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Boron deficiency is a prevalent challenge for plant nutrition supply in many alkaline/calcareous soils. The current research aimed to examine the effects of boron supply to bell pepper plants through fertigation and foliar application. The experiment had seven treatments, comprising a control group, boric acid as fertigation (0.5, 1, and 2 g L-1), and foliar application (0.5, 1, and 2 g L-1) with three replications in controlled greenhouse conditions. The treatments were applied on Lorca bell peppers in a completely randomized design. The results showed that fertigation and foliar application increased all measured characteristics compared to the control group. Increasing the boric acid concentration in foliar application caused a decrease in fruit count per plant, fruit fresh weight, fruit yield per plant, and fruit width. Both fertigation and foliar boric acid applications at a low level (0.5 g L-1) and as separate treatments caused the highest fruit weight, length, width, and fruit count per plant. Higher boric acid concentrations increased chlorophyll a, b, total chlorophyll, leaf carotenoid content, soluble sugars, total soluble solids, titratable acidity, total phenols, and fruit ascorbic acid content. The highest chlorophyll a, b, total chlorophyll, leaf carotenoid content, and fruit ascorbic acid were observed in response to the high concentration of boric acid foliar application (2 g L-1). Overall, the boron supplement as a foliar application (0.5 to 1 g L-1) or fertigation (0.5 to 1 g L-1) improved quantitative and qualitative performance in bell peppers. [ABSTRACT FROM AUTHOR]

Climate change, through increased aridity, threatens ecosystems, including Morocco's endemic Argania Spinosa L. Skeels. This study assesses the impact of aridity on argan trees by analyzing morphological, ecophysiological, and biochemical parameters across various regions and comparing them with historical data. Significant variations were observed in leaf area, leaf length, chlorophyll content, relative water content, polyphenols, flavonoids, soluble sugars, and antioxidant activity, while leaf width ratio and chlorophyll ratio remained stable. Tioughza exhibited the largest leaf area (136.07 mm2), the highest chlorophyll content (436.76 mg/m2), and superior water retention (52.27%). Conversely, Ezzaouite showed the smallest leaf area (85.76 mm2) and lowest water content (37.68%). Increased aridity has intensified these differences, revealing the argan tree's vulnerability to climate change. The findings underscore the need for targeted conservation efforts, including reforestation, strengthened legislation, and enhanced genetic research, to sustain this vital species. [ABSTRACT FROM AUTHOR]

Introduction Intercropping reduces the application of chemical pesticides to control pests and weeds, reducing the environmental risks associated with chemical pesticide application (Himmelstein et al., 2017). Biochar is a soil amendment because of its potential to retain water and nutrients, prevent nitrogen leaching, increase soil fertility, and improve plant growth (Fang et al., 2018; Munoz et al., 2016). Other benefits of vermicompost are increased stability of soil resources, maintenance of production, reduction of environmental pollution, and increased soil biological activity too (Demir, 2019). Therefore, the purpose of this study was to investigate the quality of forage turnip (Brassica rapa var. rapa) leaves in different intercropping ratios of forage turnip and basil (Ocimum basilicum) using biochar as soil amendment and vermicompost. Materials and Methods A biennial study was conducted on the quality performance of forage turnip (Brassica rapa var. Rapa) in the form of split-plot factorial in a randomized complete block design with three replications in the research farm of Islamic Azad University of Karaj in two years (2018-2019). The treatments of this study include: intercropping in four ratio (100% forage turnip (monoculture), 90% forage turnip + 10% basil, 80% forage turnip + 20% basil, 70% forage turnip + 30% basil), in main plots, and vermicompost in two levels (15, 18.5 ton.ha-1) and biochar in two levels (No consumption and 5 ton.ha-1) which was placed in subplots. The forage turnip cultivar was PacFB05. In this study, Photosynthetic pigments were measured by the Arnon (1967) method, membrane permeability (Ferrat and Loval, 1999), relative moisture content (Bertin et al., 1996), soluble leaf sugars (Sheligl, 1986), catalase (Dazy et al., 2008) and soil respiration (Isermeyer, 1952). Using SAS software (Ver.9) for data analysis of a two-year experiment and analysis of means was done with Duncan’s test in significance at 5% probability level. Excel software was used to plot the graphs. Results and Discussion The results of this study indicated that by increasing the ratio of basil in intercropping, the quality traits of forage turnip leaves increased. Consumption of biochar and application of vermicompost at the level of 18.5 ton.ha-1 increased the quality of forage turnip leaves. The highest chlorophyll a ((17.52 mg.g-1Fw), chlorophyll b (8.76 mg.g-1Fw) total chlorophyll (26.38 mg.g-1Fw), carotenoids (6.91 mg.g-1Fw), relative water content (59.54%), of soluble sugars (69.43%), catalase (0.018 micromole Fresh weight/min) were due to the interaction of (70% forage turnip + 30% basil) × vermicompost 18.5 ton ha-1 × application of biochar. The highest value of membrane stability index was related to 100% forage turnip × vermicompost 15 ton ha-1 (4.85 (mol.ml-1.s-1)). The highest amount of soil respiration is associated with the interaction of vermicompost 18.5 ton.ha-1 × 70% forage turnip + 30% basil with value of 0.28 (micromole.gsoil-1.hour-1)), interaction of biochar ×70% forage turnip + 30% basil (0.32 (micromole.gsoil-1.hour-1)), and interaction of vermicompost of 18.5 ton.ha-1 × biochar 0.31 (micromole. g soil-1.hour-1). Due to the potential of biochar (water and food retention and prevent of nitrogen leaching) it can increase the availability of water and nutrients for the plant, which leads to increased photosynthesis of the plant and thus the quality of forage turnip leaves (Akhtar et al., 2015; Hammer et al., 2015). Vermicompost increases soil organic matter and the uptake of zinc, copper, iron, phosphorus, potassium, and nitrogen in soil. The presence of these elements in the soil and their absorption by the roots increases vegetative growth and leaf production in the plant, which causes the level of light absorption, photosynthetic level, the formation of hydrocarbons in the leaves, and the resulting growth also increases leaf quality (Theunissen et al., 2010). Conclusion The results of this study indicated that the application of vermicompost ​​18.5 ton ha-1 and biochar increased forage turnip quality, which is due to the availability of water and nutrients for forage turnip. The best intercropping ratio was related to 70% forage turnip + 30% basil, which can be said to be due to the increase in the percentage of basil and the competition of plants for better use of intercropping components of growth sources such as light, water, and food.

