Negative Effects Of Water Stress Research Articles

Seedling priming with UV-A radiation induces positive responses in tomato and bell pepper plants under water stress

Stimulating crops to cope with various stressful conditions is an increasingly interesting strategy, even more so when this process is done through seed or seedling priming, since it is simpler and cheaper. The use of UV-A radiation for this purpose can be a viable, economical and environmentally friendly alternative. That is why the aim of this study was to evaluate if seedling priming with UV-A radiation is capable to help tomato and bell pepper plants tolerate water stress. For this, an experiment was carried out in both crop plants, where UV-A radiation was applied directly on the seedlings prior to transplanting on a single occasion, and for two hours. The crops were developed both in optimal water conditions and under water stress conditions. The results obtained show that priming with UV-A decreased the negative effects of water stress in tomato, increased fruit yield by 24.5% and root dry biomass by 46% compared to the stressed control. UV-A priming increased the proline content 294% when there was no stress, and 164% under water stress. Moreover, phenolic compounds were increased by UV-A priming under water stress. In bell pepper, priming with UV-A increased root dry biomass 26% compared to stressed control, but there were no differences in fruit yield. UV-A priming increased 68% more MDA when there was no stress, while under water stress increased 34%. In addition, UV-A priming increased chlorophyll content under water stress. Seedling priming with UV-A radiation can be an efficient strategy to induce tolerance to water stress in agricultural crops, with the great advantage that it is an easy-to-apply and environmentally friendly technology.

Investigating the synergistic effects of biochar, trans-zeatin riboside, and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat

BackgroundWater stress is a major danger to crop yield, hence new approaches to strengthen plant resilience must be developed. To lessen the negative effects of water stress on wheat plants, present study was arranged to investigate the role of synergistic effects of biochar, trans-zeatin riboside (t-ZR), and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat.ResultsIn a three-replication experiment comprising of four treatments (T0: Control, T1: Drought stress (DS), T2: DS + t-ZR with biochar, T3: DS + A. brasilense with biochar), we observed notable improvements in soil quality and enzymatic activities in water-stressed wheat plants with the application of t-ZR and A. brasilense with biochar. In drought stress, Treatment having the application of A. brasilense with biochar performs best as compared to the other and significant increased the enzymatic activities such as peroxidase (7.36%), catalase (8.53%), superoxide dismutase (6.01%), polyphenol oxidase (14.14%), and amylase (16.36%) in wheat plants. Different enzymatic activities showed different trends of results. Soil organic C, dissolved organic C, dissolved organic N also enhanced 29.46%, 8.59%, 22.70% respectively with the application of A. brasilense with biochar under drought stress condition.ConclusionsThe synergistic action of A. brasilense and biochar creates an effective microbiological environment that supports essential plant physiological processes during drought stress. This enhancement is attributed to improved soil fertility and increased organic matter content, highlighting the potential of these novel strategies in mitigating water stress effects and enhancing crop resilience.

Boron Nutrition in Coffee Improves Drought Stress Resistance and, Together with Calcium, Improves Long-Term Productivity and Seed Composition

Coffee production around the world is under threat due to climate variability and change, and drought stress will increase in many coffee regions; nutrient management practices can enhance the adaptation capacity of coffee production. Considering that coffee is a crop sensitive to boron (B) deficiency, this research investigated how B nutrition improves resistance to drought stress in coffee under controlled conditions as well as how the interaction with calcium (Ca2+) influences productivity, seed composition, and soil fertility during a production cycle of 5 years. Under controlled conditions for seven months, coffee plants were submitted to water stress with and without B nutrition. In the field, the coffee plantation was exposed to two B rates (0.6 and 1.1 kg.ha−1-year−1) with a fixed calcium (Ca2+) rate and a control without Ca2+ and B. After 9 months of growth and seven months of water deficit, under controlled conditions, the application of B significantly (p < 0.05) reduced the negative effect of water stress on coffee growth. Under field conditions, after a production cycle of 5 years, the application of 0.6 kg B and 77 kg CaO. ha−1.year−1 yielded 14% more than the control without B and Ca2+. An increase in the B rate to 1.1 kg.ha−1.year−1 with the same Ca2+ rate increased the productivity significantly (p < 0.05) by 37% compared to the control. The B application also improved significantly (p < 0.05) the B content in the soil at 0–30 cm. The B treatments influenced the biochemical composition of the green coffee beans, with a significant (p < 0.05) inverse correlation between the B content of the green coffee beans and caffeine and unsaturated fatty acids (UFAs), mainly, oleic, linoleic, and linolenic acids, which are considered negative descriptors of the coffee quality.

