Showing papers in "Acta Physiologiae Plantarum in 2013"
TL;DR: Metal detoxification through MAPK cascade and synthesis of metal-detoxifying ligands will be of considerable interest in the field of plant biotechnology and the photoprotective roles of pigments of xanthophylls cycle under HMs stress were discussed.
Abstract: Heavy metal (HMs) contamination is widespread globally due to anthropogenic, technogenic, and geogenic activities. The HMs exposure could lead to multiple toxic effects in plants by inducing reactive oxygen species (ROS), which inhibit most cellular processes at various levels of metabolism. ROS being highly unstable could play dual role (1) damaging cellular components and (2) act as an important secondary messenger for inducing plant defense system. Cells are equipped with enzymatic and non-enzymatic defense mechanisms to counteract this damage. Some are constitutive and others that are activated only when a stress-specific signal is perceived. Enzymatic scavengers of ROS include superoxide dismutase, catalase, glutathione reductase, and peroxidase, while non-enzymatic antioxidants are glutathione, ascorbic acid, α-tocopherol, flavonoids, anthocyanins, carotenoids, and organic acids. The intracellular and extracellular chelation mechanisms of HMs are associated with organic acids such as citric, malic and oxalic acid, etc. The important mechanism of detoxification includes metal complexation with glutathione, amino acids, synthesis of phytochelatins and sequestration into the vacuoles. Excessive stresses induce a cascade, MAPK (mitogen-activated protein kinase) pathway and synthesis of metal-detoxifying ligands. Metal detoxification through MAPK cascade and synthesis of metal-detoxifying ligands will be of considerable interest in the field of plant biotechnology. Further, the photoprotective roles of pigments of xanthophylls cycle under HMs stress were also discussed.
426 citations
TL;DR: The main objective of this review is to provide an overview of various crops in which seed priming is practiced and about various seed-priming methods and its effects.
Abstract: Plants are exposed to any number of potentially adverse environmental conditions such as water deficit, high salinity, extreme temperature, submergence, etc. These abiotic stresses adversely affect the plant growth and productivity. Nowadays various strategies are employed to generate plants that can withstand these stresses. In recent years, seed priming has been developed as an indispensable method to produce tolerant plants against various stresses. Seed priming is the induction of a particular physiological state in plants by the treatment of natural and synthetic compounds to the seeds before germination. In plant defense, priming is defined as a physiological process by which a plant prepares to respond to imminent abiotic stress more quickly or aggressively. Moreover, plants raised from primed seeds showed sturdy and quick cellular defense response against abiotic stresses. Priming for enhanced resistance to abiotic stress obviously is operating via various pathways involved in different metabolic processes. The seedlings emerging from primed seeds showed early and uniform germination. Moreover, the overall growth of plants is enhanced due to the seed-priming treatments. The main objective of this review is to provide an overview of various crops in which seed priming is practiced and about various seed-priming methods and its effects.
376 citations
TL;DR: Co-relating all these data into a signal network model will be an uphill task, and solving this will give a clearer picture of the intricate abiotic stress signalling network in the plant kingdom.
Abstract: Significance of naturally occurring intracellular polyamines (PAs), such as spermine, spermidine, and putrescine, in relation to the mechanism and adaptation to combat abiotic stress has been well established in plants. Because of their polycationic nature at physiological pH, PAs bind strongly to negative charges in cellular components such as nucleic acids, proteins, and phospholipids. Accumulation of the three main PAs occurs under many types of abiotic stress, and modulation of their biosynthetic pathway confers tolerance to drought or salt stress. Maintaining crop yield under adverse environmental conditions is probably the major challenge faced by modern agriculture, where PAs can play important role. Over the last two decades, genetic, transcriptomic, proteomic, metabolomic, and phenomic approaches have unraveled many significant functions of different PAs in the regulation of plant abiotic stress tolerance. In recent years, much attention has also been devoted to the involvement of PAs in ameliorating different environmental stresses such as osmotic stress, drought, heat, chilling, high light intensity, heavy metals, mineral nutrient deficiency, pH variation, and UV irradiation. The present review discusses the various reports on the role of PAs in the abiotic stress of plants with a note on current research tendencies and future perspectives. Co-relating all these data into a signal network model will be an uphill task, and solving this will give a clearer picture of the intricate abiotic stress signalling network in the plant kingdom.
334 citations
TL;DR: The results indicate that NaCl-induced oxidative stress hampers the normal functioning of the cell and indicates that the genes involved in the antioxidative process are triggered by oxidative stress induced by environmental change.
Abstract: The present study was conducted to evaluate the effect of NaCl on growth and some key antioxidants in chickpea. Eight genotypes of chickpea were grown hydroponically for 15 days and then treated with different concentrations of salt [0 mM (T0), 25 mM (T1), 50 mM (T2), 75 mM (T3), and 100 mM (T4)]. Salinity showed marked changes in growth parameters (fresh and dry weight of root and shoot). The level of lipid peroxidation was measured by estimating malondialdehyde content. Lipid peroxidation increases with the increase in NaCl concentration in all genotypes but salt-tolerant genotypes (SKUA-06 and SKUA-07) were least affected as compared to other genotypes. The chlorophyll content was also affected with elevated levels of NaCl. Increased concentration of salt increased the activity of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase in all chickpea genotypes but maximum activity was observed in salt-tolerant (SKUA-06 and SKUA-07) genotypes. Two genotypes of salt-tolerant and salt-sensitive varieties were analyzed further by real time PCR which revealed that the expression of SOD, APX and CAT genes were increased by NaCl in the salt-tolerant variety. The enhancement in tolerance against salt stress indicates that the genes involved in the antioxidative process are triggered by oxidative stress induced by environmental change. The results indicate that NaCl-induced oxidative stress hampers the normal functioning of the cell. The efficient antioxidants play a great role in mitigating the effect of NaCl stress in chickpea. This screening of NaCl-tolerant genotypes of chickpea can be performed on salt-affected land.
