Content Of Primary Metabolites Research Articles

Study on the photosynthetic growth characters in Cimicifuga dahurica (Turcz.) Maxim under different supplemental light environments

Cimicifuga dahurica (C. dahurica) is an important medicinal plant in the northern region of China. The best supplemental light environment helps plant growth, development, and metabolism. In this study, we used two-year-old seedlings as experimental materials. The white light as the control (CK). The different ratios of red (R) and blue (B) combined light were supplemented (T1, 2R: 1B, 255.37 μmol·m-2·s-1; T2, 3R: 1B, 279.69 μmol·m-2·s-1; T3, 7R: 1B, 211.16 μmol·m-2·s-1). The growth characteristics, photosynthetic pigment content, photosynthesis and chlorophyll fluorescence parameters, and primary metabolite content were studied in seedlings. The results showed that: 1) The fresh weight from shoot, root, and total fresh weight were significantly (P < 0.05) increased under T2 and T3 treatment. 2) The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (Chl) were significantly (P < 0.05) increased under T2 treatment, and carotenoid (car) content was reduced. 3) The photochemical quenching (qP), the actual photosynthetic efficiency of PSII (Y(II)), and the photosynthetic electron transfer rate (ETR) from leaves were significantly (P < 0.05) increased under T1 treatment. The Net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) were significantly (P < 0.05) increased under T2 and T3 treatments. 4) A total of 52 primary metabolites were detected in C. dahurica leaves. Compared with CK, 14, 15, and 18 differential metabolites were screened under T1, T2, and T3 treatments. In addition, D-xylose, D-glucose, glycerol, glycolic acid, and succinic acid were significantly (P < 0.05) accumulated under the T2 treatment, which could regulate the TCA cycle metabolism pathway. The correlation analysis suggested that plant growth was promoted by regulating the change of D-mannose content in galactinol metabolism and amino sugar and nucleotide sugar metabolism. In summary, the growth of C. dahurica was improved under T2 treatment.

Effect of Low Temperature on Content of Primary Metabolites in Two Wheat Genotypes Differing in Cold Tolerance.

The study of cold-tolerance mechanisms of wheat as a leading cereal crop is very relevant to science. Primary metabolites play an important role in the formation of increased cold tolerance. The aim of this research is to define changes in the content of primary metabolites (soluble proteins and sugars), growth, and photosynthetic apparatus of freezing-tolerant and cold-sustainable wheat (Triticum aestivum L.) genotypes under optimal conditions and after prolonged (7 days) exposure to low temperature (4 °C). In order to gain a deeper comprehension of the mechanisms behind wheat genotypes' adaptation to cold, we determined the expression levels of photosynthetic genes (RbcS, RbcL) and genes encoding cold-regulated proteins (Wcor726, CBF14). The results indicated different cold-adaptation strategies of freezing-tolerant and cold-sustainable wheat genotypes, with soluble proteins and sugars playing a significant role in this process. In plants of freezing-tolerant genotypes, the strategy of adaptation to low temperature was aimed at increasing the content of soluble proteins and modification of carbohydrate metabolism. The accumulation of sugars was not observed in wheat of cold-sustainable genotypes during chilling, but a high content of soluble proteins was maintained both under optimal conditions and after cold exposure. The adaptation strategies of wheat genotypes differing in cold tolerance were related to the expression of photosynthetic genes and genes encoding cold-regulated proteins. The data improve our knowledge of physiological and biochemical mechanisms of wheat cold adaptation.