Unraveling the effects of melatonin on drought-stressed pear rootstocks: A comparative analysis of Dargazi and Pyrodwarf

Drought stress is known as one of the major challenges in most fruit-growing areas. This research aimed to investigate the amelioration effect of pre-drought exogenous melatonin application on the physiological and biochemical response of `Dargazi’ seedling and `Pyrodwarf’ clonal pear rootstocks, grown under water stress and controlled greenhouse conditions. Drought stress was applied by withholding irrigation water for 40 days on one-year-old un-grafted seedlings and clonal pear rootstocks. Gas exchange, chlorophyll content, relative water content, lipid peroxidation, and enzyme antioxidant activity were examined. Pre-drought treatment of melatonin significantly increased drought tolerance, successfully recovered the lost growth and considerably improved photosynthetic efficiency. The adverse effect of drought stress was ameliorated by melatonin through the possible osmotic adjustment such as the increase of proline (102 and 92 g/g FW for `Dargazi' and `Pyrodwarf' respectively) and soluble sugars as well as the improvement of the antioxidative defense system through the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). The `Dargazi’ seedling rootstock showed better tolerance to drought stress with higher photosynthesis, leaf water content, chlorophyll content, antioxidant enzyme activity, lower lipid peroxidation, and H2O2 generation than the Pyrodwarf clonal rootstock. Also, melatonin ameliorated the negative effect of water stress on photosynthesis and growth parameters through the possible inducing osmotic adjustment and anti-oxidative system under the severe drought stress condition on pear rootstocks. SOD, APX, POD, and CAT activities in Dargazi rootstock were significantly higher than those in control plants by 76.1 %, 34.9 %, 20.93 %, and 124.42 % respectively. Similarly, SOD, APX, POD, and CAT in Pyrodwarf pear rootstock increased in enzyme activities by 56.92 %, 24.37 %, 35.53 %, and 259.52 %, respectively. It is concluded that melatonin application as a pre-drought treatment mitigates the negative effects of drought stress in both rootstocks and the Dargazi rootstock exhibits remarkable resilience to drought stress.

Effect of tebuconazole and azoxystrobin on the physiological parameters of wheat seedlings and their resistance to water stress

Strobilurin and triazole class fungicides are actively used in agriculture as part of dressers to protect plants from fungal disease. In addition, they have various physiological effects on plants, including increased resistance to adverse environmental factors. The combined effect of these fungicides under water stress is understudied. The present work aims to examine the individual and combined effects of tebuconazole and azoxystrobin on the growth characteristics of wheat and its resistance to water stress. The study used winter wheat (Triticum aestivum L. ) plants grown from seeds treated with tebuconazole (2 mg/50 g seeds) and azoxystrobin (4 mg/50 g seeds) suspensions separately or together. In order to create water stress, five-day seedlings were transferred to 20% polyethylene glycol solution (PEG 6000), with stability assessed at seven and nine days. Tebuconazole was found to have a retardant effect on shoots and stimulate root growth. Azoxystrobin inhibited shoot growth and particularly root growth. When used together, tebuconazole partially reduced azoxystrobin-induced root inhibition. Azoxystrobin increased the negative effect of water stress, while tebuconazole effectively protected the root system of seedlings, partially reducing the effect of azoxystrobin. The stimulation of root growth with tebuconazolewas concluded to play an important role in providing resistance of winter wheat to water stress and to have the potential for use in agriculture.