264 citations
TL;DR: Increasing concentrations of this metal promoted a strong reduction of the maximum photochemical efficiency of PSII and an impairment of net CO2 assimilation rate, which ultimately results in a strong inhibition of plant growth.
Abstract: In this article we discuss and update some of the effects of Cd toxicity on the photosynthetic apparatus in a model crop Lactuca sativa. Seeds of L. sativa were germinated in solutions with 0, 1, 10 and 50 μM of Cd(NO3)2 and then transferred to a hydroponic culture medium. After 28 days, the effects of Cd on the photosynthetic apparatus of lettuce were analysed. Exposure of lettuce to 1 μM Cd(NO3)2 affected already plant growth (dry biomass), but, did not induce serious damages in the photosynthetic apparatus. However, increasing concentrations of this metal to 10 and 50 μM promoted a strong reduction of the maximum photochemical efficiency of PSII and an impairment of net CO2 assimilation rate, putatively due to Rubisco activity decrease. This ultimately results in a strong inhibition of plant growth. Nutrient uptake and carbohydrate assimilation were also severely affected by Cd.
238 citations
TL;DR: In this article, the effect of 6-nm Fe2O3 nanoparticles and citrate-coated IONPs on photosynthetic characteristics and root elongation during germination of Glycine max (L) Merr was investigated.
Abstract: There is an urgent need to address comprehensive biosafety issues associated with the use of Fe2O3 nanoparticles (IONPs). The present study was performed to investigate the effect of 6-nm IONPs and citrate-coated IONPs (IONPs-Cit) on photosynthetic characteristics and root elongation during germination of Glycine max (L) Merr. Plant physiological performance was assessed after foliar and soil IONPs fertilization. No adverse impacts at any growth stage of the soybeans were observed after application of IONPs. The Fe2O3 nanoparticles produced a significant positive effect on root elongation, particularly when compared to the bulk counterpart (IOBKs) suspensions of concentrations greater than 500 mg L−1. Furthermore, IONPs-Cit significantly enhanced photosynthetic parameters when sprayed foliarly at the eight-trifoliate leaf stage (P < 0.05). The increases in photosynthetic rates following spraying were attributed to increases in stomatal opening rather than increased CO2 uptake activity at the chloroplast level. We observed more pronounced positive effects of IONPs via foliar application than by soil treatment. This study concluded that IONPs coated with citric acid at IONPs to citrate molar ratio of 1:3 can markedly improve the effectiveness of insoluble iron oxide for Fe foliar fertilization.
176 citations
TL;DR: In this article, the authors simplified the physiological adaptive mechanisms in plants grown in saline soil and put forward a practical procedure for discerning physiological status and responses in order to evaluate negative effects of salt stress by the changes in biomass, crop yield and photosynthesis.
Abstract: There is large area of saline abandoned and low-yielding land distributed in coastal zone in the world Soil salinity which inhibits plant growth and decreases crop yield is a serious and chronic problem for agricultural production Improving plant salt tolerance is a feasible way to solve this problem Plant physiological and biochemical responses under salinity stress become a hot issue at present, because it can provide insights into how plants may be modified to become more tolerant It is generally known that the negative effects of soil salinity on plants are ascribed to ion toxicity, oxidative stress and osmotic stress, and great progress has been made in the study on molecular and physiological mechanisms of plant salinity tolerance in recent years However, the present knowledge is not easily applied in the agronomy research under field environment In this review, we simplified the physiological adaptive mechanisms in plants grown in saline soil and put forward a practical procedure for discerning physiological status and responses In our opinion, this procedure consists of two steps First, negative effects of salt stress are evaluated by the changes in biomass, crop yield and photosynthesis Second, the underlying reasons are analyzed from osmotic regulation, antioxidant response and ion homeostasis Photosynthesis is a good indicator of the harmful effects of saline soil on plants because of its close relation with crop yield and high sensitivity to environmental stress Particularly, chlorophyll a fluorescence transient has been accepted as a reliable, sensitive and convenient tool in photosynthesis research in recent years, and it can facilitate and enrich photosynthetic research under field environment
151 citations
TL;DR: Some of the most important details including the mechanisms and processes regarding the effects of soil microbes on the availability and hence uptake of nutrients by plant are reviewed.
Abstract: It is likely to provide plants with their necessary nutrients using chemical and biological fertilization. Although chemical fertilization is a quick method, it is not recommendable economically and environmentally, especially if overused. Biological fertilization is the use of soil microbes including arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria to inoculate plants. It has been proved that biological fertilization is an efficient method to supply plants with their necessary nutrients. It is economically and environmentally recommendable, because it results in sustainability. In this article, some of the most important details including the mechanisms and processes regarding the effects of soil microbes on the availability and hence uptake of nutrients by plant are reviewed. Such details can be important for the selection and hence production of microbial inoculums, which are appropriate for biological fertilization.
149 citations
TL;DR: In this article, the short-term application of silicon on growth, osmotic adjustment and ion accumulation in sorghum (Sorghum bicolor L. Moench) under salt stress was investigated.
