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[Objective] Jujube is a vital cash crop in Xinjiang. This study examined the combined effect of irrigation and potassium fertilization on physiological traits of jujube leaves and fruit yield to determine the optimal irrigation and fertilisation strategy for its sustainable production in this region. [Method] The field experiment was conducted from 2022 to 2023 in an 8-year grey jujube orchard in Aksu, Southern Xinjiang. There were three irrigation treatments by irrigating 100% (T1), 75% (T2) and 50% (T3) of estimated evapotranspiration. Each irrigation treatment had three potassium fertilizations: 240 kg/hm2 (A), 180 kg/hm2 (B) and 120 kg/hm2 (C). During the experiment, we measured the photosynthetic traits of the jujube leaves and ultimate fruit yield. [Result] Both irrigation amount and potassium fertilization significantly impacted growth and development of the jujube. The net photosynthetic rate, transpiration rate and chlorophyll content of the jujube increased with increasing irrigation amount and potassium fertilization. Increasing potassium fertilization increased soluble sugar in jujube leaves, with its content in T1-A, T2-A and T3-A in 2023 increasing by 37.0%, 36.9% and 28.7%, respectively, compared to that in 2022. The abscisic acid (ABA) in jujube leaves varied with irrigation amount, being the highest in T3-C. The irrigation water use efficiency increased as the plant grew, and the fruit yield increased with the increase in potassium fertilization. When potassium application was 240 kg/hm2, T1 and T2 increased the fruit yield by 56.77% and 45.52% in 2022, and 51.46% and 37.61% in 2023, compared to T3. Water use efficiency of T2-A was 8.88 kg/(hm2·mm) and 9.14 kg/(hm2·mm) in 2022 and 2023, respectively. [Conclusion] Among all treatments we compared, irrigating 75% of estimated evapotranspiration combined with a 240 kg/hm2 of potassium fertilization is optimal for improving fruit yield and water use efficiency of jujube in Southern Xinjiang.

A selective and efficient olefin epoxidation has been developed by Fe3O4@SiO2/(TEMPO)-copolymer-(Chlorophyll b)-Co(III) NPs as a heterogeneous magnetically recyclable nanocatalyst. The nanocatalyst was synthesized through several steps including chlorophyll b de-metallation, imine functionalization with ally amine, co-polymerization with acrylated TEMPO, re-metalation with cobalt, and immobilization on magnetite NPs. Selective catalytic epoxidation of olefins was accomplished under mild conditions and in an O2 atmosphere. High selectivity and conversion were achieved for a variety of substrates. The results indicated a synergistic effect between TEMPO moieties and the coordinated Co(III) centers as two active sites. The epoxide products could be separated by the heterogeneous poly(benzoic acid) with the highest possible isolated yields. Also, the heterogeneous nanocatalyst could be recycled for at least 7 consecutive cycles with a negligible reactivity loss. A selective and efficient olefin epoxidation with smart isolation has been developed by Fe3O4@SiO2/(TEMPO)-copolymer-(Chlorophyll b)-Co(III) NPs under mild conditions. [ABSTRACT FROM AUTHOR]

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An organic solvent‐free method based on limited dosing options (biocatalyst and zinc chloride) for the quick and mild recovery of chlorophyll (Chl) from spinach has been proposed. This tailored, custom‐made protocol has been designed to produce stable green natural colorants. The kinetics of pigment extraction turned out to be a very useful tool to identify the proper conditions, in terms of biocatalyst dose (0.10–50 U/g), extraction time (1–48h), and ZnCl2 amount (50–300ppm), both for enhancing the recovery yield and preserving the green color. Considering the extraction kinetics, the recovery yield, and the colorimetric data, the suitable conditions to produce stable green and food‐grade colorants are 0.10 U/g of enzyme, 3h, and 150ppm of ZnCl2 at 25°C. The extraction yield of Chl (4863µg/U) was about 51% greater than control, with a higher extraction rate constant (5.43 × 10−4 g/(µg min)). Considering the impact of ZnCl2 amount on Chl, its protective action resulted to be more noticeable toward Chl a: at 150ppm, an increased amount of about 2.5 and 1.5 times was found for Chl a and Chl b, respectively, in comparison to the reference (0ppm ZnCl2). Practical Application: This research demonstrates how a suitable kinetic approach helps to provide a tailored protocol, customized for the vegetable matrix, to produce stable green natural colorants from spinach. Lowering enzyme dosage and ZnCl2 amount during the extraction of chlorophyll at low temperature is crucial for its potential use as a colorant in food industry, providing high economic values through saving time and environmental protection. [ABSTRACT FROM AUTHOR]

Cactaceae are a significant group of ornamental plants in the horticultural market. In the present study, X-rays were used for the first time to induce mutational changes in the cactus Copiapoa tenuissima. The aim of this study was to assess the genetic variability in seedlings exposed to in vitro X-ray irradiation at doses of 0, 15, 20, 25, and 50 Gy (radiation time from 5 min 13 s to 17 min 22 s) by morphological analysis, a spectrophotometric evaluation of plant pigment content, and the confirmation of changes at the genetic level using SCoT (start codon targeted) markers. The results showed that the percentage of colorful seedlings increased with the radiation dose and was the highest for the 50 Gy dose (4.89%). The radiation doses of 25 and 50 Gy generated seedlings with a new color (orange-brown), which had not yet been observed in C. tenuissima. With the increase in the radiation dose, as compared to control seedlings, brown seedlings showed an increase in the concentrations of carotenoids, chlorophyll a, and chlorophyll b, while green seedlings showed an increase in the concentrations of anthocyanins and chlorophyll b and a decrease in the concentrations of carotenoids and chlorophyll a. The unweighted pair group method analysis showed a very large genetic distance among the tested genotypes exposed to X-rays. The results of the present study provide a novel direction for using X-rays to breed new cultivars of C. tenuissima. [ABSTRACT FROM AUTHOR]

To evaluate the effect of foliar application of Farmax nano fertilizer and Amino Acid on morological traits and photosynthetic pigments of chicory (Cichorium intybus L.), an experiment was conducted based on randomized complete design in aeroponic system and in the independent experiments. The treatments in the effects of Farmax nano fertilizer were including control, 3 and 5 ml/l Farmax nano fertilizer and in the effects of Amino Acid were including control, Amino Acid (3 and 6 mg/l). Foliar application of fertilizers was done at 20, 40 and 60 days after transplanting in aeroponic. After 6 month morphological traits and photosynthetic pigments were measured. Based on the results of the variance analysis, the effect of different Farmax nano fertilizer and Amino Acid on morological traits and photosynthetic pigments were significant. The results in the effect of showed that 5 ml/l of Farmax nano fertilizer has produced the highest of plant height, root length, leaf number, fresh weight of shoot, dry weight of shoot, fresh weight of root, dry weight of root, leaf area, chlorophyll a, chlorophyll b and carotenoid. Also the results showed that mrological traits and photosynthetic pigments were increased by the foliar application of amino acids compared to the control. Overall, the results showed that feeding chicory with the Farmax nano fertilizer and Amino Acid could improve the morphological traits and photosynthetic pigments in the plant. [ABSTRACT FROM AUTHOR]

The accurate determination of magnesium isotope values of chlorophyll a and chlorophyll b is particularly important for the study of magnesium biosynthesis pathways during chlorophyll formation. HPLC is required before MC-ICP-MS can be utilized, but HPLC lacks a method for separating chlorophylls. Therefore, it is necessary to develop a set of methods for separating plant chlorophyll a and chlorophyll b. The samples separated by this method are suitable for magnesium isotope determination by MC-ICP-MS. Based on the detection wavelength of 665nm and C18 column (7.6mm×250mm, 5μm), the HPLC conditions were optimized by three-factor and three-level orthogonal design to obtain the required parameters. The correlation coefficients of chlorophyll a and chlorophyll b standard curves in the concentration range of 5−50mg/L were greater than 0.9996, the detection limits were 0.40−1.09mg/L, the quantification limits were 1.22−3.31mg/L, the relative standard deviation was less than 8.10%, and the recoveries were 91.92%−111.11%. The magnesium isotope data of the isolated samples also showed that the column temperature of 25℃, flow rate of 1mL/min, and methanol-acetone (80∶20, V/V) mobile phase were reliable as HPLC separation conditions. The method established in this paper provides technical support for the separation of chlorophyll a and chlorophyll b in plants, and the separated samples can be used for magnesium isotope determination. [ABSTRACT FROM AUTHOR]