Impact of biostimulants based amino acids and irrigation frequency on agro-physiological characteristics and productivity of broccoli plants

Abstract scientists are concerned about the utilizing of biostimulants-based amino acids in plant feeding and mitigating negative effects of water stress. As a result, two-year field experiments were conducted at Faculty of Agriculture's experimental station at Cairo University to study the effectiveness of liquid yeast waste (CMS) and Cargo amino acids (AAs) on the agro-physiological features of broccoli plants with different irrigation frequencies (every 5, 10, and 15 days). Compared with control plants, the foliar application of AAs and CMS significantly increased plant height, photosynthesis pigments, head weight, head diameter, head height, plant yield, and quality at different irrigation frequencies. Likewise, both treatments (CMS and AAs) significantly improved ascorbic acids by 16.65% and 15.95% and increased total phenol content by 24.10% and 36.60%, respectively, compared to control plants. Accordingly, the highest productivity was achieved for broccoli grown under irrigation every five days with the CMS bio-stimulant, where it was 3111.17 kg ha-1, while the lowest productivity was achieved for the control treatment in which no biostimulants were added and irrigation frequency every 15 days, and the productivity was 1376.22 kg ha-1. Plants irrigated every 15 days produced the highest levels of abscisic acid (ABA) and superoxide dismutase (SOD), followed by plants irrigated every 10 days and every 5 days. Exogenous application of amino acids bio-stimulants could be suggested to improve vegetative growth, biochemical characteristics, productivity, and nutritional value as well as to mitigate negative effects of water scarcity.

Zinc and amino acids improve the growth, physiological, and biochemical attributes of corn under different irrigation levels

The global challenge of food security is threatened by drought stress. Exogenous application of zinc and amino acids could alleviate the negative impacts of water shortage on the growth, physiological, and biochemical attributes of plants. Based on this hypothesis, a field study was conducted to assess the effects of chelated zinc applied through irrigation systems and foliar amino acids on the growth, physiological and biochemical attributes of corn, under three irrigation levels at the recommended irrigation level (100%), and at 75% and 50% of the recommended rate. The treatments were arranged in randomized complete block design in triplicate. Treatment effects on yield varied with intensity and duration of water stress. An irrigation level of 100% means the normal supply of recommended water. In results, the implementation of irrigation levels on corn led to varying impacts on yield, depending on the intensity and duration of the water stress. Plants responded by reallocating nutrient accumulation within their tissues, which played a crucial role in mitigating the negative effects of water stress. The application of zinc and amino acids individually showed positive effects on corn improvement, as these promoted antioxidant defense systems and enhanced corn yield. However, the combined application of foliar amino acids and soil-applied zinc, particularly under the 75% irrigation level, had a tremendous effect on various examined parameters. There was an increase in catalase by 65.9%, superoxide dismutase by 17.1%, and peroxidase by 15.1%, resulting in improved corn yield by 114.6% and decreased hydrogen peroxide contents by 74.2% compared to control. In conclusion, adopting 75% of the applied water and treating corn plants with a combination of zinc and amino acids resulted in the highest yield, nutrient accumulation, antioxidant enzymes, chlorophyll contents, relative water contents, and carbohydrate levels.

Inoculating moldavian balm (Dracocephalum moldavica L.) with mycorrhizal fungi and bacteria may mitigate the adverse effects of water stress

Plant growth-promoting bacteria (PGPBs) play a crucial role in mitigating the oxidative damage caused by water stress in different plant species. The aim of this study was to determine the effects of PGPBs and mycorrhiza-like fungi (Piriformospora indica) on improving drought tolerance in moldavian balm (Dracocephalum moldavica L.), a medicinal and aromatic plant. For this purpose, a greenhouse study was conducted in a factorial experiment based on a randomized complete design with three replications. Results indicate that water stress reduces the membrane stability index (MSI), total chlorophyll content (Chlt), carotenoids, and maximum photochemical efficiency of photosystem II (Fv′/Fm′) in moldavian balm plants, while increasing superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and hydrogen peroxide (H2O2) content compared to the control (no water stress). Inoculation with PGPBs and Piriformospora indica helped alleviate the negative effects of water stress. The highest MSI (48%) and Fv′/Fm′ value (0.82) were observed when inoculated with Enterobacter and Piriformospora, respectively, under non-water-stressed conditions. Inoculation with Agrobacterium, Piriformospora, and Enterobacter improved the Chlt and leaf proline contents, as well as the SOD activity under high water stress, compared to the non-inoculated control values. Furthermore, inoculation with Pseudomonas under high water deficit stress levels increased the MDA content (0.51 mmol g−1 FW) and H2O2 levels (0.40 mmol g−1 FW). The highest yield of flowering branches (2.414 g pot−1) in moldavian balm was obtained with Enterobacter. Based on the enhanced physiological and biochemical responses, as well as increased antioxidant enzyme activity that improve water tolerance in this plant, it is recommended to use PGPBs and Piriformospora indica fertilization.