Abstract: Silicon has been widely reported to have a beneficial effect on improving plant tolerance to biotic and abiotic stresses. However, the mechanisms of silicon in mediating stress responses are still poorly understood. Sorghum is classified as a silicon accumulator and is relatively sensitive to salt stress. In this study, we investigated the short-term application of silicon on growth, osmotic adjustment and ion accumulation in sorghum (Sorghum bicolor L. Moench) under salt stress. The application of silicon alone had no effects upon sorghum growth, while it partly reversed the salt-induced reduction in plant growth and photosynthesis. Meanwhile, the osmotic potential was lower and the turgor pressure was higher than that without silicon application under salt stress. The osmolytes, the sucrose and fructose levels, but not the proline, were significantly increased, as well as Na+ concentration was decreased in silicon-treated plants under salt stress. These results suggest that the beneficial effects of silicon on improving salt tolerance under short-term treatment are attributed to the alleviating of salt-induced osmotic stress and as well as ionic stress simultaneously.
149 citations
TL;DR: In this paper, the authors evaluated the changes in physiological and biochemical characteristics and established the optimum osmotic stress level in which differences in drought resistance between the genotypes could be revealed.
Abstract: In this study, the seedlings of two wheat cultivars were used: drought-resistant Chinese Spring (CS) and drought-susceptible (SQ1). Seedlings were subjected to osmotic stress in order to assess the differences in response to drought stress between resistant and susceptible genotype. The aim of the experiment was to evaluate the changes in physiological and biochemical characteristics and to establish the optimum osmotic stress level in which differences in drought resistance between the genotypes could be revealed. Plants were subjected to osmotic stress by supplementing the root medium with three concentrations of PEG 6000. Seedlings were grown for 21 days in control conditions and then the plants were subjected to osmotic stress for 7 days by supplementing the root medium with three concentrations of PEG 6000 (D1, D2, D3) applied in two steps: during the first 3 days of treatment −0.50, −0.75 and −1.00 and next −0.75, −1.25 and −1.5 MPa, respectively. Measurements of gas exchange parameters, chlorophyll content, height of seedlings, length of root, leaf and root water content, leaf osmotic potential, lipid peroxidation, and contents of soluble carbohydrates and proline were taken. The results highlighted statistically significant differences in most traits for treatment D2 and emphasized that these conditions were optimum for expressing differences in the responses to osmotic stress between SQ1 and CS wheat genotypes. The level of osmotic stress defined in this study as most suitable for differentiating drought resistance of wheat genotypes will be used in further research for genetic characterization of this trait in wheat through QTL analysis of mapping population of doubled haploid lines derived from CS and SQ1.
144 citations
TL;DR: Evidence is provided that the tolerant genotypes were equipped with better management of physiological processes along with an efficient antioxidative defence system, sensitivity of which can be evaluated to a sufficient level of certainty at seedling stage.
Abstract: An experiment was conducted to find out the effect of short-term heat stress on morpho-physiological characters and antioxidants in 10 diverse wheat genotypes. Seed were aseptically grown in test tubes containing filter paper whose lower half was dipped in one-fourth MS media. Heat stress conditions were created by exposing the seedlings at 45 °C for 2 h after 7 days of their germination. Measurements were taken after 3 days of treatment. Heat stress significantly reduced the shoot dry mass, root dry mass, shoot length and root length in all the genotypes. The chlorophyll content and membrane stability index decreased, whereas proline content increased in heat-treated plants. There was significant increase in the activity of catalase, guaiacol peroxidase and superoxide dismutase under stress conditions. The genotypic variations were also significant. On the basis of a coordinated simulation of all these parameters, wheat genotypes Raj 4037 and PBW 373 were identified as tolerant to high temperature stress. The study provides evidence that the tolerant genotypes were equipped with better management of physiological processes along with an efficient antioxidative defence system, sensitivity of which can be evaluated to a sufficient level of certainty at seedling stage.
TL;DR: The fresh and dry mass were the greatest under RB, which were significantly higher than other light treatments, and the concentration of photosynthetic pigments and chlorophyll biosynthesis precursors were higher under RB.
Abstract: The aim of this study was to evaluate the effects of different light quality of light emitting diode (LED) on the growth, concentration of chlorophyll and chlorophyll biosynthesis precursors of non-heading Chinese cabbage (Brassica campestris L.). Seedlings of the cultivar Te Ai Qing were cultured for 28 days under 6 treatments: red light (R), blue light (B), green light (G), yellow light (Y), red plus blue light (RB) and dysprosium lamp (CK). Lighting experiments were performed under controlled conditions (photon flux density 150 μmol m−2 s−1; 12 h photoperiod; 18–20 °C). The fresh and dry mass were the greatest under RB, which were significantly higher than other light treatments. The fresh mass under RB was almost twice higher compared to other light treatments. Plant height was highest under R treatment and was lowest under B. RB treatment also lowered the plant height significantly. The highest soluble sugar concentration was observed under B. The soluble protein concentration was the greatest under RB. The R treatment was adverse to pigment accumulation. The concentration of photosynthetic pigments and chlorophyll biosynthesis precursors were higher under RB. The RB treatment was beneficial to pigment accumulation.
TL;DR: Despite the considerable progress in clarifying the role of this polysaccharide in plants that has been achieved during the last period, many questions regarding its synthesis or involvement in defense responses still remain to be solved.
