Higher Amount Of Proline Research Articles

The role of the application of nanosilver and humic acid on the physiological and yield traits of corn (Zea Mays L.) under deficit irrigation conditions

Water deficit is the most common abiotic stress and at least 75% of corn fields in Iran are exposed to drought stress during different stages of growth. humic acid (HA) and nanosilver (NS) can help mitigate abiotic stresses in plants; especially drought stress. A field experiment was conducted to study the effect of humic acid and nanosilver on the physiological traits and yield of corn during two crop years. Experimental treatments were including deficit irrigation (100%, 80%, 60% of crop water requirement (CWR)) and nanosilver (0 (NS0), 60 (NS60), 80 (NS80) and 100 (NS100) microliters/liter/ha) and humic acid (control (HA0), 500 (HA500) and 1000 (HA1000) g/ha). The highest amount of chlorophyll a, b and total in 100% CWR+NS60+HA1000 was obtained. The highest amount of proline in 60% CWR + NS60 +HA1000 as well as treatment NS0 +HA1000 were observed. In all irrigation levels, the application of NS100 has reduced chlorophyll a and total. The yield components were affected by HA and nanosilver foliar spraying. The highest grain yield was observed in 100% CWR with the application of NS60 +HA500 at the rate of 10,582 kg/ha. In conditions of 100% CWR, nanosilver concentrations had a positive effect on plant growth and yield, and with increasing stress, high concentrations of nanosilver had a negative effect on growth and yield, but with the combined application of nanosilver and HA, the effect of drought stress decreased, which indicates the positive effect of HA in improving plant growth and yield.

Evaluation of Maize Varieties at Seedling Stage under Drought Stress Based on Morpho-physiological and Biochemical Attributes

A hydroponic pot experiment was driven to investigate the improvement of drought tolerance in six maize varieties (e.g. Gold Star, BHM 14, Paloan, Bharti 981, BHM 9, Pioneer) based on morpho-physiological and biochemical characteristics. Six Maize varieties were used as test crops and the experiment was laid out in a completely randomized design (RCBD) with three replications. Drought stress was imposed 14 days after sowing by using the PEG solution. The results revealed that BHM 14 possessed the longest root length (69.33 cm), higher shoot length (42.67 cm), longest total plant height (112.00 cm), highest fresh root weight (3.32 g), high leaf greenness found in BHM 14 measured by SPAD meter in both top and lower leaves, high amount of proline whereas, Paloan produced shortest total plant height (78.50 cm), lowest fresh root weight (1.52 g), lowest proline after 42 days of sowing under stress condition. The maximal photochemical efficiency (Fv/Fm) appeared to measure photosynthesis whereas Pioneer was comparatively higher in stress conditions. The fresh weight of root and shoot was significantly least affected in stress conditions, whereas BHM 14 performed better in stress conditions. On the other hand, varieties had a significant difference in total dry matter of control condition and stress condition. Therefore, it is suggested that BHM 14 showed maximum drought tolerance in respect of growth and morpho-physiological changes under drought conditions.

Exposure to TiO2 nanoparticles improves the physiological characteristics of drought‐challenged chickpeas (Cicer arietinum L.)

AbstractDrought stress markedly affects plant growth and crop production. In turn, treatment with some metal‐based nanoparticles (NPs) such as TiO2‐NPs could improve the plant tolerance against drought stress. In the present study, the effects of different levels of moisture regime (40%, 60%, and 90% field capacity [FC]) in conjunction with various concentrations of TiO2‐NPs (0, 5, 10, 20, and 40 mg. L−1) on chickpea were studied. Exposure of drought‐challenged chickpea plants to TiO2‐NPs raised antioxidant enzyme activity compared with plants grown under drought without TiO2‐NP treatment. The highest activity of ascorbate peroxidase (APX) was observed at 40% FC and application of 40 mg. L−1 TiO2‐NPs. Moreover, peroxidase (POX) activity has increased with the enhancing concentration of TiO2‐NPs to 20 mg. L−1 at 90% FC. In comparison, the application of 40 mg. L−1 TiO2‐NPs and decreasing levels of FC caused a rise in the activity of superoxide dismutase (SOD). Exposure to TiO2‐NPs raised the amount of total phenols and 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate (DPPH) at different levels of moisture regime. The content of malondialdehyde (MDA) at 60% FC has decreased by 22% after treatment with 20 mg. L−1 TiO2‐NPs compared with control plants. Also, treatment with TiO2‐NPs heightened the proline content, and the highest amount of proline was obtained at 40% FC by applying 20 mg. L−1 NPs. The treatment with TiO2‐NPs in the moisture regimes led to higher chlorophyll and carotenoid production in chickpea plants. Taken together, the application of TiO2‐NPs could raise the defense potential of chickpea plants against oxidative stress caused by the generation of reactive oxygen species.