Stimulating growth, root quality, and yield of carrots cultivated under full and limited irrigation levels by humic and potassium applications

Water stress poses a significant challenge for carrot cultivation, leading to decreased yield and inefficient water use efficiency. Therefore, it is crucial to provide plants with suitable supplements that enhance their stress resistance. In this study, we investigated the effectiveness of humic and potassium applications on carrot growth, yield characteristics, root quality, and water use efficiency under varying irrigation levels. A split-split plot experiment was conducted, with two levels of gross water requirements (GWR) (100% and 80%) assigned to the main plots. The subplots were treated with humic acid through foliar application (Hsp) or soil drenching (Hgd). The sub-subplots were further divided to assess the impact of foliar potassium sources (potassium humate, Kh) and mineral applications (potassium sulfate, K2SO4). The results revealed a substantial reduction in carrot yield under limited irrigation, reaching about 32.2% lower than under GWR100%. Therefore, under limited irrigation conditions, the combined application of Hgd and K2SO4 resulted in a significant yield increase of 78.9% compared to the control under GWR80%. Conversely, under GWR100%, the highest average yield was achieved by applying either Hsp and Kh or Hsp and K2SO4, resulting in yields of 35,833 kg ha−1 and 40,183 kg ha−1, respectively. However, the combination of Hgd and Kh negatively affected the yield under both GWR100% and GWR80%. Nonetheless, applying Kh in combination with Hgd under GWR80% led to improved nitrogen, phosphorus, potassium, potassium/sodium ratio, and total sugar concentrations, while reducing sodium content in carrot roots. Based on this study, it is recommended to adopt GWR80% and treat plants with a combination of Hgd and foliar K2SO4. This approach can help plants overcome the negative effects of water stress, improve yield and root quality, and achieve optimal water use efficiency.

Combined effects of shade and drought on physiology, growth, and yield of mature cocoa trees

Climate models predict decreasing precipitation and increasing air temperature, causing concern for the future of cocoa in the major producing regions worldwide. It has been suggested that shade could alleviate stress by reducing radiation intensity and conserving soil moisture, but few on-farm cocoa studies are testing this hypothesis. Here, for 33 months, we subjected twelve-year cocoa plants in Ghana to three levels of rainwater suppression (full rainwater, 1/3 rainwater suppression and 2/3 rainwater suppression) under full sun or 40 % uniform shade in a split plot design, monitoring soil moisture, physiological parameters, growth, and yield. Volumetric soil moisture (ϴw) contents in the treatments ranged between 0.20 and 0.45 m3m−3 and increased under shade. Rainwater suppression decreased leaf water potentials (ѱw), reaching −1.5 MPa in full sun conditions indicating severe drought. Stomatal conductance (gs) was decreased under the full sun but was not affected by rainwater suppression, illustrating the limited control of water loss in cocoa plants. Although pre-dawn chlorophyll fluorescence (Fv/Fm) indicated photoinhibition, rates of photosynthesis (Pn) were highest in full sun. On the other hand, litter fall was highest in the full sun and under water stress, while diameter growth and carbon accumulation increased in the shade but was negatively affected by rainwater suppression. Abortion of fruits and damage to pods were high under shade, but dry bean yield was higher compared to under the full sun. The absence of interactions between shade treatments and rainwater suppression suggests that shade may improve the performance of cocoa, but not sufficiently to counteract the negative effects of water stress under field conditions.

