Search

Passive measurement of sun-induced chlorophyll fluorescence (F) represents the most promising tool to quantify changes in photosynthetic functioning on a large scale. However, the complex relationship between this signal and other photosynthesis-related processes restricts its interpretation under stress conditions. To address this issue, we conducted a field campaign by combining daily airborne and ground-based measurements of F (normalized to photosynthetically active radiation), reflectance and surface temperature and related the observed changes to stress-induced variations in photosynthesis. A lawn carpet was sprayed with different doses of the herbicide Dicuran. Canopy-level measurements of gross primary productivity indicated dosage-dependent inhibition of photosynthesis by the herbicide. Dosage-dependent changes in normalized F were also detected. After spraying, we first observed a rapid increase in normalized F and in the Photochemical Reflectance Index, possibly due to the blockage of electron transport by Dicuran and the resultant impairment of xanthophyll-mediated non-photochemical quenching. This initial increase was followed by a gradual decrease in both signals, which coincided with a decline in pigment-related reflectance indices. In parallel, we also detected a canopy temperature increase after the treatment. These results demonstrate the potential of using F coupled with relevant reflectance indices to estimate stress-induced changes in canopy photosynthesis., (© 2020 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Tsoongiodendron odorum is a rare and characteristic plant species with an extremely limited population. Understanding the photosynthetic and physiological properties of this species is crucial for implementing proper protective cultivation methods. No reports have yet been made on the study of photosynthetic physiological characteristics at different growth stages. In this study, the photosynthetic responses of the leaves of Tsoongiodendron odorum juvenile and adult were examined and the chlorophyll content and anatomical characteristics of the leaf surface were compared. The results showed that: the rate of net photosynthetic (Pn) of adult trees was significantly higher than that of juvenile under various light intensity, and there was light inhibition in juvenile species under high light intensity; the maximum net photosynthetic rate (Pmax) and light saturation point (LSP) of adult tree was significantly higher than those of juvenile, while the dark respiration rate (Rd) and light compensation point (LCP) of juvenile were higher than those of significant adult. Stomatal conductance (Gs) and transpiration rate (Tr) were higher in adult trees than in juveniles under high light intensity. Additionally, adult trees had significantly higher levels of chlorophyll b and total chlorophyll compared to juveniles, and their tissues differed significantly. Results of correlation and redundancy analysis showed that photosynthetic rate was positively correlated with leaf area, palisade cell tissue thickness, palisade-spongy ratio, xylem thickness, phloem thickness, and vascular cambium thickness. In conclusion, it is suggested that shading treatment should be carried out, and the shading degree should be gradually decreased with the growth of the plants to prevent the growth of Tsoongiodendron odorum from being limited by too strong or too weak light environment. [ABSTRACT FROM AUTHOR]

Nowadays, the nutritional value of cookies is relatively low. To reduce wheat flour usage in the cookies, the freeze-dried whole leaf (WL) and chloroplast-rich fraction (CRF) derived from Thai jasmine rice grass were used as a food ingredient to increase the nutrients of cookies. Chloroplast is a rich source of macro and micronutrients. Thus, the use of chloroplast might improve the nutrients in food products. This research aimed to study the physical and chemical characteristics of freeze-dried WL and CRF from Thai jasmine rice grass. The nutritional and physical properties of the butter cookies substituted wheat flour with WL or CRF (0%, 2%, and 4% (w/w)) were also investigated. The result showed that CRF derived from Thai jasmine rice grass contained a significantly larger amount of macro and micronutrients (protein, lipid, ash, β-carotene, and total carotenoids) compared with WL (P<0.05), except for carbohydrate, fiber, total chlorophyll, and total phenolic compound. Furthermore, the cookies replaced wheat flour with 4% WL from Thai jasmine rice grass, containing the highest fiber led to a decreased spread ratio and increased the hardness of cookies. Whilst the cookies substituted with 4% CRF (w/w) were similar in texture to the cookies containing only wheat flour (P>0.05). Moreover, the replacement of wheat flour with freeze-dried WL and CRF derived from Thai jasmine rice grass enhanced nutrients and antioxidant activity compared with cookies in the absence of WL and CRF. The butter cookies with 4% replacement of WL showed the highest level of chlorophyll and total phenolic; the cookies with 4% replacement of CRF contained the largest amount of β-carotene (provitamin A) and total carotenoids. However, both cookies containing either WL or CRF were not significantly different in antioxidant activity (P>0.05). [ABSTRACT FROM AUTHOR]

Cowpea is an important grain and vegetable legume that is grown under water deficit-prone tropical and subtropical regions. These regions require genotypes of cowpea that can be established rapidly at the seedling stage. A better understanding of the phenomenon that happens during cowpea germination can help us to develop the varieties that have traits to establish early in the soil. The present study was conducted to investigate the phenophasic variation in cotyledon chlorophyll content and chlorophyll fluorescence in the germinating cowpea at different developmental stages because both are indicators of photosynthetic capacity and compared to gas exchange parameters; they are high throughput, speedy and simple in nature. Total chlorophyll content and chlorophyll fluorescence parameters viz. maximum fluorescence (Fm), the maximum quantum efficiency of PSII (Fv/Fm), potential photosynthetic activity of PSII (Fv/F0), steady-state relative fluorescence decline ratio (Rfd-Lss) and steady-state coefficient of photochemical quenching based on lake model (qL_Lss) were measured in the cotyledons of germinating cowpea seedlings at the three phenophasic stages that are named as closed, opened and unfurled primary leaf (UPL) cotyledon stages. It was revealed that total chlorophyll content, Fm, Fv/Fm, Fv/F0, Rfd-Lss and qL_Lss are significantly higher in UPL cotyledons as compared to closed cotyledons across all the cowpea genotypes which are the reliable indicators of photosynthetic efficiency. Moreover, total chlorophyll content in cowpea cotyledon was also found to be significantly and positively correlated with chlorophyll fluorescence parameters. The present study suggests that UPL cotyledons have better-developed photosynthesis apparatus, and plants tend to be independent of cotyledonary storage for their growth at this phenological stage. Apart from that, it was also evident that there is a natural variation of chlorophyll fluorescence parameters in the cowpea cotyledons with a genetic basis that can be utilized in breeding and selection programs of early establishing cowpea genotypes where chlorophyll fluorescence can be used as an selection tool. [ABSTRACT FROM AUTHOR]

Introduction: Plants that display heteroblasty possess conspicuous variations in leaf morphology between their juvenile and adult phases, with certain species retaining juvenile-like leaves even in adulthood. Nevertheless, the ecological advantages of maintaining two or more distinct leaf types in heteroblastic plants at the adult stage remain unclear. Method: The aim of this study is to examine the adaptive significance of heteroblastic leaves sampled from branches with divergent functions (sterile and fertile branches) of mature Ficus pumila individuals by comparing their morphological, anatomical, and physiological characteristics. Result: Leaves on sterile branches (LSs) exhibited a significantly larger specific leaf area, thinner palisade and spongy tissues, lower chlorophyll contents, and lower light saturation points than leaves on fertile branches (LFs). These results demonstrate that LSs are better adapted to low light environments, while LFs are well equipped to take advantages of high light conditions. However, both LFs and LSs have a low light compensation point with no significant difference between them, indicating that they start to accumulate photosynthetic products under similar light conditions. Interestingly, significant higher net photosynthetic rate was detected in LFs, showing they have higher photosynthetic capacity. Furthermore, LFs produced significant more nutrients compared to LSs, which may associate to their ability of accumulating more photosynthetic products under full light conditions and higher photosynthetic capacity. Discussion: Overall, we observed a pattern of divergence in morphological features of leaves on two functional branches. Anatomical and physiological features indicate that LFs have an advantage in varied light conditions, providing amounts of photosynthetic products to support the sexual reproduction, while LSs adapt to low light environments. Our findings provide evidence that heteroblasty facilitates F. pumila to utilize varying light environments, likely associated with its growth form as a climbing plant. This strategy allows the plant to allocate resources more effectively and optimize its overall fitness. [ABSTRACT FROM AUTHOR]