Metabolome and ROAV analysis reveal the effective flavor improvement in the golden biomass of chlorophyll-deficient mutant of Auxenochlorella pyrenoidosa

The green microalga Auxenochlorella pyrenoidosa is realized a promising source of alternative protein due to its high protein content and fermentable property, but the deep green color and off-odor are the bottlenecks for its application in foods. Using atmospheric and room temperature plasma (ARTP) mutagenesis, a novel chlorophyll-deficient mutant, A4-1 strain with golden color and better flavor, was successfully obtained in our previous work. In this study, to reveal the formation of the improved flavor in A4-1 strain compared to the wild type (WT), the volatiles basis was analyzed by HS-SPME Arrow-GC-MS, and the potential precursors causing flavor improvement were explored by UPLC-ESI-MS/MS. Results showed the volatiles were mainly composed of hydrocarbons, terpenoids, esters, ketones, alcohols, and aldehydes, and 29 of which were significantly different between the two biomass, largely attributed to variations of primary metabolite content, particularly those enriched in the fatty acids and amino acids. The analysis of relative odor activity value (ROAV) verified that β-ionone, dimethyl trisulfide and (Z)-6-nonenal were the main odorants, in which the lower contributions of dimethyl trisulfide (off-flavor, rancid or cooked oniony) and (Z)-6-nonenal (off-flavor, stink or fishy) were found in A4-1, which made A4-1 biomass become more neutral and superior to WT biomass in terms of odor perception. It is the first report of flavor improvement for green microalgae through breeding technology, and the novel biomass of A4-1 strain will broaden A. pyrenoidosa biomass in food application.

Study of the metabolome features of patients with COVID-19

Aim. To analyze the metabolomic profile of patients with coronavirus disease 2019 (COVID-19) using mass spectrometry methods and taking into account clinical and laboratory history. Studying the relationship between the severity of COVID-19 symptoms and the concentration of primary metabolites, primarily amino acids.Material and methods. The retrospective study included serum samples from a total of 935 people (445 men and 490 women) with COVID-19 from the collection of the biobank of the City Hospital № 40. A metabolomic profile was studied in all samples using chromatography-mass spectrometry. The R language was used for statistical data processing.Results. Based on the analysis, a difference in the metabolic profile of patients with COVID-19 was identified depending on the disease severity — for 52 of the 84 detected compounds, differences were observed with a significance of p&lt;0,01. Significant differences in concentration were recorded for organic acids, amino acids and their derivatives.Conclusion. Using samples from the biobank collection, a metabolomic study of the biomaterial of patients hospitalized with a diagnosis of COVID-19 was carried out. According to the results obtained, kynurenine, phenylalanine and acetylcarnitine are associated with COVID-19 severity. Differences in the metabolomic profile were identified in patients with cytokine storm at the time of blood collection. Potential biomarkers for cytokine storm were identified.

Effect of Drying Post-Harvest on the Nutritional Compounds of Edible Flowers

The post-harvest techniques are the most critical point to ensure the quality of edible flowers (EFs) and to keep the bioactive metabolites available for human nutrition. The different species of EFs also represent a problem in improving their consumption with safety. The present study focused on the description of the effects of the commonly used drying treatments in the phytonutritional composition of four species of EFs, Callianthe megapotamica, Callianthe striata, Nemesia strumosa and Salvia elegans. The bioactive metabolites and antioxidant activity were determined after freeze-drying (FD) and hot-air-drying (HA) treatments in comparison to fresh flowers. All EFs showed different mineral/trace compositions with potassium as the main element and 70–86% water loss. Both post-harvest treatments increased all the metabolites and antioxidant activity in each species. C. striata with FD treatment had the highest content of primary and secondary metabolites. N. strumosa has the highest ascorbic acid content with the HA treatment. All species had significant antioxidant activity, increasing with FD for C. striata while HA is more recommended for the other species. The post-harvest techniques are able to preserve and increase the bioactive metabolites and must be chosen according to each EF species.

Morpho-physiology and metabolite content of Cosmos caudatus Kunth. and yellow and orange Cosmos sulphureus Cav.

