Abiotic Stress Factors Research Articles

Gümüş Nitrat ve Ön Soğuk Uygulamalarının Çilek Anter Kültüründe Kallus Oluşumuna Etkileri

Strawberry (Fragaria x ananassa Duch.) which is one of the widely grown berry species in the world has economic and commercial importance. In commercial strawberry varieties, in order to increase yield and quality, it is necessary to obtain starting materials that are resistant/tolerant to biotic and abiotic stress factors. Biotechnological methods have an important place in strawberry breeding studies due to the long and costly process of classical breeding methods, the genetic expansion of seed production, high ploidy level and strong heterozygosity. Haploid plant production is an efficient breeding method that has been successfully applied to most plant species. However, due to the lack of sufficient haploid studies on strawberry and the fact that a specific protocol for this species has not yet been developed the necessary progress has not been made in this regard. In this study, the effectiveness of some factors determine the success in anther culture which has a significant place in obtaining haploid strawberries was investigated. For this reason, first, different sodium hypochlorite doses (NaOCl; 1%, 2%, 3%) and application durations (10, 15, 20 min) were used to determine the appropriate method for sterilisation, then cold pre-treatments (24, 36, 48, 72 hours at +4 °C) and different silver nitrate doses (AgNO3; 10, 20, 30, 40 mg l-1) were employed for callus induction in Festival strawberry variety. At the conclusion of the study it was observed that the lowest contamination rate (1%) was obtained by soaking in 1% sodium hypochlorite solution for 10 minutes. Cold pre-treatment of flower buds at +4 °C for 36 hours produced the highest callus induction rate (96%). The evaluation of the effect of AgNO3 application at different doses on the callus induction rate revealed that the highest callus induction (82%) was obtained from 20 mg l-1 AgNO3 dosage. This study showed that anther culture practices in strawberry can be improved by using cold pre-treatment, appropriate sterilization method and silver nitrate addition to the medium.

Molecular structure and functions of vacuolar processing enzymes in plants

Vacuolar processing enzymes (VPEs) are plant proteases belonging to the C13 protease family. The specific activity of VPEs was characterized by comparing them to animal caspases. VPEs perform many important functions at various stages of plant ontogenesis, playing a role not only in the proper development of the plant organism but also in plant reactions to biotic and abiotic stress factors. A particularly important role of VPEs is noted in the processing of vacuolar proteins, enabling the production of their mature and active forms. VPEs are involved in programmed cell death, but despite residual evidence, we also suggest that VPEs are involved in autophagy. Based on literature data on autophagy in yeast, we formulate a hypothesis that VPEs during autophagy in plant cells are involved in the degradation of autophagic bodies - one of the final stages of autophagy.

Secondary Metabolite Production In Plants: In Response To Biotic And Abiotic Stress Factors

Secondary metabolites (SMs) play vital roles in plant defence mechanisms, adaptation to environmental conditions, and interactions with other organisms. Biotic and abiotic stress factors can significantly influence the production, accumulation, and composition of SMs in plants. Understanding the intricate relationship between stress and SM production is crucial for enhancing plant resilience, agricultural productivity, and the development of novel phytopharmaceuticals. This research provides current knowledge regarding the impact of biotic and also abiotic stress on SMs in plants. Biotic stress factors such as pathogen infection, and herbivore attacks, as well as abiotic stress factors like drought, along with temperature extremes, and also salinity, can profoundly influence the biosynthesis and accumulation of SMs in plants. We discussed the methodology based on secondary sources underlying physiological, biochemical, and molecular mechanisms involved in stress-induced SM synthesis and highlight the potential implications for plant biology, agriculture, and human health. The study also emphasizes the functions of SMs in plants including defence against herbivores, pathogens, and abiotic stresses. The mechanism by which thesecompounds act as allelochemicals and signalling molecules is also discussed.

