REVIEW | doi:10.20944/preprints202108.0383.v1
Subject: Chemistry, Analytical Chemistry Keywords: Bacterial carotenoids; Cell disruption; HPLC separation; MS analysis; Food and textile applications
Online: 18 August 2021 (14:09:35 CEST)
Natural carotenoids are secondary metabolites that exhibit antioxidant, anti-inflammatory and anti-cancer properties. These types of compounds are in high demand by pharmaceutical, cosmetic, textile and food industries, leading to the search for new natural sources of carotenoids. In recent years, the production of carotenoids from bacteria has become of great interest for industrial applications. In addition to carotenoids with C40-skeletons, some bacteria have the ability to synthesize characteristic carotenoids with C30-skeletons. In this regard, a great variety of methodologies for the extraction and identification of bacterial carotenoids has been reported and this is the first review that condenses much of this information. To understand the diversity of these carotenoids, we present their biosynthetic origin in order to focus on the methodologies employed in their extraction and characterization. Special emphasis has been made on high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the analysis and identification of bacterial carotenoids. We end up this review showing their potential commercial use of bacterial carotenoids. This review is proposed as a guide for the identification of these metabolites, which are frequently reported in new bacteria strains.
ARTICLE | doi:10.20944/preprints201801.0156.v1
Subject: Biology, Other Keywords: Dunaliella salina; new isolates; characterization; light intensity; β-carotene; carotenoids; correlations; lutein; classification
Online: 17 January 2018 (12:04:11 CET)
The halotolerant microalga Dunaliella salina has been widely studied for natural β-carotene production. This work shows biochemical characterization of three newly isolated Dunaliella salina strains DF15, DF17 and DF40 compared with D. salina CCAP 19/30 (confirmed to be D. tertiolecta) and D. salina UTEX 2538 (also known as D. bardawil). Although all three new strains have been genetically characterized as Dunaliella salina strains, their ability to accumulate carotenoids and their capacity for photoprotection against high light stress are different. DF15 and UTEX 2538 reveal great potential for producing large amount of β-carotene and maintained a high rate of photosynthesis under light of high intensity; however, DF17, DF40 and CCAP 19/30 showed increasing photoinhibition with increasing light intensity, and reduced contents of carotenoids, in particular b-carotene, suggesting that the capacity of photoprotection is dependent on the cellular content of carotenoids, in particular β-carotene. Strong positive correlations were found between the cellular content of each of all-trans β-carotene, 9-cis β-carotene, all-trans α-carotene and zeaxanthin but not lutein in the D. salina strains. Lutein was strongly correlated with respiration in photosynthetic cells and strongly related to photosynthesis, chlorophyll and respiration, suggesting an important and not hitherto identified role for lutein in co-ordinated control of the cellular functions of photosynthesis and respiration in response to changes in light conditions, which is broadly conserved in Dunaliella strains. Statistical analysis based on biochemical data revealed a different grouping strategy from the genetic classification of the strains. The significance of these data for strain selection for commercial carotenoid production is discussed.
ARTICLE | doi:10.20944/preprints201811.0548.v1
Subject: Chemistry, Food Chemistry Keywords: Persimmon, Diospyrus kaki Thunb., var. Rojo Brillante, astringent, carotenoids, carotenoid esters, HPLC-PDA-MS (APCI+), processing effects
Online: 22 November 2018 (14:26:40 CET)
Carotenoid and carotenoid esters profiles of peel, pulp and whole fruit tissues of astringent persimmon (Diospyrus kaki Thunb., var. Rojo Brillante) have been characterized in detail and quantified for the first time. Carotenoids were determined by HPLC-PDA-MS/MS (APCI+), using a reverse phase C30 column. A total of 38 carotenoids were identified and quantified, corresponding to 21 free carotenoids (13 xanthophylls and 8 hydrocarbon carotenes) and a total of 17 carotenoid esters. The qualitative profiles are very similar among tissues, differing only in the carotenoids concentration. The most important identified free xanthophylls were (all-E)-β-cryptoxanthin, (all-E)-antheraxanthin, (all-E)-lutein, (all-E)-zeaxanthin and (all-E)-violaxanthin . Hydrocarbon carotenoids found were (all-E)-β-carotene, (all-E)-α-carotene, (9Z)-β-carotene, (13Z)-β-carotene, (9Z)-α-carotene, and lycopene. The most abundant carotenoid esters were (all-E)-lutein-3-O-palmitate, (all-E)-zeaxanthin myristate, (all-E)-zeaxanthin palmitate and (all-E)-cryptoxanthin laurate. Processing by high pressures produced no regular effect on persimmon carotenoids and pasteurization affected negatively the content of all carotenoids from all studied persimmon tissues. This work will contribute to the development of scientific research about the bioaccessibity and bioavailabity of each individual free or esterified persimmon carotenoids in order to a better understanding of the carotenoid compounds impact in human health.