Introduction: It is predicted that the world population will grow to 9.3 billion by 2050 and the urban population will increase by 73%, growing from 3.6 billion to 6.3 billion. This huge population requires abundant food production. A plant factory with artificial light (PFAL) is a closed growing system that is insulated against heat and air. The plants grow on shelves under horizontal artificial lighting. The main goal of PFAL is commercial plant production, but mini PFALs do not have commercial goals and are used to produce plants in small domestic sizes. Plants that are less than 30 cm tall, and grow well in relatively low light conditions and at high planting densities, are suitable for the plant factory. Therefore, plants such as rice, wheat, and potatoes are not suitable for cultivation in a plant factory. The main purpose of this research is to study the proper light quality for growing radish plants. All light treatments had a significant effect on biomass, sugar, and photosynthetic pigments of radish. The results showed that the highest amount of chlorophyll a was 0.964 mg g-1 fresh leaf weight and the lowest amount was 0.318 mg g-1 fresh leaf weight. For chlorophyll b, the highest value was 0.666 mg g-1 wet weight and the lowest value was 0.229 mg g-1 wet weight. The highest and lowest carotenoid contents were 74.75 mg g-1 and 30.6 mg g-1 wet weight, respectively. The highest sugar content was 0.717 μg g-1 dry weight and the lowest was 0.02 μg g-1 dry weight. The highest fresh and dry weights of the plant were 0.27 g and 0.014 g, respectively, while the lowest values recorded were 0.155 g and 0.007 g, respectively. In this study, plant length was also examined, but no significant difference was observed between different light treatments. Based on these findings, it can be concluded that the light composition (R2, G0, B1) was the most suitable light regime for use in the designed system. Materials and Methods: The plant studied in this investigation was radish. The place of growth was a vertically built system consisting of four floors, each divided into two sections. A controller was required in each section to regulate parameters such as light time, temperature, and moisture. The controllers were designed using Fritzing software and built with parts and sensors like DHT 11, Arduino UNO based on ATMEGA328P, Relay module Arduino, data logging shield, and driver module RC. A programming platform like Arduino was used to write codes for controlling the remaining parameters. This study tested seven different light treatments, plus sunlight as a control, to investigate their effects on radish growth. The light treatments were developed by adjusting the number of three different lights: red, green, and blue. LEDs were installed after designing and constructing the m-PFAL system. Based on previous research conducted in this field, all LED lights were positioned above the shelves to ensure that the plants received an appropriate amount of light in a vertical orientation. Additionally, light reflectors were installed beside the plants to provide proper lighting for the lower leaves. The experimental design involved a completely randomized design with eight treatments and three replications, and all data analysis was conducted through SAS software. The average comparison was performed using the Duncan method at a probability of 1% and 5%. Results and Discussion: The results indicate that the light regime (R2, G0, B1) resulted in the highest amount of chlorophyll "a", which was significantly different from both the control and other treatments. The treatment with the lowest amount of chlorophyll "a" was (R1, G0, B0), which did not differ significantly from the control or (R1, G1, B1). The treatment with the highest amount of chlorophyll "b" was (R2, G0, B1), which differed significantly from the control but not from (R2, G1, B0) or (R1, G0, B2). Using a mixed light treatment of blue and red resulted in higher amounts of photosynthesis pigments, especially when the red light was more prevalent. The treatment with the highest wet weight was (R2, G0, B1), which did not differ significantly from natural light. The treatment with the lowest wet weight was the just red light treatment, which was much lower than the other treatments. The dry weight of the radish was 4-6 percent of its wet weight, and the treatment with the highest dry weight was (R2, G0, B1), which did not differ significantly from (R0, G1, B2) or (R1, G0, B0). The treatment with the highest amount of sugar was (R2, G0, B1), which was significantly higher than other optical regimes used and natural light. Because the production of carbohydrates and sugar is directly related to photosynthesis, it can be concluded that the state of photosynthesis was most proper in the (R2, G0, B1) treatment. Conclusion: This study investigated the optimal light quality for the healthy and rapid growth of radish plants in a plant factory. LED lights can be an excellent alternative to natural light when there are limitations, such as in greenhouses or multi-floor plantings. The results show that the best light mixture was red and blue lights, with more red light than blue light, while the worst light regime was just red color, which had a negative effect on all parameters. [ABSTRACT FROM AUTHOR]

This study investigated the effects of various maltodextrin contents (0, 6, 7.5, 9, and 10.5 g/100 g of pulp) on the drying rate and powder quality of avocado pulp dried by refractance window technique. Increasing the maltodextrin addition level significantly decreased the drying rate and prolonged the drying time. The maltodextrin considerably affected the drying rate of pulp when its moisture content was higher than 1.0 g/g dry weight. A significant improvement was found in the retention of total contents of phenolics and chlorophylls, antioxidant capacity, and color in avocado powder obtained from pulp with maltodextrin. The addition of 9 g maltodextrin/100 g of pulp allowed to retain 85.60% TPC, 78.78% total chlorophyll content, 83.48% DPPH radical scavenging activity, and 78.89% ferric reducing antioxidant power. However, maltodextrin in the amount of 10.5 g/100 g of pulp had a negative impact on moisture removal and deteriorated the quality of the dried avocado. These findings may have practical application for the production of dried avocado and other fruits. [ABSTRACT FROM AUTHOR]

In connection with global warming, the study of plant adaptation to climate change, resistance to lack of moisture and high temperatures becomes relevant. Meteorological and phenological observations prove that a change in temperature conditions leads to an earlier start of vegetation and a lengthening of the growing season in all investigated gooseberry varieties. To assess the functional state of the photosynthetic apparatus of plants, a minimally invasive instrumental method of determining the intensity of chlorophyll fluorescence in plant leaves, adapted to work on the domestic photofluorimeter "Floratest", was used. Based on the results of the analysis of the parameters of the chlorophyll fluorescence induction curves (Fo, Fpl, Fmax, Ft) and the comparison of the coefficients for these values (Kpl, K1, K2), it was established that Fo and Kpl are the most informative. A strong correlation dependence of the indicator of the background level of fluorescence at the time of full opening of the shutter (Fo) was established. The value of Fо correlates positively with indicators of the moisture regime, negatively – with temperature indicators. Correlations between the fluorescence growth index and the variable (Kpl) showed the opposite: the largest positive correlation was observed with mean maximum temperature, the smallest with precipitation. On the basis of mathematical analysis and modeling of the obtained FIC curves and indicators of agro-climatic conditions, the values of the maximum temperature and the minimum amount of precipitation, which are critical for the functioning of the gooseberry photosynthetic apparatus, were determined. Such a study makes it possible to evaluate the course of photochemical reactions associated with the work of plant photosystems according to standard coefficients of photochemical activity, which have already been tested in numerous works of domestic researchers on a wide range of agricultural crops. [ABSTRACT FROM AUTHOR]