Chlorophyll b is synthesized from chlorophyllide a, catalyzed by chlorophyllide a oxygenase (CAO). To examine whether reduced chlorophyll b content regulates chlorophyll (Chl) synthesis and photosynthesis, we raised CAO transgenic tobacco plants with antisense CAO expression, which had lower chlorophyll b content and, thus, higher Chl a/b ratio. Further, these plants had (i) lower chlorophyll b and total Chl content, whether they were grown under low or high light; (ii) decreased steady-state levels of chlorophyll biosynthetic intermediates, due, perhaps, to a feedback-controlled reduction in enzyme expressions/activities; (iii) reduced electron transport rates in their intact leaves, and reduced Photosystem (PS) I, PS II and whole chain electron transport activities in their isolated thylakoids; (iv) decreased carbon assimilation in plants grown under low or high light. We suggest that reduced synthesis of chlorophyll b by antisense expression of CAO, acting at the end of Chl biosynthesis pathway, downregulates the chlorophyll b biosynthesis, resulting in decreased Chl b, total chlorophylls and increased Chl a/b. We have previously shown that the controlled up-regulation of chlorophyll b biosynthesis and decreased Chl a/b ratio by over expression of CAO enhance the rates of electron transport and CO2 assimilation in tobacco. Conversely, our data, presented here, demonstrate that-antisense expression of CAO in tobacco, which decreases Chl b biosynthesis and increases Chl a/b ratio, leads to reduced photosynthetic electron transport and carbon assimilation rates, both under low and high light. We conclude that Chl b modulates photosynthesis; its controlled down regulation/ up regulation decreases/ increases light-harvesting, rates of electron transport, and carbon assimilation. [ABSTRACT FROM AUTHOR]

The chlorophyllide a oxygenase (CAO) plays a crucial role in the biosynthesis of chlorophyll b (Chl b). In the moss Physcomitrium patens (P. patens), two distinct gene copies, PpCAO1 and PpCAO2, are present. In this study, we investigate the differential expression of these CAOs following light exposure after a period of darkness (24 h) and demonstrate that the accumulation of Chl b is only abolished when both genes are knocked out. In the ppcao1cao2 mutant, most of the antenna proteins associated with both photosystems (PS) I and II are absent. Despite of the existence of LHCSR proteins and zeaxanthin, the mutant exhibits minimal non-photochemical quenching (NPQ) capacity. Nevertheless, the ppcao1cao2 mutant retains a certain level of pseudo-cyclic electron transport to provide photoprotection for PSI. These findings shed light on the dual dependency of Chl b synthesis on two CAOs and highlight the distinct effects of Chl b deprival on PSI and PSII core complexes in P. patens, a model species for bryophytes. [ABSTRACT FROM AUTHOR]

Photocatalytic conversion of organic compounds has recently emerged as a cost‐effective, safe, and easy‐to‐operate procedure to synthesize value‐added materials. In this study, the magnetic titanium dioxide‐based (Fe3O4/SiO2/TiO2) photocatalyst was designed to synthesize conjugated derivatives of tetrahydroquinoline through a photoinduced electron transfer (PET) reaction. Chlorophyll b was immobilized on the surface of magnetic titanium dioxide, as a natural visible‐light‐sensitive compound using 3‐aminopropyltriethoxysilane (APTES) as a coupling agent containing terminal amine (Fe3O4/SiO2/TiO2‐NH2‐Chb) to improve light harvesting ability. Fourier transform infrared (FT‐IR), powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA), energy‐dispersive X‐ray spectrometer (EDS), and vibrating sample magnetometer (VSM) results confirmed the successful synthesis of Fe3O4/SiO2/TiO2‐NH2‐Chb. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images displayed the preserved spherical morphology of Fe3O4/SiO2/TiO2‐NH2‐Chb. Chlorophyll b‐modified magnetic titanium dioxide was highly active under visible‐light irradiation toward the cyclization of (E)‐3‐[4‐(dimethylamino)phenyl)]‐1‐arylprop‐2‐en‐1‐one with 1‐aryl‐1H‐pyrrole‐2,5‐dione to achieve new tetrahydroquinoline derivatives with conjugated structure in high yields at ambient temperature, in air. The incorporation of chlorophyll b in the photocatalyst plays an important role in the photocatalytic mechanism, facilitating photoinduced electron transfer to the conduction band of TiO2. Moreover, the magnetic property enabled easy recovery of the photocatalyst and improved its reusability up to three runs. The characteristics of tetrahydroquinoline derivatives were studied by FT‐IR, CHN, 1H NMR, and 13C NMR analyses. [ABSTRACT FROM AUTHOR]

Background and Aim: Air pollution is currently one of the most important environmental issues. The most common effect of air pollution on plants is the gradual decomposition of chlorophyll and leaf yellowing, which may result in the reduction of photosynthetic capacity. This study aimed to investigate the effect of air pollution on the chlorophyll content and zonation of leaf chlorophyll content of two tree species in Malayer city, Iran. Materials and Methods: Samples were collected from two tree species, namely, Platanus orientalis and Robinia pseudoacacia in different parts of Malayer city, Iran (clean and polluted areas), each with three replications. The concentration of pigments in the leaves was measured by the Lichtenthaler (1987) method, which is the modified Arnon method (1949), at 663 and 645 nm wavelengths, absorbance being measured using a spectrophotometer. Results: Data analysis showed that the a, b and total chlorophyll contents in the acacia tree species in the southern parts (southwest) of the study area reached their maximums, while their contents were lowest in the eastern and north-western parts and low to medium in the central parts of the study area. On the other hand, as regards the sycamore species, in the eastern and north-western parts of the study area the a, b, and total chlorophyll contents were the highest and reached their minimums in the south-western parts. However, as in the case of the acacia species, in the central parts of the study area the contents of the tree chlorophylls were low to medium. Conclusion: The results of this study show that the a, b and total leaf chlorophyll contents of the two acacia and plantain species were higher in the polluted areas as compared to those in clean areas. On this basis, it can be said that a higher physiological index, such as an increased chlorophyll content, indicates the plant's response for resistance to air pollutants. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of salinity stress and foliar application of silica on Camelina sativa oil plant, a factorial study was carried out in the growth chamber of the laboratory of the Department of Biology, Behbahan Khatam Alanbia University of Technology, in 3 replications based on a completely randomized block design. Treatments included salinity stress at two levels (0 and 100 mM NaCl) and potassium silicate solution at two levels (0 and 5 mM). The physiological and biochemical traits of Camelina sativa under salinity stress were evaluated along with the role of osmotic substances such as soluble sugar and soluble protein in reducing the harmful effects of salinity stress. Results showed that salinity stress significantly reduced the amount of chlorophyll a, b, and total in Camelina sativa, while silica treatment significantly reduced the harmful effects of salinity. Soluble sugar content of leaves in response to salinity stress was 46% lower than in the control plant. Salinity stress combined with silica increased the amount of soluble sugar 27% more than the control plant. Results also showed that in the treatment with silica under 100 mM salinity level, the amount of leaf proteins was almost 10% less than the control plants. The results of measuring the plant’s antioxidant capacity of FRAP showed that in response to silica treatment without salinity, no significant difference was observed in the amount of antioxidant capacity of FRAP, while in the combined treatment of salinity stress + silica it decreased by 9% compared with the control plants. The results of this study supports the beneficial role of silica as an environmentally friendly compound to increase plant resistance to salinity stress. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum Mill.) is one of the widely cultured vegetables under protected cultivation, in which insufficient light is one of the major factors that limit its growth, yield, and quality. Chlorophyll b (Chl b) is exclusively present in the light-harvesting complex (LHC) of photosystems, while its synthesis is strictly regulated in response to light conditions in order to control the antenna size. Chlorophyllide a oxygenase (CAO) is the sole enzyme that converts Chl a to Chl b for Chl b biosynthesis. Previous studies have shown that overexpressing CAO without the regulating domain (A domain) in Arabidopsis overproduced Chl b. However, the growth characteristics of the Chl b overproduced plants under different light environmental conditions are not well studied. Considering tomatoes are light-loving plants and sensitive to low light stress, this study aimed to uncover the growth character of tomatoes with enhanced production of Chl b. The A domain deleted Arabidopsis CAO fused with the FLAG tag (BCF) was overexpressed in tomatoes. The BCF overexpressed plants accumulated a significantly higher Chl b content, resulting in a significantly lower Chl a/b ratio than WT. Additionally, BCF plants possessed a lower maximal photochemical efficiency of photosystem II (Fv/Fm) and anthocyanin content than WT plants. The growth rate of BCF plants was significantly faster than WT plants under low-light (LL) conditions with light intensity at 50–70 µmol photons m−2 s−1, while BCF plants grew slower than WT plants under high-light (HL) conditions. Our results revealed that Chl b overproduced tomato plants could better adapt to LL conditions by absorbing more light for photosynthesis but adapt poorly to excess light conditions by accumulating more ROS and fewer anthocyanins. Enhanced production of Chl b is able to improve the growth rate of tomatoes that are grown under LL conditions, indicating the prospect of employing Chl b overproduced light-loving crops and ornamental plants for protected or indoor cultivation. [ABSTRACT FROM AUTHOR]