Physiological and biochemical changes in response to Moringa oleifera biostimulant in petunia plants under water deficit

The present paper aimed to evaluate the effects of LME (Moringa oleifera leaf extract) in modifying growth, ornamental value and several physiological and chemical parameters of petunia (Petunia hybrida E.Vilm.) ‘GO!Tunia® Neon Pink’. Three level of water deficit were considered: control (100% of WCC, Water Container Capacity = 100% CC), 60% and 40% of WCC; for each level treatments with LME were also considered. Water deficit reduced growth parameters compared with full irrigation and LME application promoted almost all the growth parameters in both control and stressed conditions. The behavior in growth parameters is correlated with a decrease in photosynthesis activity and plant water status. Deficit irrigation reduced the Relative Water Content (RWC) without differences linked to LME application. The chlorophyll content was unchanged for effect of water deficit and enhanced by LME treatment. The capacity to accumulate protective compounds (Proline, MDA) allowed plant to reduce the negative effects of water stress; LME treatment is not always able to increase these compounds in more stressed plants. LME application increased GPX and SOD activities in plants grown under drought stress, and this facilitated the ROS scavenging and maintenance of plant growth under stress. Total phenol compounds (TPC) showed significant differences in relation to the water deficit treatments, but not to biostimulants; the interaction effect was significant. Total soluble sugars in the leaf tissues were significantly affected only by deficit irrigation treatments. Drought stress also affected the production of endogenous level of hormones and amino acid. The highest content for almost all free amino acids was observed in the most stressed treatment (40% CC and 40% CC + LME). The response of petunia plants to water deficit was related to its ability to decrease aerial growth and to modify leaf gas exchange, increasing secondary osmolytes and enzyme activity to contrast the ROS activity.

Interaction Effects of Sowing Date, Irrigation Levels, Chitosan, and Potassium Silicate On Yield and Water Use Efficiency for Maize Grown Under Arid Climate

Adopting foliar antiperspirants reduces the negative effects of water stress on crop production. In this study effects of chitosan (Ch) and potassium silicate (PS) on maize sowing at two sowing dates under irrigation water levels (100% of irrigation water applied −Ir00 and 70% of irrigation water applied −Ir70) were investigated. Thus, during the spring and fall seasons of 2020–2021, a field experiment of two similar experiments was conducted at the experimental farm of Water Studies and Research Complex (WSRC) station, National Water Research Center, Toshka—Abu Simbel City, Egypt, which the sowing dates were allocated in the main plot, then a strip-plot design with five replicates was used. It was found that sowing maize seeds in the fall season led to attaining a higher maize yield than in the spring. Moreover, the adoption of Ir70 provides better maize yield and water use efficiency than Ir100, particularly at the fall season sowing date. In addition, the adoption of the higher Ch concentrations in the spring, led to better improvements in maize yield particularly under Ir70, while the adoption of the higher concentrations of PS in the fall seasons, led to better maize yield. It was concluded based on present findings that applying chitosan as foliar applications with concentrations at 500 (mg l−1) under Ir70 in the fall had significant effects to maintain the higher maize yield, water use efficiency and irrigation water use efficiency in the arid regions as Toshka district and other similar areas.

Effects of Plant Growth-Promoting Rhizobacteria on the Physioecological Characteristics and Growth of Walnut Seedlings under Drought Stress

Drought is one of the most brutal environmental factors limiting the productivity of fruit trees. The search for new and efficient microorganisms from unexplored environments that can be used to mitigate the negative effects of water stress is an interesting alternative to alleviate the drought stress experienced by plants. This study aimed to determine the effects of PGPR inoculation on the growth and physioecological characteristics of walnut (Juglans regia) seedlings under drought stress. A pot experiment was conducted using J. regia seedlings with controlled water supplies at different levels (light, moderate, and severe drought stress and control) and with or without inoculation with Bacillus cereus L90, a type of PGPR that produces high levels of cytokinins and indoleacetic acid (IAA). Under well-watered conditions, there was no obvious effect of PGPR inoculation on the antioxidant enzyme activities, osmotic adjustment levels, and photosynthetic characteristics of J. regia. As the stress intensity increased, B. cereus inoculation increased the antioxidant enzyme activities in walnut seedlings and changed their photosynthetic characteristics. However, levels of osmotic adjustment substances were decreased as a result of PGPR inoculation. Regardless of water status, B. cereus inoculation induced a significant increase in IAA, gibberellins, and zeatin contents in J. regia. Under well-watered and light stress conditions, the abscisic acid content of walnut was significantly increased by B. cereus inoculation. Additionally, B. cereus inoculation significantly promoted the growth of plants in terms of ground diameter and plant height. As a result, PGPR inoculation could improve the drought resistance of J. regia and improve its photosynthetic characteristics and growth, suggesting that it is a useful supplementary measure for use in afforestation in arid and semiarid environments.