REVIEW | doi:10.20944/preprints202008.0119.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: astaxanthin; cardiovascular disease; atherosclerosis; inflammation; oxidative stress; carotenoids; antioxidant
Online: 5 August 2020 (09:53:14 CEST)
Cardiovascular disease is the most common cause of death. Oxidative stress and inflammation are pathophysiological processes involved in the development of cardiovascular diseases, so anti-inflammatory and antioxidant agents that modulate redox balance have become the targets of research to evaluate their molecular mechanisms and therapeutic properties. Astaxanthin, a carotenoid of the xanthophyll group, has potent antioxidant effects due to its molecular structure and its arrangement in the plasma membrane, factors that favor the neutralization of reactive oxygen and nitrogen species. This carotenoid also stands out for its anti-inflammatory activity, possibly interrelated with its antioxidant effect, as well as for its modulation of lipid and glucose metabolism. Considering the potential positive effects of astaxanthin on cardiovascular health evidenced by preclinical and clinical studies, this paper describes the molecular and cellular mechanisms related to the antioxidant and anti-inflammatory properties of this carotenoid in cardiovascular diseases, especially atherosclerosis.
ARTICLE | doi:10.20944/preprints201710.0031.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Breast milk; Carotenoids; Tocopherols; Colostrum; Lactation stage; Cross-sectional study
Online: 6 October 2017 (08:39:21 CEST)
This study aims to quantify carotenoids and tocopherols in human milk from healthy Chinese women, and to explore their associations with region, lactation stage, and maternal socio-economic and obstetric factors. Human milk was obtained from 509 healthy mothers and the compounds of carotenoids and tocopherols were analyzed by high-performance liquid chromatography after mild saponification and solvent extraction. Socio-economic and obstetric characteristics of the mothers and their dietary intakes through a single 24-hour dietary recall were evaluated. The median content of each component [μg/100mL, median (interquartile range)] in colostrum and mature milk was, respectively, β-carotene 8.0 (4.7-15.2) and 1.8 (1.4-2.7), β-cryptoxanthin 6.2 (2.4-12.9) and 1.8 (1.1-3.4), lutein 5.7 (2.9-10.2) and 3.4 (1.5-6.0), lycopene 6.3 (4.0-9.9) and 1.4 (1.1-2.0), zeaxanthin 1.0 (0.6-1.5) and 1.0 (0.6-1.4), α-tocopherol 645 (388-1176) and 211 (131-321), γ-tocopherol 68 (48-121) and 77 (45-120). The levels of all those vitamins presented regional differences, and decreased as lactation stage increased except for zeaxanthin and γ-tocopherol. Associations of carotenoid contents with maternal education, delivery mode, and present body mass index were found in multivariate analyses. These results suggest that some region, lactation stage, obstetric and socio-economic factors are associated with human milk concentrations of carotenoids and tocopherols in healthy Chinese mothers.