Detecting the contents of chlorophyll (chlorophyll a, chlorophyll b) is important to instruct vegetable growth. However, the traditional spectrophotometry used in measuring these contents requires expensive equipment, is destructive, time-consuming, toxic (acetone), and unable to measure in situ. To make the detection nondestructive, quick, cheap, safe, and on-site, a low-cost micro-pocket photosynthetic chlorophyll content meter was developed in this study. The meter consisted of a micro-controller of STC12C5A60S2, three light-emitting diodes at 460, 660, and 980 nm, a digital light sensor, three keys, one organic light-emitting diode display, and a power supply unit. The software was developed by using the C language. The leaves of leaf lettuce, garden sass, and spinach were used as samples. The models used to predict the contents of chlorophyll a, chlorophyll b, and total chlorophyll, as well as SPAD values, were established based on the absorbance of vegetable leaves at three wavelengths by using the multiple linear regression method. The root-mean-squares errors of the developed meter for chlorophyll a, chlorophyll b, total chlorophyll, and SPAD value were 0.068 mg/g, 0.024 mg/g, 0.085 mg/g, and 1.7, respectively. The meter was small in size and low in cost. The contents of chlorophyll a, chlorophyll b, total chlorophyll, and SPAD value, could be given in 2 s. [ABSTRACT FROM AUTHOR]

The general objective is the study of the photosynthesis process in corn plants, the necessary basis for the great adaptation capacity of plants to climate changes. These studies are important because they participate in the identification of solutions involved in increasing corn production and its quality. The experience was organized at the farm "Vasile Adamachi" within the USV Iasi, in the spring of 2021 and the analyzes on the collected physiological material were carried out in the plant physiology laboratory of the USV Iasi. The research material was represented by the hybrid DKC 4598 produced by the Bayer Group with the FAO 350-390 group. The analysis of the photosynthesis process in maize in the context of the climatic conditions specific to the growing season of 2021 was carried out by quantitatively determining of the content of photosynthetic pigments and chlorophyll fluorescence. The results obtained by the analyse of the photosynthesis process were correlated with the production obtained. The results obtained from the fluorescence analysis show us that the corn plants studied had the highest light quantification capacity in the 6 and 8 node phenophases. The recorded differences do not show an effort in the ability of the plants to adapt to the weather conditions of 2021 in North-Eastern Moldova. [ABSTRACT FROM AUTHOR]

Alterations of chloroplast membrane lipids might serve as indicators of eco-physiologically induced and plant nutrition-induced changes during plant growth. The change in the degree of fatty acid saturation in the membranes is in particular a strategy of plants to adapt to abiotic stress conditions. Green multi-leaf lettuce plants (Lactuca sativa L.) were subjected to three different sulfur (S) levels. Sulfoquinovosyl diacylglycerol derivatives (SQDG) might be affected by S nutrition. Therefore, the present study was conducted to investigate the impact of S fertilization on the content and composition of individual SQDG. In addition to a change in the SQDG composition, a general change in the total lipid composition of the chloroplast membrane was observed. A significant increase in total SQDG content and doubling of the galactolipid content and significant alterations of individual SQDG were observed at elevated levels of S fertilization. High levels of S supply demonstrated a clear trend of increasing total chloroplast lipid content and concentrations of linolenic acid, in addition to a further decline in palmitic acid. The study opens perspectives on S supply and its crucial role in the build-up of photosynthetic apparatus. Moreover, it emphasizes the role of S-containing compounds, including sulfolipids, in modulating physiological adjustment mechanisms to improve tolerance ability to various abiotic stresses in plants and, consequently, plant food quality. [ABSTRACT FROM AUTHOR]

Watermelon possesses diverse ovary, fruit, and seed morphological traits and the successful identification of QTLs/genes controlling these traits are of great significance to breeders. Whole-genome re-sequencing using next-generation sequencing technology was employed to detect SNPs in the parental lines P1 (ZXG1553) and P2 (W1-17), for CAPS marker and linkage map development. The linkage map was developed by genotyping of 138 polymorphic CAPS markers with 191-F2 mapping population that covered all 11 chromosomes with a total length of 1853.34 cM. A total of thirty QTLs (2 Ovary weight, 2 Ovary length, 3 Ovary width, 4 Ovary hairiness, 2 Fruit weight, 1 Fruit length, 1 Fruit width, 1 Brix, 1 Rind thickness, 1 Seed length, 2 Seed width, 4 Rind chlorophyll a, 3 Rind chlorophyll b, and 3 Rind total chlorophyll) were detected for 14 significant ovary, fruit, and seed morphological traits. The QTLs exhibited different LOD score range (2.50 ~ 20.97) and phenotypic explained variance (3.30 ~ 25.91%) for all morphological traits. These detected QTLs and corresponding flanking CAPS markers could be valuable data to facilitate the further investigation in watermelon breeding programs and in-depth genetic basis studies. [ABSTRACT FROM AUTHOR]

Contextualization: The areas planted with stevia have been growing significantly in response to the new trends in consumption of low-calorie and natural foods. The effects of high radiation levels, due to global climate change, have evidenced the need to development new studies about the physiological behavior of the photosynthetic pigments of agricultural species. Knowledge gap: The lack of knowledge of the behavior of stevia crops in the context of current and future environmental changes (mainly, the increases in solar radiation levels) means that farmers and producers do not obtain the expected yields. Purpose: The objective of this study was analyze the effect of different levels of solar radiation and nitrogen fertilization, under greenhouse conditions, on the production of photosynthetic pigment in Stevia rebaudiana Bert. Methodology: The trial was done using as completely randomized design (CRD), employing a 2 x 6 factorial arrangement and 16 replicates per treatment; factor A corresponded to two levels of incident solar radiation (300 and 1.500 pmol photons, m-2 s-1 corresponding to 20% and 100% radiation respectively) and factor B corresponded to six doses of nitrogen (0, 60, 120, 180, 240 and 300 kg ha-1). Chlorophyll a, b, and total chlorophyll content was evaluated in young and healthy leaves eight months after transplanting. Results and conclusions: The results showed that the contents of chlorophyll a, b and total were significantly affected by solar radiation, but not by the nitrogen supplied. In both radiation environments, the contents of chlorophyll a were higher than the contents of chlorophyll b in all plants evaluated. In the environment of lower solar radiation (300 pmol of photons m-2 s-1), the maximum levels of the photosynthetic pigments were presented. In the environment of 1.500 pmol of photons. m-2 s-1, the contents of chlorophyll a, b and total were lower in control plants (0 kg ha-1). [ABSTRACT FROM AUTHOR]