Determination of Amino acid Profile and Some Characteristics of Collagen Extracted from Skin and Bone of Luciobarbus esocinus (Heckel, 1843)

Acid soluble collagens (ASC) from bone (ASC-B) and skin (ASC-S) of mangar (Luciobarbus esocinus (Heckel, 1843) were extracted, characterized, and their amino acid profiles were determined. To best of our knowledge, the current study is the first research that used this species as a source of collagen. Both ASC-S and ASC-B from mangar skin and bone contained glycine as the major amino acid and high amounts of proline, hydroxyproline, alanine, and glutamic acid. On the basis of dry weight, yields of ASC-S and ASC-B were 9.38 and 3.71%, respectively. Furthermore, fourier transform infrared spectroscopy proved that both collagens were integrated and native. Additionally, the results of XRD demonstrated that both of the collagens reserved their helical structures. The screened collagens had prominent absorptions at 230 nm by UV-Vis spectra. Additionally, the SEM studies have shown that both ACS-S and ASC-B have porous and fibrous nature. According to the UV–Vis and FTIR results, extracted collagens were characterized as type I collagen based on their amino acid composition. According to the obtained results, the collagen isolated from mangar can potentially be an alternative source of vertebrate collagens for use in the diet and other industries such as medical and pharmaceutical industries.

Control of fibrosis with enhanced safety via asymmetric inhibition of prolyl‐tRNA synthetase 1

Prolyl‐tRNA synthetase 1 (PARS1) has attracted much interest in controlling pathologic accumulation of collagen containing high amounts of proline in fibrotic diseases. However, there are concerns about its catalytic inhibition for potential adverse effects on global protein synthesis. We developed a novel compound, DWN12088, whose safety was validated by clinical phase 1 studies, and therapeutic efficacy was shown in idiopathic pulmonary fibrosis model. Structural and kinetic analyses revealed that DWN12088 binds to catalytic site of each protomer of PARS1 dimer in an asymmetric mode with different affinity, resulting in decreased responsiveness at higher doses, thereby expanding safety window. The mutations disrupting PARS1 homodimerization restored the sensitivity to DWN12088, validating negative communication between PARS1 promoters for the DWN12088 binding. Thus, this work suggests that DWN12088, an asymmetric catalytic inhibitor of PARS1 as a novel therapeutic agent against fibrosis with enhanced safety.

Salinity stress improves antioxidant potential by modulating physio-biochemical responses in Moringa oleifera Lam.

Moringa oleifera Lam. is a common edible plant, famous for several nutritional and therapeutic benefits. This study investigates the salt -induced modulations in plant growth, physio-biochemical responses, and antioxidant performance of M. oleifera grown under 0, 50, and 100 mM NaCl concentrations. Results showed that the plant effectively managed moderate salinity (50 mM NaCl) by maintaining succulence, weight ratios, and biomass allocation patterns of both shoot and root with minimal reduction in dry biomass. However, high salinity (100 mM NaCl) remarkably declined all growth parameters. The plant accumulated more Na+ and Cl−, while less K+ under salinity as compared to the control. Consequently, osmotic potentials of both root and leaf decreased under salinity, which was corroborated by the high amount of proline and soluble sugars. Increased level of H2O2 with significantly unchanged membrane fluidity indicating its role in perceiving and managing stress at moderate salinity. In addition, increased activities of superoxide dismutase, and catalase, with increased glutathione and flavonoid contents suggest an integrated participation of both enzymatic and non-enzymatic antioxidant components in regulating ROS. On the other hand, high salinity caused an outburst of ROS indicated by high H2O2, MDA, and electrolyte leakage. As a response, moringa drastically increased the activities of all antioxidant enzymes and contents of antioxidant molecules including ascorbic acid, glutathione, total phenols, and flavonoids with high radical scavenging and reducing power capacities. However, a considerable amount of energy was used in such management resulting in a significant growth reduction at 100 mM NaCl. This study suggests that moringa effectively resisted moderate salinity by modulating physio-biochemical attributes and effectively managing ion toxicity and oxidative stress. Salt stress also enhanced the medicinal potentials of moringa by increasing the contents of antioxidant compounds including ascorbic acid, glutathione, total phenols, and flavonoids and their resulting activities. It can be grown on degraded/ saline lands and biomass of this plant can be used for edible and medicinal purposes, besides providing other benefits in a global climate change scenario.