Abstract. Saleh I, Aziz SA, Melati M, Andarwulan N. 2023. Morpho-physiology and metabolite content of yellow and orange Cosmos sulphureus Cav. and Cosmos caudatus Kunth. Biodiversitas 24: 5739-5746. Cosmos sp., known as kenikir in Indonesia, is an underutilized vegetable commodity. Cosmos sulphureus Cav. (C. sulphureus), with orange and yellow flowers, is commonly found as an ornamental plant. C. sulphureus can also be used as vegetable crops, although the Cosmos species widely used as a vegetable is Cosmos caudatus Kunth. (C. caudatus). This study investigated the growth, shoot production, primary and secondary metabolite content, and antioxidant activity of yellow and orange C. sulphureus and C. caudatus. This experiment was arranged using a Randomized Completely Block Design (RCBD) with one factor: Cosmos species (yellow and orange C. sulphureus and C. caudatus) with six replications. The result showed that plant height, leaf number, and branch number were not significantly different among the three Cosmos studied; however, the shoot weight per plant of orange C. sulphureus was significantly higher than the others. The antioxidant activity and phenol content of C. sulphureus were lower than that of C. caudatus. Meanwhile, crude fiber, flavonoid, anthocyanin, and carotenoid content were not significantly different among the three kinds of Cosmos. Orange C. sulphureus could be a functional vegetable, although its antioxidant activity is lower than C. caudatus.

ZmDRR206 functions in maintaining cell wall integrity during maize seedling growth and defense response to external stresses

Plants adaptively change their cell wall composition and structure during their growth, development, and interactions with environmental stresses. Dirigent proteins (DIRs) contribute to environmental adaptations by dynamically reorganizing the cell wall and/or by generating defense compounds. A maize DIR, ZmDRR206, was previously reported to play a dominant role in regulation of storage nutrient accumulation in endosperm during maize kernel development. Here we show that ZmDRR206 mediates maize seedling growth and disease resistance by coordinately regulating biosynthesis of cell wall components for cell-wall integrity (CWI) maintenance. Expression of ZmDRR206 was induced in maize seedlings upon pathogen infection. ZmDRR206 overexpression in maize resulted in reduced seedling growth and photosynthetic activity but increased disease resistance and drought tolerance, revealing a tradeoff between growth and defense. Consistently, ZmDRR206 overexpression reduced the contents of primary metabolites and down-regulated genes involved in photosynthesis, while increasing the contents of major cell wall components, defense phytohormones, and defense metabolites, and up-regulated genes involved in defense and cell-wall biosynthesis in seedlings. ZmDRR206-overexpressing seedlings were resistant to cell-wall stress imposed by isoxaben, and ZmDRR206 physically interacted with ZmCesA10, which is a cellulose synthase unit. Our findings suggest a mechanism by which ZmDRR206 coordinately regulates biosynthesis of cell-wall components for CWI maintenance during maize seedling growth, and might be exploited for breeding strong disease resistance in maize.

Estimation of Secondary Metabolites in Gliricidia Sepium from Primary Compounds and Regrowth Age

The objective is to estimate the content of secondary metabolites in Gliricidia Sepium from the age and content of primary compounds (nitrogen, fructose, glucose, and sucrose). The present study was developed following a randomized block design, with three treatments (60, 120 and 180 days) and n repetitions. Nitrogen (N), glucose (Glu), fructose (Frut) and sucrose (Suc) content were evaluated for validation. In addition, mathematical models were validated for the estimation of secondary metabolites from the primary ones and regrowth age. To establish the functional relationship between age and primary metabolites, regression equations were analyzed. Reporting a decrease for N, Glu, Frut and Suc with the highest values at 60 days, and quadratic equations with R2 greater than 0.91 were adjusted. The regrowth age had a marked effect on the contents of primary metabolites (N, Glu, Frut and Suc), which explains the close relationship through the established regression equations. As well as it was evidenced that the validation of the models for the prediction of secondary metabolites in both periods of the year, can be applied due to the dependence of these compounds on their precursors (nitrogen and sugars).

New Insights on Primary and Secondary Metabolite Contents of Seven Italian Wild Food Plants with Medicinal Applications: A Comparative Study.