Drought stress has become more common in recent years as a result of climate change impacts on the production of banana crops and other fruit trees. The growth and productivity of Musa spp are severely impacted by the gradual degradation of water resources and the erratic distribution pattern of annual precipitation amount. The aim of the work includes increased drought tolerance in light of water scarcity in the world as a result of the bananas’ being gluttonous for water needs. This investigation was carried out from 2019 to 2020 to study the effect of potassium silicate on morphological growth and biochemical parameters of Musa acuminata L under drought stress by PEG. As a result, drought stress reduced the morphological characteristics such as shoots number, shoot length, roots number, and survival percentage and biochemical characteristics such as chlorophyll a, b, carotenoids, stomatal status, and RWC. While proline content increased in the leaf of M. acuminata L. Media complemented with K2SiO3 (2 to 6 mM) either individually or in combination with PEG led to an improvement in all morphological and biochemical characteristics. The activities of CAT, POD, and PPO enzymes increased significantly compared to control. Furthermore, the lowest PPO, CAT, and POD activity were achieved. Additionally, K2SiO3 treatments under drought stress successfully enhanced the leaf stomatal behavior. Our results suggest that K2SiO3 can help to maintain plant integrity in the tested cultivar under drought stress. [ABSTRACT FROM AUTHOR]

Our research aimed to study the correlation between the SPAD-502 readings and the color space CIE L*a*b* values in two cultivars of Alstroemeria sp. during leaf senescence and to evaluate the statistical criteria used in the selection of the best fit calibration functions. We demonstrate the importance of the Akaike information criterion and the parsimonious function besides the coefficient of determination. The reliability of the functions was tested by Student's t-test comparison between the chlorophyll (Chl) estimated from SPAD readings and their chemical concentrations. Polynomial and Hoerl function described well the changes in Chl a and total Chl (a+b) during senescence, but calibration functions are required to perform for each cultivar. We demonstrated that CIE L*a*b* system is reliable to estimate SPAD reading at stages of leaf senescence of Alstroemeria sp. and can be used instead of SPAD-502. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The genotype CR60 is a spontaneous Cherry Red variant (containing granular red dapples on flue-cured leaves) of the Yunyan 87 (Y87) tobacco; it accumulates higher concentration of iron (Fe) in leaves than Y87, but the physiological differences between them remain largely unknown. We investigated the physiological and molecular mechanisms of CR60 in response to Fe deficiency under hydroponic conditions. Our results showed no significant phenotypic difference between Y87 and CR60 at optimal (40 μM) and high Fe (160 and 320 μM) concentrations. By contrast, CR60 exhibited higher tolerance to Fe deficiency (0 μM) than Y87, as shown by higher concentrations of chlorophyll in CR60 leaves after 21-day Fe-deficiency stress. Transcriptome profiling coupled with RT-PCR analyses found that the expression of IRT1 and several genes associated with chlorophyll biosynthesis and photosynthesis (e.g., PRO , GSA , FD1 , PsbO , and PC) was higher in CR60 than Y87. These results indicated that CR60 maintains sufficient Fe uptake, chlorophyll biosynthesis and photosynthetic rate when subjected to Fe starvation. [ABSTRACT FROM AUTHOR]

The content of chlorophylls (Chl) (a+b), total carotenoids (x+c), and the pigment ratios of Chl a/b and Chls to carotenoids (a+b)/(x+c) of green leaves of five C4 plants were determined and compared to those of C3 plants. The C4 plants were: Pacific and Chinese silvergrass (Miscanthus floridulus and Miscanthus sinensis), sugar cane (Saccharum officinarum) as well as feed and sugar maize (Zea mays). The three C3 plants were beech, ginkgo, and oak. C4 plants possess higher values for the ratio Chl a/b (3.4-4.5) as compared to the C3 plants (2.6-3.3). Sugar maize had the highest values for Chl a/b (4.04-4.70) and exceptionally high contents of total carotenoids and consequently lower values for the ratio of (a+b)/(x+c) (mean: 3.75 ± 0.6). During autumnal senescence also C4 plants showed a faster decline of Chl b as compared to Chl a yielding high values for Chl a/b of 6 to 8. Chlorophylls declined faster than carotenoids yielding low (a+b)/(x+c) values below 1.0. [ABSTRACT FROM AUTHOR]

Metabolic activities such as breathing and digestion, resulting from natural functions of the body through oxidation, lead to the formation of free radicals that cause cancer, premature cardiac aging and some chronic diseases. Antioxidants are substances that remove free radicals and prevent cell damage. Seafood significantly contributes to the elimination of free radicals, especially owing to its high quality nutrient content. In this context, the objective of the study was to determine the radical antioxidant capacity and the total amount of carotenes in razor clams. The IC50 (mg g−1) value of the DPPH radical sweeping effect varied over the months (p < 0.05), showing the highest value in June, gradually decreasing from September and reaching the lowest level in February. The total amount of carotenoids also varied, with the highest value in September (p < 0.05). The total amount of chlorophyll ranged from 6.15 μg g−1 in August to 66.71 μg g−1 in December. [ABSTRACT FROM AUTHOR]

Isophorone (3,5,5‐trimethylcyclohex‐2‐en‐1‐one) is a plant‐derived volatile compound with strong phytotoxic activity. Here, we aimed to elucidate the mechanism of action of isophorone, and to this end, the effects of isophorone on shoot fresh weight, chlorophyll content, electrolyte leakage, and lipid peroxidation of Lactuca sativa L. and photosynthetic electron transport activity in chloroplast isolated from Spinacia oleracea L. were investigated. Isophorone induced light‐independent decreases in shoot fresh weight and light‐dependent chlorosis. In addition, increased electrolyte leakage and lipid peroxidation occurred under light conditions. However, the inhibitory activity on photosynthetic electron transport was unexpectedly low, and electrolyte leakage and lipid peroxidation were induced even under dark conditions. These results suggest that the inhibition of photosynthetic electron transport is not the main mechanism of action of isophorone and that the phytotoxic effects are mainly due to light‐independent oxidative damage and subsequent loss of cell membrane integrity. [ABSTRACT FROM AUTHOR]

Radish and leaf vegetables contain a lot of vitamins and nutrients. Consumers increasingly think about a healthy and balanced diet. Experiments were carried out to clarify the effect of irrigation on the yield and the quality of lettuce, leaf mustard and radish. The experiments were arranged in high tunnels of the Pure Horticultural Research Centre during spring and autumn months of 2013. Leaf lettuce cv. 'Grand Rapids'; leaf mustard cv. 'Scala'; and radish cv 'Rudolf' were grown in 3 replicas; the total area of each experimental plot was 1 m². The necessity of irrigation was determined by tensionmeters. The control variant had optimal soil moisture, the experimental plot had moisture deficit. The yield and its quality were determined at the end of the experiment. The results revealed the tendency that the higher yield of leaf vegetables was obtained at an optimal moisture variant. Radish was less sensitive to soil moisture deficit in comparison with lettuce and mustard. Irrigated vegetables had the tendency of having preference in organoleptic testing of vegetables. A higher content of chlorophylls was obtained at the optimal moisture variant. [ABSTRACT FROM AUTHOR]

