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Assessment of Environmental Susceptibility/Vulnerability of Soils
62-74Views:100Soils represent a considerable part of the natural resources of Hungary. Consequently, rational land use and proper soil management – to guarantee normal soil functions – are important elements of sustainable (agricultural) development, having special importance both in the national economy and in environment protection.
The main soil functions in the biosphere are as follows: conditionally renewable natural resource; reactor, transformer and integrator of the combined influences of other natural resources (solar radiation, atmosphere, surface and subsurface waters, biological resources), place of „sphere-interactions”; medium for biomass production, primary food-source of the biosphere; storage of heat, water and plant nutrients; natural filter and detoxication system, which may prevent the deeper geological formations and the subsurface waters from various pollutants; high capacity buffer medium, which may prevent or moderate the unfavourable consequences of various environmental stresses; significant gene-reservoir, an important element of biodiversity.
Society utilizes these functions in different ways (rate, method, efficiency) throughout history, depending on the given natural conditions and socio-economic circumstances. In many cases the character of the particular functions was not properly taken into consideration during the utilization of soil resources, and the misguided management resulted in their over-exploitation, decreasing efficiency of one or more soil functions, and – over a certain limit – serious environmental deterioration.
Soil resources are threatened by the following environmental stresses:
– soil degradation processes;
– extreme moisture regime;
– nutrient stresses (deficiency or toxicity);
– environmental pollution.
Environmental stresses caused by natural factors or human activities represent an increasing ecological threat to the biosphere, as well as a socio-economic risk for sustainable development, including rational land use and soil management.
The stresses are caused by the integrated impacts of various soil properties, which are the results of soil processes (mass and energy regimes, abiotic and biotic transport and transformation and their interactions) under the combined influences of soil forming factors. Consequently, the control of soil processes is a great challenge and the main task of soil science and soil management in sustainable development.
The efficient control of these processes necessitates the following consecutive steps:
• registration of facts and consequences (information on land and soil characteristics, land use, cropping pattern, applied agrotechnics, yields, with their spatial and temporal variability);
• evaluation of potential reasons (definition and quantification of soil processes, analysis of influencing factors and their mechanisms);
• assessment of the theoretical, real, rational and economic possibilities for the control of soil processes (including their risk-assessment and impact analysis);
• elaboration of efficient technologies for the „best” control alternatives (best management practice).
Scientifically based planning and implementation of sustainable land use and rational soil management to ensure desirable soil functions, without any undesirable environmental side-effects, require adequate soil information. In the last years such data were organized into a computer-based GIS soil database in Hungary, giving opportunities for the quantification, analysis, modelling and forecasting of the studied environmental stresses and for the efficient and scientifically based prevention, elimination or reduction of environmental stresses and their unfavourable ecological and economical consequences.
Special attention was paid to the assessment of various soil degradation processes, as: (1) soil erosion by water or wind; (2) soil acidification; (3) salinization and/or alkalization; (4) physical degradation (structure destruction, compaction); (5) extreme moisture regime: drought sensitivity and waterlogging hazard; (6) biological degradation; (7) unfavourable changes in the plant nutrient regime; (8) decrease of natural buffering capacity, (9) soil (and water) pollution.
The actions against undesirable environmental stresses and their unfavourable consequences are important elements of sustainable, efficient, economically viable, socially acceptable and environmentally sound crop production and agricultural development. These are joint tasks of the state, decision makers on various levels, the land owners, the land users and – to a certain extent – of each member of the society. -
The effects of drought stress on soybean (Glycine max (L.) Merr.) growth, physiology and quality – Review
19-24Views:217Abiotic stresses are one of the most limiting factors inhibit plant's growth, leading to a serious production loss. Drought stress is one of the most destructive abiotic stresses and is still increasing year after year resulting in serious yield losses in many regions of the world,
consequently, affecting world’s food security for the increasing world population. Soybean is an important grain legume. It is one of the five major crops in the world, an essential source of oil, protein, macronutrients and minerals, and it is known as the main source of plant oil and protein. Harvested area of soybean is increasing globally year after year. However, soybean is the highest drought stress sensitive crop, the water deficit influences the physiology, production and seed composition of this crop. We introduce a review for literatures concerning the changes of the above traits of soybean exposed to drought stress, with past explanations for these changes. -
Screening of paprika (Capsicum annuum L.) varieties resistant to NaCl salt stress
105-110Views:178Salinity stress is one of the environmental factors that negatively affect the growth and production of pepper plants. The 100 seeds' weight was measured. The total fresh weight of five seedlings and the growth rate of one seedling of three paprika varieties were also measured under the influence of NaCl at a salinity level threshold of (3 dS m‑1). The proportion of tissue water content in three pepper cultivars was measured according to a mathematical formula at the end of the experiment. In terms of seed weight, the (Carma) cultivar outperformed other types greatly. Except for the superiority of both (Carma, and Bobita F1) over (Fokusz) variety in total fresh seedlings weight under sodium chloride as abiotic stress, there are no significant differences in the total seedlings' dry weight and the rate of seedling growth. The non-drought-resistant type (Bobita F1) loses water the fastest, at 89.61%, compared to drought-tolerant kinds, which lose water at a slower rate (Carma, and Fokusz). The results demonstrate the (Carma) variety's numerical vigor, particularly in the growth rate. More testing is needed to determine the selection of varieties that are resistant to abiotic and biotic stresses.