Finding methods, which may improve wheat (Triticumaestivum L.) growth and tolerance under drought stress, are of significance. The hypothesis was plant growth regulators (PGRs) are able to alter wheat physiology in a way so that the plant would be able to resist the stress. Accordingly, PGRs affecting wheat response in drought stress was investigated in greater details. Different PGRs, at different drought levels (80 (S1), 100- (S2) and 120-mm (S3) evaporation from pan class A) affecting wheat biochemical and nutritional properties including nutrient uptake (N, P, K) were tested. Experimental treatments including control (water, T1), and PGRs of gibberellic acid (GA3, 110 mgL−1, T2), salicylic acid (SA, 1.5 mM, T3), and benzyl adenine (60 mgL−1, T4), GA3 + SA (T5), as well as superoxide dismutase (SOD, 5 gL−1, T6) were tested in two different locations. Wheat biochemical and nutritional parameters including grain protein, chlorophyll a and b, leaf relative water at flowering and ripening, wet and dry gluten index, soluble sugars, and grain nutrient uptake were significantly enhanced by PGRs. The grain protein was in the range of 9.90 (S3T1) and 15.01% (S1T5); however, T5 treatment significantly enhanced it at the second (14.47%) and third (13.96%) level of drought. Although the single use of PGR was effective on the alleviation of stress, the combined use of GA3 + SA followed by the single use of SOD, were the most effective ones. Treating wheat plants with the tested PGRs is recommendable to improve wheat biochemical and nutritional properties in the arid and semi-arid areas. [ABSTRACT FROM AUTHOR]

In arid and semi-arid areas salinity reduces agricultural productivity. Biostimulants based on amino acids promote plant growth and yield while significantly reducing abiotic stresses-related injuries. As a result, current study assessed the effect of biostimulants based on free amino acids on Moldavian balm under salinity stress. A factorial experiment using a randomized complete block design with three replications was done. The plants were imposed with four levels of salinity (0, 20, 40 and 60 mM NaCl) and were treated using four formulations of amino acids (Kadostim, Fosnutren, Humiforte and Aminolforte). The results revealed that increasing the salinity level significantly reduced growth parameters such as fresh and dry weight of biomass, root length, shoot length, secondary branch length, crown diameter, internode number, internode length, secondary branch number, leaf number and biochemical parameters such as RWC, chlorophyll a, b, total and carotenoids while increased some osmolytes such as soluble sugar and proline in root and shoot. Leaf spraying of the bio-stimulates based on amino acids, significantly improved the negative effects of salinity stress on growth and biochemical parameters in Moldavian balm, and among them Kadostim had the most significantly positive effects on morphological and biochemical parameters and followed by Aminolforte. [ABSTRACT FROM AUTHOR]

Plants respond to different stresses using different mechanisms depending on the plant species and variety. This study aims to assess the physiological behavior of durum wheat (Triticumdurum Desf.) under various types of abiotic stress and to look for possible correlations between biochemical and physiological parameters during each stress. Simeto variety is grown in a hydroponic culture chamber and then subjected to four stresses (salinity, cold, heat, and drought) during the stem extension stage. The contents of water, chlorophyll, total sugars, and proline are measured on the fresh leaves of stressed plants. The highest proline values for salt and heat stress were 1.53 and 1.56 µmol/g fr wt, respectively. Water stress increased the content of soluble sugars by 59.62 µmol/g fr wt significantly. When compared to the control and cold stress (16.61 µg/g fr wt), salinity, drought, and heat stress significantly increased the chlorophyll content of cultivated wheat, which was 57.43 µg/g fr wt. Drought and salinity stresses were applied to cultivated durum wheat, resulting in a decrease in water content in fresh leaf tissues of 39.28 and 19.45%, respectively. The water content of the control wheat crop was 79.31%. Wheat's stress response is based on an osmoregulatory mechanism that involves proline accumulation. Salt and heat were the primary stressors with the greatest negative impact on cultivated wheat. The most significant associations between heat stress and soluble sugars levels and their correlation with proline, and total chlorophyll content and its correlation with chlorophyll a were discovered. [ABSTRACT FROM AUTHOR]

Drought stress is one of the major abiotic stresses that impair the growth and production of canola plants in arid and semi-arid zones, which necessitates the development of drought-resilient cultivars. The study aimed at determining the morphological, biochemical, and physiological responses of six different canola cultivars under three drought stresses imposed by polyethylene glycol. The main and interaction effects of cultivar and drought stress were determined using analysis of variance. The results showed a considerable decline in root length due to drought stress regardless of the cultivar. A significant interaction between cultivar and stress was detected on dry weight, height, and leaf area traits. Accordingly, growth parameters were observed to be linked with drought tolerance, and Hyola308 and Sarigol were identified as the most drought tolerant and sensitive cultivars, respectively. The values of chlorophyll contents in Hyola308 cultivar were remarkably higher than those in Sarigol under moderate-drought stress, while Sarigol maintained higher chlorophyll contents under severe stress. Increasing drought stress enhanced proline content and antioxidant enzyme activities (catalase and peroxidase) regardless of the cultivar. But a significant decrease in total soluble sugar was observed as drought intensity increased. This reduction in total soluble sugar content was about 38% lower in Hyola308 than in Sarigol. Therefore, some canola cultivars might mitigate drought stress effects by enhancing their proline and antioxidant system during drought stress. Furthermore, maintaining higher soluble sugar levels and greenness stability in response to increased drought stress might be a part of Hyola308's cultivar stress management strategy. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanoparticles (TiO2NPs) are widely used in agriculture in order to increase the yield and growth characteristics of plants. This study investigated the effects of TiO2NPs on photosynthetic pigments and several biochemical activities and antioxidant enzymes of the Vitex plant. Different concentrations of nanoparticles (0, 200, 400, 600 and 800 ppm) at five levels were sprayed on Vitex plants on the 30th day of the experiment. TiO2NPs at different concentrations had positive effects on root and shoot dry weight and a negative effect on leaf dry weight. The amount of chlorophyll increased with the concentration of TiO2NPs; however, the amount of chlorophyll b showed a decreasing trend while the total chlorophyll had a constant trend. The highest amount of soluble sugar was obtained in the treatment of 200 ppm nanoparticles. The application of TiO2NPs did not have any effect on the content of proline and soluble proteins of Vitex plant. The effects of foliar TiO2NPs, compared to the control, showed a significant increase in the activity of antioxidant enzymes. In general, TiO2NPs had a favorable effect on dry matter production and some antioxidant and biochemical properties of the Vitex plant.