The SPAD-502 meter is a portable tool that is extensively used for the rapid, accurate and nondestructive measurement of leaf chlorophyll concentrations. Measurements with the SPAD-502 meter produce relative SPAD meter values that are proportional to the amount of chlorophyll present in the leaf. In order to convert these values into absolute units of chlorophyll concentration, calibration curves must be derived and utilized. Here, we present calibration equations for rice that can be used to convert SPAD values into total chlorophyll per unit leaf area (mg cm-2; y = 0.178x - 3.531) or per unit fresh weight of leaf tissue (3.53 mg g-1). These relationships were derived using leaf analysis of two rice genotypes (cv. 'Manaswinee' and cv. 'Hasanta') raised with three nutrient management practices (100% Soil Test Based Nitrogen Recommendation (STBNR), 75% STBNR + in situ green manuring (GM) of dhaincha and 50% STBNR+ in situ green manuring of dhaincha) under puddled transplanting condition during Kharif seasons of 2018 and 2019 at Agronomy Main Research Farm, OUAT, Bhubaneswar, Odisha, India. Chlorophyll concentrations were determined at active tillering, heading and physiological maturity stages. Our results revealed that the converted SPAD values differed from photometric measurements of solvent-extracted chlorophyll by regression coefficient (r) values ranging from 0.711 to 0.862 and the relationship was linear using different models. Application of 75% Soil Test Based Nitrogen Recommendation (75 kg N ha-1) with green manuring of dhaincha in rice showed the maximum linear regression coefficient (r=0.862) in rice genotype 'Hasanta' at the heading stage. [ABSTRACT FROM AUTHOR]

To study the changes in the contents of chlorophyll a and chlorophyll b in cabbage waste during anaerobic digestion, two types of leafy cabbage waste were treated by fermentation, and the relationship between the degradation of chlorophyll a and chlorophyll b in cabbage waste and gas production potential during anaerobic digestion was analyzed using an anaerobic batch fermentation unit maintained at a constant temperature of (35 ± 1) °C. The results showed that, following anaerobic digestion, the gas production rates of common cabbage, Chinese cabbage, and mixed cabbage were 36 mL/g, 33 mL/g, and 27 mL/g, respectively. The total solids (TS) gas production rates were 838 mL/g, 774 mL/g, and 549 mL/g, respectively, whereas the volatile solids (VS) gas production rates were 1061 mL/g, 1134 mL/g, and 636 mL/g. During the biogas fermentation process, the content of chlorophyll a in each type of cabbage waste was consistently higher than that of chlorophyll b. Moreover, chlorophyll degradation correlated with daily gas production. Among the cabbage waste types analyzed, mixed cabbage had the highest chlorophyll a and chlorophyll b degradation rates of 81.71% and 99.08%, respectively, compared to that of common cabbage or Chinese cabbage alone. These findings extend the current knowledge on anaerobic fermentation treatment of cabbage waste. [ABSTRACT FROM AUTHOR]

Cold is an environmental factor limiting the growth and yield of agricultural crops. To find cold-tolerant pistachio rootstocks, a factorial experiment was conducted at Pistachio Research Center (PRC), Rafsanjan, Iran during 2017-2018. The factors included six rootstocks (Badami Zarand, Ghazvini, Sarakhs, Integerrima × Badami Zarand, Integerrima × Ghazvini and Integerrima × Sarakhs) and four thermal treatments (4, 0, -2, and -4°C) with three iterations. Seedlings in 6-8 leaf stage were placed in thermal treatments for two hours. Ionic leakage, pH of leaked solution, chlorophyll fluorescence, photosynthesis efficiency index, chlorophyll (a, b, total) and carotenoid contents were the traits assessed in this study. Based on the results, a decrease in temperature made an increase in ionic leakage rate, conversely making decreases in pH of the leaked solution, photosynthetic pigments contents, Fv/Fm and PI index. In addition, the highest photosynthetic pigments, pH of leaked solution, Fv/Fm and PI index were observed in Ghazvini and Integerrima × Ghazvini rootstocks. Meanwhile, the highest ionic leakage was observed in Integerrima × Badami Zarand. In aggregate, Ghazvini and Integerrima × Ghazvini were identified as the most cold-tolerant rootstocks, while Integerrima × Badami Zarand was the most cold-sensitive rootstock.

Abstract Background Chlorophylls play important roles in photosynthesis, and thus are critical for growth and related metabolic pathways in photosynthetic organisms. They are particularly important in microalgae, emerging as the next generation feedstock for biomass and biofuels. Nannochloropsis are industrial microalgae for these purposes, but are peculiar in that they lack accessory chlorophylls. In addition, the localization of heterologous proteins to the chloroplast of Nannochloropsis has not been fully studied, due to the secondary plastid surrounded by four membranes. This study addressed questions of correct localization and functional benefits of heterologous expression of chlorophyllide a oxygenase from Chlamydomonas (CrCAO) in Nannochloropsis. Results We cloned CrCAO from Chlamydomonas, which catalyzes oxidation of Chla producing Chlb, and overexpressed it in N. salina to reveal effects of the heterologous Chlb for photosynthesis, growth, and lipid production. For correct localization of CrCAO into the secondary plastid in N. salina, we added the signal-recognition sequence and the transit peptide (cloned from an endogenous chloroplast-localized protein) to the N terminus of CrCAO. We obtained two transformants that expressed CrCAO and produced Chlb. They showed improved growth under medium light (90 μmol/m2/s) conditions, and their photosynthetic efficiency was increased compared to WT. They also showed increased expression of certain photosynthetic proteins, accompanied by an increased maximum electron-transfer rate up to 15.8% and quantum yields up to 17%, likely supporting the faster growth. This improved growth resulted in increased biomass production, and more importantly lipid productivity particularly with medium light. Conclusions We demonstrated beneficial effects of heterologous expression of CrCAO in Chlb-less organism N. salina, where the newly produced Chlb enhanced photosynthesis and growth. Accordingly, transformants showed improved production of biomass and lipids, important traits of microalgae from the industrial perspectives. Our transformants are the first Nannochloropsis cells that produced Chlb in the whole evolutionary path. We also succeeded in delivering a heterologous protein into the secondary plastid for the first time in Nannochloropsis. Taken together, our data showed that manipulation of photosynthetic pigments, including Chlb, can be employed in genetic improvements of microalgae for production of biofuels and other biomaterials.

In mature leaves, cell-to-cell transport via plasmodesmata between mesophyll cells links the production of assimilates by photosynthesis with their export to sink organs. This study addresses the question of how signals derived from chloroplasts and photosynthesis influence plasmodesmata permeability. Cell-to-cell transport was analyzed in leaves of the Arabidopsis chlorophyll b -less ch1-3 mutant, the same mutant complemented with a cyanobacterial CAO gene (PhCAO) overaccumulating chlorophyll b , the trxm3 mutant lacking plastidial thioredoxin m3, and the ntrc mutant lacking functional NADPH:thioredoxin reductase C. The regulation of plasmodesmata permeability in these lines could not be traced back to the reduction state of the thioredoxin system or the types and levels of reactive oxygen species produced in chloroplasts; however, it could be related to chloroplast ATP and NADPH production. The results suggest that light enables plasmodesmata closure via an increase in the ATP and NADPH levels produced in photosynthesis, providing a control mechanism for assimilate export based on the rate of photosynthate production in the Calvin–Benson cycle. The level of chlorophyll b influences plasmodesmata permeability via as-yet-unidentified signals. The data also suggest a role of thioredoxin m3 in the regulation of cyclic electron flow around photosystem I. [ABSTRACT FROM AUTHOR]

The 'Regulation of Photosynthesis' session was one of the largest events of the Congress, with 17 talks and 9 poster presentations. It covered many topics on the cutting edge of modern photosynthesis research: from the electron transport within the cytochrome b6f-complex to the novel role of carbonic anhydrase in the regulation of pH within the thylakoid lumen, the expanding role of retrograde signaling in all aspects of plant life including the regulation of cell-to-cell traffic via plasmodesmata, and the development of new non-invasive techniques to measure photosynthetic response. Here, a short survey of the presented reports is given. [ABSTRACT FROM AUTHOR]