Wild food plants are widely consumed all over the world and many have both nutritional and therapeutic value due to the presence of biologically active compounds. The present research, for the first time, aims to compare primary and secondary metabolite levels among different plant organs (flower, leaf, stem, root, bark) of seven species (Borago officinalis L., Cynodon dactylon (L.) Pers., Foeniculum vulgare Mill., Hypericum perforatum L., Malva sylvestris L., Sambucus nigra L., Urtica dioica L.) collected in three different Italian regions (Liguria, Tuscany, Apulia). Plant organ samples were extracted with water or 95% (v/v) methanol and liquid fractions were analyzed using spectrophotometric assays. The best results were obtained for Hypericum perforatum L. samples, followed by Sambucus nigra L. and Borago officinalis L. As also confirmed via PCA analysis on normalized data, flower and leaf extracts of all species exhibited higher levels of polyphenols (up to 105.7 mg GA eq/gDW), reducing sugars (up to 389.2 mg GLUC eq/gDW), proteins (up to 675.7 mg BSA eq/gDW) and of antioxidant capacity (up to 263.5 mg AA eq/gDW). No differences among the regions of gathering were detected after spectrophotometric assays, which was confirmed via PCA analysis. These data contribute to further validate the traditionally reported healing effects of these species on human health.

Effects of Exhaustion Gases from Biodiesel Blends on the Lichen Cladonia verticillaris: A Complimentary Evaluation

The objective of this study was to evaluate the effects of gases emitted by blends of biodiesel with petroleum diesel at intermediate concentrations (between 10 % and 40 %) on the biochemistry of the lichen Cladonia verticillaris (Raddi) Fr. Samples of the respective species were exposed to the gases during a period of sixty minutes, using a stationary engine, with blends of 20 % (B20), 25 % (B25) and 30 % (B30) of biodiesel, from the oil from cotton, to petroleum diesel. In the period of 30, 60 and 90 days, the concentrations of primary metabolites (chlorophylls and pheophytins) and secondary (protocetraric acid and fumarprotocetraric acid) were determined. A control group was used for comparison purposes. The gases emitted during the combustion process were also evaluated at three times (0 minutes, 30 minutes and 60 minutes). The results did not show significant differences for chlorophylls, when all treatments and control materials were compared, however, variations were observed for the other metabolites. The concentration of protocetraric acid was higher compared to fumarprotocetraric acid, indicating that there were blocks in the synthesis of the metabolic pathway. Cluster analysis showed that for groups B20 and B25, pheophytins are related to CO2, while for B30 their chlorophylls are related to NO2. The results demonstrate that the respective mixtures do not affect the integrity of the species, confirming the recommendation to use mixtures of biodiesel with petroleum diesel up to 40 %. Keywords: biofuels, environmental impact, living organisms, lichen substances, biomonitoring.

Black Queens of Fruits: Chemical Composition of Blackberry (Rubus subg. rubus Watson) and Black Currant (Ribes nigrum L.) Cultivars Selected in Serbia.

Black fruits, especially blackberries and black currants, are highly appreciated by consumers due to their nutraceutical properties, which have reported health benefits. This study aimed to assess the fruit quality of the blackberry (cv. 'Čačanska Bestrna') and black currant (cv. 'Čačanska Crna') created at the Fruit Research Institute, Čačak (Republic of Serbia) by evaluating basic quality parameters (fruit weight, soluble solids), and content of primary (sugars and organic acids) and secondary (phenolic compounds) metabolites. Additionally, the study examined the quality of frozen and long-term frozen storage (6, 9, and 12 months). The results showed that 'Čačanska Crna' contained a high level of total soluble solids (15.23°Bx), sugars (93.06 mg g-1), and a high index of sweetness (159.48) as well as a high content of acids (34.35 mg g-1) in the fruit. Both species were found to contain forty-seven phenolic compounds, including phenolic acids, flavanols, and anthocyanins, analyzed using high performance liquid chromatography-mass spectrometry (HPLC-MS). 'Čačanska Bestrna' had the highest amounts of phenolic acids (66.85 mg 100 g-1) and flavanols (53.99 mg 100 g-1), whereas 'Čačanska Crna' showed the highest levels of flavonols (8.57 mg 100 g-1) and anthocyanins (139.11 mg 100 g-1). Furthermore, the study revealed that anthocyanins were the most abundant phenolic group in both blackberries and black currants, and their levels remained constant during frozen storage. The sugar content in both species remained unchanged, while the acid concentration increased over time in blackberries but remained consistent in black currants. Overall, the findings highlight the superior phenolic content, particularly anthocyanins, of the cultivars with black fruits selected in Serbia. These cultivars have great commercial potential for the fresh market and processing. Moreover, the study suggests that frozen storage is an effective method for preserving their quality and beneficial properties.