ARTICLE | doi:10.20944/preprints201909.0152.v1
Subject: Chemistry, Medicinal Chemistry Keywords: chlorophyll; carotenoids; methanol; photo-protection; phytoextraction; Portulaca oleracea
Online: 15 September 2019 (15:04:55 CEST)
The chlorophyll is one of the most important natural pigments used extensively in the food industry. Two important factors for the production of chlorophyll are the use of plants rich in chlorophyll and efficiency of extraction method. Present investigation was performed to compare the extraction of photosynthetic pigments by using solvents of different chemical nature. The purslane plants with different growth behavior viz. Scrollable and standing were grown under shade and sunshine stress condition. Different solvents including diethyl ether, 5% ethanol, pure acetone, 20% acetone, pure methanol and 10% methanol were used to extract chlorophyll and carotenoids from the purslane plant. The results indicated that stress, growth type and different solvents had a significant effect on the extraction of chlorophyll and carotenoids. Different trend was observed in extraction rate for chlorophylls and carotenoids. Among the solvents, pure methanol was the best for extraction of chl a. Methanol and acetone were appropriate solvents to achieve the highest amount of chlorophyll from plant tissues. Among different solvents, pure methanol for chl a, pure acetone and methanol for carotenoids were best solvent for purslane plant with a growing type scrollable of under shade.
ARTICLE | doi:10.20944/preprints201810.0449.v1
Subject: Life Sciences, Biotechnology Keywords: green algae; biomass; fatty acids; Tetraselmis straiata; lipids; carotenoids; raceway ponds
Online: 19 October 2018 (11:09:56 CEST)
In the process of modernization and development, a human being always needed energy, which increased the dependency on the available sources of fossil fuel. Tetraselmis, a green algal genus belong to the order Chlorodendrales, are described by their strong green coloured chloroplast, flagellated cell bodies, and the occurrence of a pyrenoid within the chloroplast. In this study, four different strains of Tetraselmis species were successfully isolated from the saltpans Kovelong, Chennai, Tamil Nadu, India. The isolated strains were cultured in the normal basal medium and their morphological features were subsequently studied. The species of Tetraselmis straiata (T. straiata) Butcher BBRR1 was confirmed using molecular identification of 18S rRNA gene analysis and its observed systematic position. Among the four different isolates, T. straiata Butcher BBRR1 recorded a highest biomass concentration of 0.58 ± 0.021 g L-1, 15% lipids, 19% proteins and 17% carbohydrates when it grown under laboratory condition. Whereas, in open raceway ponds, T. straiata BBRR1 produced 0.95 ± 0.06 g L-1 biomass, 19% lipids, 28% proteins and 21% carbohydrates in an modified CFTRI I medium. The fatty acids profile of T. straiata Butcher BBRR1showed the presence of 33.14 % Palmitic acid, 22.64% 11- Octadecenoic acid and 21.94% Heptadecanoic acid. Since T. straiata BBRR1 can be cultivated in open ponds without a major contaminations, this species can be used as novel biomass feedstock to produce biofuels. This study may suggest the potential of T. straiata BBRR1 for biofuel production and could compete the energy demand in the future. In addition, this species contains healthful components of carotenoids, lipids and proteins, all these may provide a health benefits beyond basic nutrition.
REVIEW | doi:10.20944/preprints202012.0696.v1
Subject: Medicine & Pharmacology, Allergology Keywords: microalgae; carotenoids; chlorophylls; lipids; mycosporin-like amino acids; antioxidants; UV-screen
Online: 28 December 2020 (12:15:07 CET)
A prominent feature of stress-tolerant microalgae is their versatile metabolism allowing then to synthesize a broad spectrum of molecules with beneficial effects on many aspects of human body functioning. This is in line with the current understanding that many stress-induced deleterious processes in the human body and in photosynthetic cell are mediated by the same mechanisms such as free-radical attacks and lipid peroxidation. These related risks are kept at bay by optical screening of harmful UV, enzymatic ROS elimination systems, and potent low-molecular antioxidants. Microalgae synthesize a broad spectrum of compounds exerting antioxidant and/or UV-absorbing properties. In microalgae, they increase stress-resilience of these organisms. In human body, they exhibit photoprotective, antiaging, and sunscreen activities. Therefore, these algal metabolites were recognized as promising ingredients for innovative cosmetics and cosmeceutical formulations. Ever increasing effort is being invested into the search for new natural biologically active substances from microalgae. This trend is also fueled by the growing demand for natural raw materials for food, pharmaceuticals and cosmetology associated with the global transition to a "greener" lifestyle. Here, we review the currently accumulated knowledge about the main groups of cosmeceutical compounds from microalgae.