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Physiological traits and yield of three soybean (Glycine max (L.) Merr.) genotypes as affected by water deficiency
11-15Views:220Soybean is a very important legume; it has the highest protein content, and it is a very important source of vegetable oil. Soybean is droughtsusceptible, and drought is one of the major abiotic stresses that has been increasing over the past decades as a result of the global climatic changes. To evaluate the influence of drought stress, three soybean genotypes were grown under rainfed conditions, and compared to irrigated controls. The obtained results showed that the chlorophyll content, leaf area index and plant height decreased under drought stress conditions, which led to noticeable and sometimes significant yield reduction. Our results suggest more specific studies on the physiological changes of the local soybean genotypes under drought stress to better select the adopted ones.
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Does drought stress always negatively affect the yield and quality of soybean in Hungary?
37-40Views:223Globally-fluctuating climate imposed serious abiotic stresses on the agricultural sector, leading to noticeable, and sometimes disastrous, losses in yields and/or quality of crops; however, in certain cases, plants could survive stress with relatively low reductions, and sometimes even with some enhancements as a reaction to changed environment, especially in the case of mild stress. An experiment was conducted in 2017 and 2018 in Debrecen, Hungary to evaluate the mild drought stress influence on the yield and quality of three soybean cultivars. The results showed that both ES Pallador and Pedro cultivars could achieve more yield when subjected to mild drought conditions; however, protein concentration was enhanced in ES Pallador whereas slightly degraded in Pedro under drought. The cultivar Pannonia Kincse followed different trend; both yield and protein concentration were reduced under drought. Oil concentration of the three cultivars did not show significant changes; however, it always followed opposite trend to that of protein concentration. It could be concluded that both ES Pallador and Pedro are recommended to be grown under rain fed conditions in Debrecen, whereas Pannonia Kincse is recommended under irrigation conditions.
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Effect of arginine, putrescine and spermidine on the polyamine, proline and chlorophyll content of tobacco (Nicotiana tabacum L.)
39-43Views:156Polyamines, such as spermidine (Spd) spermine (Spm) and their direct precursor, the diamine putrescine (Put) are vital and essential aliphatic amines which are also present in plants. Although ethylene and polyamines are also involved in fruit ripening, the genes coding them must also take part in other biosynthetic pathways. In the ethylene and polyamines play an important role in development of salt stress tolerance, and in responses for biotic and abiotic stresses. Exogenous application of all three main polyamines (Put, Spd, Spm) increase salt tolerance of plants, but, accordingly to previous experiments, spermidine has the main effect on the enhancement of salt tolerance. Nicotiana tabacum L. plants were grown in vitro on MS medium, the treatments were as follows: arginine (150 mg l-1), putrescine (10 mg l-1), spermidine (10
mg l-1). Proline, chlorophyll a, b and polyamine contents were measured. The obtained results show that the arginine decarboxylase and the spermidine synthase genes involved in polyamine metabolism, cannot be enhanced by exogenous addition of their precursor molecules. On the contrary, the spermine synthase gene has a positive effect to the lower-class forms of polyamines. -
Investigation of Potato (Solanum tuberosum L.) Salt Tolerance and Callus Induction in vitro
51-55Views:114Potato production plays an important role in Hungary and the other countries of Europe. Consumption of potato products has increased to a large extent during the past several years. We can satisfy market demands with high quality and virus-free varieties.