Agro-Morphological, Yield and Biochemical Responses of Selected Wheat (Triticum aestivum L.) Genotypes to Salt Stress

Wheat is affected by various biotic and abiotic stresses, especially salinity, which reduces the growth and yield drastically. With this view, an experiment was conducted to observe genotypic differences in agro-morphological, yield, and biochemical responses to salinity. Experimental variables consisted of five salt-tolerant genotypes (G 13, G 20-1, G 9, G 22, G 20-2), one susceptible genotype (G 24) and one standard check variety (BARI ghom 25), which assigned to four levels of salinity with electrical conductivities 0, 4, 8 and 12 dS m−1. Irrespective of genotypes, salinity stress significantly decreased the yield and yield attributes. However, maximum total tillers plant−1, effective tillers plant−1, number of grains spike−1, and grain yield plant−1 was found in salt tolerant genotype G 20-2, followed by genotypes G 13, G 20-1, and the lowest was observed in salt-susceptible genotype G 24. The lowest reduction percentage of yield and yield attributes were also observed in salt tolerant genotype G 20-2 followed by genotypes G 13, G 20-2, and the maximum reduction percentage was found in salt-susceptible genotype G 24. Results showed that the highest amount of proline, glycinebetaine, soluble sugar and soluble protein content were observed in salt-tolerant genotype G 20-2, followed by genotypes G 13, G 20-1, and the minimum was found in salt-susceptible genotype G 24. On the other hand, the lowest hydrogen peroxide (H2O2) and melondealdehyde (MDA) accumulation was detected in the same salt-tolerant genotype G 20-2, followed by G 13, G 20-1, and the maximum was observed in salt-susceptible genotype G 24. Therefore, higher accumulations of compatible solute in the tolerant genotypes reduce the oxidative stress, and provide the higher yield.

Infestation Differences and Control of the Clearwing Moth (Synanthedon myopaeformis Borkh.) in Apple Orchards, Egypt.

<b>Background and Objective:</b> The clearwing moth (<i>Synanthedon myopaeformis</i> Borkh.) is considered one of the most dangerous pests infesting apple orchards in Egypt, causing the destruction of apple trees and a significant reduction in tree vigour and yield. Therefore, controlling it has become an important issue. The present study aimed to investigate the differences in <i>S. myopaeformis</i> infestation in apple orchards in different geographical regions and the infestation rates to different agricultural operations. <b>Materials and Methods:</b> The infestation percentages of <i>S. myopaeformis</i> in different geographical regions under varying agricultural operations were determined. Additionally, the amounts of chemical components (e.g., phenols, proline and total carbohydrates and proteins) in the stems and leaves of both infested and healthy apple trees were determined. Finally, the efficacy of seven different materials of varying types to control the borer was tested by painting the trunks of the apple trees. <b>Results:</b> The highest numbers of <i>S. myopaeformis</i> were recorded in July at locations with varying agricultural operations: Melig (25.88 adults), Kafer-Aleim (20.30 adults) and Al-Khatatba (13.02 adults). The emergence percentages recorded at the abovementioned locations were 44.55, 33.40 and 22.05%, respectively. The infested trees contained high amounts of proline and phenols in both stems and leaves, whereas total carbohydrate and protein contents were low. The highest reduction in the emergent population was recorded with the use of the pesticide Ranous (82.16%) and the application of used motor oil on the trunk (78.15%). <b>Conclusion:</b> The proposed treatment of infested apple trees is painting the trunks during the summer months, when <i>S. myopaeformis</i> activity is high, with motor oil and the pesticide Ranous. The accumulation of phenol and proline in the infested trees indicated a type of direct defense mechanism against <i>S. myopaeformis</i> attacks.

