in young plant organs. HPLC profiling revealed that rutin was the most abundant compound in all organs, with flowers having the highest levels, while astragalin was only found in flowers. Silique extracts, particularly accession KF-14, recorded the highest TPC, which corresponded to the strongest radical scavenging activity in ABTS and DPPH assays and a strong linear correlation. The germplasm contained accessions with significantly different and varying levels of bioactive compounds and AOA. These findings potentiate the exploitation of CG organs such as siliques for AOA, flowers for rutin and astragalin, and young shoots for flavonoids. Moreover, the significant accumulation of the compounds in particular accessions of the germplasms suggest that such superior accessions may be useful candidates in genetic breeding programs to improve CG vegetable.

Effects of Cultivation Management on Pearl Millet Yield and Growth Differed with Rainfall Conditions in a Seasonal Wetland of Sub-Saharan Africa

The production of pearl millet (Pennisetum glaucum (L.) R.Br.) is important in Namibia, in sub-Saharan Africa, owing to the prevailing low precipitation conditions. Most fields supporting crop production in northern Namibia are located in a network of seasonal wetlands. The aim of the present study was to evaluate the effects of ridging and fertilizer application on the yield and the growth of pearl millet in the seasonal wetlands under different rainfall conditions. The study was conducted for two years (2017–2018) in the experimental fields in northern Namibia, and yield, yield components, and growth parameters were evaluated in relation to the application of different fertilizers (manure and mineral) with and without ridge-furrows. Manure fertilizer application presented the highest yield in 2018, whereas mineral fertilizer application showed the highest yield in 2017. The proportion of rainfall was the highest during the mid-growth period in 2017, and the reproductive stage in 2018. Thus, pearl millet plants under manure fertilization overcame damage resulting from waterlogging stress during the seed setting stage by improving the soil and plant nutrient conditions. In contrast, the plants under mineral fertilization were more tolerant to large amounts of rain during the mid-growth period. In this study, yield was mainly determined by total dry weight, and it was closely related to panicle density in both years. Therefore, we concluded that fertilizer application, including additional fertilizer based on the growth diagnostic, could be important for improving crop production in seasonal wetlands.

Antimicrobial Activity and Chemical Composition of Essential Oil from Thymus daenensis and Thymus fedtschenkoi During Phenological Stages

Variation in chemical composition and biological activity of essential oils of medicinal plants may be observed due to the developmental stage of collected plant materials. In the present study, we compared the chemical compositions and antimicrobial activity of the essential oils from the aerial part of Thymus daenensis Celak. and Thymus fedtschenkoi Ronniger at different developmental stages. The highest essential oil content in both species was observed at the full flowering stage. The phenolic monoterpene thymol (71.9-73.9 %) and the monoterpene alcohol linalool (45.5-83.1 %) were the most abundant constituents at all phenological stages of T. daenensis and T. fedtschenkoi, respectively. All the essential oils possessed high antibacterial and antifungal activities against the microorganisms tested (Staphylococcus aureus, Bacillus cereus, Enterococcus faecium, Escherichia coli, Salmonella enteritidis, and Candida albicans), although of different degrees. The essential oils from T. fedtschenkoi appeared to be more active on almost all bacterial and fungal strains than that of T. daenensis (with MIC values of 1-16 mg/ml and 2-32 mg/ml, respectively). The effect of the plant phenological stage on the antimicrobial activity and constituents of T. fedtschenkoi essential oil was more pronounced than for T. daenensis. Interestingly, the antimicrobial effects of T. fedtschenkoi essential oil obtained at the seed set stage was noteworthy against all tested microorganisms, apart from the resistant E. faecium. Overall, this study highlighted the importance of the choice of the harvesting time to achieve the optimum of essential oil quality and quantity together with the antimicrobial activities, which are exploited in the pharmaceutical and food industries.

The Quality of Greek Oregano (O. vulgare L. Subsp. hirtum (Link) Ietswaart) and Common Oregano (O. vulgare L. Subsp. vulgare) Cultivated in the Temperate Climate of Central Europe.