Abstract: Callose (β-1,3-glucan) is a linear plant polysaccharide that plays an important role in different stages of individual development as well as in defense against unfavourable environmental factors. In plants, it is synthesized by callose synthases, and degraded by β-1,3-glucanases. This review summarizes the current knowledge on structure and function of callose in plant tissue as well as its importance under stress conditions. Despite the considerable progress in clarifying the role of this polysaccharide in plants that has been achieved during the last period, many questions regarding its synthesis or involvement in defense responses still remain to be solved. A more in-depth understanding of callose function in plants will require integration of different experimental approaches from the field of chemistry, cell biology, genetics as well as systemic biology.
TL;DR: In this paper, the arsenic uptake and accumulation, the changes in gas exchange and in chlorophyll a fluorescence parameters as well as the chloroplastic pigments content were measured.
Abstract: Arsenate (AsV) and arsenite (AsIII) contamination can promote several disturbances in plant metabolism, besides affecting directly human and animal health due to the insertion of this metalloid in the food chain. Therefore, the arsenic (As) uptake and accumulation, the changes in gas exchange and in chlorophyll a fluorescence parameters as well as the chloroplastic pigments content were measured. The As accumulation in leaves and roots increased with the increase of AsV and AsIII concentration, except at the highest AsIII concentration, probably because of AsIII extrusion mechanism. Although the highest As concentration has been found in roots, significant amount was transported to the leaves, especially when plants were exposed to AsIII. The As accumulation decreased the relative growth rate (RGR) of leaves and roots. However, at 6.6 μmol L−1 AsV, an increase in leaves RGR was observed, possibly related to the changes in phosphate (PV) nutrition caused by As. AsV and AsIII interfered negatively in the photosynthetic process, except at 6.6 μmol L−1 AsV. The observed reduction seemed to be associated to the interference in the photochemical and biochemical steps of photosynthesis; however, chlorophyll a fluorescence results indicate that the photosynthetic apparatus and chloroplastic pigments were not damaged. So, lettuce plants demonstrated to be able to accumulate As and also to protect the photosynthetic apparatus against the harmful effects of this metalloid, probably through the activation of tolerance mechanisms.
TL;DR: Results showed that growing sugarcanes in combination with soybean can be considered a good agriculture management practice, helping to promote plant growth, yield and increase soil nutrients.
Abstract: The effects of sugarcane plantation intercropped with soybean on plant growth, yield, enzyme activity, nitrogen and phosphorus contents, the microbe quantity of rhizosphere soil were investigated. Results showed that dry weight of biomass and yield under sugarcane/soybean intercropping were increased by 35.44 and 30.57 % for sugarcane, and decreased by 16.12 and 9.53 % (100-grain weight) for soybean, respectively. The nitrogenase activity of intercropping soybean nodule was significantly increased by 57.4 % as compared with that in monoculture models. The urease activities of intercrops sugarcane and soybean were promoted by 89 and 81 % as compared to that of the monoculture models, respectively. The effective nitrogen and phosphorus contents of rhizospheric soil of intercrops sugarcane and soybean were increased by 66 and 311.7 %, respectively, as compared to those in the monoculture system. Microbe number of rhizosphere soil in the intercropping pattern increased significantly as compared to those in the monoculture models. The quantities of bacteria, fungi, and actinomyces increased by 42.62, 14.5 and 78.5 % in the intercropping sugarcane, while the intercropping soybean increased by 188, 183 and 73 %, respectively. Therefore, growing sugarcanes in combination with soybean can be considered a good agriculture management practice, helping to promote plant growth, yield and increase soil nutrients.
TL;DR: Exogenous MEL applied into the seeds could be a good biostimulator improving not only seed germination, seedling/plant growth but also crop production especially under stress conditions and it is believed that this compound can increase food quality and may improve human health.
Abstract: Melatonin (MEL) was thought to be only a neurotransmitter found in vertebrates until its detection in other organisms including plants. Although the number of publications on MEL function in plants is expanding, the knowledge of this subject is still insufficient. Among many functions which MEL performs in plants, its role as an antioxidant and a growth promoter is most supported by experimental evidence. This compound is an independent plant growth regulator and it may mediate the activities of other plant growth regulators. Due to its antioxidant properties MEL may also stabilize cell redox status and protect tissues against reactive oxygen and nitrogen species which accumulated under stressful environment. Some researchers propose that MEL could be used to improve the phytoremediation efficiency of plants against different pollutants. In this paper we show that exogenous MEL applied into the seeds could be a good biostimulator improving not only seed germination, seedling/plant growth but also crop production especially under stress conditions. We also believe that this compound can increase food quality (the aspect of functional food) and may improve human health. Since MEL is inexpensive and safe for animals and humans its application as a biostimulator could be a good, feasible and cost-effective method useful in agriculture.
TL;DR: This review summarizes in detail the knowledge about organization and gene structure, and transcriptional expression of ACO genes from different plant species and the perspectives of manipulating ACO gene as a method in biotechnological modification of ethylene synthesis are discussed.
Abstract: Ethylene, a gaseous plant hormone regulates essentially all physiological processes during the plant’s life cycle. The practical implications of ethylene biosynthesis regulation for plant improvement have supported the continuous basic research on dissecting the structure of genes encoding ethylene biosynthetic enzymes, their differential expression patterns, and mechanisms underlying their transcriptional activity. ACC oxidase (ACO) is involved in the final step of ethylene production in plant tissues. In various plants several ACO isoforms have been isolated which are encoded by a multigenic family. There is a strong evidence that ACO gene expression is positively correlated to the ethylene production rates and its multiple isoforms are under development and environmental control. Thus, the regulation of ACO gene activity may act either as an additional or in several cases also as a main level for controlling ethylene biosynthesis in higher plants. This review summarizes in detail the knowledge about organization and gene structure, and transcriptional expression of ACO genes from different plant species. The perspectives of manipulating ACO gene as a method in biotechnological modification of ethylene synthesis are also discussed.