The Effect of Acidic pH on Growth Kinetics, Biomass Productivity, and Prima-ry Metabolite Contents of Euglena sp.

The Effect of Acidic pH on Growth Kinetics, Biomass Productivity, and Prima-ry Metabolite Contents of Euglena sp.

Bioremediation of Catechol and Concurrent Accumulation of Biocompounds by the Microalga Crypthecodinium cohnii.

Burgeoning commercial applications of catechol have led to its excessive accumulation in the environment, thereby posing a severe ecological threat. Bioremediation has emerged as a promising solution. The potential of the microalga Crypthecodinium cohnii to degrade catechol and use the byproduct as a carbon source was investigated in this study. Catechol significantly increased C. cohnii growth and was rapidly catabolized within 60 h of cultivation. Transcriptomic analysis highlighted the key genes involved in catechol degradation. Real-time polymerase chain reaction (RT-PCR) analysis showed that transcription of key genes CatA, CatB, and SaID involved in the ortho-cleavage pathway was remarkably increased by 2.9-, 4.2-, and 2.4- fold, respectively. Key primary metabolite content was also markedly altered, with a specific increment in polyunsaturated fatty acids. Electron microscopy and antioxidant analysis showed that C. cohnii could tolerate catechol treatment without morphological aberrations or oxidative stress. The findings provide a strategy for C. cohnii in the bioremediation of catechol and concurrent polyunsaturated fatty acids (PUFA) accumulation.

Influence of Different Rootstocks on Fruit Quality and Primary and Secondary Metabolites Content of Blood Oranges Cultivars.

Blood oranges have high concentrations of bioactive compounds that are beneficial to health. In Europe, the cultivation of blood oranges is increasing due to their excellent nutritional properties. In Citrus crops, rootstocks play an important role in juice and can increase the content of bioactive compounds. The morphological, qualitative and nutritional parameters were analyzed in cultivars 'Tarocco Ippolito', 'Tarocco Lempso', 'Tarocco Tapi' and 'Tarocco Fondaconuovo' grafted onto Citrus macrophylla and Citrus reshni. 'Tarocco Lempso' grafted onto Citrus macrophylla obtained the highest values of weight (275.78 g), caliber (81.37 mm and 76.79 mm) and juice content (162.11 g). 'Tarocco Tapi' grafted onto Citrus reshni obtained the most interesting qualitative parameters (15.40 °Brix; 12.0 MI). 'Tarocco Lempso' grafted onto Citrus reshni obtained the most intense red juice (a* = 9.61). Overall, the highest concentrations of primary metabolites were in proline, aspartate, citric acid, and sucrose. The results showed that 'Tarocco Ippolito' juice grafted onto Citrus reshni had the highest levels of total hydroxycinnamic acids (263.33 mg L-1), total flavones (449.74 mg L-1) and total anthocyanins (650.42 mg L-1). To conclude, 'Tarocco Lempso' grafted onto Citrus macrophylla obtained the best values of agronomic parameters, and the cultivars grafted onto Citrus reshni obtained significantly higher concentrations in primary and secondary metabolites.

Impact of Light and Dark Treatment on Phenylpropanoid Pathway Genes, Primary and Secondary Metabolites in Agastache rugosa Transgenic Hairy Root Cultures by Overexpressing Arabidopsis Transcription Factor AtMYB12.

