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This study aimed to examine the effects of seed priming with different boron concentrations on the germination and seedling growth of spinach under drought-stress conditions. Seeds of the spinach cultivar Matador and sodium borate (Na2B8O13.4H2O) were used as materials. The seeds were primed with 0 (distilled water), 1, 10, 100, 500, and 1000 ppm B for 24 hours, with unprimed seeds serving as a control. Drought stress was induced by polyethylene glycol (PEG 6000) solution at a water potential of -3 bar and distilled water denoted as control conditions. A standard germination test was performed between papers at 20°C for 14 days. The germination percentage, mean germination time, germination index, seedling growth parameters, and root/shoot length ratio were investigated. The findings revealed that drought stress reduced germination percentage, germination index, and seedling growth of unprimed seeds of spinach. However, boron priming improved these parameters while mitigating the negative effects of drought stress. Under drought conditions, seed priming with 1 ppm B shortened mean germination time. Similarly, seedling fresh and dry weight of spinach were improved by seed priming with 100-1000 ppm B, whereas root growth was stimulated by 10 ppm B. The highest root/shoot ratio was found at 10 ppm B. Boron priming was more efficient in promoting seedling growth than germination in spinach. As a result, seed priming with 10-100 ppm B should be recommended to improve the germination and seedling growth performance of spinach in the event of drought stress after planting. [ABSTRACT FROM AUTHOR]

This study focused on mitigating effects of an animal-derived biostimulant on sugar beet plantlets subjected to drought stress. The experiment was performed at the Seed Science and Technology Laboratory of the Eskişehir Osmangazi University, Faculty of Agriculture, Department of Field Crops, in 2024. It was established by the randomized plot 2x5 factorial experimental design (ANOVA) with four replications. The sugar beet cultivar Mohican was sprayed by an animalderived biostimulant (Andolamin®) containing 11% amino acids. Different levels of the biostimulant (control, 12.5, 25, 50, and 75 mL/L) were treated twice at 2-day intervals. Morphological and physiological measurements were made at 7 days after the first application on sugar beet plants grown under two irrigation regimes (water deficit (WD) 50% of field capacity and well-watered (WW) 80% of field capacity). The findings showed that drought had a hazardous impact on sugar beet's number of leaves (NL), fresh (LFW) and leaf dry weight (LDW), relative water content (RWC), and leaf area (LA). Leaf surface temperature (LST), chlorophyll content (Chl), and electrolyte leakage (EL) were higher in plants under water deficit. Foliar biostimulant application mitigated the effect of drought stress on seedlings through improving LFW, LDW, Chl, EL, and LA. On the other hand, biostimulant treatment had no significant effects on NL, and RWC in seedlings exposed to drought stress. It was concluded that animal-derived biostimulant application may be used for alleviating the harmful effects of drought stress and may stimulate the growth of sugar beet seedlings. [ABSTRACT FROM AUTHOR]

This study was to investigate the effects of three exogenous substances on chemical constituents of Isatis indigotica leaves and their efficacy in alleviating drought stress, and explore the methods of applying exogenous substances to efficient cultivation of Isatis indigotica. Polyethylene glycol (PEG) was used to simulate drought stress to deal with seeds of Isatis indigotica at the germination stage (concentration: 0, 10%, 15%, and 20%). Simultaneous operation of exogenous growth regulators [microbial inoculum (MI), γ-aminobutyric acid (GABA) and salicylic acid (SA)] and PEG were implemented in seeds of Isatis indigotica. The effects of drought stress and the mitigation of exogenous substances were observed by statistics of seed germination potential, germination rate, hypocotyl length, and radicle length of each treatment. The effects of exogenous substances on the content of alkaloids, crude protein and free amino acids in the leaves of Isatis indigotica grown in a greenhouse were determined after spraying exogenous substances on the plants. The differences of germination potential, germination rate, hypocotyl length, and radicle length among 15% PEG stress treatment, 10% PEG stress treatment and the control were significant (P<0.05). According to the predesigned germination standard, the seeds did not germinate under 20% PEG stress treatment. When the PEG concentration was 15%, the results of seed germination potential and germination rate after adding MI were significantly different from those under stress alone (P<0.05). When exposed to 10% PEG stress, the supplementation of GABA led to a notable increase in radicle length of Isatis indigotica seeds, showing significant differences compared to other three treatments. The application of MI and GABA under 15% PEG stress resulted in a significant increase in the radicle and hypocotyl length of Isatis indigotica seeds compared to other two treatments. The content of the total alkaloids in leaves of Isatis indigotica was significantly increased after spraying GABA. Meanwhile, the contents of crude protein and the total free amino acids were kept constant after spraying exogenous substances. Application of MI and GABA could alleviate drought stress of Isatis indigotica. The content of the total alkaloids in leaves of Isatis indigotica could significantly increase after spraying GABA. [ABSTRACT FROM AUTHOR]