TL;DR: The results obtained in this study showed that Scutia buxifolia has antibiofilm and anti-herpetic activities and that these properties are reported for the first time for this species.
Abstract: Antimicrobial and antiviral activities of the fractions from Scutia buxifolia stem bark and leaves were evaluated. Best antimicrobial results occurred with the ethyl acetate (EA) and n-butanolic (NB) fractions from the leaves against Micrococcus sp. (minimal inhibitory concentration—MIC = 62.5 μg/ml), and NB fraction from stem bark and leaves against Klebsiella pneumoniae and Enterococcus faecalis (MIC = 62.5 μg/ml). The most active fractions were selected and fractioned into silica column to perform an in vitro antibiofilm assay, which evidenced subfractions EA2 and EA3 as the more active against Candida albicans (biofilm inhibitory concentration—BIC = 582 ± 0.01 μg/ml) and Staphylococcus aureus (BIC = 360 ± 0.007 μg/ml), respectively. The NB (selectivity index—SI = 25.78) and the EA (SI = 15.97) fractions from the stem bark, and the EA (SI = 14.13) fraction from the leaves exhibited a potential antiviral activity towards Herpes Simplex Virus type 1 whereas EA2 and EA3 subfractions from leaves (SI = 12.59 and 10.06, respectively), and NB2 subfraction from stem bark (SI = 12.34) maintained this good activity. Phenolic acids and flavonoids (gallic acid, chlorogenic acid, caffeic acid, rutin, isoquercitrin, quercitrin and quercetin) were identified by HPLC and may be partially responsible for the antimicrobial and antiherpes activities observed. The results obtained in this study showed that Scutia buxifolia has antibiofilm and anti-herpetic activities and that these properties are reported for the first time for this species.
TL;DR: A protocol has been standardized for establishment and characterization of cell suspension cultures of Stevia rebaudiana in shake flasks, as a strategy to obtain an in vitro stevioside producing cell line, and the effect of growth regulators, inoculum density and various concentrations of macro salts have been analyzed to optimize the biomass growth.
Abstract: A protocol has been standardized for establishment and characterization of cell suspension cultures of Stevia rebaudiana in shake flasks, as a strategy to obtain an in vitro stevioside producing cell line. The effect of growth regulators, inoculum density and various concentrations of macro salts have been analyzed, to optimize the biomass growth. Dynamics of stevioside production has been investigated with culture growth in liquid suspensions. The callus used for this purpose was obtained from leaves of 15-day-old in vitro propagated plantlets, on MS medium fortified with benzyl aminopurine (8.9 μM) and naphthalene acetic acid (10.7 μM). The optimal conditions for biomass growth in suspension cultures were found to be 10 g l−1 of inoculum density on fresh weight basis in full strength MS liquid basal medium of initial pH 5.8, augmented with 2,4-dichlorophenoxy acetic acid (0.27 μM), benzyl aminopurine (0.27 μM) and ascorbic acid (0.06 μM), 1.0× NH4NO3 (24.7 mM), 3.0× KNO3 (56.4 mM), 3.0× MgSO4 (4.5 mM) and 3.0× KH2PO4 (3.75 mM), in 150 ml Erlenmeyer flask with 50 ml media and incubated in dark at 110 rpm. The growth kinetics of the cell suspension culture has shown a maximum specific cell growth rate of 3.26 day−1, doubling time of 26.35 h and cell viability of 75 %, respectively. Stevioside content in cell suspension was high during exponential growth phase and decreased subsequently at the stationary phase. The results of present study are useful to scale-up process and augment the S. rebaudiana biological research.
TL;DR: Sodium concentration, lipid peroxidation, hydrogen peroxide content and electrolyte leakage were increased under salt stress and significantly decreased when 0.1 mg l−1 EBL was sprayed, clearly, EBL alleviates salt-induced inhibition of productivity by altering the physiological and biochemical properties of the plant.
Abstract: Two wheat (Triticum aestivum L.) cultivars, Sids 1 and Giza 168, were grown under non-saline or saline conditions (4.7 and 9.4 dS m−1) and were sprayed with 0.00, 0.05 and 0.10 mg l−1 24-epibrassinolide (EBL). Salt stress markedly decreased plant productivity and N, P, and K uptake, particularly in Giza 168. A follow-up treatment with 0.1 mg l−1 EBL detoxified the stress generated by salinity and considerably improved the above parameters, especially in Sids 1. Organic solutes (soluble sugars, free amino acids, proline and glycinebetaine), antioxidative enzymes (superoxide dismutase, peroxidase, catalase and glutathione reductase), antioxidant molecules (glutathione and ascorbate) and Ca and Mg levels were increased under saline condition, and these increases proved to be more significant in salt-stressed plants sprayed with EBL, particularly at 0.1 mg l−1 EBL with Sids 1. Sodium concentration, lipid peroxidation, hydrogen peroxide content and electrolyte leakage were increased under salt stress and significantly decreased when 0.1 mg l−1 EBL was sprayed. Clearly, EBL alleviates salt-induced inhibition of productivity by altering the physiological and biochemical properties of the plant.
TL;DR: In this paper, various developments that have taken place in the last decade with respect to identifying and altering the function of color-related genes are described, and various approaches also have discovered a strong relationship between phenyl propanoid/flavonoid gene expressions for fruit skin coloration.