In this study, the effects of nitrate (NO3−) to ammonium (NH4+) ratios on vegetative growth parameters, mineral uptake, physiological and biochemical responses of two semi-vigorous apple rootstocks (MM106 and MM111) in hydroponically grown under greenhouse conditions were evaluated. Treatments were five nutrient solutions of differing NO3−:NH4+ ratios as follows (100:0, 80:20, 60:40, 40:60, 20:80) and two apple rootstocks. After 120 days of treatment, parameters were determined. The NO3−:NH4+ ratios significantly affected the vegetative growth of MM106 and MM111 rootstocks. Rootstocks fertilized with a high NH4+ ratio produced larger leaves, longer roots, stems, and diameter, while the plants under NO3− treatment alone had smaller and shorter roots. N-form significantly influenced the uptake and utilization of essential plant nutrients in both rootstocks. Leaf concentrations of nitrogen (N), potassium (K), and calcium (Ca) were highest with NO3−. Leaf concentrations of phosphorous (P), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) increased as NH4+ supplied more of the N-ratio. The highest chlorophyll a and b and total chlorophyll were observed at the 20:80 NO3−:NH4+ ratio. In comparison, the lowest content was at the highest dose of NO3− (100:0) treatment. The highest soluble sugars were obtained in the leaves of MM106 and MM111 at the ratio of 80:20. Soluble sugars in the root of both rootstocks decreased by increasing the NH4+ ratios in the nutrient solution. Our results show that supplying rootstocks with high NO3− as N form can affect vegetative growth and mineral uptake at this stage of growth. [ABSTRACT FROM AUTHOR]

Salinity is among the most significant threats hindering global food security. The impact of Trichoderma, biochar, and combination on Spinach plants under salt stress conditions was investigated. Our results confirmed that salt stress (75, 150 mM) negatively affected morphological and physiological parameters of Spinach plants such as shoot (26.4%, 45.9%), and root length (16.1%, 51.2%), fresh and dry weights of root and shoot, membrane stability index (9.8%, 18.5%), relative water content(4.5%, 16.8%), chlorophyll content, mineral contents, endogenous phytohormones (auxin, gibberellins, abscisic acid, jasmonic acid, and salicylic acid) and total soluble protein content. However, electrolyte leakage, lipid peroxidation, reactive oxygen species production (such as hydrogen peroxide and hydroxyl radical), sodium, soluble sugars, proline contents, and antioxidant enzymes activities (peroxidase, catalase, and superoxide dismutase) significantly increased as a response to salt stress. The use of Trichoderma, biochar, and combination led to significant increases in all the above parameters; nevertheless, these treatments led to significant decreases in EL%, MDA, ROS, and sodium content in the stressed plants. The results proved the combination of Trichoderma and biochar is the most effective in alleviating the damaging impacts of salt on Spinach plants by increasing the up-regulation of antioxidants and decreasing membrane leakage and ROS. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) is known as an influential signal molecule in plant responses to environmental stresses. In this study, the effects of SA as a pre-treatment of psyllium (Plantago ovata) seeds on seedling growth, photosynthetic pigments, proteins and amino acids, and accumulation of soluble sugars and starch in response to salinity stress were investigated. Psyllium seeds were soaked with 0 and 500 μM SA for 24 h and sown in the research greenhouse of Iranshahr University in 2019, and the seedlings were exposed as a factorial design to 0, 25, 50, 100, 150 and 300 mM NaCl at 3-day intervals for 20 days. The results showed the seedling growth rate, photosynthetic pigments including chlorophylls and carotenoids, protein concentration as well as accumulation of soluble sugars and starch were severely reduced due to salinity stress. However, the accumulation of free amino acids and proline increased in response to salt stress. SA treatment improved the length of the shoot, increased the amount of pigments, decreased the amount of amino acids, and caused the accumulation of proteins and proline. In addition, an increase in the amount of non-reducing sugars and starch, which was associated with no change or decrease in the concentration of reducing sugars at high salinity levels, occurred in response to SA. These results show that priming the seeds with SA before sowing can increase the plant tolerance to salinity stress through the accumulation of non-reducing sugars and proline and thus maintain the turgor pressure of cells.

To point out the photosynthetic ability of perennial legume species, we measured the following parameters: chlorophyll content and soluble sugar content. Sampling was done on permanent pastures at different altitude levels: 90 m, 330 m, 900 m, and 1,800 m. Soluble sugar content was measured in samples from variants fertilized with mineral nitrogen and with organic fertilizers (through animal folding). Results showed that, as far as chlorophyll content is concerned, there is a negative relation between this parameter and the altitude level of the pasture. Perennial legume species on the pastures had a lower content of soluble sugars in all the variants fertilized with mineral fertilizers and with organic fertilizers compared to the control variant.

A two-year (2020-21) study was conducted to investigate the possibility of relying of ten-years old pear trees grown on sandy loam soil irrigated by drip on citric acid (CA), gibberellic acid (GA3) and humic acid (HA). The CA was applied at the concentrations of 500, 1000 and 1500 ppm, GA3 at 50, 100 and 150 ppm and HA at 3, 4 and 5%, whereas water spray was used as the control. The results of our study proved that CA, GA3 and HA improved the shoot length, shoot thickness, leaf area and leaf chlorophyll of pear as compared with the control. Moreover, they also positively increased the fruit set percentage and final yield of 'Le Conte' pear. The fruit weight, size and firmness were also improved under the influence of aforementioned treatments. The fruit soluble solids, total sugars, leaf nitrogen, leaf phosphorus and leaf potassium of pear were also enhanced as compared with the control. Additionally, spraying of GA3 at 150 ppm, as well as, HA at 5 and 4% were the superior treatments and showed the most significant impact on plant growth, yield, fruit quality and leaf mineral content of pear. This study provides a basis for the future elucidation of HA-, GA3- and CA-modulated molecular mechanisms in pear, which can make a significant contribution in the scientific community. [ABSTRACT FROM AUTHOR]

The present work aimed to evaluate some eco-physiological responses of Alhagi graecorum to elucidate its osmotic adjustment and physiological adaptation mechanisms to withstand hyper-aridity. The plant samples were collected from eight locations in the Dakhla Oasis during the winter and summer of 2017. The chlorophyll (Chl a & b) contents and their ratio increased significantly during summer enabling the plants to adapt to light condition changes. There was a greater accumulation of anions and cations in plant tissues during winter more than in summer except, for K +that exhibited the opposite trend during summer. Soluble sugars (SS) and soluble proteins (SP) were higher than total free amino acids (TAA) during summer. The total phenolics (Ph) and total antioxidants (Anti. Ox.) in this plant were higher during winter than in summer; whereas total flavonoids (Flav) displayed the opposite response. The results indicated close relationships among the high macronutrient contents, cool-moist conditions, and Ph and Anti. Ox. accumulation in winter. Ph and Anti. Ox. served as active compounds for perseverance or raw material for metabolic processes that let such plants maintain an abundant rate of growth under severe arid conditions. [ABSTRACT FROM AUTHOR]