Exogenous melatonin induces salt and drought stress tolerance in rice by promoting plant growth and defense system

Due to global climate change, crops are certainly confronted with a lot of abiotic and biotic stress factors during their growth that cause a serious threat to their development and overall productivity. Among different abiotic stresses, salt and drought are considered the most devastating stressors with serious impact on crop’s yield stability. Here, the current study aimed to elucidate how melatonin works in regulating plant biomass, oxidative stress, antioxidant defense system, as well as the expression of genes related to salt and drought stress in rice plants. Eight groups of rice plants (3 replicates, 5 plants each) underwent varied treatments: control, melatonin, salt, drought, salt + drought, salt + melatonin, drought + melatonin, and salt + drought + melatonin. Melatonin (100 µM) was alternately applied a week before stress exposure; salt stress received 100 mM NaCl every 3 days for 3 weeks, and drought stress involved 10% PEG. Young leaves were randomly sampled from each group. The results showed that melatonin treatment markedly reduces salt and drought stress damage by promoting root, shoot length, fresh and dry weight, increasing chlorophyll contents, and inhibiting excessive production of oxidative stress markers. Salt and drought stress significantly decreased the water balance, and damaged cell membrane by reducing relative water contents and increasing electrolyte leakage. However, melatonin treated rice plants showed high relative water contents and low electrolyte leakage. Under salt and drought stress conditions, exogenous application of melatonin boosted the expression level of salt and drought stress responsive genes like OsSOS, OsNHX, OsHSF and OsDREB in rice plants. Taken together, our results reveal that melatonin treatment significantly increases salt and drought tolerance of rice plants, by increasing plant biomass, suppressing ROS accumulation, elevating antioxidants defense efficiency, and up-regulating the expression of salt and drought stress responsive genes.

Salicylic acid alleviates the effects of cadmium and drought stress by regulating water status, ions, and antioxidant defense in Pterocarya fraxinifolia.

Pterocarya fraxinifolia (Poiret) Spach (Caucasian wingnut, Juglandaceae) is a relict tree species, and little is known about its tolerance to abiotic stress factors, including drought stress and heavy metal toxicity. In addition, salicylic acid (SA) has been shown to have a pivotal role in plant responses to biotic and abiotic stresses. The current study is focused on evaluating the impact of foliar application of SA in mediating Caucasian wingnut physiological and biochemical responses, including growth, relative water content (RWC), osmotic potential (Ψs), quantum yield (Fv/Fm), electrolyte leakage, lipid peroxidation, hydrogen peroxide, and antioxidant enzymes, to cadmium (Cd; 100 µM) and drought stress, as well as their interaction. Moreover, the antioxidant activity (e.g., ascorbate peroxidase, catalase, glutathione reductase, peroxidase, and superoxide dismutase activities) of the stressed trees was investigated. The study was conducted on 6-month-old seedlings under controlled environmental conditions in a greenhouse for 3 weeks. Leaf length, RWC, Ψs, and Fv/Fm were decreased under all treatments, although the effect of drought stress was the most pronounced. An efficient antioxidant defense mechanism was detected in Caucasian wingnut. Moreover, SA-treated Caucasian wingnut plants had lower lipid peroxidation, as one of the indicators of oxidative stress, when compared to non-SA-treated groups, suggesting the tolerance of this plant to Cd stress, drought stress, and their combination. Cadmium and drought stress also changed the ion concentrations in Caucasian wingnut, causing excessive accumulation of Cd in leaves. These results highlight the beneficial function of SA in reducing the negative effects of Cd and drought stress on Caucasian wingnut plants.

Rice PIFs: Critical regulators in rice development and stress response.

Phytochrome-interacting factors (PIFs) belong to a subfamily of the basic helix-loop-helix (bHLH) family of transcription factors, which serve as a "hub" for development and growth of plants. They have the capability to regulate the expression of many downstream genes, integrate multiple signaling pathways, and act as a signaling center within the cell. In rice (Oryza sativa), the PIF family genes, known as OsPILs, play a crucial part in many different aspects. OsPILs play a crucial role in regulating various aspects of photomorphogenesis, skotomorphogenesis, plant growth, and development in rice. These vital processes include chlorophyll synthesis, plant gravitropism, plant height, flowering, and response to abiotic stress factors such as low temperature, drought, and high salt. Additionally, OsPILs are involved in controlling several important agronomic traits in rice. Some OsPILs members coordinate with each other to function. This review summarizes and prospects the latest research progress on the biological functions of OsPILs transcription factors and provides a reference for further exploring the functions and mechanism of OsPILs.