Results of potato production depend on tolerance/resistance to abiotic stresses. In many cases, increased concentration of NaCl causes yield loss. Selection of salt tolerant varieties proved to be a difficult problem. Nowadays, the salt tolerance of potato varieties can be determined by cell/tissue/ protoplast techniques. Somaclonal variation provides a great potential for selection of lines resistant to salt stress. In vitro shoots and callus, derived plantlets selected for salt tolerance/resistance provide material for micropropagation.
In vitro shoot development of potato (Solanum tuberosum L. cv. Kuroda) was investigated under salt stress (40 mM, 80 mM, 120 mM NaCl) conditions. Shoot heights of plantlets cultured under salt conditions were lower than the control through the investigation. However, the shoot development of plantlets originated from in vitro meristems was almost at the same level as the control under 40 mM NaCl concentration.
There was no significant difference in the in vitro biomass production between control and treatment with 40 mM NaCl concentration. We measured a significant decrease in dry-matter mass under 120 mM NaCl concentration. There is a need for more investigation of different genotypes and for a conclusion as to whether in vitro tolerance could occur under in vivo circumstances in plants originated from somaclones as well.
Under in vitro conditions, we investigated shoot and leaf callus initiation using different culture media with different 2,4-D concentrations. Under dark conditions, callus induction of shoot/leaf decreased as the 2,4-D concentrations increased.
In light conditions, there was a little callus induction, while callus initiation from the shoot from 5 μM to 12 μM 2,4-D concentration showed a significant increase -
Behavior of some Hungarian wheat varieties to seed soaking in gibberellic acid under salt stress
7-17Views:234Various abiotic stresses including high salinity strongly affect seed germination. Three Hungarian wheat landraces Gamási, Fóti and Kartali have been tested for seed germination, seedling growth and chemicals parameters when seeds were soaked in gibberellic acid (GA3) at the concentrations of 0, 75 and 150 ppm and at four levels of salinity stress 0, 5, 10 and 15 dSm-1. A laboratory experiment took place at Research Institute of Nyíregyháza. Factorial Experiment based on Randomized Complete Block Design (RCBD) in four replications has been conducted. Seed soaking in GA3 before sowing significantly affected germination characteristics, seedling properties and the results of chemical analysis. The highest germination as well as K+ content of seeds were observed at seed soaking into 150 ppm GA3. However, Na+ and proline contents in seedling were decreased. The behavior of the tested Hungarian wheat varieties was genotype-dependent. Increasing salinity stress up to 15 dSm-1 significantly affected germination characteristics, seedlings parameters and chemical analysis. Fóti variety turned out to be the best at 150 ppm GA3 compared to the other two varieties. Moreover, it had the lowest Na+ and proline contents and highest K+ content.
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Assessing the impact of salinity stress on some morpho-physiological traits of two chickpea genotypes under hydroponic conditions
47-53Views:9Evaluating the performance of crop species to salinity stress is considered an intricate task due to differences in performance, response and susceptibility at different phenological stages of chickpea crop. Assessment of the performance of chickpea genotypes in response to NaCl-induced salinity stress at the initial vegetative phase is of great importance to have a crystal idea about the threshold level of tolerance. An experiment was carried out under hydroponic conditions to evaluate the performance of two chickpea genotypes (ELMO and ORION), in response to different salinity levels (0, 25, 50 and 75 mM NaCl) as factorial arrangement under completely randomized design with three replications. The average of shoot and root dry matter weight was significantly higher for the ELMO genotype at the control treatment (1.143, 0.4133 g respectively), while it was significantly lower in the two genotypes ORION and ELMO at the highest salinity level (0.267 and 0.2700; 0.0433 and 0.0533 g respectively). The root to shoot ratio was significantly higher in both genotypes in the control and the lowest salt level (25 mM NaCl), without significant differences among them (47.98, 43.30, 37.10 and 36.25% respectively). The relative water content and stomatal conductance were significantly higher in the ORION genotype (88.01%; 335.40 mmol m-2 s-1) compared to ELMO (84.09%; 299.10 mmol m-2 s-1), and increasing salinity level caused a proportional decline in both traits, where they were significantly lower at the highest salt level (75Mm) (77.45%; 87.50 mmol m-2 s-1). Results indicate genotypic variability in response to NaCl-induced salinity stress under hydroponic conditions and the physiological traits are more expressive and reliable as selection criteria than morphological ones.