In nature, soil salinity and fluctuating light (FL) often occur concomitantly. However, it is unknown whether salt stress interacts with FL on leaf photosynthesis, architecture, biochemistry, pigmentation, mineral concentrations, as well as whole-plant biomass. To elucidate this, tomato (Solanum lycopersicum) seedlings were grown under constant light (C, 200 μmol m−2 s−1) or FL (5-650 μmol m−2 s−1), in combination with no (0 mM NaCl) or moderate (80 mM NaCl) salinity, for 14 days, at identical photoperiods and daily light integrals. FL and salt stress had separate effects on leaf anatomy, biochemistry and photosynthetic capacity: FL reduced leaf thickness as well as nitrogen, chlorophyll and carotenoid contents per unit leaf area, but rarely affected steady-state and dynamic photosynthetic properties along with abundance of key proteins in the electron transport chain. Salt stress, meanwhile, mainly disorganized chloroplast grana stacking, reduced stomatal density, size and aperture as well as photosynthetic capacity. Plant biomass was affected interactively by light regime and salt stress: FL reduced biomass in salt stressed plants by 17%, but it did not affect biomass of non-stressed plants. Our results stress the importance of considering FL when inferring effects of salt-stress on photosynthesis and productivity under fluctuating light intensities. [ABSTRACT FROM AUTHOR]

To investigate the effect of NaCl salinity (0, 4, 8 and 12 dS m-1) on some morpho-physiological indices of Rosa damascenea Kashan genotype, a factorial pot experiment was designed based on randomized complete block design with four replications and three pots per replication (with total of 48 pots) on open air countineued for two years, and results of the second year data are reported. The results showed that salinity stress reduced fresh and dry weight of leaves and shoots. Also, the relative water content (RWC) of leaf and shoot decreased under salinity stress. Mean comparison showed that chlorophylls and carotenoids content were inversely associated with increasing salinity levels. The lowest levels of chlorophyll and carotenoids were observed in 12 dS m-1 treatment. Antioxidant enzymes activity such as superoxide dismutase (SOD), catalase (CAT) and guaiacolytic peroxidase (GPX) increased by increasing salt stress, although the lowest activity was observed in control treatment. Total phenol content of the leaves was also affected by increased salinity stress, but there was no significant difference between treatments. In addition, the results showed that by increasing salinity stress, the amount of soluble proteins decreased and its lowest amount was observed with 12 dS m-1 treatment. According to the results, salinity stress reduced plant growth by its effects on physiological and biochemical characteristics of Rosa damascena. Thus, it seems that the Damask Rose can tolerate a salinity level of up to 8 dS m-1, without detrimental effects on plant growth. [ABSTRACT FROM AUTHOR]

Chloroplast development and chlorophyll metabolism have been well described in model plants but not in perennial woody crops. Of particular interest is the interplay between light and hormones under shade conditions. We report that the shade induced accumulation of chlorophylls in Camellia sinensis cv. Shuchazao leaves is at least as a result of (a) positive changes in chloroplast development and (b) light/hormonal regulation of genes and transcription factors involved in the chlorophyll biosynthesis pathway. Under shade conditions, leaves developed an abundance of enlarged chloroplasts encapsulating more prominent thylakoid membranes. Four major metabolites in the chlorophyll biosynthesis pathway namely Chl a , Chl b , DPP, and Mg-Proto IX increased under shade conditions while PBG decreased significantly. Significant changes were found at the transcription level of regulators of chloroplast biogenesis (GLK1 and LHCB), the structural genes in the chlorophyll biosynthesis pathway (HEMA1 , CLH1 , PORA , and CAO) and potential components involved in light signaling (PHYA , CRY1 , HY5 , and DELLAs). Two central signal integrators (GLK1 and LHCB) between the nucleus and chloroplast showed clear responses to shade, suggesting a crucial role of light in regulating chloroplast development in tea leaves. Concurrent with the changes in gene expression, the concentrations of endogenous phytohormones (auxin, cytokinin, and gibberellins) increased significantly in the later stages of shade conditions. Two key integrators involved in the hormone signal pathways, EIN3 and EBF1/2, increased under shade conditions suggesting that shade induced changes to hormone levels may play some role in modulating chlorophyll biosynthesis in the tea leaves. Overall, this data suggests that the light and hormone influence over chloroplast development and chlorophyll biosynthesis in Camellia is similar to that of Arabidopsis. This study provides new insights into the molecular mechanisms that regulate chlorophyll biosynthesis in response to light and hormones in a commercially important woody plant such as Camellia , which may facilitate the breeding of high-chlorophyll tea cultivars for the improvement of sensory features of the green tea product. [ABSTRACT FROM AUTHOR]

The purpose of this study was to show the extent of phenotypic plasticity of the grass Deschampsia caespitosa from four habitats with different soil properties by comparing selected leaf traits and content of silicon and other elements. Morphological, biochemical, and optical properties were examined in leaves, but content of silicon and other elements also in soil samples. Plant-available silicon in the soil was determined following extraction in CaCl2. Bulk element analysis was conducted using X-ray fluorescence spectrometry. The habitats of D. caespitosa differed significantly according to soil structure, which resulted in significantly different leaf traits, including leaf optical properties and content of minerals. There was no correlation between leaf silicon and plant-available or total soil silicon, while positive correlation was seen between leaf calcium and total soil calcium. In addition, plant-available silicon showed strong positive correlation with leaf calcium and phosphorus. The majority of D. caespitosa leaf and soil properties differed significantly among habitats. [ABSTRACT FROM AUTHOR]

Hydroponically grown loquat seedlings were subjected to increasing NaCl concentrations (0, 12, 24, and 48 mM) for 42 d. At the whole plant level, Na+ and Cl- accumulated proportionally to the salt treatments; however, Na+ accumulated prevalently in leaves whilst Cl- accumulated prevalently in stems. Reduction of leaf biomass was only observed in seedlings grown with 48 mM NaCl, whereas net photosynthesis declined along with increasing NaCl concentration and salinity led to general accumulation of glucose, reduction of mannitol and sorbitol, and changes in pigment composition in loquat leaves. Increasing level of salinity induced accumulations of both proline and H2O2 but not of malondialdehyde byproducts. Dramatic alteration of sugar patterns in the leaves poses serious concerns about possible effects of salinity to fruit production. Further research is necessary to investigate the concentration at which NaCl significantly compromises the yield of this economically important fruit species. [ABSTRACT FROM AUTHOR]