Analyzing the impact of extreme heat events and drought on wheat yield and protein concentration, and adaptation strategies using long-term cultivar trials under semi-arid conditions

Extreme weather events, lower precipitation and higher temperatures play a relevant role in the assessment of wheat yield and protein concentration under future weather conditions in Mediterranean environments. To explore this topic, a dataset of long-term wheat cultivar trials carried out in 17 locations in Andalusia, southern Spain, between 1990 and 2017, and covering a wide range of weather conditions, has been analyzed.The occurrence of maximum temperatures surpassing 32.5°C during heading showed significant correlations with yield, and generated reductions of up to 30% of the maximum observed yield. Similarly, water stress up to 20 days after heading or numerous days with both high temperatures and water stress up to 45 days after heading, also showed significant correlations with yield, and generated reductions of up to 23% and 41%, respectively. Moreover, irrigation showed a very relevant role, with the minimum relative yield increasing from 9% under rainfed conditions to 56% with irrigation supply higher than 150mm. For protein concentration, frequent joint events combining mild temperatures and severe water stresses around heading showed increases of 3 %-units. The future weather conditions projected for southern Spain will enhance risk of yield reduction and protein concentration increases, with a high spatial variability.Earlier sowing dates reduce the coincidence of extreme weather events with critical crop development stages, and thus the effects on yield and protein concentration, even identifying conditions that the impact was fully reversed. Similarly, irrigation during heading mitigated the negative effects of water stress on yield and the positive effects on protein concentration.The combination of long-term cultivar trials under semi-arid weather conditions, modeling and future climate projections constitutes an excellent tool for the assessment of vulnerable/suitable areas, and for the identification of site-specific adaptation measures to ensure the sustainability of wheat-growing areas in southern Europe.

DNA-binding domain in MYB transcription factor family in date palm

Date palm (Phoenix dactylifera L.) is one of the most important economic plants which belongs to the Arecaceae family in arid and semi-arid areas. The genetic map of the date palm genome is incomplete, which hindered the expansion of molecular studies. Bioinformatics is a way that the researcher compares different plant species to find similarities and differences between them. MYB is a transcription factor family that has well-known functions in many plants, especially Arabidopsis. DNA-binding domains are pieces of peptides (a group of amino acids) that are folded independently and are highly attracted to DNA. The study aims to identify the DNA-binding domains for the MYB family in Date Palm to diagnose drought-related genes in the date palm genome through bioinformatics. The main approach followed in the research is to use a set of approved sites to align members of MYB proteins in Arabidopsis with the date palm genome to determine the most closely related MYB proteins in date palms. The results indicated a group of date palm proteins, which considered candidate proteins or genes to have an effective role in resisting or reducing the negative effects of water stress on date palms. Also, numbers of palm proteins have the same alignment effect and DNA-binding domains, which means that they may be close to each other in function and structure.