Abstract: Fruit skin coloration is a unique phase in the life cycle of fruiting plants and is mainly attributed to anthocyanin pigments. Anthocyanins are the largest and most diverse group of plant pigments derived from the phenyl propanoid pathway. They are water-soluble phenolic compounds that form part of a large and common group of plant flavonoids. Coloration encompasses several physiological and biochemical changes that happen through differential expression of various developmentally regulated genes. Due to research importance and economic value, Arabidopsis thaliana (chromosome no. = 5) and Vitis vinifera (chromosome no. = 19) have been used for investigations of the structural genes involved in anthocyanin biosynthesis. Thus for this review, V. vinifera is used as a model crop. In anthocyanin biosynthesis, a wide range of constructive genes including phenylalanine ammonia lyase, chalcone synthase and anthocyanidin synthase that are regulated by MYB transcription factors are involved. These genes are coordinately expressed and their levels of expression are positively related to the anthocyanin concentrations. Expression or suppression of the constructive genes contributes to a variety of changes that make fruits visually attractive and edible. Transgenic approaches also have discovered a strong relationship between phenyl propanoid/flavonoid gene expressions for fruit skin coloration. In this study, various developments that have taken place in the last decade with respect to identifying and altering the function of color-related genes are described.
TL;DR: In this article, the role of abscisic acid (ABA) application in some physiological parameters, in two hybrids with contrasting drought resistance (DKB 390 and BRS 1030 resistant and sensitive, respectively) was determined in previous studies.
Abstract: Drought is a major limitation of maize cultivation in Brazil. Agronomic and physiological practices have been considered to overcome this stress and consequently, increase grain production. The present study investigated the role of abscisic acid (ABA) application in some physiological parameters, in two hybrids with contrasting drought resistance (DKB 390 and BRS 1030 resistant and sensitive, respectively). Contrasting resistance to drought in these genotypes was determined in previous studies. Water deficit was imposed for 10 days at flowering stage, in association with the application of 100 μM abscisic acid on plant canopy. Evaluations of gas exchange, chlorophyll fluorescence, relative water content (RWC), and endogenous ABA content were performed during stress period and also at water recovery (recovery irrigation). A significant functional relationship was observed between RWC and the parameters of gas exchange and fluorescence. During water recovery, no differences were observed among the treatments. DKB 390 presented higher photosynthesis rate (P
n) and electron transport rate (ETR) under water stress, while BRS 1030 presented higher intercellular CO2 concentration (C
i) and lower photochemical quenching (qP), non-photochemical quenching (NPQ), and lower F
v/F
m ratio. DBK 390 was more responsive to ABA application than BRS 1030, presenting higher endogenous ABA content in the first day of stress. DBK 390 with ABA application reduced the effect of water stress through maintenance of water status, an increase of photosynthetic parameters, and a decrease of decline in the functions of photosystem II during stress.
TL;DR: In this paper, the root tip cells of two true leaves seedlings were imbibed in 0.25 % (w/v) colchicine solution for 24, 48, 72, 96 and 168 hours.
Abstract: Echinacea purpurea (L.) is one of the important medicinal plant species. To obtain the tetraploid plants of Echinacea purpurea with improved medicinal qualities, the root tips of two true leaves seedlings were imbibed in 0.25 % (w/v) colchicine solution for 24, 48, 72, 96 and 168 h. The ploidy level of plants was determined by chromosome counting of root tip cells, and confirmed by flow cytometric analysis. Tetraploid induction occurred in seedlings treated for 24, 48 and 72 h at colchicine solution. The morphological, physiological, cytological, and phytochemical characteristics of diploid and colchicine-induced tetraploid plants were compared. Results indicated that tetraploid plants had considerable larger stomata, pollen grain, seed and flower. Moreover, chloroplast number in guard cells, amount of chlorophyll (a, b, and a + b), carotenoids as well as width and thickness of leaves were increased in tetraploids. However, stomata frequency, leaf index, plant height, and quantum efficiency of photosystem II in tetraploid were lower than diploid plants. High-performance liquid chromatography analysis showed that leaves of the tetraploid plants had more cichoric acid (45 %) and chlorogenic acid (71 %) than diploid plants. It was concluded that morphological and physiological characteristics can be used as useful parameters for preliminary screening of putative tetraploids in this species.
TL;DR: In this paper, the effects of different liquid media: Murashige and Skoog (MS), Gamborg et al. (B5) and Woody Plant (WP) with full and half-strength (½MS, ½B5, ½WP), on biomass accumulation and rosmarinic acid (RA) content were investigated.
Abstract: Hairy roots of Dracocephalum moldavica L. were induced using Agrobacterium rhizogenes strain A4. Transformed roots were obtained from shoot explants with low transformation frequency of up to 3 %. The effects of different liquid media: Murashige and Skoog (MS), Gamborg et al. (B5) and Woody Plant (WP) with full- and half-strength (½MS, ½B5, ½WP), on biomass accumulation and rosmarinic acid (RA) content were investigated. The hairy roots were cultured in photoperiod (16 h light/8 h dark) and darkness. Biomass of D. moldavica hairy roots was the highest (7.23 g flask−1 of fresh weight and 0.89 g flask−1 of dry weight) in the cultures grown in WP medium under periodic light. Ultra performance liquid chromatography analysis revealed the highest RA content (78 mg g−1 dry wt) in roots cultured in ½B5 medium under photoperiod conditions. It was about tenfold higher compared to roots of field-grown mother plants. Antioxidant activities and total phenolic contents of methanolic extracts of D. moldavica hairy roots cultured in ½B5 and WP media under photoperiod and darkness and roots of field grown plants were compared. All extracts were investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and phosphomolybdenum reduction assays. Total phenolic contents were estimated by the Folin–Ciocalteu method. The methanolic extract of D. moldavica hairy roots grown in ½B5 medium under photoperiod possessed the strongest effects on reducing Mo and DPPH radical scavenging. The activities were significantly higher (p ≤ 0.05) than those of methanolic extract of roots of intact plants grown in the field. The most active methanolic extract of hairy roots was characterized by the highest level of rosmarinic acid and total content of phenolic compounds.