The purpose of the study was to determine the differences between two subspecies: O. vulgare L. subsp. hirtum (Link) Ietswaart (Greek oregano) and O. vulgare L. subsp. vulgare (common oregano) growing in cultivation conditions within temperate climate of Central Europe. The characteristic of the subspecies was undertaken in terms of selected morphological parameters and the quality of the raw material. The herb of both subspecies was evaluated on the content and composition of essential oil by hydrodistillation followed by GC-MS and GC-FID (gas chromatography coupled with mass spectrometry and flame ionization detector), the total content of phenolic acids (according to PP 6th ed.) and the content of rosmarinic acid (by HPLC). The sensory evaluation (QDA) was performed, as well. Greek oregano was distinguished by visibly higher number of glandular trichomes on the leaves (up to 4.85 per 1 mm2) followed by higher content of essential oil in the herb (up to 3.36 g × 100 g−1 DW) in comparison to common oregano. Based on the essential oil composition, Greek oregano was classified as mixed carvacrol/γ-terpinene chemotype, while common oregano as mixed sabinyl/cymyl type rich in sesquiterpenes. Greek oregano was also characterized by higher total content of phenolic acids (up to 6.16 g × 100 g−1 DW) and rosmarinic acid (up to 6787.2 mg × 100 g−1 DW) than common oregano. Essential oil content reached the maximum at the beginning of blooming (common oregano) and at the full blooming stage (Greek oregano). In turn, the amount of phenolic acids followed by rosmarinic acid was the highest at the beginning of seed-setting stage, in the case of both subspecies. The differences between subspecies concerning chemical composition (especially essential oil) were reflected in the sensory attributes, where both odor and taste notes were found at higher level for Greek oregano. Results of our work indicate that Greek oregano is well adapted to grow in the temperate zone conditions. Such adaptation was reflected mainly in the satisfied yield and maintaining characters typical for the Mediterranean plant, e.g., a high essential oil content followed by high carvacrol share, traits the most important from practice viewpoint.

Impact evaluation of growth stage and species on morpho-physiological traits and bioactive constituent of essential oil in Ocimum through multi-year experiment

The genus Ocimum displays excellent variability among the species and sub-species due to the highly cross-pollinated nature and interspecific hybridization. The present investigation was carried out to identify the commercially promising growth stage(s) in different Ocimum for exatraction of oil and bioactive compounds at heighest. A set of three cultivated species were evaluated to study the variation in morpho-physiological traits and essential oil composition harvested at three stages namely vegetative, flowering and seed setting stage. The experiment was conducted for three consecutive years in factorial randomized complete block design with three replicates. The analysis of variance exhibited that the individual effect of Ocimum species and growth stage along with their interaction effect was significant in all the morpho-physiological parameters and bioactive constituent of oil in a pooled analysis. Highest plant height (103.95 cm) was observed in O. gratissimum L. harvested at seed setting stage while harvesting at flowering stage exhibited maximum leaf area (26.80 cm2), oil (0.52 %) and eugenol content (85.82 %). Sweet basil harvested at seed setting stage disclosed maximum branches per plant (21.53) and leaves per plant (4949) although linalool content (47.99 %) was found highest in harvested at flowering stage. O. basilicum L. was detected a great source of methyl chavicol (7.48 %) though this species was weaker source for methyl cinnamate. Among the studied species, O. gratissimum showed a negligible amount of methyl eugenol content in oil. A positive correlation between the morpho-physiological traits, oil content and its constituents with the various growth stages were recorded. None of bioactive compounds exhibited any correlation with oil content. Principle component analysis revealed that of the total variation, O. gratissimum contributed maximum (61.58 %) variation followed by O. basilicum (35.36 %). The results of current study suggested that the different Ocimum species can be harvest at various growth stages to get the maximum yield and target chemical compounds based on the needy industrial value.