Drought mitigation in cocoa (Theobroma cacao L.) through developing tolerant hybrids

BackgroundCocoa, being a shade loving crop cannot withstand long periods of water stress. Breeding for drought tolerance is the need of the hour due to change in climatic condition and extension of crop to non-traditional areas. Hybrids were produced by crossing four tolerant genotypes in all possible combination. The cross GV1 55 x M 13.12 didn’t yield any fruit due to cross incompatibility between these genotypes. Various biochemical parameters act as the true indicators to select tolerant and susceptible types. The major biochemical parameters considered after imposing stress included proline, nitrate reductase activity, superoxide dismutase content and glycine betaine.ResultsThe drought tolerant hybrids were having high amount of proline, superoxide dismutase enzyme and glycine betaine content. Normally, plants having drought stress show low amount of nitrate reductase activity. However, in case of hybrids, the drought tolerant hybrids were having higher NR activity than the susceptible hybrids. The highest amount of NR was found in the control plants kept at fully irrigated conditions.ConclusionsThis experiment showed the role of different biochemical enzymes and osmolytes in giving tolerance to plants during drought stress. Logistic regression analysis selected proline and nitrate reductase as the two biochemical markers for identifying efficient drought tolerant genotypes in the future breeding programmes.

Exogenous proline alters the leaf ionomic profiles of transgenic and wild-type tobacco plants under water deficit

Water deficit can reduce the absorption, accumulation, partition, and use of nutrients in plants. To mitigate the effects of this stress, plants produce osmolytes, such as proline, which may assist in preventing nutrient deficiencies under water deficiency. Therefore, the objective of this work was to evaluate the effects of exogenous proline application on the ionomic profile of wild-type and genetically modified tobacco (Nicotiana tabacum L.) overproducing proline under water deficit conditions. For this, the exogenous proline application in transgenic tobacco plants with constitutive expression of a mutated heterologous delta-1-pyrroline-5-carboxylate synthase enzyme (VaP5CSF129A) with reduced feedback inhibition and wild-type was studied. Water supply was suspended three days after foliar applications of 10 mM proline and the mineral elements content were determined in leaves nine days after the suspension of irrigation. Hierarchical clustering showed a clear differentiation between groups of plants with or without exogenous proline application, demonstrating that this treatment affected the ionomic profile of tobacco plants more than the water regime. The absorption and translocation mechanisms that were probably affected by the higher amount of proline allowed the separation the mineral elements into five groups by multivariate analysis. Notably, potassium was the nutrient present in the greatest content in tobacco leaves. In general, micronutrients were detected in larger amounts in transgenic plants, with the exception of iron possibly due to the competition with copper. Thus, the data suggest that proline might act, directly, or indirectly as a mitigator of nutritional deficiencies caused by water deficiency in tobacco, if applied prior to the onset of the water deficit conditions.

Salt stress induced accumulation of biomolecules in groundnut genotypes

Salinity is one of the environmental limiting factors in agricultural production. The aim of this study was to find out one of more salt tolerant groundnut genotypes through monitoring the growth and changes in biomolecules under salt stress condition. Purposively four groundnut genotypes, including a Traditional variety, Zhingabadam, Binachinabadam-1 and Dacca-1 were grown under three salinity levels viz. 0, 3 and 5 dSm-1. The experiment was laid out in two factorial completely randomized design with three replications. This experiment was done in soil based pot culture up to 40 days. Increasing salt concentration drastically reduced all the growth parameters, and increase proline and sugar content of leaf. Among the varieties Traditional variety, Zhingabadam and Dacca-1 had statistically similar shoot and root dry weight. The leaves of the Traditional variety contain the highest amount of proline of 14.52 and 36.24 mg/100g fresh leaves in 3 and 5 dS/m salinity, respectively which was 236 and 737 % higher than that of respective control. At EC of 3 and 5 dS/m, the variety Binachinabadam-1 was appeared to be susceptible, having an increase of 6 and 113% proline content over the respective control. Based on the shoot dry weight, root dry weight, proline content, total sugar, reducing sugar and relative water content, the Traditional variety was strongly recommended to be grown in the coastal salt affected soils. The Zhingabadam and Dacca-1 variety also could be recommended as they had comparable performance of the Traditional variety.