The leaves of scorzonera are vulnerable to mechanical damage due to heavy rainfall or wind. The aim of the study was to determine the impact of pre-sowing exposure of scorzonera seeds to laser light on the mechanical strength of the leaves and the content of photosynthetic pigments. The research material consisted of scorzonera leaves obtained from seeds treated with He-Ne laser light at the wavelength of 632.8 nm, surface power density of 5 mW cm–2, and exposure time of 1, 5, 10, and 30 minutes. Young’s modulus measurements showed that the leaves of the plants grown from seeds subjected to laser light stimulation were characterized by better mechanical strength compared to the leaves of the control. The highest values of the Young’s modulus were recorded for scorzonera plants grown from seeds subjected to laser light exposure for 10 minutes. Exposure to light for a period of 1, 5 and 30 minutes significantly affected the content of chlorophylls and carotenoids in the leaves relative to the control. The largest increase in the content of photosynthetic pigments was recorded for 1 minute. The improvement in the mechanical strength of scorzonera leaves may reduce their vulnerability to mechanical damage during vegetation. [ABSTRACT FROM AUTHOR]

Copyright of Bodenkultur: Journal for Land Management, Food & Environment is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Suji (Dracaena angustifolia (Medik.) Roxb.) leaves are famous chlorophyll source used as food colorant in Indonesia and other south-east Asian countries. Its chlorophyll has unique characteristics which can degrade through enzymatic and non-enzymatic reactions. This article summarizes traditional application of Suji leaves, the characteristics of Suji leaf chlorophyll, postharvest stability, and several ways to retain its green color. Potential development of Suji leaf extract as food colorant or food ingredients are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Morphology, anatomy and physiology of sun and shade leaves of Abies alba were investigated and major differences were identified, such as sun leaves being larger, containing a hypodermis and palisade parenchyma as well as possessing more stomata, while shade leaves exhibit a distinct leaf dimorphism. The large size of sun leaves and their arrangement crowded on the upper side of a plagiotropic shoot leads to self‐shading which is explainable as protection from high solar radiation and to reduce the transpiration via the lamina. Sun leaves furthermore contain a higher xanthophyll cycle pigment amount and Non‐Photochemical Quenching (NPQ) capacity, a lower amount of chlorophyll b and a total lower chlorophyll amount per leaf, as well as an increased electron transport rate and an increased photosynthesis light saturation intensity. However, sun leaves switch on their NPQ capacity at rather low light intensities, as exemplified by several parameters newly measured for conifers. Our holistic approach extends previous findings about sun and shade leaves in conifers and demonstrates that both leaf types of A. alba show structural and physiological remarkable similarities to their respective counterparts in angiosperms, but also possess unique characteristics allowing them to cope efficiently with their environmental constraints. [ABSTRACT FROM AUTHOR]

Fresh and frozen wheatgrass juice (WgJ) stored for three months were examined in terms of: polyphenolic components, total chlorophylls and carotenoids, antioxidant and enzymatic activity and color. Juices were prepared from summer and winter grass, at two growth stages (16 and 21 cm). Raw WgJ (100 g) contained: 5.04 dry matter; 4.59 total extract; and 0.820 ash. Raw WgJ (1 L) contained also 391.4 mg chlorophylls; 79.1 mg carotenoids; 920.9 mg total polyphenols, with a mean antioxidant activity of 9.57 and 93.07 µM Troloxeq/mL (DPPH) and (ABTS) respectively; catalase and peroxidase activity were 114.94 and 0.13 U, respectively. Summer WgJ (fresh and frozen) had higher chlorophylls, carotenoids, total polyphenols concentration, increased enzymatic activity, better color than winter WgJ, but lower levels of dry matter, ash, and extract. Freezing and storage of juices significantly reduced the level of dry matter, chlorophylls, carotenoids, antioxidant, and catalase activity. Color deterioration was also noted. Practical applications Sprouts and wheat grass are young plants, including active enzymes, easily absorbed vitamins, minerals and phytochemicals. Due to the lack of human enzymes digesting cellulose, which large amounts are found in the grass a better alternative is to drink wheatgrass juice. They represent one of the latest discoveries in nutrition. The best way is to drink fresh juice immediately after production, so they do not lose during storage labile compounds. The consumption of wheatgrass juice brings a lot of benefits. Not everyone can afford a grass breeding and production of juice at home. A long list of beneficial properties of juice obtained from wheat grass making it the product of an increasingly desired by consumers. The process of freezing is still one of the least invasive and universal methods for maintaining the product almost unchanged while significantly extend the life of. [ABSTRACT FROM AUTHOR]

Seedlings of Sinapis alba L. species (white/yellow mustard) were grown in nutrient solution containing different concentrations 50, 100, 250 and 500 mg/kg Cu for 10 days. Seedlings were measured and weighed at the end of the experiment. Leaf pigment concentration (chlorophylls a and b and carotenoids), tissular copper concentration and Biological Accumulation Coefficients (BAC) were determined. Copper content in Sinapis alba L. tissues reached 74.54 - 171.20 mg/kg dry mass, with highest values at high ambient concentration. BAC reached 1.49 at 50 mg/kg and was subunitary at higher concentrations, between 0.75 - 0.34. Shoot length and biomass emphasize a significant decrease at high ambient copper levels, while photosynthetic pigment concentrations did not decrease. These results indicate a limited tolerance of white mustard to high copper concentrations and a limited bioaccumulation potential of this metal. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Light-emitting diodes (LEDs) are a promising technology with a potential to improve the irradiance efficiency, light quality, and the light spectrum for increasing plant yield and quality. In this experiment, we investigated the impacts of various LED light qualities, including 100% red, 100% blue, 70% red + 30% blue, and 100% white, on the growth and photosynthesis, phytochemical contents, and mineral element concentrations in lettuce ( Lactuca sativa L. cv. 'Grizzly') in comparison to normal greenhouse conditions. Photon flux of 300 µmol m s was provided for 14 h by 120 LEDs set on a 60 cm × 60 cm sheet of aluminum platform in the growth chambers, where plants were grown for 60 d. Fresh mass per plant was significantly higher when grown under 100% blue and 70% red + 30% blue LEDs compared to the other environments including greenhouse conditions. Phytochemical concentrations and a nutritive value of lettuce were also significantly affected by the light treatments. Chlorophyll and carotenoid concentrations increased in the plants grown under 70% red + 30% blue LEDs compared to those grown in the greenhouse. Vitamin C content was 2.25-fold higher in the plants grown under 100% blue LEDs compared to those grown in the greenhouse. Higher photosynthesis and maximal quantum yield of PSII photochemistry were also observed in the plants treated with LED lights. The application of LED light led to the elevated concentrations of macro-and micronutrients in lettuce possibly because of the direct effect of LED light and lower stress conditions in the growth chambers compared to the greenhouse. Although the mechanism of the changes in lettuce grown under LED is not well understood, the results of this study demonstrated that LED light could be used to enhance the growth and nutritional value of lettuce in indoor plant production facilities. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Agronomy is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sarracenia is a genus of carnivorous plants characterised by leaves modified into pitchers which lure, trap and digest insects. The aim of this study was to analyse the photochemical efficiency and contents of photosynthetic pigments and phenolic compounds in different pitcher parts - operculum, wing, pitchertube upper part and pitcher-tube lower part of three morphologically different Sarracenia hybrids. The photochemical efficiency of the operculum and the pitcher-tube upper part was lower than that of the pitcher-tube lower part and wing, especially in hybrid B. In all hybrids, the wing had higher amount of chlorophyll a than other pitcher parts. In contrast, a higher amount of phenolic compounds, in particular anthocyanins, was measured in the operculum and the pitcher-tube upper part, parts which are red-coloured and participate in luring and trapping insects. Although there were some differences among the hybrids, the results show that amount of phenolic compounds and photosynthetic pigments as well as photochemical efficiency are related to the function of the pitcher part analysed. [ABSTRACT FROM AUTHOR]