Salt stress is one of the important abiotic factors responsible for inhibiting the growth and development of commercially important crops. The demand for salt-tolerant varieties is growing tremendously with increasing soil salinity. In the present study, the effect of salt stress on four commercially important potato cultivars ['Kufri Chipsona-1' (CS-1), 'Kufri Chandramukhi' (KCM), 'Kufri Pukhraj' (KP), and 'Kufri Jyoti' (KJ)] was examined to identify the salt-tolerant levels using in vitro screening. The nodes from microshoots of these cultivars were cultured for 40 days on MS1 medium (basal MS medium + 10 µM AgNO3) containing 0, 100, 200, and 300 mM NaCl. Compared to the control, the morpho-physiological traits varied significantly with maximum growth reduction in cultivar 'KJ' cultivar and minimum in 'CS-1'. The cultivar 'CS-1' showed no sign of leaf senescence and remained green on all the salt concentrations, while the other three cultivars ('KCM', 'KP', and 'KJ') turned brown and did not tolerate higher (300 mM) NaCl concentration. Moreover, cultivar 'CS-1' was found to have high chlorophyll, carotenoid, proline, sugars, and soluble protein contents on a medium containing 300 mM NaCl compared to the other three cultivars. As part of the antioxidant defense system, the analysis of various enzymes (peroxidase, ascorbate peroxidase, catalase, and superoxide dismutase) also showed a significant increase in their activity with an increasing NaCl concentration in cultivar 'CS-1'. The study concluded that cultivar 'CS-1' possessed a higher level of salt tolerance and could adapt to saline environment. We can further conclude that the accumulation of osmolytes and increased antioxidant enzyme activities have an important role in imparting salt tolerance to the plants. Therefore, the outcomes of the study can be utilized as a platform to develop screening strategies for the improvement of commercially important crops. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the effects of two irrigation levels, 100 percent of field capacity (FC) (control) and 30 percent FC (deficit irrigation) on vegetative growth, biochemical status, and water use efficiency of five pomegranate cultivars (Wonderful, Manfalouty, Acco, Assuity and Early 116) over two seasons in 2019 and 2020. The results showed that deficit irrigation reduced the dry weight of the shoots and roots, as well as the chlorophyll content of the leaves, in all the pomegranate cultivars. Under stress, proline content, total soluble sugars, total phenols, and peroxidase activity all increased significantly. The Manfalouty cultivar had the highest shoot and root dry weights, as well as the highest water use efficiency, proline content, and total phenols. Furthermore, when compared to other cultivars, Wonderful cultivar had the highest chlorophyll content during both seasons. In comparison to the other cultivars studied, Wonderful cultivar showed the limited or no significant increase in peroxidase activity. This could be due to a genotype's variable peroxidase activity potential in pomegranate cultivars under water stress. The obtained results indicate that Manfalouty and Wonderful cultivars are more tolerant of deficit irrigation than the other cultivars studied. [ABSTRACT FROM AUTHOR]

Potassium (K) levels are decreasing worldwide in agricultural soils, and K deficiency is becoming a major issue. Study on damask rose response to K application is scarce. Furthermore, despite its importance in the cell division, photosynthesis and protein synthesis, there is a lack of published reports on plant responses to zinc (Zn) application. Further research is required to understand the damask rose's response to both elements. This study investigated the effects of K and Zn foliar application on the vegetative growth, flower yield, and volatile oil content and composition of damask rose. K and Zn nutrition was applied either individually or combined as K2SO4 and ZnSO4 at 0.5 or 1.0%. Foliar application of K2SO4 and ZnSO4 was applied with a manual pump four times in each growing season, the first at the beginning of stem elongation and leaf formation, and then at two-weekly intervals. Results showed that K and/or Zn treatments significantly improved the growth characters, flower yield, relative water content (RWC), stomatal conductance, and essential oil content and composition such as linalool, nerol, citronellol, geraniol, and nonadecane. The chlorophyll content, total soluble sugars (TSS), and protein content also increased, but free amino acid content decreased, suggesting that the distribution of nitrogenous compounds (between amino acids and proteins) and their transformation were influenced by K and Zn supply. Individual applications of K or Zn increased the N, P, K, and Zn contents in damask rose leaves, relative to the control, which increased further with combined applications of K and Zn. Results suggest that foliar application of K and/or Zn could be part of the damask rose fertilization program to provide plants with the optimum level of nutrition for improving the quantity and quality of flowers and essential oil yields.

Salicylic acid (SA) is known as an influential signal molecule in plant responses to environmental stresses. In this study, the effects of SA as a pre-treatment of psyllium (Plantago ovata) seeds on seedling growth, photosynthetic pigments, proteins and amino acids, and accumulation of soluble sugars and starch in response to salinity stress were investigated. Psyllium seeds were soaked with 0 and 500 μM SA for 24 h and sown in the research greenhouse of Iranshahr University in 2019, and the seedlings were exposed as a factorial design to 0, 25, 50, 100, 150 and 300 mM NaCl at 3-day intervals for 20 days. The results showed the seedling growth rate, photosynthetic pigments including chlorophylls and carotenoids, protein concentration as well as accumulation of soluble sugars and starch were severely reduced due to salinity stress. However, the accumulation of free amino acids and proline increased in response to salt stress. SA treatment improved the length of the shoot, increased the amount of pigments, decreased the amount of amino acids, and caused the accumulation of proteins and proline. In addition, an increase in the amount of nonreducing sugars and starch, which was associated with no change or decrease in the concentration of reducing sugars at high salinity levels, occurred in response to SA. These results show that priming the seeds with SA before sowing can increase the plant tolerance to salinity stress through the accumulation of non-reducing sugars and proline and thus maintain the turgor pressure of cells. [ABSTRACT FROM AUTHOR]

Potassium (K) levels are decreasing worldwide in agricultural soils, and K deficiency is becoming a major issue. Study on damask rose response to K application is scarce. Furthermore, despite its importance in the cell division, photosynthesis and protein synthesis, there is a lack of published reports on plant responses to zinc (Zn) application. Further research is required to understand the damask rose's response to both elements. This study investigated the effects of K and Zn foliar application on the vegetative growth, flower yield, and volatile oil content and composition of damask rose. K and Zn nutrition was applied either individually or combined as K2SO4 and ZnSO4 at 0.5 or 1.0%. Foliar application of K2SO4 and ZnSO4 was applied with a manual pump four times in each growing season, the first at the beginning of stem elongation and leaf formation, and then at two-weekly intervals. Results showed that K and/or Zn treatments significantly improved the growth characters, flower yield, relative water content (RWC), stomatal conductance, and essential oil content and composition such as linalool, nerol, citronellol, geraniol, and nonadecane. The chlorophyll content, total soluble sugars (TSS), and protein content also increased, but free amino acid content decreased, suggesting that the distribution of nitrogenous compounds (between amino acids and proteins) and their transformation were influenced by K and Zn supply. Individual applications of K or Zn increased the N, P, K, and Zn contents in damask rose leaves, relative to the control, which increased further with combined applications of K and Zn. Results suggest that foliar application of K and/or Zn could be part of the damask rose fertilization program to provide plants with the optimum level of nutrition for improving the quantity and quality of flowers and essential oil yields. [ABSTRACT FROM AUTHOR]

A two-year (2020-21) study was conducted to investigate the possibility of relying of ten-years old pear trees grown on sandy loam soil irrigated by drip on citric acid (CA), gibberellic acid (GA3) and humic acid (HA). The CA was applied at the concentrations of 500, 1000 and 1500 ppm, GA3 at 50, 100 and 150 ppm and HA at 3, 4 and 5%, whereas water spray was used as the control. The results of our study proved that CA, GA3 and HA improved the shoot length, shoot thickness, leaf area and leaf chlorophyll of pear as compared with the control. Moreover, they also positively increased the fruit set percentage and final yield of ‘Le Conte’ pear. The fruit weight, size and firmness were also improved under the influence of aforementioned treatments. The fruit soluble solids, total sugars, leaf nitrogen, leaf phosphorus and leaf potassium of pear were also enhanced as compared with the control. Additionally, spraying of GA3 at 150 ppm, as well as, HA at 5 and 4% were the superior treatments and showed the most significant impact on plant growth, yield, fruit quality and leaf mineral content of pear. This study provides a basis for the future elucidation of HA-, GA3- and CA-modulated molecular mechanisms in pear, which can make a significant contribution in the scientific community.