Tall fescue is a superturfgrass: Tolerance to shade conditions under deficit irrigation

To evaluate the morpho-physiological characteristics of some cool-season turfgrass species under shade stress, an experiment was conducted outdoor in two subsequent years. Then, tall fescue, as the best-recognized turf from the former test, was exposed to combined drought and shade stress, aiming to measure to what extent shade can decrease turfgrasses water consumption and alleviate drought effects. The first test included 35 treatments at 7 different levels of continuous and temporal shade conditions in the morning and afternoon (60% and 80%) and full sunlight, and 5 cool-season turfgrass species, i.e., tall fescue ( Festuca arundinacea Schreb.), red fescue ( Festuca rubra L.), perennial ryegrass ( Lolium perenne L.), Kentucky bluegrass ( Poa pratensis L.) and sheep fescue ( Festuca ovina L.)]. The second test was consisted of 9 treatment, including 3 different irrigation intervals (i. e. 3, 6, and 9 days), 3 shade stress (i.e. full sunlight, 60% and 80% permanent shade), and 3 replications. Seeds of different cool-season turfgrass species were sown in April 2015 and 2016 in a loamy soil. Treated turfgrasses were evaluated for morpho-physiological and biochemical characteristics. Results showed that in the first test tall fescue has the highest quality in terms of morpho-physiological characteristics at a high level of shade stress (80% continuous shade). Perennial ryegrass and Kentucky bluegrass showed weak tolerance to shade stress conditions. The 80% constant shade had the greatest influence on turfgrass qualitative and quantitative traits, but in some cases did not show a significant difference between temporal shades. Turfgrasses quality decreased by increasing the intensity and duration of shade; however tall fescue was an excellent turfgrass species under shade stress conditions. Although visual quality, tiller density, and total chlorophyll content of tall fescue were significantly reduced by less frequent irrigation, they were improved by shade treatment compared with control plants. In addition, tall fescue has the highest amount of proline, catalase activity, starch, and reducing sugars under 9 days of drought and 60% shade stress. This is the first report of the interaction of shade and drought stress on the biochemical and morpho-physiological responses of tall fescue plants.

Comparison of physiological effects of osmotic stress on two wheat genotypes

Revealing stress tolerance mechanisms in plants would contribute to the selection of crop varieties with a higher capacity for surviving in unfavourable environments. In this regard, it is essential to identify possible physiological features that might be beneficial for increasing plant resistance to stress. Two contrasting common wheat (Triticum aestivum L.) cultivars with different drought tolerance were subjected to 48 h treatment with 20% polyethylene glycol 8000, which provoked an extra degree of osmotic and oxidative stress as well as distinct physiological responses. Better water retention capacity in leaves and lesser extent of membrane injury found in cultivar ‘Guinness’ compared to cultivar ‘Niki’ correlated with increased osmotic adjustment by accumulating higher amounts of proline and higher antioxidant scavenging capacity in the former. Compared to soluble sugars and total free amino acids, proline contributed to a greater extent to preserving leaf water. It was speculated that such a combination of features would set a genotypic advantage for this cultivar, which could also determine better performance under drought conditions in the field.

Addition of Aegilops biuncialis chromosomes 2M or 3M improves the salt tolerance of wheat in different way

Aegilops biuncialis is a promising gene source to improve salt tolerance of wheat via interspecific hybridization. In the present work, the salt stress responses of wheat-Ae. biuncialis addition lines were investigated during germination and in young plants to identify which Aegilops chromosomes can improve the salt tolerance of wheat. After salt treatments, the Aegilops parent and the addition lines 2M, 3M and 3M.4BS showed higher germination potential, shoot and root growth, better CO2 assimilation capacity and less chlorophyll degradation than the wheat parent. The Aegilops parent accumulated less Na in the roots due to an up-regulation of SOS1, SOS2 and HVP1 genes, while it contained higher amount of proline, fructose, glucose, galactose, maltose and raffinose. In the leaves, lower Na level was accompanied by high amount of proline and increased expression of NHX2 gene. The enhanced accumulation of sugars and proline was also observed in the roots of 3M and 3M.4BS addition lines. Typical mechanism of 2M addition line was the sequestration of Na into the vacuole due to the increased expression of HVP1 in the roots and NHX2 in the leaves. These results suggest the Aegilops chromosomes 2M and 3M can improve salt tolerance of wheat in different way.