Modern agricultural farming requires precise, quick and nondestructive methods for determination of basic plant physiological parameters. One of the widely used and informative parameters is chlorophyll content in plant leaves. Determination of chlorophyll content by nondestructive methods is well elaborated for main field crops, but these methods are not widely used for chlorophyll content determination in leafy vegetables. The aim of the study was to compare two nondestructive methods with a classic biochemical chlorophylls determination method. Pigment content was expressed regarding to the leaf weight and leaf area. For nondestructive chlorophyll determination were used: a low cost handheld chlorophyll meter atLEAF+ and Miniature Leaf Spectrometer CI-710 (CID- Bio-Science). Chlorophylls content was determined using one of the 21 indices incorporated in Cl-710. For comparison of methods four different plant species (lettuce, leaf mustard, radish and cabbage) were used. Plants were grown at four illumination conditions - natural light, illumination supplemented with red, blue and mixed red/blue LED light. Results showed that at the majority of the investigated wavelengths, readings of the chlorophyll meter atLEAF+ and indices used for calculation are more sensitive to chlorophyll a content calculated per unit area. The maximum sensitivity of reflectance to variation with pigment content is found at 605 nm and 696 nm and in the near infrared region (740-930 nm). Higher correlation between non-destructive methods and biochemical analyses was observed in radish and leaf mustard leaves. The highest correlation coefficient was obtained with Difference Vegetation Reflectance index (NDVI) and Simple Ratio Pigment Index (SRPI). Nondestructive chlorophyll determination with chlorophyll meter atLEAF+ and Miniature Leaf Spectrometer CI-710 can completely replace biochemical analyses. [ABSTRACT FROM AUTHOR]

Chloroplasts are commonly the site of the earliest abiotic injury visible in plant ultrastructure. In this study, six inbred lines of maize ( Zea mays L.) were used to analyze changes in the ultrastructure of chloroplasts and related physiological parameters under conditions of drought stress simulated by 20% polyethylene glycol 6000 (−0.6 MPa) for two days. Chloroplasts of three maize lines proved to be more sensitive. They showed changes in the ultrastructure in response to drought, including damage of thylakoid membranes, an increase in the number and size of plastoglobuli, swelling of thylakoid membranes both stromal and granal, disorganization of the thylakoid membrane system, an obvious increase in the intrathylakoid space, and a decrease in the length-to-width ratio and area of chloroplasts. In addition, the contents of malondialdehyde increased markedly in the sensitive lines. Contrary to the sensitive lines, stable structures and shapes of chloroplasts were observed in the drought-resistant lines; it could be considered as an advantage contributing to drought tolerance in the plants. In addition, the drought index of leaf fresh mass (LMDI) in the drought-sensitive lines was ≤ 0.5, which was also associated with a lower content of leaf chlorophyll. In contrast, drought tolerance coincided with lesser growth reduction, and higher LMDI and leaf chlorophyll content. [ABSTRACT FROM AUTHOR]

At present, chlorophyll meters are widely used for a quick and nondestructive estimate of chlorophyll (Chl) contents in plant leaves. Chl meters allow to estimate the Chl content in relative units - the Chl index (CI). However, using such meters, one can face a problem of converting CI into absolute values of the pigment content and comparing data acquired with different devices and for different plant species. Many Chl meters ( SPAD-502, CL-01, CCM-200) demonstrated a high degree of correlation between the CI and the absolute pigment content. A number of formulas have been deduced for different plant species to convert the CI into the absolute value of the photosynthetic pigment content. However, such data have not been yet acquired for the atLEAF+ Chl meter. The purpose of the present study was to assess the applicability of the atLEAF+ Chl meter for estimating the Chl content. A significant species-specific exponential relationships between the atLEAF value (corresponding to CI) and extractable Chl a, Chl b, Chl ( a+ b) for Calamus dioicus and Cleistanthus sp. were shown. The correlations between the atLEAF values and the content of Chl a, Chl b, and Chl ( a+ b) per unit of leaf area was stronger than that per unit of dry leaf mass. The atLEAF value- Chl b correlation was weaker than that of atLEAF value-Chl a and atLEAF value-Chl ( a+ b) correlations. The influence of light conditions (Chl a/ b ratio) on the atLEAF value has been also shown. The obtained results indicated that the atLEAF+ Chl meter is a cheap and convenient tool for a quick nondestructive estimate of the Chl content, if properly calibrated, and can be used for this purpose along with other Chl meters. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Applied Technology for Agricultural Science / Revista Brasileira de Tecnologia Aplicada nas Ciências Agrárias is the property of Brazilian Journal of Applied Technology for Agricultural Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study compared the relationship between chlorophyll (Chl) content, gas exchange, Chl fluorescence characteristics, and leaf color, using paired near-isogenic lines (NILs) of a medium-green leaf inbred line SN12 and a yellow-green leaf mutant SN62 to explore the photosynthesis of the yellow-green mutant. The SN62 was found in a female parent, Xianyu 335, which grew normally, although there were small yellow spots on the leaves at the seedling stage and yellow-green leaves appeared from the seedling to the maturation stage. The results indicated that Chl a ( b), quantum efficiency of PSII, and maximal quantum yield of PSII photochemistry of SN62 were significantly lower than those of SN12, but there were almost no differences in the net photosynthetic rate ( P). There was no significant correlation between Chl a ( b) and P of inbred lines with different leaf colors. In the reproductive stage, photochemical quenching, effective quantum yield of PSII photochemistry, and the electron transport rate of SN62 increased obviously, and all parameter values exceeded the values of SN12. It explained that increasing the openness of the PSII reaction center was able to compensate for the lower Chl content, which was beneficial for harvesting more light energy for photochemical reactions. It also ensured that P was not reduced. [ABSTRACT FROM AUTHOR]

With the aim of improving shade tolerance of cucumber, Cucumis x hytivus, a newly synthesized allotetraploid, was obtained by crossing a shade tolerant wild relative, Cucumis hystrix, with a cultivated cucumber, Cucumis sativus L. 'BejingJietou.' The results show that the new C. x hytivus only partly is an intermediate hybrid and it has not only chlorophyll deficiency, which recovers during leaf development, but also lower carotenoid content. Three light conditions with the combination of different light intensities and photoperiods were employed to investigate the photosynthetic response of these three Cucumis species to low light and long photoperiod. The consistent order of Pmax and DWS being lowest in C. hystrix, medium in C. x hytivus and highest in 'BejingJietou' suggests the three species to have genetically different photosynthetic efficiency, which relates well with the natural habitats of the parent species and the hybrid as intermediate. C. x hytivus appears to be inhibited by the low light levels to the same extent as the cultivated 'BeijingJietou,' which indicates neither improvement of shade tolerance nor hypothetical heterosis effect in C. x hytivus. However, unexpectedly, the PSII of C. hystrix was affected by the long photoperiod in the long term, suggested by the decrease of Fv/Fm. This sensitivity toward day length has not been passed on to C. x hytivus. [ABSTRACT FROM AUTHOR]