Yield prediction models of organic oil rose farming with agricultural unmanned aerial vehicles (UAVs) images and machine learnaing algorithms

The alternative solution for predicting yields involves leveraging the latest technological advancements in unmanned aerial vehicles (UAVs) imagery. This approach aims to empower agricultural systems operating in nature-dependent conditions, enabling them to optimize the utilization of limited resources effectively. This study aimed to provide the agricultural data management needed for the adoption of sustainable agriculture systems and the transition of precision to smart agriculture systems by combining technology. The study was carried out in the 2019–2020 vegetation period to determine the effect of the parameters on the yield in the areas where organic farming is grown in Isparta oil rose (Rosa Damascena Mill.) and to develop yield prediction models by combining them with spectral measurements. In the study, the phenological, morphological, and biochemical changes of the Isparta oil rose were examined periodically, and the effects of biotic and abiotic stress factors during the vegetation period were determined in the study and testing area. For the early yield prediction of organic Isparta oil rose was chosen thirteen parameters as soil moisture, pH, electrical conductivity (EC), soil temperature, and nine vegetation indices were derived from UAV-acquired multispectral images. The parameters were functioned in machine learning algorithms, which were multiple linear regression (MLR), multivariate adaptive regression splines (MARS), decision trees (chi-squared automatic interaction detector (CHAID), exhaustive chi-squared automatic interaction detector (ExCHAID), classification and regression tree (CART)), random forest (RF)) and artificial neural network (ANN), to develop the prediction models. Early period (day 69) for organic rose yield prediction models were determined to be useable as MARS 1 (0.907 R2), ExCHAID 1 (0.888 R2), CART 1 (0.931 R2), and RF 1 (0.909 R2).As a result of the study, the models can be used integrated with UAV and soil data for the early prediction of Isparta oil rose yield under organic farming systems, especially during the Agriculture 4.0 transition phase in our country. It is such that models be developed and used in different ecologies for sustainable agricultural systems.

Role of RNA interference in drought stress management: physiological, biochemical and molecular approach

Plants frequently encounter unfavourable growth conditions due to various biotic and abiotic stress factors. Drought is a significant abiotic stress factor that negatively impacts plant growth and development resulting in reduced crop productivity. Through evolution, plants have developed dynamic mechanisms that involve complex cross-talk between different regulatory levels, providing flexibility in their response to environmental stressors. Small non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and small interfering RNAs (siRNAs), have been discovered to play a crucial role in regulating molecular response to stress, and to be the key players in the RNA interference (RNAi) process. RNAi is a reliable strategy for precise regulation of gene expression and has emerged as a game-changer in mitigating plant responses to abiotic stress such as drought. This review summarises the role of RNAi in drought mitigation and its mechanism of action, compiling the current understanding of drought-responsive miRNAs functional at physiological, biochemical and molecular levels in major cereals. Moreover, we discuss the fine-tuning of miRNAs using the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9) system, a genome editing tool which can enhance the precision of gene expression regulation and increase plant tolerance to drought stress. These technologies have significant potential in ensuring global food security and sustainable agriculture by increasing crop yield and resilience to environmental stress.

Comparative analysis of defensive secondary metabolites in wild teosinte and cultivated maize under flooding and herbivory stress.

Climate change is driving an alarming increase in the frequency and intensity of abiotic and biotic stress factors, negatively impacting plant development and agricultural productivity. To survive, plants respond by inducing changes in below and aboveground metabolism with concomitant alterations in defensive secondary metabolites. While plant responses to the isolated stresses of flooding and insect herbivory have been extensively studied, much less is known about their response in combination. Wild relatives of cultivated plants with robust stress tolerance traits provide an excellent system for comparing how diverse plant species respond to combinatorial stress, and provide insight into potential germplasms for stress-tolerant hybrids. In this study, we compared the below and aboveground changes in the secondary metabolites of maize (Zea mays) and a flood-tolerant wild relative Nicaraguan teosinte (Zea nicaraguensis) in response to flooding, insect herbivory, and their combination. Root tissue was analyzed for changes in belowground metabolism. Leaf total phenolic content and headspace volatile organic compound emission were analyzed for changes in aboveground secondary metabolism. Results revealed significant differences in the root metabolome profiles of teosinte and maize. Notably, the accumulation of the flavonoids apigenin, naringenin, and luteolin during flooding and herbivory differentiated teosinte from maize. Aboveground, terpenes, including trans-α-bergamotene and (E)-4,8-dimethylnona-1,3,7-triene, shaped compositional differences in their volatile profiles between flooding, herbivory, and their combination. Taken together, these results suggest teosinte may be more tolerant than maize due to dynamic metabolic changes during flooding and herbivory that help relieve stress and influence plant-insect interactions.