Taraxacum pieninicum Pawł. is listed as critically endangered species, for which currently applied protection methods are insufficient. The aim of this study was to investigate the possibility of T. pieninicum storage in the form of synthetic seeds under slow-growth conditions in combination with ABA treatment, as one of the ex situ protection methods of this species. The obtained results indicated that darkness was much more favorable condition for synseed storage and did not generate additional stress during cold exposure in contrast to the light conditions. The preculture of shoot tips on the medium supplemented with ABA led to a decrease in the shoots proliferation rate and inhibition of their growth. ABA clearly inhibited growth of the encapsulated shoot tips also during cold storage. Biochemical parameters showed that ABA effectively reduced the negative effect of the cold stress, what was found on the basis of analyzes of H2O2 and TBARS levels in the stored material. Moreover, synseeds stored under light conditions and treated with ABA exhibited decreased level of endogenous jasmonic acid what indicated interaction between those two phytohormones at a low temperature. The study also demonstrated that in vitro culture, cold storage and ABA treatment had no effect on the flowering process of this species after acclimatization to ex vitro conditions. Key message: The aim of this research was to assess ABA effect on post-storage regrowth and the stress factors level in plants obtained after long-term storage of Taraxacum pieninicum synthetic seeds. [ABSTRACT FROM AUTHOR]

Zinc (Zn 2+ ) is one of the essential micronutrient elements for plant growth. In the present study, effect of different concentrations of zinc on some physiological and biochemical properties of basil (Ocimum basilicum) was investigated. Basil seedlings were exposed to six zinc (ZnSO 4 ) levels (0, 50, 100, 200, 400, and 800 mg/L) in 3 days’ intervals for a period of 30 days. The root and shoot growth, leaf number and area, photosynthetic pigments content, total soluble sugars and proteins, phenolic compounds, antioxidant power and mineral elements contents including zinc and potassium were significantly increased in effect of zinc levels up to 200 mg/L. Inversely, ferrous and calcium contents was drastically decreased concomitant with increasing zinc concentration but magnesium content remained unchanged. Our results indicated a dual role of zinc with optimum concentration of 200 mg/L, and a decrease in the root and shoot growth, pigment and phenolic contents under and over optimum concentration, whereas sugars and protein accumulation were occurred concomitantly with increasing zinc in the medium. However, the decrease of these parameters at the highest zinc concentration did not reach the level of control plants, which means that this species has a high resistance against zinc metal stress and because of the relative accumulation of zinc in polluted areas may has an important role for human nutrition. In general, the results point to important role of zinc in maintaining and protecting of basil seedlings against radical oxygen species.

In order to elucidate the impact of soil salinity on foliar metabolism indicators of radish (Raphanus sativus L.), two genotypes of Radish "National" and "Cerise" were subjected to increasing salt treatments add ECe of soil (control (0.6 dS m-1), 5.63 and 12.18 dS m-1). The laboratory test showed that soil salinity had adverse effects on most of the physiological and biochemical parameters in the leaves of both radish varieties. Chlorophyll pigments decreased in the two radish varieties and the rate of chlorophyll degradation was higher in "Cerise" vr. under severe salinity stress. On the other hand, leaf carotenoids substantially decreased in "National" vr. The total soluble sugars and total soluble proteins decreased in both radish varieties under salinity stress. However, total soluble proteins were higher in the salt stressed leaves of "Cerise" vr. These results showed that greater salt tolerance in "National" vr. was associated with phenolics and antioxidant activity which indicated stimulation of foliar metabolism associated with antioxidant potential. [ABSTRACT FROM AUTHOR]

Since the response of plant species to air pollutants is variable, the classification of plants into sensitive and tolerant groups is vital because the former can serve as biological indicators and the latter as sinks for the air pollutants. The morphological, biochemical, and physiological effects of fluoride stress were investigated in mulberry plants (Morus alba L.) grown at different distances from a phosphate fertilizer factory in Tunisia. Gas exchange (photosynthetic rate, stomatal conductance, and transpiration rate), photosynthetic pigments (chlorophyll and carotenoids) and water status (leaf relative water content) were decreased in the mulberry leaves grown near the polluted sites. However, lipid peroxidation (malondialdehyde content) and osmotic regulator (proline and soluble sugars content) levels were increased as compared to the control site. The obtained results suggest that Morus alba leaves could be considered as an air pollution bioindicator. [ABSTRACT FROM AUTHOR]

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Vegetable product quality is an important consideration for consumers. Long-term root cooling could improve certain food quality of horticultural crops, but often comes at the expense of reduced shoot biomass or yield. Since few studies have investigated how fast Chinese broccoli (Brassica oleracea var. alboglabra Bailey) responds to changes of root temperature, we shortened the duration of the root cooling treatment to one week before harvest to make the production system more effective. The aim of this study was to improve the food quality of Chinese broccoli without causing deleterious effects on plant growth and yield. The seedlings were cultivated hydroponically at two root temperatures (10 and 20 °C) during the last week prior to harvest in summer 2018 (Exp-1) and autumn 2019 (Exp-2). Plant growth, yield, physiological variables, soluble sugars, total chlorophyll, glucosinolates and mineral elements concentration were examined. The results showed that the yield reduction was alleviated compared to results over the long-term. Specifically, yield was not affected by root cooling in Exp-1 and reduced by 18.9% in Exp-2 compared to 20 °C. Glucose and fructose concentrations of the leaves were increased when the root temperature was 10 °C in both experiments with a more pronounced impact in Exp-2. In addition, root cooling produced a significant accumulation of individual glucosinolates, such as progoitrin, gluconapin, 4-methoxyglucobrassicin and 4-hydroxyglucobrassicin, in the stems of Exp-1 and the leaves of Exp-2. Minerals, such as N, showed reductions in the shoot, but accumulation in the root. Therefore, compared to long-term root cooling, short-term (one week) reduction of the root temperature is more economical and could help improve certain quality characteristics of Chinese broccoli with less or even no yield reduction.