The decline of fruit chlorophyll is a valuable indicator of fruit ripeness. Fruit chlorophyll content can be nondestructively estimated by UV/VIS spectroscopy at fixed wavelengths. However, this approach cannot explain the complex changes in chlorophyll catabolism during fruit ripening. We introduce the apparent peak position of the red band chlorophyll absorption as a new qualitative spectral indicator. Climacteric fruit (apple: n = 24, mango: n = 38, tomato: n = 48) were analysed at different ripeness stages. The peak position and corresponding intensity values were determined between 650 and 690 nm of nondestructively measured fruit spectra as well as of corresponding spectra of fruit extracts. In the extracts, individual contents of chlorophyll a, chlorophyll b, pheophytin a and carotenoids were analysed photometrically, using an established iterative multiple linear regression approach. Nondestructively measured peak positions shifted unimodal in all three fruit species with significant shifts between fruit ripeness classes of maximal 2.00 ± 0.27 nm (mean ± standard error) in tomato and 0.57 ± 0.11 nm in apple. Peak positions in extract spectra were related to varying pigment ratios ( R = −0.91), considering individual pigments in the pool. The peak intensities in both spectral readings, nondestructive and fruit extracts, were correlated with absolute chlorophyll contents with R = −0.84 and R = 1.00, respectively. The introduced spectral marker of the apparent peak position of chlorophyll absorbance bears the potential for an advanced information gain from nondestructive spectra for the determination of fruit ripeness. [ABSTRACT FROM AUTHOR]

Parameters of chlorophyll fluorescence induction (CFI) are widely used for assessment of the physiological state of higher plant leaves in biochemical, physiological, and ecological studies and in agricultural applications. In this work we have analyzed data on variability of some CFI parameters - Φ = F/ F (relative value of variable fluorescence), q (non-photochemical quenching coefficient), R ('vitality index') - in autumnal leaves of ten arboreous plant species of the temperate climatic zone. The correlation between the chlorophyll content in the leaves and fluorescence parameters characterizing photosynthetic activity is shown for two representative species, the small-leaved linden Tilia cordata and the rowan tree Sorbus aucuparia. During the period of mass yellowing of the leaves, the Φ value can be used as an adequate characteristic of their photochemical activity, while in summer the q or R values are more informative. We have established a correlation between the Φ value, which characterizes the maximal photochemical activity of the photosystem II, and 'chromaticity coordinates' of a leaf characterizing its color features. The chromaticity coordinates determined from the optical reflection spectra of the leaves serve as a quantitative measure of their hues, and this creates certain prerequisites for a visual expert assessment of the physiological state of the leaves. [ABSTRACT FROM AUTHOR]

Samples of potatoes were harvested in 2007 in Friuli Venezia Giulia ( Italy) and were stored at 6.5C for 6 months to assess quality characteristics, mainly related to the sprouting trend of tubers. The quality changes during cold storage were monitored using conventional measures (i.e., weight, visual appearance, morphological control, number and length of buds, ° Brix) and nondestructive methods (fluorometry and colorimetry). Among 17 cultivars, seven were stored at a lower temperature (0C) for 4 months and then 10C for 15 days to verify the reversible interconversion between starch and sugar induced by the storage temperature. The most important results were given by fluorometric analysis, which provided useful information for predicting the sprouting trend of tubers, as well as other objective analytical tests: the quantum yield had in most cultivars the minimum value in predicting sprouting time. After the low-temperature storage, the quantum yield was irreversibly reduced. Practical Applications Nondestructive techniques based on chlorophyll fluorescence measurements are used to monitor quality changes during post harvest storage of fruit and vegetables. Fluorometric values give indications not only about the chlorophyll amount, but also on the physiological state of photosynthetic apparatus. Even if potato tubers in good storage conditions don't produce chlorophyll, they possess a photosynthetic apparatus whose physiological state can be measured by fluorometry. Potatoes stored at low temperatures are subject to the sweetening process, but starch is synthesized again when potatoes are transferred to normal temperatures. The photosynthetic apparatus is damaged by low temperatures, as indicated by the decrease of fluorometric values, and this process is not reversible. The fluorometric indexes can be measured in order to check if potatoes were properly stored and evaluate differences of behavior in storage. The nondestructive method will enhance monitoring of potatoes quality during storage, thus minimizing both time and food wastages. [ABSTRACT FROM AUTHOR]

The article focuses on the study of the chlorophyll fluorescence induction (CFI) on the plant leaf ontogeny in wheat. The light dependence of the aging process of the leaf is discussed, along with the nonphotochemical component of fluorescence quenching. The range of excitation light intensity is also evaluated.

Copyright of Revista Brasileira de Biociencias is the property of Revista Brasileira de Biociencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The continuous increase of heavy metal ions in the environment is imposing serious problems in agricultural yield and increases human health threats through accumulation in the food chain. Various studies have shown that heavy metals influence the metabolic processes and pigment concentrations in leaves, and thus affect the laser induced fluorescence (LIF) spectra. Leaf level in vivo LIF spectra using the 488 nm and 355 nm laser lines, fluorescence induction kinetics (FIK) using the 488 nm laser line, and photosynthetic pigments of the control and nickel treated wheat seedlings were measured. The peak parameters of the blue and UV-excited spectral bands were calculated by Gaussian curve fitting. The FIK measured at both the chlorophyll (Chl) fluorescence bands was used to evaluate the fluorescence decrease ratio (R Fd). The variations in R Fd and fluorescence ratios of intensities, bandwidth and band area, with varying concentrations of nickel, were revealed as promising parameters in determining the health status of wheat seedlings. These leaf level findings can be extended at canopy level in the field using laser based light detection and ranging (LIDAR) systems. [ABSTRACT FROM AUTHOR]

The effects of graded sodium chloride (NaCl) concentrations (0-, 50-, 100-, 150-, and 200-mM) on photosynthetic pigment contents in in vitro grown shoots of important medicinal plant species (Centaurium erythraea Rafn) were investigated. Non-transformed, one AtCKX1 and two AtCKX2 transgenic centaury lines, with altered cytokinin profiles, were used in this study. The chlorophyll (Chl) and carotenoid contents differed in the non-transformed and transgenic lines. In general, salinity significantly reduced the Chl a and Chl b contents in comparison to the NaCl-free medium. The lowest Chl content was observed in AtCKX2 transgenic shoots grown on all the culture media. The total carotenoid content was increased in shoots of non-transformed and both AtCKX2 transgenic lines grown in 50-mM NaCl. On the other hand, in concentrations >50-mM NaCl, the total carotenoid content was decreased in all analysed centaury shoots. The Chl a/Chl b ratio in all the shoots increased progressively in the graded NaCl concentrations. Contrarily, the addition of NaCl in the culture medium reduced the Chl/carotenoid ratio in centaury shoots. Taken together, the results of this study partly explained the mode of centaury plant adaptations to salt stress in vitro. Thus, the results on centaury shoots confirmed that the determination of the photosynthetic pigment contents can be a very useful non-destructive screening method in order to discriminate susceptible and resistant plant species/lines to salt stress conditions. [ABSTRACT FROM AUTHOR]