Chlorophylls function in photosynthesis, and are critical to plant developmental processes and responses to environmental stimuli. Chlorophyll b is synthesized from chlorophyll a by chlorophyll a oxygenase (CAO). Here, we characterize a yellow-green leaf (ygl) mutant and identify the causal gene which encodes a chlorophyll a oxygenase in maize (ZmCAO1). A 51 bp Popin transposon insertion in ZmCAO1 strongly disrupts its transcription. Low enzyme activity of ZmCAO1 leads to reduced concentrations of chlorophyll a and chlorophyll b, resulting in the yellow-green leaf phenotype of the ygl mutant. The net photosynthetic rate, stomatal conductance, and transpiration rate are decreased in the ygl mutant, while concentrations of δ-aminolevulinic acid (ALA), porphobilinogen (PBG) and protochlorophyllide (Pchlide) are increased. In addition, a ZmCAO1 mutation results in down-regulation of key photosynthetic genes, limits photosynthetic assimilation, and reduces plant height, ear size, kernel weight, and grain yield. Furthermore, the zmcao1 mutant shows enhanced reactive oxygen species production leading to sensitivity to waterlogging. These results demonstrate the pleiotropy of ZmCAO1 function in photosynthesis, grain yield, and waterlogging tolerance in maize. [ABSTRACT FROM AUTHOR]

We prepared composite electrodes using TiO 2 coated with chlorophylls a and b as photoelectric conversion material and MnO 2 as energy storage material and investigated their photoelectrochemical capacitor properties. The coating with the combination of chlorophylls a and b improved the photoelectric conversion function of TiO 2 , compared with the coating with each alone. Na + adsorption on MnO 2 was enhanced with increasing the chlorophyll coating amount. The reason is that more chlorophylls a and b absorb visible light in different wavelengths to promote an easier photoexcited electron transfer to MnO 2 , just as they improve the efficiency of photosynthesis reactions in nature.

Background. The main share in the landscaping of the city of Yoshkar-Ola is made up of such deciduous woody and shrub plantings such as Betula pendula Roth., Tilia cordata Mill., Syringa vulgaris L., Acer negundo L., Populus pyramidalis Salisb., etc. Coniferous plants are not so usually used as often as deciduous plants in landscaping urban areas. However, most of them belong to the group of evergreens and play the role of green spaces all year round. In score of the high sensitivity to gaseous pollutants in cities, the problem arises using of it in urban landscaping. But such species of introduced conifers as Picea pungens Engelm., Thuja occidentalis L., Juniperus sabina L. are notable for their significant resistance to technogenic pollution. Materials and methods. The studies were conducted during 2018 in three different zones of Yoshkar-Ola which differ with degrees of anthropogenic load (recreational, residential, industrial). The objects of the study were Picea pungens Engelm., Thuja occidentalis L., Juniperus sabina L. The content of photosynthetic pigments (chlorophyll a and b, carotenoids) was studied in the needles of the second year of life in seasonal dynamics (May, July, October, December). Results. The study found that with an increasing of anthropogenic load, the quantitative content of photosynthetic pigments decreased in the needles of introduced plant species. Needle Picea pungens Engelm. was characterized by the highest content of the studied types of pigments. Conclusions. The obtained data expand the idea of the pigment composition of conifers growing in urban environment. The quantitative content of photosynthetic pigments depends on the species, season of the year and place were, it grows.

One of the major constraints limiting biomass production in autotrophs is the low thermodynamic efficiency of photosynthesis, ranging from 1 to 4%. Given the absorption spectrum of photosynthetic pigments and the spectral distribution of sunlight, photosynthetic efficiencies as high as 11% are possible. It is well-recognized that the greatest thermodynamic inefficiencies in photosynthesis are associated with light absorption and conversion of excited states into chemical energy. This is due to the fact that photosynthesis light saturates at one quarter full sunlight intensity in plants resulting in the dissipation of excess energy as heat, fluorescence and through the production of damaging reactive oxygen species. Recently, it has been demonstrated that it is possible to adjust the size of the light harvesting antenna over a broad range of optical cross sections through targeted reductions in chlorophyll b content, selectively resulting in reductions of the peripheral light harvesting antenna size, especially in the content of Lhcb3 and Lhcb6. We have examined the impact of alterations in light harvesting antenna size on the amplitude of photoprotective activity and the evolutionary fitness or seed production in Camelina grown at super-saturating and sub-saturating light intensities to gain an understanding of the driving forces that lead to the selection for light harvesting antenna sizes best fit for a range of light intensities. We demonstrate that plants having light harvesting antenna sizes engineered for the greatest photosynthetic efficiency also have the greatest capacity to mitigate high light stress through non-photochemical quenching and reduction of reactive oxygen associated damage. Under sub-saturating growth light intensities, we demonstrate that the optimal light harvesting antenna size for photosynthesis and seed production is larger than that for plants grown at super-saturating light intensities and is more similar to the antenna size of wild-type plants. These results suggest that the light harvesting antenna size of plants is designed to maximize fitness under low light conditions such as occurs in shaded environments and in light competition with other plants.

Chlorophylls a and b, phenolic compounds, carotenoids in total antioxidants from the leaves of eleven varieties of orange and purple sweet potatoes were assessed by spectrophotometry. Using the ABTS method, BF59XCIP1 (43.450 mg ET/g) has the highest antioxidant content ahead of BF59XCIP4, TUSKEGEE-POURPRE CAP VERT and TIB17 (40.969 mg ET/g) and TUSKEGEE-POURPRE (38.161 mg ET/g). The leaves of MOTHER DELIGHT, accumulate much more phenolic compounds (27.37 mg EAG/g) than TIB21 and TIB29 which have an average content of 24.78 mg EAG/g. The lowest levels are observed in TUSKEGEE-POURPRE, BF59XCIP1, TUSKEGEE-POURPRE CAP VERT with an average content of 14.94 mg EAG/g and TUSKEGEE-ORANGE (19.104 mg EAG/g). For Chl b, the extraction solvent accounts for 81.23% of the significant differences observed. Methanol is the best extraction solvent for Chl a (71.93g/100g) and Chl b (56.98g/100g) ahead of the acetone-water system (Chl a 60.81g/100g; Chl b 29.71g/100g). For carotenoids, the extraction solvent (72.5%) has a strong influence in favour of the acetone-water system, which can extract 11,967 g of total carotenoids in 100 g of leaves. [ABSTRACT FROM AUTHOR]

Chlorophyll b was extracted from Heliotropium europaeum plant, then immobilized on magnetic nanoparticles (Fe3O4@SiO2@Chl‐Mg) and found as an efficient and green catalyst for the preparation of a variety of benzimidazoles and spirooxindoles in mild conditions. The catalyst was fully characterized by Fourier‐transform infrared (FTIR), ultraviolet–visible (UV–vis) spectroscopy, X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDX), thermogravimetric (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) analyses. To prove the catalytic influence of Mg over the reactions, the catalytic activity of the demetalated chlorophyll b as well as some other control experiments was investigated. High to excellent yields were achieved for all entries, whether benzimidazole or spirooxindole derivatives at short reaction times. The catalyst could be recovered and reused for several consecutive runs by a simple external magnetic field without any considerable reactivity loss. The properties of the recovered catalyst were investigated by various analyses. Finally, the reasonable mechanisms were proposed for the reactions based on the literature. [ABSTRACT FROM AUTHOR]

Water availability in soil modulates plant acclimatisation responses in different habitats. In this study, we evaluated the effect of water deficit on the physiological, biochemical and growth responses of Vachellia farnesiana. Open environment experiment was conducted during 90 days and two conditions of hydration were tested: full hydration (H) and water deficit (WD) at 25% of field capacity. The relative water content (RWC) of the leaves under WD showed a 30.2% decrease (P < 0.01), compared with the hydrated plants at 30 days. A decrease in the RWC led to decrease in the osmotic potential (Ψs), quantum yield of PSII (F v/ F m) and lesser content of chlorophylls a and b under WD. A greater carotenoid content and simultaneous increase in the content of proline, H2O2 and phenolic compounds of the leaves was also observed in WD. Water deficit also promoted differences in the nitrogen, phosphorus, and potassium content of the leaves when compared with hydrated plants. Although they showed growth deficit, plants of V. farnesiana demonstrated resistance to WD through physiological and biochemical adjustments. Plants live in constantly changing environments that are often unfavourable or stressful for growth and development. The drought causes water deficit in plants and affects water relations, membrane integrity, pigment content, and photosynthesis. Our hypothesis is that Vachellia farnesiana plants show tolerance to drought due to the mechanisms of protection of the photosynthetic apparatus, osmotic adjustment and reduction of oxidative damages. [ABSTRACT FROM AUTHOR]