TL;DR: In this paper, the role of exogenous foliar application of 5-aminolevulinic acid (ALA) on water relations, gas exchange, chlorophyll fluorescence, and the activities and gene expression patterns of antioxidant enzymes in leaves of oilseed rape under drought stress and recovery conditions was evaluated.
Abstract: This study evaluates the role of exogenous foliar application of 5-aminolevulinic acid (ALA) on water relations, gas exchange, chlorophyll fluorescence, and the activities and gene expression patterns of antioxidant enzymes in leaves of oilseed rape under drought stress and recovery conditions. Seedlings at four-leaf stage were imposed to well-watered condition (80 % of water-holding capacity) or drought stress (40 % of water-holding capacity) and subsequently foliar sprayed with water or ALA (30 mg l−1). Drought suppressed the accumulation of plant biomass and decreased chlorophyll content and leaf water status (relative water content and water potential). The actual quantum yield of photosystem II and electron transport rates were hampered in parallel to net photosynthetic rate. However, drought stress induced the accumulation of malondialdehyde (MDA) and hydrogen peroxide, enhanced the activities of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and superoxide dismutase and up-regulated the expression of APX and GR. After rehydration for 4 days, the growth of drought-treated seedlings was restored to normal level for most of the physiological parameters. Foliar application of ALA maintained relatively higher leaf water status and enhanced chlorophyll content, net photosynthetic rate, actual quantum yield of photosystem II, photochemical quenching, non-photochemical quenching and electron transport rates in stressed leaves. Exogenous ALA also alleviated the accumulation of MDA and hydrogen peroxide, increased the activities of antioxidant enzymes and enhanced the expression of CAT and POD in drought-treated plants. These results indicate that ALA may effectively protect rapeseed seedlings from damage induced by drought stress.
TL;DR: Salinity tolerance of sugar beet (Beta vulgaris L.) cultivars in terms of growth, proline and soluble sugars concentrations, and Na+/K+ and Na+)/Ca2+ ratios were analyzed in this paper.
Abstract: Salinity tolerance of sugar beet (Beta vulgaris L.) cultivars in terms of growth, proline and soluble sugars concentrations, and Na+/K+ and Na+/Ca2+ ratios were analyzed in this study. Three-week-old seedlings of three sugar beet cultivars, ‘Gantang7’, ‘SD13829’, and ‘ST21916’, differing in salinity tolerance, were treated with 0, 50, 100, and 200 mM NaCl. Plant shoots and roots were harvested at 7 days after treatment and subjected to analysis. Low concentration of NaCl (50 mM) enhanced fresh and dry weights of shoot and root in ‘Gantang7’, whereas high one (200 mM) reduced growth in all cultivars and the less reduction was observed in ‘ST21916’. Shoot proline was strongly induced by salinity stress in both ‘Gantang7’ and ‘SD13829’, while it remained unchanged in ‘ST21916’. The addition of 50 mM NaCl significantly increased shoot soluble sugars concentrations in ‘Gantang7’ while it had no significant effects in the other two cultivars. ‘Gantang7’ also showed a higher level of root soluble sugars concentration as compared to the other two cultivars. At 50 mM NaCl, the lower shoot Na+ concentration, and the higher shoot K+ and root Ca2+ concentration in ‘Gantang7’ resulted in the lower shoot Na+/K+ and root Na+/Ca2+ ratio. However, ‘SD13829’ maintained a lower Na+/K+ ratio in both shoot and root when subjected to 200 mM NaCl treatment. According to comprehensive evaluation on salinity tolerance, it is clear that ‘Gantang7’ is more tolerant to salinity than the other two cultivars. Therefore, it is suggested that ‘Gantang7’ should be more suitable for cultivating in the arid and semi-arid irrigated regions.
TL;DR: This review focuses on recent developments on improvement in salinity tolerance aiming to contribute sustainable plant yield under saline conditions in the face of climate change.
Abstract: Salinity stress is one of the major abiotic stresses affecting plant growth and productivity globally. In order to improve the yields of plants growing under salt stress bear remarkable importance to supply sustainable agriculture. Acclimation of plants to salinized condition depends upon activation of cascade of molecular network involved in stress sensing/perception, signal transduction, and the expression of specific stress-related genes and metabolites. Isolation of salt overly sensitive (SOS) genes by sos mutants shed us light on the relationship between ion homeostasis and salinity tolerance. Regulation of antioxidative system to maintain a balance between the overproduction of reactive oxygen species and their scavenging to keep them at signaling level for reinstating metabolic activity has been elucidated. However, osmotic adaptation and metabolic homeostasis under abiotic stress environment is required. Recently, role of phytohormones like Abscisic acid, Jasmonic acid, and Salicylic acid in the regulation of metabolic network under osmotic stress condition has emerged through crosstalk between chemical signaling pathways. Thus, abiotic stress signaling and metabolic balance is an important area with respect to increase crop yield under suboptimal conditions. This review focuses on recent developments on improvement in salinity tolerance aiming to contribute sustainable plant yield under saline conditions in the face of climate change.