Agastache rugosa, otherwise called Korean mint, has a wide range of medicinal benefits. In addition, it is a rich source of several medicinally valuable compounds such as acacetin, tilianin, and some phenolic compounds. The present study aimed to investigate how the Tartary buckwheat transcription factor AtMYB12 increased the primary and secondary metabolites in Korean mint hairy roots cultured under light and dark conditions. A total of 50 metabolites were detected by using high-performance liquid chromatography (HPLC) and gas chromatography-time-of-flight mass spectrometry (GC-TOFMS). The result showed that the AtMYB12 transcription factor upregulated the phenylpropanoid biosynthesis pathway genes, which leads to the highest accumulation of primary and secondary metabolites in the AtMYB12-overexpressing hairy root lines (transgenic) than that of the GUS-overexpressing hairy root line (control) when grown under the light and dark conditions. However, when the transgenic hairy root lines were grown under dark conditions, the phenolic and flavone content was not significantly different from that of the control hairy root lines. Similarly, the heat map and hierarchical clustering analysis (HCA) result showed that most of the metabolites were significantly abundant in the transgenic hairy root cultures grown under light conditions. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) showed that the identified metabolites were separated far based on the primary and secondary metabolite contents present in the control and transgenic hairy root lines grown under light and dark conditions. Metabolic pathway analysis of the detected metabolites showed 54 pathways were identified, among these 30 were found to be affected. From these results, the AtMYB12 transcription factor activity might be light-responsive in the transgenic hairy root cultures, triggering the activation of the primary and secondary metabolic pathways in Korean mint.

Fruit Quality and Primary and Secondary Metabolites Content in Eight Varieties of Blood Oranges

In Europe, the cultivation of blood oranges for fresh consumption is increasing due to their excellent organoleptic and nutraceutical properties, which give this fruit the status of functional food. Blood orange has a higher content of bioactive compounds, which confer additional benefits for human health. The main morphological and qualitative parameters were studied together with the content of primary metabolites by 1H NMR and secondary metabolites by HPLC-ESI-DAD-MSn from eight varieties of blood orange grafted on Citrus macrophylla. Tarocco Dalmuso was the variety with the highest values of weight (350.6 g), caliber (86.4 mm and 88.6 mm) and juice content (214.2 g). Tarocco Gallo obtained the most interesting qualitative parameters (13.95 °Brix; 22.75 MI). The most intense red juice was in Sanguinelli (a* = 9.45) and, in crust, it was in Tarocco Scirè (a* = 40.13). The most abundant primary metabolites were proline, aspartate and asparagine, citric acid and sucrose. The results showed that the juice of the Moro had the highest levels of total flavones and flavanones (90.07 and 592.88 mg L−1, respectively), and Sanguinelli in total anthocyanins (101.06 mg L−1). To conclude, Tarocco Dalmuso obtained the best values of agronomic parameters, and Moro and Sanguinelli in the content of phenolic compounds.

Metabolic profiling and gene expression analysis reveal the quality deterioration of postharvest toon buds between two different storage temperatures.

Toon buds, a popular woody vegetable, contain large amounts of nutrients. However, toon buds have strong respiratory metabolism after harvest and are highly prone to decay, resulting in quality deterioration. Low temperature can effectively inhibit postharvest senescence of toon buds. GC-TOF-MS combined with quantitative real-time PCR was used to elucidate the toon bud deterioration mechanism after harvest by analyzing the difference in the relative contents of primary metabolites and their derivatives, and the expression of key genes associated with metabolic pathways in toon buds between low temperature and room temperature storages for 72h. Results showed that the ethylene synthesis in toon buds accelerated under room temperature storage, along with significant changes in the primary metabolic pathway. The catabolism of amino acids, fatty acids, and cell membrane phospholipids was accelerated, and the gluconeogenesis synthesis was strengthened. Moreover, the sucrose synthesis was increased, the glycolysis and TCA cycle were broken down, and the pentose phosphate pathway was vigorous. As metabolic intermediates, organic acids were considerably accumulated. Moreover, varieties of toxic compounds were produced in parallel with the activation of aromatic compounds. This work provided a comprehensive understanding of the metabolic regulation, thereby revealing how low and room temperatures differentially influenced the quality deterioration of postharvest toon buds.

A metabolome genome-wide association study implicates histidine N-pi-methyltransferase as a key enzyme in N-methylhistidine biosynthesis in Arabidopsis thaliana.