Growth and non-structural carbohydrates response patterns of Eucommia ulmoides under salt and drought stress.

Salinity and droughts are severe abiotic stress factors that limit plant growth and development. However, the differences and similarities of non-structural carbohydrates (NSCs) responses patterns of trees under the two stress conditions remain unclear. We determined and compared the growth, physiology, and NSCs response patterns and tested the relationships between growth and NSCs concentrations (or pool size) of Eucommia ulmoides seedlings planted in field under drought and salt stress with different intensities and durations. We found that drought and salt stress can inhibit the growth of E. ulmoides, and E. ulmoides tended to enhance its stress resistance by increasing proline concentration and leaf thickness or density but decreasing investment in belowground biomass in short-term stress. During short-term drought and salt stress, the aboveground organs showed different NSCs response characteristics, while belowground organs showed similar change characteristics: the starch (ST) and NSCs concentrations in the coarse roots decreased, while the ST and soluble sugar (SS) concentrations in the fine roots increased to enhance stress resistance and maintain water absorption function. As salt and drought stress prolonged, the belowground organs represented different NSCs response patterns: the concentrations of ST and SS in fine roots decreased as salt stress prolonged; while ST in fine roots could still be converted into SS to maintain water absorption as drought prolonged, resulting in an increase of SS and a decrease of ST. Significant positive relationships were found between growth and the SS and total NSCs concentrations in leaves and branches, however, no significant correlations were found between growth and below-ground organs. Moreover, relationships between growth and NSCs pool size across organs could be contrast. Our results provide important insights into the mechanisms of carbon balance and carbon starvation and the relationship between tree growth and carbon storage under stress, which were of great significance in guiding for the management of artificial forest ecosystem under the context of global change.

Evaluation of growth, physiological response, and drought resistance of different flue-cured tobacco varieties under drought stress.

In recent years, more severe droughts have occurred frequently in many parts of the world, drought stress is the primary abiotic stress factor restricting the growth and quality of flue-cured tobacco. Therefore, screening dryland cultivation-compatible flue-cured tobacco varieties will help reduce the negative impact of drought. Tobacco varieties were selected: Qinyan 96 (Q96), Zhongyan 101 (Z101), Yunyan 87 (Y87), and Yunyan 116 (Y116). A pot experiment was conducted with four water supply gradients: sufficient, mild stress, moderate stress, and severe stress. The aim was to analyze inter-varietal differences in agronomic traits, photosynthetic traits, reactive oxygen species (ROS) metabolism, and antioxidant enzyme system under drought stress. Additionally, the drought resistance of four flue-cured tobacco varieties was evaluated using principal component analysis and membership function analysis. The results showed that drought intensification inhibited seedling growth and development across all varieties, with Q96 showing the least decrease and Y116 the greatest. With the increasing degree of drought stress, photosynthetic rates (Pn), transpiration rate (Tr), and stomatal conduction (Gs) have shown gradually decreasing trends, while substomatal cavity CO2 concentration (Ci) showed a growing trend. Severe drought corresponded with lower chlorophyll content and decreased the maximal photochemical efficiency (Fv/Fm), photosystem II (PSII), and photochemical quenching coefficient (qP) in all varieties, while steady-state non-photochemical quenching (NPQ) increased. Increased drought stress led to significantly higher reactive oxygen species (ROS) and malondialdehyde (MDA) content accumulation in tobacco seedlings. The antioxidant enzyme activities in, Q96, Z101, and Y87 increased under mild drought stress, whereas Y116 showed decreased activity. The drought resistance ranking among the four varieties is as follows: Q96 > Z101 > Y87 > Y116. Therefore, Q96 is a promising drought-tolerant breeding material that can be used as a reference for dryland cultivation of flue-cured tobacco.