Biomarkers associated with cheese quality uncovered by integrative multi-omic analysis

Cheese quality is determined by many dynamic complex interactions that occur between cheese microbiota, metabolites and milk substrates. Here we report that application of multi-omics and data integration (by Data Integration Analysis for Biomarker discovery using Latent components, DIABLO) is able to identify and rank biomarkers (taxa and metabolites) which could discriminate, at the molecular level, cheddar cheeses of different quality made by the same manufacturer and to the same specifications. Samples of high-quality mature cheddar had higher amounts of proline, histidine, isoleucine and aspartic acid but lower amounts of stearic acid and octadecanol relative to the lower-quality cheddar. Furthermore, Streptococcus species (presumably S. thermophilus) were present in higher abundance relative to Lactococcus lactis in the higher-quality cheddar. Integrative analysis also revealed significant relationships between these multi-omics biomarkers. Together these results highlight the potential for this approach for identifying biomarkers that could be used to discriminate cheeses of varying quality and as a complementary approach to the current manual sensory evaluation of cheese.

Effect of Drought Stress on Certain Morphological and Physiological Characteristics of a Resistant and a Sensitive Canola Cultivar.

Water stress is one of the main abiotic factors that reduces plant growth, mainly due to high evaporative demand and low water availability. In order to evaluate the effects of drought stress on certain morphological and physiological characteristics of two canola cultivars, we conducted a factorial experiment based on a completely randomized design. The findings show that drought stress exacerbations result in the plant's response to stress due to increased canola resistance caused by changes in plant pigments, proline, catalase, ascorbate peroxidase, peroxidase, superoxide dismutase and malondialdehyde, glucose, galactose, rhamnose and xylose. These in turn ultimately influence the morphological characteristics of canola. Drought stress reduces the concentration of carotenoids, chlorophyll a, chlorophyll b, total chlorophylls; however, glucose, galactose, rhamnose, xylose, proline, catalase, ascorbate peroxidase, peroxidase, superoxide dismutase, malondialdehyde (in leaves and roots) and the chlorophyll a and b ratios were increased. Reduction of plant height, stem height, root length, fresh and dry weight of canola treated with 300 g/l PEG compared to non-treatment were 0.264, 0.236, 0.394, 0.183 and 0.395, respectively. From the two canola cultivars, the morphological characteristics of the NIMA increased compared to the Ks7 cultivar. Interaction effects of cultivar and drought stress showed that NIMA cultivar without treatment had the highest number of morphological characteristics such as carotenoid concentration, chlorophyll a, chlorophyll b, total chlorophylls a and b, whereas the cultivar with 300 g/l PEG (drought stress) had the highest amount of proline, malondialdehyde, soluble sugars and enzymes in leaves and roots. Increasing activity of oxidative enzymes and soluble sugars in canola under drought stress could be a sign of their relative tolerance to drought stress.

Physiochemical Responses and Cold Survival Mechanism of Rice Seedlings of Selected Cultivars in Northwest Bangladesh

Cold stress at seedling stage is a serious concern to the sustainable rice production in some regions of the world. A field experiment was carried out to investigate the physiological parameters of seedlings of selected five rice cultivars, namely Binadhan-6, BR-26, BRRI dhan28, BRRI dhan29, and BRRI dhan50 (Banglamoti) for cold survival mechanism during low temperature in the Northwest Bangladesh. The field experiment was arranged following Randomized Complete Block Design (RCBD) with three replications. The physiological parameters such as leaf proline, chlorophyll, total carotenoid content, relative water content (RWC) and starch were determined. In this study, the rice cultivars showed significant variation of physiological activities at low temperature. BRRI dhan28 synthesized the highest amount of proline (1.25 mg g-1), chlorophyll-a (2.63 mg g-1), chlorophyll-b (0.85 mg g-1), relative water content (93.33%) and starch (28.21%) content. Significant variability was observed among the cultivars during the experiment time for their survivability. The sequence of survival potentiality was observed as BRRI dhan28> BRRI dhan29> BR-26> BINA dhan-6> BRRI dhan50. The present finding infers that BRRI dhan28 showed the best survival potentiality based on the synthesis of proline, chlorophyll and other physiological parameters.