ARTICLE | doi:10.20944/preprints202201.0437.v1
Subject: Biology, Plant Sciences Keywords: cyanobacteria; Phormidium; Cyanothece; culture growth; light; chlorophyll; carotenoids; phycocyanin; phycoerythrin; allophycocyanin; phycobiliproteins
Online: 28 January 2022 (12:21:12 CET)
Cyanobacteria are extensively studied and cultured because they can produce many value-added substances among which are pigments, mainly the phycobiliproteins phycocyanin (PC), phycoerythrin (PE), allophycocyanin (APC) and chlorophyll-a and carotenoids as well. As numerous cyanobacterial species await optimization for maximizing pigment production, we examined here two local marine species, Phormidium sp. and Cyanothece sp. batch cultured under 18-19.5 oC, at 40 ppt salinity with Walne’s nutrient medium, using white LED light of low (2000 lux) and high (8000 lux) intensity and additionally blue, green and red LED light. Significant differences were found among the intensities and colors of light used. Maximum growth was induced by high white light in both species (2.15 g dw/L in Phormidium and 1.47 g/L in Cyanothece). Next to them was green light (1.25 g/L) in Cyanothece and low white and green (1.26 – 1.33 g/L) in Phormidium. Green light maximized phycocyanin content in Phormidium (0.45 mg/mL), while phycoerythrin was maximized (0.17 mg/mL) by blue light and allophycocyanin by all colors (~0.80 mg/mL). All colors maximized phycocyanin in Cyanothece (~0.32 mg/mL) while phycoerythrin and allophycocyanin were maximized under green light (~0.138 and 0.38 mg/mL respectively). In Phormidium maximization of chlorophyll-a (9.3 μg/mL) was induced by green light while total carotenoids and b-carotene (3.05 and 0.89 μg/mL respectively) by high white light. In Cyanothece both white light intensities along with green light maximized chlorophyll-a content (~9 μg/mL) while high white light and green maximized total carotenoids (2.6-3.0 μg/mL).
ARTICLE | doi:10.20944/preprints201807.0470.v1
Subject: Chemistry, Food Chemistry Keywords: Arthrospira platensis; carotenoids; natural pigments; spirulina powder; C-phycocyanin; antioxidant activity
Online: 25 July 2018 (06:19:11 CEST)
Arthrospira platensis is the widely available source of spirulina and contains distinctive natural pigments including carotenoids and C-phycocyanin (C-PC). In this study, the major carotenoid and C-PC contents were determined in seven commercially available spirulina powder products and laboratory-prepared A. platensis trichomes (AP-1) by an LC-DAD method and a UV-Visible spectrometry, respectively. The correlation of these two pigment content levels with Hunter color coordinates and antioxidant activity was also evaluated. The L* value failed to show a significant correlation with pigment content, but a positive correlation was observed between a* values and the contents of total carotenoid and C-PC. As b* values decreased, the total carotenoid and C-PC contents increased. AP-1 exhibited the highest content of total carotenoids, chlorophyll a and C-PC, and antioxidant activities among the samples. This observation could be related to degradation of these pigments during the mass production process. The carotenoid profiles suggested that the commercial spirulina powders originated from two different sources, A. platensis and A. maxima. Total carotenoid and C-PC content exhibited positive significant correlations with antioxidant activities measured by DPPH and ABTS assays. These results provide a strong scientific foundation for the establishment of standards for the commercial distribution of quality spirulina products.
REVIEW | doi:10.20944/preprints201809.0262.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Fusarium graminearum; color; pigments; polyketides; carotenoids
Online: 14 September 2018 (11:20:34 CEST)
Several studies explore in depth the biochemistry and genetics of the pigments present in Fusarium graminearum but there is a need to discuss about their relationship with the mold’s observable surface color pattern variation throughout its lifecycle. Furthermore, they require basic cataloguing and description of their major features known so far. Colors are a viable alternative to size measurement in growth studies. When grown on yeast extract agar (YEA) at 25 °C, F. graminearum initially exhibits a whitish mycelium, developing into a yellow-orange mold by the sixth day and then turning into wine-red. The colors are likely due to accumulation of the golden yellow polyketide aurofusarin and the red rubrofusarin, but the carotenoid neurosporaxanthin possibly play also a major role in the yellow or orange coloration. Torulene might contribute for red tones but it perhaps ends up being converted into neurosporaxanthin. Culmorin is also present but it does not contribute for the color, though it was initially isolated in pigment studies, and there is the 5-deoxybostrycoidin-based melanin, but it occurs mostly in the teleomorph’s perithecium. There is still a need to chemically quantify the pigments throughout the lifecycle, analyze their relationships and how much each impacts F. graminearum surface color.