TL;DR: In this paper, the authors compared chemlali extra-virgin olive oils from different locations in northern, central and southern Tunisia in terms of their quality indices, fatty acids, sterol content, phenolic composition and sensory profiles to show the classification of oil samples according to the geographical area.
Abstract: The present work aims at the characterizing chemlali extra-virgin olive oils from different locations in northern, central and southern Tunisia in terms of their quality indices, fatty acids, sterol content, phenolic composition and sensory profiles to show the classification of oil samples according to the geographical area. The majority of the analytical parameters have presented statistically significant differences (p < 0.05). The main sterols found in all chemlali olive oils were β-sitosterol, ∆-5-avenasterol, campesterol and stigmasterol. The phenolic compounds present in five olive oil samples were analysed by high-performance liquid chromatography (HPLC) method, thus identifying 16 phenolic compounds belonging to different phenolic types. The results have shown no qualitative differences in the phenolic fractions among extra-virgin olive oils from different geographical regions. However, the quantitative differences were observed in a wide number of phenolic compounds. In all studied olive oil samples, secoiridoids were the most abundant, followed by lignans, phenolic alcohols and flavonoids, respectively. Although there is no significant influence on the sensory scores of oils, some slight changes in sensorial profiles were noted: slightly higher intensities of sensory characteristics that are pungent, fruity and bitter in chemlali olive oil from Hammamet and Gafsa.
TL;DR: Amplification of monomorphic bands with all primer combinations authenticated the true to type nature of the in vitro raised plants of D. asper which underwent up to 30 subculture passages over a period of approximately 2 years thereby supporting the commercial utilization of the developed micropropagation protocol.
Abstract: Dendrocalamus asper, an edible bamboo is valued for its tender edible shoots in the food industry. However, overexploitation of natural stands of D. asper coupled with minimal conservation and reforestation efforts has led to its rapid depletion in nature. Therefore protocol for rapid multiplication of D. asper via direct regeneration using nodal segments from mature clumps was standardized and more than 25,000 plants were transferred to the field (Singh et al. 2012a). However, genetic fidelity of these in vitro raised plants needs to be authenticated for commercial scale application of the developed micropropagation protocol. PCR-based molecular markers have emerged as simple, fast, reliable and labor-effective tools for testing the genetic fidelity of in vitro raised plants. This study report the genetic fidelity analysis of in vitro raised plants of D. asper for the first time using arbitrary (Random Amplified Polymorphic DNA, RAPD), semi-arbitrary (Inter-Simple Sequence Repeat, ISSR; Amplified Fragment Length Polymorphism, AFLP), and sequence-based (Simple Sequence Repeat, SSR) markers. Bulked DNA samples of 20 in vitro raised shoots (collected after every three subculture cycles starting from 3rd to 30th passage) and field transferred plantlets were compared with the mother plant DNA using 90 primer combinations (25 each of RAPD, ISSR, SSR, and 15 AFLP) and scorable bands were produced by 78 (22 RAPD, 24 ISSR, 21 SSR, and 11 AFLP) primers. A total of 146 distinct and scorable bands were produced by 22 RAPD primers with an average of 6.6 bands per primer while the number of bands for ISSR primers varied from 3 (ISSR-4 and 9) to 13 (ISSR-17), with an average of 7.1 bands per primer. Similarly, SSR markers also showed wide variation in number of bands, ranging from 2 (RM 261) to 12 (RM 44, 140, and 224) with an average of 7.8 bands. AFLP primer combinations could generate 35–72 bands with an average of 48.7 bands per primer pair. Amplification of monomorphic bands with all primer combinations authenticated the true to type nature of the in vitro raised plants of D. asper which underwent up to 30 subculture passages over a period of approximately 2 years thereby supporting the commercial utilization of the developed micropropagation protocol.
TL;DR: It was observed that pre-treatment of isolated 24-Epibrassinolide lowered the Ni ion uptake in plants and improved growth, and the amelioration of Ni toxicity was also observed by the activities of antioxidant enzymes.
Abstract: Brassinosteroids (BRs) are a group of steroidal plant hormones which are essential for growth and development of plants. These hormones affect plant growth and development through a spectrum of physiological responses. Recent reports showed their stress-protective, antiviral, antitumor and antigenotoxic potential. In the present study, an attempt was made to isolate 24-Epibrassinolide from 30-days-old Brassica juncea L. plants which was characterized by ESI–MS analysis. The ESI–MS analysis of isolated Brassinolide was compared with the standard 24-Epibrassinolide, which confirmed its MS/MS fragmentation pattern. Various concentrations of the isolated brassinosteroid were given as pre-sowing treatment to the seeds of B. juncea for 8 h. The pre-treated seeds were then raised in experimental pots containing different concentrations of nickel ion. After 30 days, plants were harvested and analyzed for growth parameters, ion uptake and antioxidant defense system. It was observed that pre-treatment of isolated 24-Epibrassinolide lowered the Ni ion uptake in plants and improved growth. The amelioration of Ni toxicity was also observed by the activities of antioxidant enzymes. The in vitro cytotoxicity of natural 24-Epibrassinolide against different cancer cell lines was checked by employing sulphorhodamine bioassay and it revealed significant inhibition in the lung cancer cell line.