Variation of Essential Oil Composition and Antioxidant Activity in Aerial Parts of Stachys Schtschegleevi Sosn at Different Growing Stages

Stachys schtschegleevii Sosn is an endemic medicinal plant that belongs to the Lamiaceae family and is mainly grown in the Northwestern parts of Iran. This plant contains essential oils that are medicinally valuable with very few available information on them. In this study, the aerial parts of S. schtschegleevii were collected at different plant growth stages (Vegetative, flowering, seed set and seed ripping) and their essential oil (EO) compositions were determined at each stage separately. In order to determine EO contents in S. schtschegleevii, the hydrodistillation method was used. The chemical compounds were then analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) methods in all studied stages. The highest EO yield was observed in the flowering stage (0.25 %). Significant variations were detected in EO compounds during various stages of growth. In vegetative stages, spathulenol (19.63 %), germacrene-D (11.3 %), α-pinene (7.8 %), α-cadinol (5.8 %) and β-eudesmol (7.2 %) were the major components; while in the flowering stages, the major compounds were α-pinene (15 %), germacrene-D (12.6 %), spathulenol (12 %) and β-pinene (5.9 %). α-pinene (17.9 %), α-cadinol (12.4 %), germacrene-D (11.6 %) and spathulenol (6.5 %) were the prominent constituent of the essential oil during seedset stage. Finally, when the seeds ripened, the main components of EO were reported as α-pinene (19.5 %), spathulenol (14.68 %), α-cadinol (10.5 %) and germacrene-D (5.6 %). In the seed ripping stage, monoterpene hydrocarbons recorded as the most dominant component (37.0 %). In the flowering stage, this component was as low as 15.4 % where the highest compound was α-pinene that followed by oxygenated sesquiterpenes. Also, the highest total phenol accumulation (81.70 mg GAE/g DW) and total flavonoid (8.70 mg QE/ g DW) were observed in the flowering stage which is also considered as the stage with maximum antioxidant activity. Based on the results, the flowering stage is the best harvesting time for S. schtschegleevii plants to produce EO for both food and pharmaceutical purposes.

Use of infrared thermography imaging for assessing heat tolerance in high and low iron pearl millet lines

In the arid regions of Asia and Africa, pearl millet serves as a staple source of dietary energy and mineral micronutrients for millions of people. These regions are more vulnerable to increased temperature. The availability of rapid and efficient screening tools based on the relevant non-destructive quantifiable traits would facilitate pearl millet improvement for heat tolerance. The objective of this study was to evaluate pearl millet lines with contrast micronutrients for heat tolerance using infrared thermal imaging, a rapid proxy-canopy (panicle and flag leaf) temperature measurement. Results showed the highly significant genotypic differences between high-Fe and low-Fe genotypes for grain Fe and Zn densities and agronomic traits. Both high-Fe and low-Fe group genotypes differed significantly for panicle temperature depression (PTD) during high- vapor deficit (VPD) at stigma stage (3.0 to 6.73°C). PTD values were positive across all genotypes during stigma stage and were very low or negative during the low-VPD. Cooler canopy temperature (high-PTD) was observed during stigma stage rather than seed-set stage at higher-VPD in both high-Fe and low-Fe genotypes. The cooler temperature achieved by panicle might be helpful in maintaining stigma receptivity for longer periods in the female parents, whereas in male parents it might be helpful in maintaining pollen viability for longer periods. Flag leaf temperature (FTD) was cooler than PTD at both high-VPD and low-VPD as well in both stigma (less by 2.1°C) and grain-filling stage (less by 2.7°C), again signifying that the reproductive parts are more prone to heat stress as compared to vegetative parts. Since, thermal imaging discriminates the heat stress and non-stress canopies, this can serve as a proxy canopy temperature tool for heat stress tolerance screening in pearl millet.

The beneficial effects of growth regulators on forage yield and quality of Amaranthus caudatus under different water stress conditions

In order to improve crop productivity, farmers should have strategies for higher quantity and quality of forage without excessive inputs, like irrigation water. In order to assess forage quality of Amaranthus caudatus in response to irrigation levels (irrigation after 70, 140 and 210 mm of evaporation from class A pan) as main plots and foliar sprays of abscisic acid (ABA; 50 μM), salicylic acid (SA; 3 g l–1) and potassium sulfate (PS; 3 g l–1) as subplots. A water shortage from 70 to 210 mm of evaporation decreased the stomata conductance and leaf-area index, but the crude protein concentration, dry matter digestibility, leaf/stem ratio, forage yield and total nitrogen were increased from 70 to 140 and then decreased. Using deficit irrigation for amaranth can reduce water usage without significant yield loss, so that water use efficiency remains at the relatively high levels. Leaf water potential, relative water content, leaf-area index, total chlorophyll, carotenoid, crude protein, dry matter digestibility, leaf/stem ratio and forage yield were increased by foliar sprays. Significant reduction in forage quality occurred at delayed harvest. Forage yield of potassium sulfate treated under severe stress was increased by 29% and 56% at flowering and seed set stages, respectively.