The protective role of exogenous proline in pepper callus exposed to long- term cold stress

Cold stress is one of the main abiotic stress factors which restricts pepper growth and development. Thus, identifying alternative strategies is critical to reduce cold damage in peppers. This study evaluated the effect of exogenous proline in reducing cold stress damage in pepper callus. For this purpose, callus was obtained from the hypocotyl explants of germinated seedlings under in vitro conditions. 0,12 and 24 mM proline were applied to the callus and developed under the same photoperiodic settings at 4?C, 8?C, 16?C and 24?C. Low temperatures increased H2O2 and MDA production with the highest H2O2 and MDA amounts determined at 4?C. Proline applications decreased the content of H2O2 at low temperatures, whereby 24 mM proline caused a significant decrease in the amount of H2O2 at 4?C. The lowest MDA accumulation was determined in the 12 mM proline application. The data indicated that the total phenolic content of pepper callus decreased with decreasing temperatures. However, the application of proline increased the total phenolic amounts with the increase in its concentration. DPPH radical scavenging activity, FRAC and total protein content decreased with decreasing the temperature to 4?C and 8?C. However, both exogenous proline applications increased DPPH radical scavenging activity, FRAC and total protein at 4?C and 8?C. The results indicated that the metabolic pathways are triggered by the application of exogenous proline.

DETERMINATION OF THE EFFECT OF DIFFERENT DOSES OF JASMONIC ACID APPLICATIONS ON ALLEVIATING SALT STRESS IN TOMATO PLANTS WITH PHYSIOLOGICAL PARAMETERS

Salt stress is one of the most important abiotic stress factors that limit productivity in crop production due to climate change, whose effects have been felt more clearly in the world in recent years, and incorrect applications in agricultural soils. Research in plant production in saline soils, based on alleviating the effects of stress through applications to plants or soil, has gained momentum in recent years. In our study, we aimed to demonstrate that foliar jasmonic acid application to tomato plants alleviates the effects of salt stress with physiological parameters. Two tomato genotypes, sensitive to salt stress (TOM 106) and tolerant (TOM 23), determined in previous studies on abiotic stress, were used as plant materials. These two genotype selections were chosen to determine how close jasmonic acid brings the sensitive genotype to the tolerant genotype in salt stress. Salt dose is 100 mM and Control (0mM), jasmonic acid doses are; It was applied as 0, 20, 30 and 40 μM. The experiment carried out in pots was carried out under controlled conditions. Plant growth parameters (plant fresh and dry weight, stem diameter and plant length) and physiological parameters (such as leaf water potential, leaf osmotic potential, photosynthetic rate, transpiration rate, internal CO2, stomatal conductivity, chlorophyll) were measured at regular intervals. Jasmonic acid applications created a statistically significant difference. As a result, it was determined that 20 and 30 μM jasmonic acid applications were more effective in reducing salt stress damage.

The effect of dietary eugenol nano-emulsion supplementation on growth performance, serum metabolites, redox homeostasis, immunity, and pro-inflammatory responses of growing rabbits under heat stress.

Heat stress (HS) is a main abiotic stress factor for the health and welfare of animals. Recently, the use of nano-emulsion essential oils exhibited a promising approach to mitigate the detrimental impacts of abiotic and biotic stresses, ultimately contributing to the global aim of sustainable livestock production. The current study was piloted to assess the impact of eugenol nano-emulsion (EUGN) supplementation on growth performance, serum metabolites, redox homeostasis, immune response, and pro-inflammatory reactions in growing rabbits exposed to HS. A total of 100 male weaning rabbits aged 35 days were divided into 4 treatments. Rabbits were fed the diet with EUGN at different concentrations: 0 (control group; EUGN0), 50 (EUGN50), 100 (EUGN100), and 150 (EUGN150) mg/kg diet for 8 weeks under summer conditions. Dietary EUGN levels significantly improved (p < 0.05) the body weight, body weight gain, carcass weights, and improved feed conversion ratio of rabbits. EUGN supplementation significantly increased Hb, platelets, and red blood cells , while the mean corpuscular hemoglobin and eosinophils were significantly decreased compared to the control one. Compared with EUGN0 stressed rabbits, all EUGN-experimental groups had a reduction in levels of total glycerides (p < 0.01), uric acid, total bilirubin, direct bilirubin, and gamma-glutamyl transpeptidase (p < 0.01). Total antioxidant capacity and glutathione peroxidase were significantly improved by EUGN treatment when compared to the control one (p < 0.01), while the EUGN100 exhibited the greatest levels of catalase. Lipid peroxidation (malondialdehyde) was significantly decreased in EUGN-treated groups. All pro-inflammatory cytokines serum interleukin 4, Interleukin 1β, and tumor necrosis factor alpha were considerably decreased after dietary EUGN supplementation (p < 0.05). The serum concentrations of immunoglobulins (IgG and IgM) were significantly improved in rabbits of the EUGN150 group. This study shows that EUGN can be used as a novel feed additive to enhance the growth performance, immune variables, and antioxidants, and reduce the inflammatory response of growing rabbits exposed to thermal stress.