The physiological and biochemical parameters and elemental composition of Hypogymnia physodes lichen samples from various phytocenoses differing in lighting conditions and atmospheric humidity were studied. A significant increase in the chlorophyll a and nitrogen contents, the maximal pheophytinization coefficient, and the minimum content of phenolic compounds were observed in H. physodes thalli under severe shading conditions in a spruce forest. Most of these biochemical parameters reached their minimum values with high insolation in birch and pine forests except for the content of phenolic compounds, which reached the maximum value. ICP–AES analysis of H. physodes thalli detected 20 elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Pb, Sn, Sr, Tl, V, W, Zn) that were found in lichen samples from all studied natural phytocenoses except for Mo, which was absent in samples from a black alder forest. The maximum concentrations for almost half of the elements (Al, B, Fe, K, Mo, Na, Sn, Ti, V) were determined in samples from the spruce forest where the thalli were more often and consistently hydrated because of the high and more stable humidity level. A complex system of correlation relationships was established based on an analysis of cross-correlations of the physiological and biochemical parameters and the metal concentrations in the samples. The results indicated a high coordination of various physiological processes. Chlorophyll a played a crucial role in maintaining their consistency with changing environmental conditions. Its content was associated with a more significant number of different parameters and elemental concentrations. [ABSTRACT FROM AUTHOR]

One of the major constraints limiting biomass production in autotrophs is the low thermodynamic efficiency of photosynthesis, ranging from 1 to 4%. Given the absorption spectrum of photosynthetic pigments and the spectral distribution of sunlight, photosynthetic efficiencies as high as 11% are possible. It is well-recognized that the greatest thermodynamic inefficiencies in photosynthesis are associated with light absorption and conversion of excited states into chemical energy. This is due to the fact that photosynthesis light saturates at one quarter full sunlight intensity in plants resulting in the dissipation of excess energy as heat, fluorescence and through the production of damaging reactive oxygen species. Recently, it has been demonstrated that it is possible to adjust the size of the light harvesting antenna over a broad range of optical cross sections through targeted reductions in chlorophyll b content, selectively resulting in reductions of the peripheral light harvesting antenna size, especially in the content of Lhcb3 and Lhcb6. We have examined the impact of alterations in light harvesting antenna size on the amplitude of photoprotective activity and the evolutionary fitness or seed production in Camelina grown at super-saturating and sub-saturating light intensities to gain an understanding of the driving forces that lead to the selection for light harvesting antenna sizes best fit for a range of light intensities. We demonstrate that plants having light harvesting antenna sizes engineered for the greatest photosynthetic efficiency also have the greatest capacity to mitigate high light stress through non-photochemical quenching and reduction of reactive oxygen associated damage. Under sub-saturating growth light intensities, we demonstrate that the optimal light harvesting antenna size for photosynthesis and seed production is larger than that for plants grown at super-saturating light intensities and is more similar to the antenna size of wild-type plants. These results suggest that the light harvesting antenna size of plants is designed to maximize fitness under low light conditions such as occurs in shaded environments and in light competition with other plants. [ABSTRACT FROM AUTHOR]

The role of α-carbonic anhydrase 4 (α-CA4) in photosynthetic machinery functioning in thylakoid membranes was studied, using Arabidopsis thaliana wild type plants (WT) and the plants with knockout of At4g20990 gene encoding α-CA4 (αCA4-mut) grown both in low light (LL, 80 μmol quanta m−2 s−1) or in high light (HL, 400 μmol quanta m−2 s−1). It was found that a content of PsbS protein, one of determinants of non-photochemical quenching of chlorophyll fluorescence, increased in mutants by 30% and 100% compared with WT plants in LL and in HL, respectively. Violaxanthin cycle pigments content and violaxanthin deepoxidase activity in HL were also higher in αCA4-mut than in WT plants. The content of PSII core protein, D1, when adapting to HL, decreased in WT plants and remained unchanged in mutants. This indicates, that the decrease in the content of Lhcb1 and Lhcb2 proteins in HL (Rudenko et al. Protoplasma 55(1):69-78, 2018) in WT plants resulted from decrease of both Photosystem II (PSII) complex content and content of these proteins in this complex, whereas in αCA4-mut plants from the latter process only. The absence of α-CA4 did not affect the rate of electron transport through Photosystem I (PSI) in thylakoids of mutant vs. WT, but led to 50–80% increase in the rate of electron transport from H2O to QA, evidencing the location of α-CA4 close to PSII. The latter difference may raise the question about its causal connection with the difference in the D1 protein content change during adapting to increased illumination in the presence and the absence of α-CA4. [ABSTRACT FROM AUTHOR]

Originating in the subtropics, cucumbers require warm weather and plenty of light, low light inhibits the growth of cucumbers. For cucumbers to efficiently absorb light energy in low light, chlorophyll synthesis is necessary. Oxygenase for chlorophyllate is encoded by CsCAO. RNA interference (RNAi) was used to reduce CsCAO expression in cucumber, reduced chlorophyll b content and Fv/Fm (maximal photochemical efficiency of photosystem II) were found in RNAi- CsCAO lines. The Arabidopsis Atcao mutant lacks chlorophyll b and has a low Fv/Fm, but overexpressing CsCAO restored the mutant's phenotype. CsCAO gene expression was found to be upregulated in the presence of low light. The Y1H screening assay revealed that CsHsfA6b and CsBLH4 were potential CsCAO expression regulators. The results of the Y1H, LUC/REN, and EMSA assays confirmed that only CsBLH4 can bind to the CsCAO promoter. Furthermore, like Atcao , the Atblh4 mutant had low chlorophyll b content and Fv/Fm. CsCAO overexpression in the Atblh4 mutant increased the content of chlorophyll b and Fv/Fm, especially under low light conditions. CsBLH4 targeting CsCAO was found to positively regulate chlorophyll b synthesis and photosynthetic capacity in cucumber under low light conditions in our study. • Low light promoted the accumulation of chlorophyll b by up-regulating the transcription level of CsCAO. • It clarified the regulatory mechanism of BLH family member involved in chlorophyll b synthesis. • The synthesis of chlorophyll plays an important role in the response of cucumber to low light stress. [ABSTRACT FROM AUTHOR]

Drought seriously reduces the quality and quantity of agronomic and horticultural plants. In such condition, using factors to reduce these effects on plants is indispensible. To evaluate the effect of water stress and different levels of ascorbic acid on the leaf relative water content, pigments, canopy temprature and dry matter of cress (Lepidium sativum L.) a split plot experiment based on randomized complete block design with three replications at the Agricultural Research Station of Zahak was conducted in 2014 where three irrigation levels (at 100, 80 and 60 percent of field capacity) assigned to the main plots and three levels of ascorbic acid (0, 5 and 10 micromolar) to the sub-plots. The results showed that the effect of irrigation regimes, ascorbic acid and their interaction was significant on the traits under evaluation. Irrigation based on 60% of field capacity as compared with that of 100% F.C. reduced relative water content, chlorophyll a and b, carotenoids and dry matter weight by 20.89, 0.06, 0,034, 0.04 and 57.8 percent respectively and a 20% increase in canopy temperature, while applying of 10 micromolar ascorbic acid relative to control increased 12.22, 0.075, 0.15, 0.05 and 57.8 percent on traits mentioned above respectively and a 3% decrease in canopy temperature. Regression model revealed that application of ascorbic acid at irrigation in 100% field capacity was not effective on these traits, except on chlorophyll b and carotenoids contents, but in irrigation at 60 and 80% percent field capacities, increased amount of relative water content, chlorophyll a, chlorophyll b, carotenoids and dry matter. Although ascorbic acid could not reduce the negative impacts of 20% decrease in irrigation but application of 10 micromolar ascorbic acid in 60% and 80% irrigation at field capacities increased dry matter significantly, as compared to that of ascorbic acid under these conditions.