REVIEW | doi:10.20944/preprints202002.0349.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: carotenoids; seaweeds; antioxidants; astaxanthin; fucoxanthin; anti-obesity; oxidative stress
Online: 24 February 2020 (12:26:44 CET)
Present-day lifestyle associated with high calorie-fat intake and accumulation, as well as energy imbalance, has led to the development of obesity and its comorbidities, which have emerged as some of the major health issues globally. To combat the disease, many studies have reported the anti-obesity effects of natural compounds in foods, with some advantages over chemical treatments. Carotenoids, particularly xanthophyll derived from seaweeds, have attracted the attention of researchers due to their notable biological activities, which are associated mainly with their antioxidant properties. Their involvement in oxidative stress modulation, regulation of major transcription factors and enzymes as well as their antagonistic effects on various obesity parameters have been examined in both in-vitro and in-vivo studies. The present review is a collation of published research over the last decade on the anti-oxidant properties of seaweed xanthophyll carotenoids, with a focus on fucoxanthin and astaxanthin and their mechanisms of action in obesity prevention and treatment.
ARTICLE | doi:10.20944/preprints201810.0037.v1
Subject: Biology, Other Keywords: Knufia petricola A95, HPLC analysis, carotenoids, black yeasts, didehydrolycopene
Online: 2 October 2018 (22:39:22 CEST)
Black yeasts are a highly specified group of fungi, which are characterized by a high resistance against stress factors. There are several factors enabling the cells to survive harsh environmental conditions. One aspect is the pigmentation, besides the melanin black yeasts often display a highly diverse carotenoid spectrum. Determination and characterization of carotenoids depend on an efficient extraction and separation, therefore especially for black yeast, characterized by thick cell walls specific protocols are needed to ensure analyses regarding stress responses in these fungi. Here we present both, a method to extract and analyze carotenoids and the unusual carotenoid composition of the black yeast Knufia petriola A95. Mechanical treatment combined with an acetonitrile extraction gave us very good extraction rates with a high reproducibility. The presented extraction and elution protocol allows the separation of the main carotenoids (7) in K. petricola A95 and should be suitable for the detection of additional carotenoids in other species. K. petricola A95 displays an unusual carotenoid composition, with mainly didehydrolycopene, torulene and lycopene. The pigment composition varied in dependency to oxidative stress but remained relatively constant if the cells were cultivated under low temperature. Black yeasts are a promising source for carotenoid production and other substances. To unravel the potential of these fungi new methods and studies are needed. The established protocol allows the determination carotenoid composition in black yeasts. Oxidative stress results in an adaptation in pigment composition in K. petricola A95. Future experiments have to be carried out to determine if didehydrolycopene functions as a protective agent itself or if it serves as a precursor for antioxidative pigments like torulene and torularhodin, which could be produced after induction under stress conditions.
Subject: Life Sciences, Biochemistry Keywords: Dunaliella salina; microalgae; red LED; blue LED; growth; carotenoids; plastoquinol:oxygen oxidoreductase; photosynthesis
Online: 19 April 2019 (09:47:41 CEST)
The halotolerant photoautotrophic marine microalga Dunaliella salina is one of the richest sources of natural carotenoids. Here we investigated the effects of high intensity blue, red and white light from light emitting diodes (LED) on the production of carotenoids by strains of D. salina under nutrient sufficiency and strict temperature control favouring growth. Growth in high intensity red light was associated with carotenoid accumulation and a high rate of oxygen uptake. On transfer to blue light, a massive drop in carotenoid content was recorded along with very high rates of photo-oxidation. In high intensity blue light, growth was maintained at the same rate as in red or white light, but without carotenoid accumulation; transfer to red light stimulated a small increase in carotenoid content. The data support chlorophyll absorption of red light photons to reduce plastoquinone in photosystem II, coupled to phytoene desaturation by plastoquinol:oxygen oxidoreductase, with oxygen as electron acceptor. Partitioning of electrons between photosynthesis and carotenoid biosynthesis would depend on both red photon flux intensity and phytoene synthase upregulation by the red light photoreceptor, phytochrome. Red light control of carotenoid biosynthesis and accumulation reduces the rate of formation of reactive oxygen species (ROS) as well as increases the pool size of anti-oxidant.