Chemical Diversity of Bastard Balm (Melittis melisophyllum L.) as Affected by Plant Development.

The phytochemical diversity of Melittis melissophyllum was investigated in terms of seasonal changes and age of plants including plant organs diversity. The content of phenolics, namely: coumarin; 3,4-dihydroxycoumarin; o-coumaric acid 2-O-glucoside; verbascoside; apiin; luteolin-7-O-glucoside; and o-coumaric; p-coumaric; chlorogenic; caffeic; ferulic; cichoric acids, was determined using HPLC-DAD. Among these, luteolin-7-O-glucoside, verbascoside, chlorogenic acid, and coumarin were the dominants. The highest content of flavonoids and phenolic acids was observed in 2-year-old plants, while coumarin in 4-year-old plants (272.06 mg 100 g–1 DW). When considering seasonal changes, the highest content of luteolin-7-O-glucoside was observed at the full flowering, whereas verbascoside and chlorogenic acid were observed at the seed-setting stage. Among plant organs, the content of coumarin and phenolic acids was the highest in leaves, whereas verbascoside and luteolin-7-O-glucoside were observed in flowers. The composition of essential oil was determined using GC-MS/GC-FID. In the essential oil from leaves, the dominant was 1-octen-3-ol, whilst from flowers, the dominant was α-pinene.

Effect of Shading on Development, Yield and Quality of Bastard Balm Herb (Melittis melissophyllum L.).

The aim of the study was to assess the effects of Melittis melissophyllum shading on its development and accumulation of phenolics. Their content (verbascoside, apiin, luteolin-7-O-glucoside, coumarin, 3,4-dihydroxycoumarin, o-coumaric acid 2-O-glucoside as well as o-coumaric, p-coumaric, chlorogenic, caffeic, ferulic and cichoric acid) was determined in the herb using HPLC-DAD. The results showed that the content of abovementioned flavonoids and phenolic acids was highest in plants grown under full sunlight. On the other hand, a higher content of coumarin was observed in shaded plants, especially after the seed-setting stage. A similar tendency was noted for the amount of chlorophyll a and b. The content of hydrogen peroxide and malondialdehyde, the activity of polyphenol oxidase and catalase and the antioxidant capacity of plant extracts (measured using DPPH, ABTS and FRAP assays) were found to be the highest in the plants grown in full sunlight. However, the plants grown in moderate (30%) shade were found to thrive best.

Developmental and chemical characteristics of Melittis melissophyllum L. in limited access of sunlight

Summary Introduction: Bastard balm grows in forests, in central and southeastern part of Europe. The herb of this species is rich in phenolics, mainly flavonoids, phenolic acids and coumarins. The plant is used in traditional European medicine, in digestive problems and for aromatizing tobacco and alcohol products. Objective: The purpose of this study was to determine the influence of shading on bastard balm development and the accumulation of phenolics in its herb, with special respect to coumarin as a quality marker of this raw material. Methods: The plants were cultivated in full sunlight, in 30% and 50% shade provided by shading nets. The herb was harvested from plants in the third year of vegetation, at four subsequent developmental stages and then subjected to chemical evaluation. In the raw material, the total contents of flavonoids, phenolic acids and coumarins was determined. The content of coumarin was analyzed using HPLC-DAD. Results: Plants grown in 30% shade produced the highest number of flowers and seeds. They produced the highest mass of herb at the beginning of the seed-setting stage. The plants grown in full sunlight revealed the highest content of flavonoids and phenolic acids, especially during flowering and at the beginning of the seed-setting stage. The mass of herb obtained by plants cultivated at deep (50%) shade was the lowest, however, the content of coumarin in these plants was the highest. Conclusion: The influence of shade on bastard balm was expressed by the herb mass and coumarin content increment. The plants thrived best in 30% shade, both in terms of flowering abundance and the mass of herb, whereas those from 50% shade were the richest in coumarin.