Diversity of nectar amino acids in the Fritillaria (Liliaceae) genus: ecological and evolutionary implications

Nectar is considered to be a primary food reward for most pollinators. It mostly contains sugars, but also has amino acids. The significance of the concentration and composition of amino acids in nectar is often less understood than that of its volume, sugar concentration and composition. However, there is a trend towards a broader approach in ecological research, which helps to understand nectar properties in an ecological context. The genus Fritillaria, exhibiting great diversity in flower morphology, nectar composition, and dominant pollinators, allows for the possibility to study some of the above. We studied the concentration and composition of amino acids in the nectar of 38 Fritillaria species attracting different groups of pollen vectors (bees, flies, passerines, and hummingbirds). The flowers of fritillaries produced nectar with a varying composition and concentration of amino acids. These differences were mostly associated with the pollinator type. The nectar of passerine bird-pollinated species was rich in amino acids, whereas humming bird-pollinated produced low amino acid nectar. Contrary to previous reports nectar of the insect-pollinated species did not contain a higher amount of proline. Two non-protein amino acids, sarcosine and norvaline, were detected in the floral nectar for the first time.

Jasmonic acid-induced metabolic responses in bitter melon (Momordica charantia) seedlings under salt stress

ABSTRACTIn the present study, effects of foliar application of 150 µM Jasmonic acid (JA), an endogenous plant growth regulator, on alleviation oxidative stress resulted from without (0 mM), low (50 mM), moderate (150 mM), and high (300 mM) NaCl in bitter melon (Momordica charantia) seedlings was investigated. High salt stress significantly decreased growth components including root length, leaf morphological properties, leaf water content, plant biomass and levels of pigments, soluble sugars, starch and proteins, but accumulated higher amounts of proline, free amino acids and the activities of ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and pyrogallol peroxidase (PPX). Exogenous JA treatment alone or combined with salt stress improved growth components with hyperaccumulation of soluble sugars, proteins, amino acids, proline and PPO activity, but was associated with a decrease in the activity of H2O2-decomposing enzymes. These results suggest that exogenous JA treatment can effectively raise salt stress tolerance of bitter melon seedlings through modifying allocation of carbon and nitrogen metabolism to adjust levels of metabolites and directing them to the growth processes.

Effect of palm leaf biochar on melon plants (Cucumis melo L.) under drought stress conditions

In order to investigate the effect of palm leaf biochar on some characteristics of Cucumis melo L. under drought stress, a split plot experiment was conducted in a completely randomized block design with three replications for two consecutive years. The main plot was irrigation level (60, 85, and 100% water requirement) and subplot was biochar in four levels (0, 0.18, 0.24, and 0.36 kg/m2). Results showed that treatment of 0.24 kg/m2 biochar and 100% water requirement increased the characteristics of water use efficiency as 88%, shoot fresh weight as 77%, shoot dry weight as 32%, root fresh weight as 100%, root dry weight as 84%, root length as 54%, and average fruit weight 84% compared to treatment without biochar and 60% water requirement. The highest level of leaf N, Mn and K, shoot length, leaf area, leaf number, fruit diameter and fruit flesh thickness in the treatment of 0.36 kg/m2 biochar and 100% water requirement were higher 58%, 48%, 65%, 18%, 50%, 95%, 43% and 55%, than to of treatment without biochar and 60% water requirement respectively and had no significant difference with the treatment of 0.24 kg/m2 biochar and 85% water requirement. The highest rates of Fe, Zn and Cu were related to 0.36 kg/m2 biochar and 60% water requirement as 60, 44 and 66% respectively compared to treatment without biochar and 100% water requirement. The biochar-free treatment with 60% water requirement accounted for the highest amount of proline due to high stress, and the proline content reduced with increasing biochar and decreasing stress in treatments. Generally, the treatments of 0.24 and 0.36 kg/m2 of biochar increased most of the characteristics, however no significant difference was observed between these treatments. Moreover, in 85% water requirement the drought stress conditions could compensate with the application of biochar. Thus, using 0.24 kg/m2 of biochar and 85% of water requirement, recommended for the best result.