REVIEW | doi:10.20944/preprints202105.0076.v1
Subject: Chemistry, Analytical Chemistry Keywords: inclusion complexes; carotenoids; cyclodextrins; natural colorants; encapsulation
Online: 6 May 2021 (12:22:38 CEST)
The use of natural carotenoids as food colorants is an important trend of innovation in the industry due to their low toxicity, their potential as bio-functional ingredients, and the increasing demand for natural and organic foods. Despite these benefits, their inclusion in food matrices presents multiple challenges related to their low stability and low water solubility. The present review covers the main concepts and background of carotenoid inclusion complex formation in cyclodextrins as a strategy for their stabilization, and subsequent inclusion in food products as color additives. The review includes the key aspects of the molecular and physicochemical properties of cyclodextrins as complexing agents, and a detailed review of the published evidence on complex formation with natural carotenoids from different sources in cyclodextrins, comparing complex formation methodologies, recovery, inclusion efficiency, and instrumental characterization techniques. Moreover, process flow diagrams (PFD), based on the most promising carotenoid-cyclodextrin complex formation methodologies, are proposed, and discussed as a potential tool for their future scale-up. This review shows that the inclusion of carotenoids in complexes with cyclodextrins constitutes a promising technology for the stabilization of these pigments, with possible advantages in terms of their stability in food matrices.
ARTICLE | doi:10.20944/preprints202112.0325.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: phenotyping; proximal sensing; reflectance imaging; vegetation indices; hyperspectral reflectance; chlorophylls; carotenoids; anthocyanins; senescence; ripening
Online: 21 December 2021 (12:23:13 CET)
Hyperspectral reflectance imaging is an emerging method for rapid non-invasive quantitative screening of plant traits. This method is essential for high-throughput phenotyping and hence for accelerated breeding of crop plants as well as for precision agriculture practices. However, extraction of sensible information from reflectance images is hindered by the complexity of plant optical properties, especially when they are measured in the field. We propose using reflectance indices (Plant Senescence Reflectance Index, PSRI; Anthocyanin Reflectance Index, ARI; and spectral deconvolution) previously developed for remote sensing of vegetation and point-based reflectometers to infer the spatially resolved information on plant development and biochemical composition using ripening apple fruit as the model. Specifically, the proposed approach enables capturing data on distribution of chlorophylls and primary carotenoids as well as secondary carotenoids (both linked with fruit ripening and leaf senescence during plant development) as well as the information on spatial distribution of anthocyanins (known as stress pigments) over the plant surface. We argue that the proposed approach would enrich the phenotype assessments made on the base of reflectance image analysis with valuable information on plant physiological condition, stress acclimation state, and the progression of the plant development.
Subject: Biology, Plant Sciences Keywords: 9-cis β-carotene; all-trans β-carotene; Dunaliella salina; red LED; blue LED; growth; light intensity; carotenoids; isomerisation
Online: 17 May 2019 (08:25:02 CEST)
Dunaliella salina is a rich source of 9-cis β-carotene, which has been identified as important in the treatment of retinal dystrophies and other diseases. We previously showed that chlorophyll absorption of red light photons in D. salina is coupled to oxygen reduction and phytoene desaturation and increases the pool size of β-carotene . Here we show for the first time that growth under red light also controls conversion of extant all-trans β-carotene to 9-cis β-carotene by β-carotene isomerases. Cells illuminated with red light from a light emitting diode (LED) during cultivation contained a higher 9-cis β-carotene content compared to cells illuminated with white or blue LED light. The 9-cis/all-trans β-carotene ratio in red light treated cultures reached >2.5:1 within 48 hours and was independent of light intensity. Illumination using red light filters that eliminated blue wavelength light also increased the 9-cis/all-trans β-carotene ratio. With norflurazon, a phytoene desaturase inhibitor which blocked downstream biosynthesis of β-carotene, extant all-trans β-carotene was converted to 9-cis β-carotene during growth with red light and the 9-cis/all-trans β-carotene ratio was ~2:1. With blue light under the same conditions, 9-cis β-carotene was likely destroyed at a greater rate than all-trans β-carotene (9-cis/all-trans ratio 0.5:1). Red light perception by the red light photoreceptor, phytochrome, may increase the pool size of anti-oxidant, specifically 9-cis β-carotene, both by upregulating phytoene synthase to increase the rate of biosynthesis of β-carotene and to reduce the rate of formation of reactive oxygen species (ROS), and by upregulating β-carotene isomerases to convert extant all-trans β-carotene to 9-cis β-carotene.