Evaluation of the prospects for the use of growth-stimulating complexes of endometabolites of cyanobacteria Arthrospira platensis in soybean cultivation

For the first time, data were obtained on the use of the cyanobacteria Arthrospira platensis endometabolite complex and its modifications, fortified (additionally enriched) with nutrients B, Se, and P in soybean cultivation technology, which acted not only as growth regulators, but also as adaptogens to external abiotic stress factors during the growing season of the studied crop. It was found that the use of complexes fortified with phosphorus and selenium in pre-sowing seed treatment (0.6 l/t) and foliar top dressing of vegetative soybean plants in the phase of 1-3 triple leaves provides the greatest increase in grain yield by 0.23 and 0.2 t/ha, or by 10.1 and 8.8% in the indeterminate Mezenka variety, and protein collection at the same time is 1022.5 and 1012.7 kg/ha, respectively.

Response to Deficit Irrigation of ‘Orogrande’ Mandarin Grafted onto Different Citrus Rootstocks in Spain

Drought is increasingly becoming an abiotic stress factor that affects citrus yield in the Mediterranean Basin, and rootstocks may impact the plants’ responses to it. This study compares the influences of Forner-Alcaide 5 (FA-5), an emerging well-established rootstock in Spain, and Carrizo citrange (CC), the common commercial rootstock of the Orogrande mandarin variety, on plants’ responses to water reduction. The deficit irrigation (DI) condition was established by 50% irrigation and evapotranspiration (ETc). The canopy volume, yield, fruit size and fruit internal quality were evaluated. The yield reduction in the CC DI was mainly due to a smaller fruit size, but in FA-5, it was due to fewer fruits without an affected caliber. Regarding Ct, the fruits from the CC DI had lower juice contents and higher rind percentages, while the differences between the Ct and DI trees were smaller in the FA-5 rootstock. The most remarkable effect was the increase in total soluble sugars (TSS) for the DI treatment. To conclude, the FA-5 rootstock had the strongest influence on Orogrande mandarin under water stress. These results can be useful for addressing water stress problems in citrus.

Effect of molybdenum application in pepper (Capsicum annuum L.) under cold stress conditions

Cold stress (low temperature stress) is one of the abiotic stress factors. It causes many morphological and physiological problems in plants. One of the applications to eliminate and alleviate these negative effects is molybdenum application. The aim of this study was to determine the effect of molybdenum application on cold stress in commercial variety Mazamort pepper. In the experiment, control, 25 ppm molybdenum concentration, 72 hours cold stress and 25 ppm molybdenum +72 hours cold stress applications were included. Pots of 2 L were used to grow the plants and the growing medium was a mixture of peat and perlite in a ratio of 2:1 by volume. Climatic chamber conditions were set to 24±1°C during the day and 18±1°C at night with 16/8 h light/dark photoperiodicity for control conditions and 24±1°C during the day and 5±1°C at night with photoperiodicity for cold stress conditions. The experiment was planned according to the random plots factorial design with 3 replications and 6 plants in each replicate. At the end of the study, plant height, stem diameter, number of leaves, plant fresh and dry weight, SPAD, wet basis moisture content, leaf proportional water content and ion leakage parameters were analysed. The highest plant height of Mazamort pepper variety was determined in 25 ppm molybdenum+72 hours cold stress application (44.51 cm). Application of 25 ppm molybdenum was effective in alleviating the negative effect of cold stress on plant stem diameter, plant fresh-dry weight and turgor potential. Moisture content wet basis was lowest in 25 ppm molybdenum +72 hours cold stress application. SPAD value in pepper plants decreased under cold stress conditions. It was observed that 25 ppm molybdenum application was ineffective and the decrease increased under cold stress conditions. Ion leakage in Mazamort pepper variety was highest under 72 hours cold stress and 25 ppm molybdenum +72 hours cold stress conditions. Under cold stress conditions, 25 ppm molybdenum application was ineffective. Molybdenum application under cold stress conditions was found to have positive effects on some parameters in general. In future studies, we believe that the application of different molybdenum concentrations and different cold stress periods will reveal the effects of molybdenum more clearly.