Root temperature has long been considered an essential environmental factor influencing the plant’s physiology. However, little is known about the effect of root temperature on the quality of the food produced by the plant, especially that of horticultural crops. To fill this gap, two independent root cooling experiments (15 °C vs. 20 °C and 10 °C vs. 20 °C) were conducted in autumn 2017 and spring 2018 in hydroponics with Chinese broccoli (Brassica oleracea var. alboglabra Bailey) under greenhouse conditions. The aim was to investigate the effect of root temperature on plant growth (biomass, height, yield) and food quality (soluble sugars, total chlorophyll, starch, minerals, glucosinolates). A negative impact on shoot growth parameters (yield, shoot biomass) was detected by lowering the root temperature to 10 °C. Chinese broccoli showed no response to 15 °C root temperature, except for an increase in root biomass. Low root temperature was in general associated with a higher concentration of soluble sugars and total chlorophyll, but lower mineral levels in stems and leaves. Ten individual glucosinolates were identified in the stems and leaves, including six aliphatic and four indolic glucosinolates. Increased levels of neoglucobrassicin in leaves tracked root cooling more closely in both experiments. Reduction of root temperature by cooling could be a potential method to improve certain quality characters of Chinese broccoli, including sugar and glucosinolate levels, although at the expense of shoot biomass.

To the better management of frostbite problem in fruit crops, evaluation of biochemical changes in buds during dormancy break is a key factor. In this study biochemical changes in terminal buds of three different walnut genotypes (early-season, mid-season, and late-season), was investigated during winter dormancy release time. Terminal bud samples were taken from the genotypes in two different times in winter (1st and 20th of March). Variables such as; bud soluble sugars, starch, proline, chlorophyll, total phenolic and protein content as well as catalase (CAT) and guaiacol peroxidase (GPO) enzymes activities were assessed. Analysis of variance ANOVA) revealed significant differences (p ≤ 0.05) for the measured variables and sampling times among the genotypes. The results indicated that the late growth genotype had the highest content of soluble sugars and proline, and the lowest amount of starch and protein (p ≤ 0.05) in comparison with early and mid-season growth genotypes. Different enzymes activities were observed in terminal buds among the genotypes. As sampling time delaying, the content of chlorophyll, CAT and GPO enzymes activity increased, while a decrease in proline and total phenol was observed. The results of this study can be considered to a better understanding of the primary mechanisms of bud dormancy break in walnut to reduce the late spring frost damage problem as well as for using in breeding programs. [ABSTRACT FROM AUTHOR]

In order to study the morphologic and physiologic responses of one Canola cultivar (Talayie) to moisture Stress, a 4- replicate CRD greenhouse experiment was conducted during at the Islamic Azad University of Jahrom. The treatments consisted of five moisture levels with intervals 7(control),14,21,28 and 35 days of irrigation .Total dry weight, stem length and root, total leaf chlorophyll, total soluble sugars and proline, Na+, K+ in leaves were measured at the final leaf growth stage. Results showed that total leaf chlorophyll and K+ significantly decreased in comparison to control. Dry weight decreased with increasing drought stress and significantly decreased in treatments of 28 and 35 day of irrigation in comparison to control. Decrease of stem length, except in treatment of 14 day of irrigation has significant in comparison to control. Na+ in leaves significantly increased with increasing of drought stress. The differences of root length between different treatments were not significant. The total soluble sugars and proline contents increased with increasing of drought stress. The sugars and proline accumulation probably play an important role in the osmoregulation and induction of drought tolerance. Decrease of k+may be lead to stomatal resistance and decreasing of photosynthesis and growth.

Resumen Se establece una comparación de algunos parámetros fotosintéticos: actividad Rubisco (Ribulosa 1, 5-bis-fosfato carboxilasa EC 4.1.1.39) contenidos de clorofilas, azúcares solubles totales y proteínas solubles totales y área foliar específica (AFE), en tres poblaciones altitudinales de Espeletia schultzii ubicadas a 3 100, 3 550 y 4 200 msnm. De acuerdo con el análisis de varianza la población a 4 200 m presentó una actividad Rubisco significativamente mayor que las otras dos, en cuyos casos los valores no fueron diferentes. Los contenidos de clorofila a presentan una leve tendencia a la disminución con la altura; mientras que la clorofila b se mantiene constante, razón por la cual la relación a/b (R a/b) disminuye con la elevación, aunque, las diferencias no son significativas. El contenido de azúcares en cada una de las poblaciones estudiadas (gm-2), aumenta con la elevación; las diferencias entre las poblaciones son significativas. Con relación al contenido de proteínas, no existen diferencias entre las poblaciones estudiadas. El área foliar específica (AFE) disminuye significativamente con la altura. Es probable que el incremento en la actividad Rubisco sea producido por una mayor activación de la enzima y no por el mayor contenido de proteína. Los azúcares solubles presentan incremento significativo, este hecho es probable que se encuentre asociado con la actividad Rubisco. De los cinco parámetros fotosintéticos medidos, tres presentan diferencias significativas asociadas con la altitud. Esto representa un compromiso entre una mayor actividad metabólica mantenida en un menor volumen celularPhotosynthesis in three altitudinal populations of the Andean plant Espeletia schultzii (Compositae). Photosynthesis was compared in three altitudinal populations of Espeletia schultzii: 3 100, 3 550 and 4 200 masl. The measured parameters were Rubisco activity (EC 4.1.139), chlorophyll, soluble protein and soluble sugars contents, and specific leaf area (SLA). The 4 200 m population had a higher Rubisco activity (at 4 °C) followed by those at 3 550 m and 3 100 m. There were no significant differences between populations at 3 100 m and 3 550 m (ANOVA), but their activities were different from those of the 4 200 m population. Chlorophyll a content decreased slightly with elevation, while chlorophyll b was constant; therefore, the Ra/b ratio decreased with elevation, but not significantly. The leaf soluble sugars content increased along the altitudinal gradient. Leaf protein content did not differ. The SLA decreased with altitude. The increase in Rubisco activity might reflect higher enzyme activation and not higher enzyme protein. The increase in soluble sugars is probably associated to Rubisco activity. Three out of the five measured parameters revealed differences with altitude, suggesting a compromise between a higher metabolic activity and a smaller cellular volume. Rev. Biol. Trop. 54 (4): 1143-1149. Epub 2006 Dec. 15

The effects of increasing the NaF concentration supplied through the irrigation water on some photosynthetic and physiological features of young olive trees grown under the ambient environmental conditions of an arid climate in Sfax, Tunisia, were investigated. Thirty-six uniform one-year-old self-rooted olive trees (Olea europaea L. cv Chemlali) were transplanted into 5 L pots and irrigated for 5 months with NaF concentrations of 0 (control), 20, 40, and 80 mM NaF. The responses of the young olive trees grown under fluoride stress were slight reductions of leaf relative water content, net photosynthesis, stomatal conductance, transpiration rate, photosynthetic pigment content, and growth traits. Interestingly, the Chemlali olive tree was relatively resistant to the fluoride stress under the experimental conditions since it maintained some photosynthetic activity and a suitable leaf relative water content. Moreover, the positive evolution in the content of proline and soluble sugars with increasing NaF stress was further evidence of the effect of these osmoticums for improving the tolerance of the Chemlali olive trees to fluoride stress. [ABSTRACT FROM AUTHOR]