The objective of this research was to investigate the effect of salt (NaCl) and acetate (NaC2H3O2) stresses on the pattern of biomass accumulation and photosynthetic pigments content in algae culture of the freshwater green alga Acutodesmus dimorphus (Turpin) P.M. Tsarenko IBASU-A 251. We demonstrated that sodium chloride introduced in a culture medium at various concentrations caused a gradual reduction of the microalga biomass whose maximum was recorded at the salt concentration of 1.5%. Addition of sodium acetate at the same concentrations led, on the contrary, to a sharp (more than two times) decrease of A. dimorphus biomass. On the 18th day of culturing under salt stress conditions the chlorophyll a content decreased 1.5-2.5 times, the chlorophyll b content – 1.3-1.7 times, while the carotenoids quantity increased 1.2-1.6 times. Under acetate stress conditions the chlorophyll a content decreased 2-3 times, that of chlorophyll b – 1.7 – 1.8 times whereas the carotenoids quantity increased within the range of 1.4-1.8 times. Increase in chemical stressors concentrations involved some reduction of the chlorophylls а/b ratio and total chlorophylls а+b content, and at the same time, the ratio carotenoids/a+b increased. Sodium acetate appeared to be a more powerful inducer of carotinogenesis than sodium chloride. The highest quantity of carotenoids was registered at 1% and 1.5% concentrations of NaC2H3O2 in the culture medium and 0.75% concentration of NaCl. The results obtained enable to regard Acutodesmus dimorphus (Turpin) P.M. Tsarenko IBASU-A 251 as an active carotenoids producer to be later applied in studies of hypersynthesis of individual classes of this pigment.

The pistachio (Pistacia vera L.), a small nut tree belonging to the Anacardiaceae family, is extensively grown in Turkey, which is one of the leading world producers of pistachios. Kernel color is an important parameter for the evaluation of raw pistachios containing chlorophylls a and b as the major pigments. Moreover, kernel color is one of the most important quality attributes evaluated by consumers, producers and distributors. Chlorophylls a and b are the predominant pigments responsible for the green color of pistachios. Pigment concentrations are influenced by a number of factors such as geographic origin, ripeness degree, storage conditions and processing methods. Chlorophylls are sensitive to heat and can be degraded into pheophytins and pyropheophytins. Therefore, the purpose of this paper is to determine the chlorophyll content of the 'Uzun' pistachio cultivar (Pistacia vera L.) using the spectrophotometric methods and different solvents.

In order to investigate the physiological responses of chickpea cultivars to supplemental irrigation and super-absorbent polymer use, an experiment has been conducted in the water year 2015, which has employed a split factorial experiment based on randomized complete block design in the research farm of Khorramabad Agricultural Research Center. The factors include supplemental irrigation time in three levels (without supplemental irrigation, irrigation in 50% of flowering, and irrigation in 50% of seed filling) as main factor and cultivars (Arman, Azad, and Greet) and super absorbent polymer (zero, 100, and 200 kg/ha) in the sub plots. Result show that the supplemental irrigation and super absorbent polymer reduce soluble carbohydrates and seed protein, increasing insoluble carbohydrates, chlorophyll a, chlorophyll b, and total chlorophyll. Supplemental irrigation at 50% of flowering stage leads to an increase in 74% of seed yield, compared to dry land condition. The highest seed yield (2179 kg/ha), biological yield (4012 kg/ha), and harvest index (54.3%) belong to Greet cultivar with supplemental irrigation at 50% of flowering stage as well as application of 200 kg/ha super absorbent polymer. According to the results, in all levels of supplemental irrigation, the use of superabsorbent polymer improves plant growth conditions, consequently increasing the seed yield to a great extent, which in turn rises further by increasing the consumption of super absorbent polymer within supplementary irrigation. By improving physiological traits, associated with drought tolerance, the use of supplemental irrigation method in areas that make this possible, especially if combined with the application of super absorbent polymers, can increase seed yield in chickpea. [ABSTRACT FROM AUTHOR]

Main conclusion: Chloroplasts deficient in the major chloroplast nucleoid-associated protein WHIRLY1 have an enhanced ratio of LHCs to reaction centers, indicating that WHIRLY1 is required for a coordinate assembly of the photosynthetic apparatus during chloroplast development. Chloroplast development was found to be delayed in barley plants with an RNAi-mediated knockdown of WHIRLY1 encoding a major nucleoid-associated protein of chloroplasts. The plastids of WHIRLY1 deficient plants had a reduced ribosome content. Accordingly, plastid-encoded proteins of the photosynthetic apparatus showed delayed accumulation during chloroplast development coinciding with a delayed increase in photosystem II efficiency measured by chlorophyll fluorescence. In contrast, light harvesting complex proteins being encoded in the nucleus had a high abundance as in the wild type. The unbalanced assembly of the proteins of the photosynthetic apparatus in WHIRLY1-deficient plants coincided with the enhanced contents of chlorophyll b and xanthophylls. The lack of coordination was most obvious at the early stages of development. Overaccumulation of LHC proteins in comparison to reaction center proteins at the early stages of chloroplast development did not correlate with enhanced expression levels of the corresponding genes in the nucleus. This work revealed that WHIRLY1 does not influence LHC abundance at the transcriptional level. Rather, WHIRLY1 in association with nucleoids might play a structural role for both the assembly of ribosomes and the complexes of the photosynthetic apparatus. [ABSTRACT FROM AUTHOR]

The discovery of valuable metabolites and microalgae containing high lipids has made these organisms economically very important. The aim of this study is to investigate the effects of different nitrogen sources on growth, protein, lipid amount and pigment content of Chlorella vulgaris. The use of ammonium nitrate as a nitrogen source resulted in high concentrations of biomass, protein and lipid while the use of sodium nitrate as a nitrogen source resulted in high concentrations of chlorophyll and astaxanthin. Concentrations of biomass, protein and lipid increased by about 200%, 127.50% and 112.14%, respectively, on day 6 in media where ammonium nitrate was used as a nitrogen source while concentrations of chlorophyll a, chlorophyll b and astaxanthin increased by 45.71%, 192.87% and 118.94%, respectively, on day 6 in media where sodium nitrate was used as a nitrogen source. In conclusion, the amount of lipid and valuable metabolites in Chlorella vulgaris grown in media with appropriate nitrogen sources can be significantly increased. [ABSTRACT FROM AUTHOR]

The chlorophyll cycle is a metabolic pathway in plants and green algae that interconverts chlorophyll a and chlorophyll b. The chlorophyll a-to-b conversion is catalyzed by a Rieske-type oxygenase, chlorophyll(ide) a oxygenase, while the chlorophyll b-to-a conversion is catalyzed in two steps by chlorophyll b reductase (a short-chain dehydrogenase) and 7-hydroxymethyl chlorophyll a reductase (a flavoprotein). The level of chlorophyll(ide) a oxygenase is regulated in a feedback loop by the accumulation of chlorophyll b in plants. In contrast, chlorophyll b reductase levels are regulated by a pool of light-harvesting complexes (LHC) that are energetically uncoupled to the core complexes of photosystems. Experimental evidence suggests that LHC levels in plants are regulated by chlorophyll b biosynthesis. LHC levels, however, appear to be independent of chlorophyll b in green algae. Instead, Prasinophytes, a group of green algae, have a chlorophyllide a oxygenase protein possessing structural alterations that differ dramatically from the rest of the green algae, which appear to boost chlorophyll b biosynthesis in these organisms. Hypothetical scenarios for the evolution of the chlorophyll cycle are presented. [ABSTRACT FROM AUTHOR]