A genome-wide association study (GWAS), which uses information on single nucleotide polymorphisms (SNPs) from many accessions, has become a powerful approach to gene identification. A metabolome GWAS (mGWAS), which relies on phenotypic information based on metabolite accumulation, can identify genes that contribute to primary and secondary metabolite contents. In this study, we carried out a mGWAS using seed metabolomic data from Arabidopsis thaliana accessions obtained by liquid chromatography-mass spectrometry to identify SNPs highly associated with the contents of metabolites such as glucosinolates. These SNPs were present in genes known to be involved in glucosinolate biosynthesis, thus confirming the effectiveness of our analysis. We subsequently focused on SNPs detected in an unknown methyltransferase gene associated with N-methylhistidine content. Knockout and overexpression of A. thaliana lines of this gene had significantly decreased and increased N-methylhistidine contents, respectively. We confirmed that the overexpressing line exclusively accumulated histidine methylated at the pi position, not at the tau position. Our findings suggest that the identified methyltransferase gene encodes a key enzyme for N-methylhistidine biosynthesis in A. thaliana.

Accumulation of Anthocyanins in Detached Leaves of Kalanchoë blossfeldiana: Relevance to the Effect of Methyl Jasmonate on This Process.

Accumulation of anthocyanins in detached leaves and in excised stems of Kalanchoë blossfeldiana kept under natural light conditions in the presence or absence of methyl jasmonate (JA-Me) was investigated. When the abaxial surface of detached leaves was held lower than the adaxial surface (the normal or natural position) under natural light conditions, anthocyanins were not accumulated on the abaxial side of the leaves. In contrast, when the adaxial surface of detached leaves was held lower than the abaxial surface (inverted position), anthocyanins were highly accumulated on the abaxial side of the leaves. These phenomena were independent of the growth stage of K. blossfeldiana as well as photoperiod. Application of JA-Me in lanolin paste significantly inhibited anthocyanin accumulation induced on the abaxial side of detached leaves held in an inverted position in a dose-dependent manner. Anthocyanin accumulation in the excised stem in response to natural light was also significantly inhibited by JA-Me in lanolin paste. Possible mechanisms of anthocyanin accumulation on the abaxial side of detached K. blossfeldiana leaves held in an inverted position under natural light conditions and the inhibitory effect of JA-Me on this process are described. The accompanying changes in the content of primary metabolites and histological analyses were also described.

Dynamic seasonal changes in photosynthesis systems in leaves of Asarum tamaense, an evergreen understorey herbaceous species.

Evergreen herbaceous species in the deciduous forest understorey maintain their photosystems in long-lived leaves under dynamic seasonal changes in light and temperature. However, in evergreen understorey herbs, it is unknown how photosynthetic electron transport acclimates to seasonal changes in forest understorey environments, and what photoprotection systems function in excess energy dissipation under high-light and low-temperature environments in winter. Here, we used Asarum tamaense, an evergreen herbaceous species in the deciduous forest understorey with a single-flush and long-lived leaves, and measured photosynthetic CO2 assimilation and electron transport in leaves throughout the year. The contents of photosynthetic proteins, pigments and primary metabolites were determined from regularly collected leaves. Both the rates of CO2 assimilation and electron transport under saturated light were kept low in summer, but increased in autumn and winter in A. tamaense leaves. Although the contents of photosynthetic proteins including Rubisco did not increase in autumn and winter, the proton motive force and ΔpH across the thylakoid membrane were high in summer and decreased from summer to winter to a great extent. These decreases alleviated the suppression by lumen acidification and increased the electron transport rate in winter. The content and composition of carotenoids changed seasonally, which may affect changes in non-photochemical quenching from summer to winter. Winter leaves accumulated proline and malate, which may support cold acclimation. In A. tamaense leaves, the increase in photosynthetic electron transport rates in winter was not due to an increase in photosynthetic enzyme contents, but due to the activation of photosynthetic enzymes and/or release of limitation of photosynthetic electron flow. These seasonal changes in the regulation of electron transport and also the changes in several photoprotection systems should support the acclimation of photosynthetic C gain under dynamic environmental changes throughout the year.