ARTICLE | doi:10.20944/preprints202112.0330.v1
Subject: Life Sciences, Other Keywords: biostimulant; carotenoids; chlorophyll; IBA; leaf senescence; NAA; phenology; soluble proteins
Online: 21 December 2021 (12:40:44 CET)
Some biostimulants, including plant origin preparations, act similarly to plant hormones. Moreover, the supplementation of known and unknown rooting cofactors can stimulate rhizogenesis in cuttings. The aim of this research was to assess the response of difficult-to-root and long-rooting stem cuttings of the once-blooming old variety Rosa ‘Hurdal’ to preparations of plant origin. The hypothesis was that plant origin preparations could enhance rooting processes by inhibiting chlorophyll a/b degradation in leaves and postponing leaf senescence, simultaneously increasing the quality of cuttings. The one-bud stem cuttings were made in four phenological stages: (H1) flower buds closed, (H2) open flowers, (H3) just after petal fall, (H4) 7-14 days after petal shedding. They were treated with either standard commercial powder preparations containing 0.4% indolebutyric acid (IBA) or 0.2% naphthalene acetic acid (NAA) as well as with commercial plant origin preparations that this work will henceforth refer to as: Algae Extract, Organic Preparation, and Plant Extract. The cuttings were evaluated after 12 weeks of rooting them in two substrates: peat-perlite and peat-sand (v:v; 1:1). Mean root percentages for both substrates were noted after preparation from stage H1 (74.5 %), H2 (59.5 %), H3 (50.8 %) shoots. The H4 cuttings didn’t root at all and were not considered further. The means for all phenology stages together were the highest by the use of 0.6 % Algae Extract, 0.012 % and 0.02 % Organic Preparation, 0.2 % and 0.4 % Plant Extract. The lowest means were reported for the control cuttings as well as NAA and IBA treatment. Plant origin preparations encouraged growth parameters but did not unequivocally inhibit the decrease of chlorophyll content in the cuttings’ leaves. Rooting percentage depended on the quality of cuttings as well as chlorophyll a/b and soluble protein content in leaves in both rooting substrates.
ARTICLE | doi:10.20944/preprints202301.0199.v1
Subject: Life Sciences, Other Keywords: Prunus cerasus; ammonium nitrate; chlorophyll; TCSA; mineral content; carotenoids
Online: 11 January 2023 (10:40:29 CET)
Nitrogen fertilization ensures the proper growth of trees. The aim of the study was to evaluate the impact of differentiated nitrogen fertilization on selected parameters. It was assumed that such analysis is an indirect picture of the needs of cherries grown in herbicide fallow. The content of minerals in two layers of the soil, in leaves, and its influence of tree growth, and the content of chlorophyll in leaves were assessed. The experiments were carried out in three different cherry orchards. Three levels of fertilization were applied in each orchard: 0 kg, 60 kg and with 120 kg N ha- 1. As expected the fertilization resulted in an increase in the content of nitrate and ammonium forms of nitrogen in the soil, however, their content was also dependent on precipitation and temperature. Additionally a high nitrogen fertilization increased the content of phosphorus and potassium and decreased the magnesium in the topsoil layer. High nitrogen fertilization caused the decrease of content of phosphorus and potassium in the leaves. The level of calcium and magnesium in leaves increased with fertilization of 60 kg N ha–1 but decreased with the dose to 120 kg N ha–1. The use of nitrogen fertilization increased the vegetative growth of trees measured by leaf area and trunk cross-sectional area. However, the chlorophyll content was not dependent on the amount of nitrogen fertilization.