Introduction Increasing world population is facing critically depletion of water resources, which will be along with increasing food demands to cover the human needs all over the world. Therefore, water scarcity is increasingly a major limitation for increased agricultural production and food security in this century. The scarcity of qualified water, has made farmers to consider the water of marginal quality for usage in agriculture. The Water’s molecular structure is affected by a magnetic field, so that a change in the water relations can affect the overall plant growth. One of the approaches that provides higher productivity and quality assurance is using static electromagnetic fields. The use of magnetically treated water for irrigation in agriculture is considered as one of the important environmental clean methods. The water treated in the magnetic field or pass through a magnetic device called magnetized water. The influence of magnetic field on various growth processes of plants such as seed germination, seedling growth, plant growth, yield and the properties of crop quality have been the object of several researches. Salinity is defined as the presence of excessive concentration of soluble salts in the soil or in the irrigation water that suppresses plant growth and eventually yield. Salt stress has been identified as one of the most serious environmental factors limiting the productivity of crop plants. The deleterious effects of salinity on plant growth are associated with 1) low osmotic potential, 2) nutritional imbalance, 3) specific ion effect, or 4) a combination of these factors. In addition, there is evidence that salt stress can induce oxidative stress due to generation of reactive oxygen species. Phaseolus vulgaris is an annual growing to 2 m height and is frost tender. Bean leaves are trifoliate (three-leaved), arranged in an alternate fashion on the stem and have oval or diamond-shaped leaflets. Leaf color can be green. The study was undertaken to evaluate the use of magnetically treated water in improving seed germination and early seedling growth (i.e., radical and plumule growth) of the bean (Phaseolus vulgaris L.) in the presence and absence of salt stress. The work was carried out at the germination stage because germination is known as a key process that allows the seed embryo to grow and evolve into photosynthetic organism, and it is also a critical stage for plant response to salinity. Materials and Methods In order to investigate the influence of magnetized water and salinity on germination characteristics and seedling of bean (Derakhshan variety), an experiment was conducted based on complete randomized design in factorial arrangement with four replications at laboratory of the Agricultural College of Ferdowsi University of Mashhad in 2014. Water types consisted of two levels (magnetized water and tap water) and five salinity levels: 0, 4, 6.5, 8.5 and 9.5 ds/m. The following indices were also measured: Final Germination Percentage (FGP) and Germination Rate (GR) was calculate base on the below equation FGP= (n / N) × 100 where n is the number of seed germination in per day and N is total number of seeds GR= where giis the number of seed germination in every count and di is the number of days till day n th. (Dere and et al., 1998) Chlorophyll concentration was calculated using the following formula Chla (μg/ml) =15.65 A666 - 7.340 A653 Chlb (μg/ml) =27.05 A653 - 11.21 A666 Cx+c=1000A470 – 2.270 Cha – 81.4Chb/227 Traits as length and dry weight of plumule and radical, biomass and seed vigor index were measured too. Data was analyzed using MSTAT-C software and means were compared using Dunkan multiple range test in 5 percent probability. Results and Discussion The results showed that germination percentage, mean germination time, length and dry weight of the plumule and radical, biomass and seed vigor index decreased with increasing salinity, but magnetized water improved them. Magnetic water increased germination by 6% and reduced the mean germination time by 8%. Magnetized water improved biomass and seed vigor by 52 and 24 percent, respectively. Using magnetic water, improved radical length and plumule by 27 and 24 percentage, respectively. The simple effect of magnetized water and salinity caused significant amounts of chlorophyll a and b and carotenoid. Application of magnetic water increased chlorophyll a (12%) in the salinity level of zero compared with non-magnetic. So that magnetized water improved amount of chlorophyll a and increased carotenoid under salinity conditions. Other results showed that plant cells treated with magnetic represent magnetic properties of atoms placed in them and activates them later on. Conclusion Overall, results showed that exposure to magnetic fields and irrigation water with different salinity levels, decreased salinity (NaCl) effects on bean, accelerated germination and seedling growth and had an important role in improving the beans germination rate.

Rye (Secale cereale L.) is one of the most important cereal crops in Eastern and Northern Europe, showing better tolerance to environmental stress factors compared to wheat and triticale. Plant response to the crude oil-polluted soil depends on plant species, oil concentration, time of exposure, etc. The current study is aimed at investigating the growth, oxidative stress and the response of antioxidative system of two rye varieties (Krona and Valdai) cultivated on crude oil-contaminated soils at different concentrations (1.5, 3.0, 6.0, and 12.0%). Inhibition of rye growth was observed at crude oil concentrations of above 3% for above-ground plant parts and of above 1.5% for roots. A decrease in content of chlorophyll a and total chlorophylls in Krona variety was detected at 1.5% oil concentration in soil and in Valdai variety at 3% oil concentration. Compared with the control, the content of malondialdehyde was significantly increased in the Krona variety at 3% oil concentration and in Valdai variety at 6% oil concentration. The crude oil-induced oxidative stress was minimized in rye plants by the enhanced contents of low-molecular antioxidants (proline, non-protein thiols, ascorbic acid, phenolic compounds) and activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. The strongest positive correlation was detected between the content of malondialdehyde and contents of proline (r = 0.89–0.95, p ≤ 0.05) and phenolic compounds (r = 0.90–0.94, p ≤ 0.05) as well as superoxide dismutase activity (r = 0.81–0.90, p ≤ 0.05). Based on the results of a comprehensive analysis of growth and biochemical parameters and of the cluster analysis, Valdai variety proved to be more resistant to oil pollution. Due to this, Valdai variety is considered to be a promising rye variety for cultivation on moderately oil-polluted soils in order to decontaminate them. At the same time, it is necessary to conduct further studies aimed at investigating oil transformation processes in the soil-rye system, which would make it possible to determine the efficiency of using this cereal for soil remediation.

The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1) in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase) and rtn16 (decreased chlorophyll a and b amounts) were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

Selenium plays an important role as an antioxidant in the prevention of cardiovascular disease. Content of selenium in the crops is constantly in the spotlight of professional public. Vegetables, as an important source of chemo protective substances, have irreplaceable position within the food of plant character. The aim of research work was to solve the Se content increasing in the seeds of garden pea (varieties Premium and Ambassador) through the foliar biofortification of the plants (50 g Se / ha and 100 g Se / ha) and to monitor its effect on production of photosynthetic pigments. In the seeds of fresh garden pea, the chlorophyll a and chlorophyll b content was determined by spectrophotometer depending on a variety and the doses of selenium. In lyophilized seeds there was measured content of selenium by ET-AAS methods. The statistically significant increase of selenium was confirmed with its increasing concentrations in case of both varieties. In the var. Ambassador there was increasing from 0.083 ±0.009 mg.kg-1 DM to 4.935 ±0.598 mg.kg-1 DM (60-fold) and in a var. Premium the values increase from 0.067±0.007 mg.kg-1 DM to 3.248 ±0.289 mg.kg-1 DM (48-fold) after application of 100 g Se / ha. After application of 50 g Se / ha in both varieties of peas there was reported 25-fold increasing in the selenium content in comparison with control. The content of photosynthetic pigments was also increased, or possibly left at level of un-fortificated variant (chla - Ambassador - 50 g Se / ha; chlb - Premium - 100 g Se / ha) by foliar biofortification. Chlorophyll a content was high significantly increased according to used statistical methods in varieties Premium, from the content of 24.527 ±5.156 mg.kg-1 FM to 66.953 ±6.454 mg.kg-1 FM, likewise the content of chlorophyll b from the value of 19.708 ±5.977 mg.kg-1 FM to 37.488 ±6.146 mg.kg-1 FM (after 50 g / ha application). Foliar biofortification of different vegetable species can provide large-scale intake of minerals with antioxidant properties for human as well as an increase of certain biologically active substances as a result of their synergies

The content of plastid pigments is an indicator of the reaction of plants to environmental changes and their adaptation to environmental conditions. In the case of damage caused by insect pests, the plants develop some compensatory and adaptive mechanisms to reduce the negative impact. In the present study, an analysis of the dependence of the content of plastid pigments and the relationship between them of the variety, the age of the plants and the damage on the root system of the alfalfa longhorn beetle larvae was performed. It has been found that the content of pigments (chlorophyll a, chlorophyll b, carotenoids) in the alfalfa leaf has been influenced by the age of the plants, with the overall pigment content decreasing with the aging of the crops. The variety („Pleven 6", „Prista 3", „Mnogolistna 1") did not have a significant effect on the content of chlorophylls and carotenoids nor on the ratio between them. An increased content of plastid pigments in plants with an alfalfa damaged root system in relation to healthy plants has been reported, which may be due to the alfalfa compensation mechanism, in the case of attack by pests. [ABSTRACT FROM AUTHOR]

Abstract: Chlorophyll a and chlorophyll b have been isolated and purified by counter current chromatography. The 1H‐, 13C‐, and 15N‐NMR spectra were recorded and compared for the 2 molecules by using arguments based on classical structural properties. This interpretation is fully corroborated by high‐level ab initio quantum chemical calculations. [ABSTRACT FROM AUTHOR]