Magnetic Field Treatment in Barley: Improved Salt Tolerance in Early Stages of Development

It is known that salinity is one of the most important abiotic stress factors reducing productivity in agriculture. High salt concentration has a negative effect on seed germination and seedling formation. Magnetic field treatment can be considered as an environmentally friendly, innovative and inexpensive method to increase tolerance to stress, as a productivity-enhancing factor in agriculture. In this study, germination rate, germination strength, shoot and root length, fresh and dry weights, chlorophyll a, b and total chlorophyll content and ion leakage values of three different barley varieties under the influence of 150 mT constant magnetic field at different time intervals were determined. In light of the results, it was determined that although it varies according to the barley varieties, it has a significant positive effect on the germination rate and strength depending on the duration of the applied magnetic field. This study revealed that the magnetic field seed treatment has different effects according to the treatment time and the severity of the salt stress.

Pollen reaction of mutant tomato forms to abiotic stress factors

The article presents the results of screening accessions of the mutant tomato gene pool (125 genotypes) based on the response of their pollen to abiotic stress factors (high, low temperatures, drought) in order to study their potential and identify genetic sources/donors of resistance. The studies were carried out in open ground conditions from 2015 to 2017 and in summer greenhouses from 2017 to 2019. High heterogeneity of the genotype-specific response of pollen of mutant forms to various stress factors was shown: with a lethal outcome to all factors (10 genotypes); highly resistant to all stressors (20 genotypes); combining resistance: to high and low temperatures (7 genotypes), to high temperature and drought (9 genotypes), to cold and drought (4 genotypes); resistant only: to high (14 genotypes) or low (17 genotypes) temperatures, drought (6 genotypes). Mutant forms (38 genotypes) with high intrapopulation variability in pollen germination and the ability to form long pollen tubes under various stressors were also identified. It was established that resistance to heat, cold and drought according on traits of the male gametophyte was determined by different genetic systems.

Germination and Seedling Properties of Lotus corniculatus L. Under Simulated Drought Stress

Drought is an important abiotic stress factor that reduces agricultural production and yield in many crops, including forage crops, in agricultural areas around the world. Lotus corniculatus L. is the agriculturally crucial perennial legume forage crop that can tolerate moderate drought. However, studies to determine the responses of L. corniculatus to drought are limited. Therefore, this study was carried out to determine the seed germination and early seedling growth properties of L. corniculatus at different PEG6000 induced-drought treatments under in vitro conditions. In order to do this, L. corniculatus (cv. ‘AC Langille’) seeds were planted in MS (Murashige and Skoog/Gamborg) medium containing 0%, 4%, and 8% (w/v) PEG6000 for 14 days. In this study, germination percentage, mean germination time, germination rate index (speed of germination), shoot and root length, root to shoot length ratio, shoot and root fresh weight, shoot and root dry weight, shoot and root dry matter ratio, root shoot dry matter ratio, shoot and root water content and seedling vigor index parameters were measured. Our results showed that increasing drought levels resulted in an overall significant reduction in germination and seedling growth parameters except shortened mean germination time (especially, 4% PEG6000 treatment) and increased shoot and root dry matter ratio at higher (especially, 8% PEG6000 treatment) drought levels. When important growth parameters such as length, fresh and dry weight, dry matter ratio and water content, which show the development of root and shoot organs, are evaluated together, it has been determined that the root is negatively affected by drought stress at a higher rate. Based on these data, it can be concluded that the L. corniculatus will suffer a high yield loss under the drought stress at the osmotic potential (-1.03 bar) created by 8% PEG6000 treatment.