Yumuşak Çekirdekli Meyve Türlerinde Kuraklığın Etkileri

Elma, armut, ayva, trabzonhurması, yenidünya, muşmula ve alıç dünyada önemli üretim potansiyeline sahip yumuşak çekirdekli meyve türleri arasındadır. Sıcaklık yetiştriciliği sınırlandıran en önemli iklim faktörüdür. Son yıllarda küresel iklim değişikliğiyle birlikte kuraklığın artması ve su kaynaklarına erişimin azalması sıcaklığın en önemli etkileri olarak ortaya çıkmaktadır. Su stresi altındaki yumuşak çekirdekli meyve türlerinde ortaya çıkan morfolojik, biyokimyasal, fizyolojik ve moleküler değişimlerin etkisi ile verim ve kalite parametrelerinin düşmesi dolayısıyla ağaçların ekonomik verim değerleri olumsuz etkilenmektedir. Dayanıklılık ıslahı, kaolin, melatonin, anti-transpirant (brasinolid), gövde azaltması, silika, nitrik oksit, besin maddesi uygulaması, mikorizal funguslar ve bitki gelişimini teşvik eden rizobakteriler ile aşılama, toprak işleme uygulamaları ve gölgelik örtü sistemleri farklı yöntemler ve uygulamalar stres faktörlerinin olumsuz etkilerini azalabilmek amacıyla yaygın olarak kullanılmaktadır. Çalışmada yumuşak çekirdekli bazı meyve türlerinde kuraklığın etkileri ortaya konulmaya çalışılmıştır.

Determining effects of foliar boron applications on yield and fruit quality of apricot trees for reducing water stress

Aims: The research was carried out to determine the effects of different boron doses on yield, yield components and quality on 5-6 years old apricot trees of Mogador variety, which were exposed to water stress in the Amik Plain in 2019. Methods and Results: The factorial experimental design was conducted on apricot trees of Mogador variety, using four doses of foliar boron (ppm) (0-B0, 150-B150, 225-B225 and 300-B300 ppm) and four irrigation levels (100%-I100, 75%-I75, 50%-I50 and 25%-I25 of available water holding capacity) in four replications. Each replication consisted of two apricot trees. The quantity of irrigation water applied in the experiment ranged from 179 to 742 mm, while the evapotranspiration varied between 295 and 832 mm during the irrigation season. Irrigation water use efficiency (IWUE) and water use efficiency (WUE) varied between 3.51-5.18 kg m-3 and 2.89-4.17 kg m-3, respectively. Boron doses did not cause significant differences in WUE and IWUE values. Each unit increase in crop water use caused an average yield increase of 16.8 kg ha-1. Relative to the full irrigation (I100), fruit weight decreased by 13 and 3% in I25 and I50, respectively, but increased by 2% in I75. Relative to the control group (B0), fruit weight increased by 2, 4, and 2% with B150, B225, and B300, respectively. Average fruit size varied between 47.40 (I75) and 42.99 mm (I25); total soluble solids (TSS) between 16.13 (I100) and 12.65 (I25); and pH between 3.16 (I100) and 3.30 (I50). The increased boron dose did not cause a significant difference in fruit size and width. The leaf boron content increased up to the B225 dose and tended to decrease at the B300 dose.Conclusions: Boron element provides an increase in yield in deficit irrigation conditions, the yield increase is higher in fully irrigated apricot trees. In full irrigation treatment (I100), the B225 treatment was more effective on the yield.Significance and Impact of the Study: The boron element is an important element that causes an increase in photosynthesis by light adsorption. There is not a lot of research investigating the effects of nutrient elements to relieve the negative effect of water stress in orchards. This research is important in terms of revealing the effects of the element boron in water stress conditions.

Effect of Wheat-Derived Biochar on Soil Nutrients Availability and Nutrients Uptake by Two Safflower (Carthamus tinctorius L.) Cultivars under Water Stress

ABSTRACT Biochar may improve the negative effects of water stress on plant dry weight and nutrients uptake of Safflower (Carthamus tinctorius L.). The effects of 1.5 and 3% biochar application to a calcareous soil cultivated with two cultivars of safflower under normal and 50% of normal irrigation on soil nutrients availability, plant dry weight, and nutrients concentration were studied. Results indicated that the biochar application increased soil electrical conductivity (from 0.52 to 1.46 dS m−1) and the availability of the soil phosphorus (from 8.0 to 13.2 mg kg−1), potassium (from 185 to 1107 mg kg−1), iron (from 0.76 to 1.40 mg kg−1) and manganese (from 1.10 to 4.57 mg kg−1). Water stress and plant cultivar treatments had no effect on the soil nutrients availability. The dry weight of Goldasht and Esfahan cultivars was 1.89 and 1.73 g pot−1, respectively, and decreased 12 and 26% with 1.5 and 3% biochar application, respectively. The decreases in the plant dry weight with water stress in soils treated with 0, 1.5, and 3% biochar were 34, 27, and 18%, respectively. The plant concentration of phosphorus, potassium, iron, and manganese was increased with biochar application and was associated with soil nutrients availability.