All abiotic stresses lead to evolution of oxidative stress. Relatively, research addressing the physiological basis of oxidative stress tolerance are scanty. Hence, the study was designed to induce oxidative stress, by in vivo treatment with hydrogen peroxide (H2O2) in rice genotypes showing contrasting behavior to flooding and salt stress. Four genotypes namely, FR 13A (tolerant to flooding stress); Co 43 (susceptible to flooding stress); FL 478 (tolerant to salinity stress) and IR29 (susceptible to salinity stress) were taken to study important physiological traits like chlorophyll contents, cell Membrane Stability (CMS), lipid peroxidation, soluble sugars, Soluble protein content and Nitrate reductase (NR) activity under oxidative stress. The flooding and saline tolerant genotypes showed a lesser per cent reduction in the chlorophyll contents and were able to maintain higher sugar contents on exposure to H2O2 treatments compared to the susceptible ones. Degradation of protein contents and reduction in CMS with increased lipid peroxidation was observed in all the varieties and the protein contents decreased with increase in concentration of H2O2 treatment. H2O2 treatments also showed a linear decrease in NRase activity in all the genotypes taken for study. [ABSTRACT FROM AUTHOR]

The objective of this work was to determine the early physiological changes throughout shelf life of fresh broccoli (Brassica oleracea L. var. italica) cv. Piracicaba Precoce at 25ºC and relative humidity of 96% in the dark until complete senescence. Head inflorescences showed lack of turgidity and commercial value when weight loss reached up to 5%, coinciding with 48 hour after harvest. Chlorophyll content was stable until 24 hours after harvesting; afterwards, an intense degradation phase took place. At 72 hours, total head yellowing was observed when chlorophyll content dropped to 30% of its initial content. Peroxidase activity increased by 1.4 fold during the first six hours, dropping to its lowest level approximately 24 hours after harvesting. However, from this time on, an increment of activity was observed until 72 hours. At 24 hours after harvesting, respiration was reduced by 50%. At later stages of senescence, respiration of florets was stable, but in a lower level than that determined at harvest. Sharp reduction of starch and reducing sugars was observed within 24 hours after harvesting, followed by continuous period of decline in starch and non-reducing sugars.Alterações fisiológicas ocorridas durante a vida de prateleira em inflorescências de brócolis (Brassica oleracea L. var. italica) cv. Piracicaba Precoce foram avaliadas durante armazenamento a 25ºC e umidade relativa de 96%. A perda de turgidez e de valor comercial das inflorescências ocorreu 48 horas após a colheita, totalizando 5% de perda da matéria fresca. O conteúdo de clorofila permaneceu inalterado até 24 horas após a colheita, seguindo-se um período de intensa degradação. As inflorescências estavam completamente amarelas 72 horas após a colheita, quando apresentavam 30% do teor inicial de clorofila. A atividade peroxidativa elevou-se em 1,4 vezes nas seis horas subseqüentes à colheita, diminuindo até 24 horas, seguido de aumento da atividade até 72 horas pós-colheita. A respiração foi reduzida em 50% nas primeiras 24 horas após a colheita, e permaneceu estável nos estádios finais do amarelecimento, mas com taxas inferiores às observadas na colheita. Os teores de amido e açúcares redutores sofreram quedas acentuadas nas 24 horas subseqüentes à colheita, bem como uma fase de persistente declínio do amido e de açúcares não-redutores.

Many factors threaten the survival of desert plant species. One of the most prevalent is aeolian dust accumulation, generated by soil surface disturbance. Nevertheless, the influence of aeolian dust accumulation on plant physiology has hardly been investigated. Therefore, the effect of aeolian dust accumulation on some biochemical parameters in Haloxylone aphyllum was evaluated for the pan-Asiatic distribution and its key role in desert rehabilitation. The amount of dust trapped by an increasing coverage of (20%) was 1.77, 1.80, 2.43, 2.10 and 2.72 times of that by the control, respectively. Reductions in chlorophyll a (Chl. a), chlorophyll b (Chl. b) and total carotenoids (Cr) were observed in the leaf samples among the treatments. The ratio of Chlorophyll a/b and chlorophyll (a+b)/Cr showed a negative correlation with dust accumulation. The obtained data revealed that, aeolian dust accumulation induced a surge of changes in biochemical (total nitrogen and, total Soluble Sugar content, main and accessory Photosynthetic Pigments) and thus in physiological performance. [ABSTRACT FROM AUTHOR]

Olive (Olea europaea L.) production is marked by annual oscillations as trees alternate from high to low crop loads in successive years. Gas exchanges and carbohydrate content of leaves and fruits in olive tree (O. europaea cv. Besbassi) were monitored at pit hardening and fruit ripening. After fruit set, three crop loads were applied (100%, 50% and 25% of the initial fruit load) by manual thinning. Severe fruit thinning reduced photosynthesis, stomatal conductance and intercellular CO[sub 2] concentration. Crop load had no significant effect on chlorophyll fluorescence parameters. The reduction of 75% of the initial crop load favoured the accumulation of starch in leaves and soluble sugars in leaves and fruits. The reduction in initial fruit load had a significant positive effect on the current year's shoot elongation and on inflorescence number the following spring. To increase the fruit size, a strong thinning (75%) was necessary, which coincided with the highest shoot vigour. Moderate thinning (50%) hardly affected leaf carbohydrate content and fruit size, but photosynthetic capacity was only limited at fruit ripening. [ABSTRACT FROM AUTHOR]

Abstract: Light management and species light plasticity are critical factors for proper crop production in nurseries. So, to assess the light necessities of Rhamnus alaternus, which is a promising native evergreen Mediterranean shrub of ornamental and ecological interest, it was exposed to five shade levels (0%, 32%, 48%, 84% and 93%) for one year (0% of shade received annual mean maximum photosynthetic photon flux density [PPFD] of 1293±415μmolm−2 s−1 with a summer mean maximum PPFD of 1541±225μmolm−2 s−1 [mean±s.d.]). The treatments providing 84% and 94% shading produced less compact plants, with greater height and less stem diameter, greater specific leaf area and higher shoot/root index. In general, the shading produced dark green leaves except the 94% treatment, in which the leaves were lighter because the relative chlorophyll content was reduced. Leaf thickness was reduced in all the shading treatments compared with the control. The stomatal density and pore area were reduced with the 84% and 93% shading treatments, as was photosystem II (PSII) efficiency and the leaf soluble sugar content (falling to 60% of the control level); in contrast, non-photochemical quenching increased. The 93% treatment caused irreversible damages in PSII because dark-adapted PSII efficiency was reduced. The results show that solar radiation can be used as a tool to improve plant quality during the nursery period. We conclude that shading screens providing more than 84% shade are not recommendable in terms of photochemical activity, soluble sugar content and overall plant quality. Shading screens of 32% and 48% improve R. alaternus quality in spring and summer, respectively. As regards its interest as an understory species for reforestation programs, we also conclude that this shrub can be adapted to a wide range of shade intensities, although its proper development would be compromised in very strong shading conditions. [Copyright &y& Elsevier]