Sea buckthorn (Hippophae rhamnoides L. (HR)) leaf powders are the underutilized, promising resource of valuable compounds. Genotype and processing methods are key factors in the preparation of homogenous, stable, and quantified ingredients. The aim of this study was to evaluate the phenolic, triterpenic, antioxidant profiles, carotenoid and chlorophyll content, and chromatic characteristics of convection-dried and freeze-dried HR leaf powders obtained from ten different female cultivars, namely 'Avgustinka', 'Botaniceskaja Liubitelskaja', 'Botaniceskaja', 'Hibrid Percika', 'Julia', 'Nivelena', 'Otradnaja', 'Podarok Sadu', 'Trofimovskaja', and 'Vorobjovskaja'. The chromatic characteristics were determined using the CIELAB scale. The phytochemical profiles were determined using HPLC-PDA (high performance liquid chromatography with photodiode array detector) analysis; spectrophotometric assays and antioxidant activities were investigated using ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (ferric ion reducing antioxidant power) assays. The sea buckthorn leaf powders had a yellowish-green appearance. The drying mode had a significant impact on the total antioxidant activity, chlorophyll content, and chromatic characteristics of the samples; the freeze-dried samples were superior in antioxidant activity, chlorophyll, carotenoid content, and chromatic profile, compared to convection-dried leaf powder samples. The determined triterpenic and phenolic profiles strongly depend on the cultivar, and the drying technique had no impact on qualitative and quantitative composition. Catechin, epigallocatechin, procyanidin B3, ursolic acid, α-amyrin, and β-sitosterol could be used as quantitative markers in the phenolic and triterpenic profiles. The cultivars 'Avgustinka', 'Nivelena', and 'Botaniceskaja' were superior to other tested cultivars, with the phytochemical composition and antioxidant activity. [ABSTRACT FROM AUTHOR]

Current trends in the industry indicate that extraction solvents should conform with the ideals of so-called "green chemistry". Therefore, the objective of the presented study was to optimize the conditions for the extraction of polyphenols, flavonoids and chlorophyll from peppermint leaves (Mentha × piperita L., Lamiaceae) and from common nettle leaves (Urtica dioica L., Urticaceae) via green chemistry. The obtained experimental results were subjected to modelling by means of the multiple regression method, while the optimization of the system was addressed via the application of the desirability function. As a result of the use of glycerol–water systems for the extraction of the tested active compounds from mint leaves and nettle leaves, extracts with higher concentrations of polyphenols, flavonoids and chlorophyll were most often obtained, when compared with the use of classical solvents such as water and ethanol. In this work, we demonstrate that the extraction temperature has significant influence on the concentration of the determined components in the extracts. To obtain the highest values of the analysed parameters, leaves of peppermint should be extracted with glycerol–water mixture at the proportions of 30.5:69.5 at a temperature of 50 °C, while the optimal conditions for the extraction of leaves of common nettle were the glycerol–water proportions of 12.5:87.5 and extraction temperature of 20 °C. Comparing the average percentage differences between the highest values of the analysed parameters obtained in the experiment and the approximated values for various temperatures with the level of desirability, one can note a high correlation that, in the analysed examples, amounted to 0.9681. The study showed that glycerol can be an alternative solvent in the extraction of polyphenols, flavonoids and chlorophyll, replacing, e.g., ethanol—which, for various reasons, cannot always be used. [ABSTRACT FROM AUTHOR]

ABSTRACTImages of chlorophyll fluorescence emitted at wavelengths above and below 700 nm were recorded from leaf sections of C4 species using confocal laser scanning microscopy (LSM). We investigated species exhibiting both NAD-malic enzyme (NAD-ME) C4 photosynthesis and NADP-malic enzyme (NADP-ME) C4 photosynthesis. Comparing LSM fluorescence of leaf sections with flow-cytometrically determined fluorescence from individual chloroplasts revealed that LSM fluorescence was distorted by the optical properties of leaf sections. Leaf section fluorescence, when corrected by transmission data derived from light transmission images, agreed with flow cytometry data. The corrected LSM fluorescence yielded information on the distribution of the individual photosystems in the C4 leaf sections: PSII concentrations in bundle sheath cells were elevated in NAD-ME species but diminished in most of the NADP-ME species investigated. The NADP-ME species, Arundinella hirta, however, showed normal PSII and increased PSI concentration in bundle sheath chloroplasts. Finally, a gradient of PSI was observed within the bundle sheath cells from Euphorbia maculata. [ABSTRACT FROM AUTHOR]

Chlorella fusca (Shihira et Krauss) strain C‐1.1.10 was grown under three different light qualities (red, white or blue light) in homocontinuous cultures. Under electron microscopy, blue light cultures showed enlarged cells, thinner cell walls and lower starch content than red light cells. Under blue light, the degree of stacking of the thylakoid membranes was significantly lower than under white or red light conditions. Changing the light from blue to red the ratio of exposed to appressed membranes was doubled. Compared to red light cells, blue light cells exhibited higher photosynthetic rates per chlorophyll molecule and contained less chlorophyll per dry weight. Blue light stimulated the content of soluble protein as well as that of soluble carbohydrates. The dry weight productivity per unit time was enhanced under blue light conditions. The thylakoid protein complexes which are generally assumed to be localized in the exposed membranes were found in higher concentrations under blue light than under red light. In blue light, both the Photosystem II/Photosystem I ratio and the ratio of light‐harvesting chlorophyll protein to P‐700 chlorophyll a‐protein were lower than in red light. Blue light cells contained twice the concentration of cytochrome f, which correlates well with their higher photosynthetic capacity. When altering the light quality, the degree of change in the reaction center complexes was much lower than expected given the corresponding degree of change in the ratio of exposed to appressed membranes. These results are discussed in light of the question as to whether the variation in the stoichiometry of the laterally distributed complexes can be explained by changes in the degree of stacking alone. [ABSTRACT FROM AUTHOR]

The level of 7 chlorophyll-carotenoid-proteins was determined in chloroplasts from radish seedlings (Raphanus sativus L. var, Saxa Treib)' grown in high-light (HL; 90 W m-2 and low-light (LL; 10 W m-2) growth conditions with and without application of the photosystem 2 herbicide bentazon (104M) and compare d with the degree of thylakoid stacking. 1. The photosynthetic apparatus of HL-chloroplasts contains higher proportions of the photosystem 1 chlorophyll a-proteins CP1 and CPIa than LL-chloroplasts or chloroplasts from bentazon-treated plants. 2. In LL-chloroplasts and in chloroplasts from bentazon-treated plants a higher proportion of light-harvesting chlorophyll a/b-proteins (LHCP1. LHCF2, LH'CP3, LHCPY) is found. Bentazon treatment changes the proportion of LHCPs to about the same levels under both HL and LL-growth conditions. The amounts of free chlorophyll found in bentazon chloroplasts (27-29%) is higher than in the HL or LL-controls (16-18%.). 3. The increase in degree of thylakoid stacking (% proportion of appressed mem- branes per total chloroplasts membranes) of LL-chloroplasts as! compared to HL- chloroplasts of 7 to 9% (3rd to 5th day of illumination) is paralleled by a similar increase in the LHCPs of 5% and 8% (3rd and 5th day). The importance of light harvesting chlorophyll a/b-proteins as a prerequisite for thylakoid stacking is discussed. [ABSTRACT FROM AUTHOR]