Transcriptional and Physiological Analyses to Assess the Effects of a Novel Biostimulant in Tomato.

This work aimed to study the effects in tomato (Solanum lycopersicum L.) of foliar applications of a novel calcium-based biostimulant (SOB01) using an omics approach involving transcriptomics and physiological profiling. A calcium-chloride fertilizer (SOB02) was used as a product reference standard. Plants were grown under well-watered (WW) and water stress (WS) conditions in a growth chamber. We firstly compared the transcriptome profile of treated and untreated tomato plants using the software RStudio. Totally, 968 and 1,657 differentially expressed genes (DEGs) (adj-p-value < 0.1 and |log2(fold change)| ≥ 1) were identified after SOB01 and SOB02 leaf treatments, respectively. Expression patterns of 9 DEGs involved in nutrient metabolism and osmotic stress tolerance were validated by real-time quantitative reverse transcription PCR (RT-qPCR) analysis. Principal component analysis (PCA) on RT-qPCR results highlighted that the gene expression profiles after SOB01 treatment in different water regimes were clustering together, suggesting that the expression pattern of the analyzed genes in well water and water stress plants was similar in the presence of SOB01 treatment. Physiological analyses demonstrated that the biostimulant application increased the photosynthetic rate and the chlorophyll content under water deficiency compared to the standard fertilizer and led to a higher yield in terms of fruit dry matter and a reduction in the number of cracked fruits. In conclusion, transcriptome and physiological profiling provided comprehensive information on the biostimulant effects highlighting that SOB01 applications improved the ability of the tomato plants to mitigate the negative effects of water stress.

دور حمض الابسيسيك في التوازن المائي لغراس الفستق الحلبي (Pistacia vera)

أجريت هذه التجربة لدراسة تأثير حمض الابسيسيك في الحفاظ على التوازن المائي تحت مستويات مختلفة من الري، حيث نفذت في مكتب الفستق الحلبي في حماة على غراس للأصل البذري للفستق حلبي (Pistacia.vera) بعمر سنتين مزروعة ضمن أكياس من البولي اتلين، وطبقت عليها ثلاث معاملات ري وثلاث معاملات حمض على الغراس خلال موسمي 2019-2020. بينت نتائج الدراسة وجود تأثير معنوي للإجهاد المائي نتيجة زيادة الفاصل الزمني بين الريات حيث تراجعت معظم مؤشرات النمو (المحور الرئيس للغراس – قطر الغراس – المساحة الورقية وغيرها) ووصلت إلى ادنى قيمة لها عند الري بفاصل 14 يوم بين الريات، أما رش الغراس بحمض الابسيسيك فقد خففت معنوياً من التأثيرات الضارة للإجهاد المائي وحسنت التوازن المائي لدى الغراس، وقد لوحظ زيادة معنوية في متوسط طول المحور الرئيس للغراس لدى الغراس المعاملة بحمض الابسيسيك (59.3 سم) مقارنة مع غراس الشاهد (55.5) تحت ظروف الإجهاد المائي، بالإضافة إلى زيادة في تركيز الكلوروفيل (38 ملغ/غ وزن رطب)مقارنة مع الشاهد (36.19ملغ/غ وزن رطب)، في حين ازداد تركيز البرولين في الأوراق المعاملة بحمض الابسيسيك (52.50 ملغ/غ وزن رطب) مقارنة مع غراس الشاهد غير المعاملة (50ملغ/غ وزن رطب) تحت ظروف الإجهاد المائي وهذه النتائج توضح الدور الهام لحمض الابسيسيك في تنظيم العلاقات المائية داخل النبات وزيادة قدرة النبات على تحمل التأثيرات السلبية للإجهاد المائي.