Due to anthropogenic influences, solar UV-B irradiance at the earth's surface is increasing. To determine effects of enhanced UV-B radiation on sweet almond (Prunus dulcis), one-year old seedlings were submitted to four levels of UV-B radiation namely 0 (UV-BC), 0.45 (UV-B1), 1 (UV-B2), 1.50 (UV-B3), and 1.96 (UV-B3) W m-2 at a PAR intensity of 300 μ mol m-2 s-1 for 5 weeks. UV-B stress led to a significant decrease (p<0.05 ) in photosynthetic and non-photosynthetic pigments such as chlorophyll a, chlorophyll b, total chlorophyll and carotenoid content, whereas a significant increase was observed for UV-B absorbing pigments (flavonoid and anthocyanin), total soluble sugars and relative electrolyte conductivity. Most of the studied parameters were only affected at high UV-B levels (> UV-B3). [ABSTRACT FROM AUTHOR]

Abstract: Red Chinese sand pears (Pyrus pyrifolia Nakai) are particular to China. In order to determine the effects of fruit bagging treatments (including bag types, bag removal patterns and dates) on fruit qualities and to understand the mechanism of coloring of red Chinese sand pears, two experiments were carried out. In the first experiment, fruit of ‘Meirensu’ were firstly covered by light-impermeable paper bags with different levels of light permeable liners during their early development stage, then, the whole bag were/not removed or only the outer layer of bags were removed 3, 2 or 1 weeks before harvest. Thus, the fruit were/not totally re-exposed or were under different levels of sunlight transmission (80.31% or 34.71%). Non-bagged fruit were used as the control. Bagging treatments significantly affected the concentration of anthocyanin and the visual qualities of pear fruit. Compared to control, fruit re-exposed totally for 2 or 3 weeks accumulated the largest amount of anthocyanin and fruit receiving 80.31% and 34.71% of sunlight for 1–3 weeks could synthesize a little anthocyanin, indicating that high light intensity is imperative for coloring in red Chinese sand pears. Bagging treatments did not affect contents of total soluble sugars, but decreased organic acids contents in fruit. In the second experiment, fruit of ‘Meirensu’ and ‘Yunhongli No. 1’ were covered with only one type of light-impermeable bag during the early development stage and totally re-exposed after the bag removal 15 days before harvest. Fruit were then collected at different intervals to trace the time-course of coloring, and related physiology and inner qualities. With increasing time after the bag removal, the concentration of chlorophyll, carotenoid, flavonoid and total phenols changed little, but the concentration of anthocyanin accumulated extremely fast within 10 days after the bag removal in both cultivars and thereafter kept constant. ‘Yunhongli No. 1’ had higher anthocyanin contents and lower hue angle than ‘Meirensu’, indicating a higher potential of anthocyanin synthesis. After the bag removal, the sucrose contents and PAL activities increased gradually and correlation analysis revealed that they were highly correlated with anthocyanin accumulation in two cultivars. This study suggests that anthocyanin biosynthesis in red Chinese sand pears is a highly light dependent process and modified by genotypes. Based on the current results, in order to obtain red Chinese sand pear fruit with attractive appearance and good inner qualities, fruit must be covered with light-impermeable bags at the early stage of fruit development and the bag should be removed totally at least 10 days before harvest. [Copyright &y& Elsevier]

Relative water content (RWC), leaf water potential (Ψw) and osmotic potential (Ψs), contents of chlorophyll (Chl) a, Chl b, soluble sugars, and seed quality (gum content) were used to evaluate the role of phosphorus in alleviation of the deleterious effect of water deficit in clusterbean ( Cyamopsis tetragonoloba L. Taub). Under water stress, Ψw, Ψs, and Chl and gum contents decreased and soluble sugar contents increased. Phosphorus application increased Chl and sugar contents in control plants and ameliorated negative effects of water stress. [ABSTRACT FROM AUTHOR]

This study reports the effects of light and CO2 availability during the acclimatisation phase on micropropagated plantlets of a chestnut hybrid (Castanea sativa×Castanea crenata). After in vitro phases at 50 μmol m−2 s−1, the plantlets were transferred directly from in vitro root induction to ex vitro acclimatisation under four different treatments corresponding to irradiances of 150 and 300 μmol m−2 s−1 each one in association with CO2 concentrations of 350 and 700 μl l−1. For all treatments, the survival rates were above 80%. CO2 concentration at 700 μl l−1 promoted growth measured as relative growth rate and net assimilation rate. Leaf area was also promoted by high CO2, but without the corresponding increase in dry weight. A biomass increase of 100% was obtained when high CO2 was combined with high irradiance. Total chlorophyll content of in vitro (persistent) and ex vitro (new) formed leaves was mainly affected by the irradiance. Chlorophyll a/chlorophyll b ratio of new leaves at the end of all the acclimatisation treatments attained the value of full autotrophic leaves. Unlike starch, the concentration of soluble sugars was significantly down-regulated by CO2 concentration. Sucrose was exported from persistent leaves independently of the treatments. As growth proceeded, new expanded leaves became the carbohydrate source and exported sucrose to the growing apices and other new leaves. The effect of high irradiance (300 μmol m−2 s−1) combined with high CO2 concentration (700 μl l−1) on the acquisition of autotrophic behaviour by the plants is discussed. [Copyright &y& Elsevier]

Soluble sugars, proline, total chlorophyll contents and electrolyte leakage were measured in two wheat ( Triticum aestivum L.) cultivars KRL 1-4 and HD 2009 at different growth stages [crown root initiation (CRI), flowering, and soft dough] under short term salinity (NaCl, CaCl2 and Na2SO4). In control plants sugar contents were maximum at flowering stage. Proline and sugar concentrations increased in both cultivars under salinity with a maximum increase at CRI. Electrolyte leakage increased and chlorophyll content decreased with the plant age. A sharp increase of electrolyte leakage was noticed at salinity of 10 and 15 dS m−1 in HD 2009 and KRL 1-4, respectively. The short-term salinity at CRI stage proved more detrimental as compared to salinity at flowering and soft dough stages in term of all biochemical changes induced. In wheat, plant resistance to salinity increased with the age of plant. The cultivar KRL 1-4 performed better under salinity as compared to HD 2009. [ABSTRACT FROM AUTHOR]