Abiotic stress reduces plant yield and quality. WRKY transcription factors play key roles in abiotic stress responses in plants, but the molecular mechanisms by which WRKY transcription factors mediate responses to drought and osmotic stresses in apple (Malus × domestica Borkh.) remain unclear. Here, we functionally characterized the apple Group III WRKY gene MdWRKY115. qRT-PCR analysis showed that MdWRKY115 expression was up-regulated by drought and osmotic stresses. GUS activity analysis revealed that the promoter activity of MdWRKY115 was enhanced under osmotic stress. Subcellular localization and transactivation assays indicated that MdWRKY115 was localized to the nucleus and had a transcriptional activity domain at the N-terminal region. Transgenic analysis revealed that the overexpression of MdWRKY115 in Arabidopsis plants and in apple callus markedly enhanced their tolerance to drought and osmotic stresses. DNA affinity purification sequencing showed that MdWRKY115 binds to the promoter of the stress-related gene MdRD22. This binding was further verified by an electrophoretic mobility shift assay. Collectively, these findings suggest that MdWRKY115 is an important regulator of osmotic and drought stress tolerance in apple. [ABSTRACT FROM AUTHOR]

Drought (water shortage) can substantially limit the yield and economic value of rose plants (Rosa spp.). Here, we characterized the effect of exogenous calcium (Ca2+) on the antioxidant system and photosynthesis-related properties of rose under polyethylene glycol 6000 (PEG6000)- induced drought stress. Chlorophyll levels, as well as leaf and root biomass, were significantly reduced by drought; drought also had a major effect on the enzymatic antioxidant system and increased concentrations of reactive oxygen species. Application of exogenous Ca2+ increased the net photosynthetic rate and stomatal conductance of leaves, enhanced water-use efficiency, and increased the length and width of stomata following exposure to drought. Organ-specific physiological responses were observed under different concentrations of Ca2+. Application of 5 mmol. L-1 Ca2+ promoted photosynthesis and antioxidant activity in the leaves, and application of 10 mmol. L-1 Ca2+ promoted antioxidant activity in the roots. Application of exogenous Ca2+ greatly enhanced the phenotype and photosynthetic capacity of potted rose plants following exposure to drought stress. Overall, our findings indicate that the application of exogenous Ca2+ enhances the drought resistance of roses by promoting physiological adaptation and that it could be used to aid the cultivation of rose plants. [ABSTRACT FROM AUTHOR]

Citrus is the typical mycorrhizal fruit tree species establishing symbiosis with arbuscular mycorrhizal (AM) fungi. However, arbuscule development and senescence in colonized citrus roots, especially in response to drought stress, remain unclear, which is mainly due to the difficulty in clearing and staining lignified roots with the conventional method. Here, we improved the observation of colonized roots of citrus plants with the sectioning method, which enabled the clear observation of AM fungal structures. Furthermore, we investigated the effects of one week of drought stress on arbuscule development and senescence with the sectioning method. Microscopy observations indicated that drought stress significantly decreased mycorrhizal colonization (F% and M%) although it did not affect plant growth performance. Fluorescence probes (WGA 488 and/or Nile red) revealed that drought stress inhibited arbuscule development by increasing the percentage of arbuscules at the early stage and decreasing the percentages of arbuscules at the midterm and mature stages. Meanwhile, drought stress accelerated arbuscule senescence, which was characterized by the increased accumulation of neutral lipids. Overall, the sectioning method developed in this study enables the in-depth investigation of arbuscule status, and drought stress can inhibit arbuscule development but accelerate arbuscule senescence in the colonized roots of citrus plants. This study paves the way to elaborately dissecting the arbuscule dynamics in the roots of fruit tree species in response to diverse abiotic stresses. [ABSTRACT FROM AUTHOR]

The main purpose of the study was to clarify the effect of selenium (Se) on DNA damage and DNA methylation in wheat (Triticum aestivum L.) plants exposed to polyethylene glycol (PEG)-induced drought stress under in vitro tissue culture. Random amplified polymorphic DNA (RAPD) and coupled restriction enzyme digestion-random amplification (CRED-RA) were utilized to explain the DNA damage grade and variations in DNA methylation patterns, respectively. The outcomes indicate that drought stress gives rise to a rise in RAPD profile variations (as DNA damage) and a decrease in genomic template stability (GTS) rate and DNA methylation changes. According to the RAPD data, the greatest GTS value was computed at 56.9% (5% PEG 6000), and the lowest GTS value was 41.2% (15% PEG 6000), demonstrating the adverse effects of PEG 6000. However, DNA damage can be reduced by treatment with sodium selenate (2, 4, and 6 µM of Na2SeO4) together with PEG (5%, 10%, and 15% PEG 6000)-induced water deficits. Moreover, according to CRED-RA analysis, PEGinduced DNA methylation rates were changed after treating different doses of Se. These data demonstrate that Se dosedependently modulates both DNA damage and methylation alterations induced by drought in wheat. [ABSTRACT FROM AUTHOR]

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Copyright of Duzce University Journal of Science & Technology is the property of Duzce University Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was conducted to investigate the effect of foliar application of amino acids on yield and yield components of oil rapeseed under late-season drought stress conditions. The experiment was conducted as factorial based on a randomized complete blocks design in the research farm of the Faculty of Agriculture at Tarbiat Modares University during the 2021-22 growing season. The experimental treatments were irrigation regimes at three levels (normal irrigation, withholding irrigation from 50% flowering stage, and withholding irrigation from pod forming) and foliar spraying at five levels (no foliar, foliar spraying 0, 1, 2, and 3 g amino acids per liter of distilled water). The results showed that plant height, shoot dry weight, 1000-seed weight, harvest index, and biological and grain yield, number of seeds per pod, and the number of pods per plant were significantly affected by the interaction of irrigation regimes and foliar spraying. The highest plant height (166.5 cm), 1000-seed weight (3.58 g), number of pods per plant (131.4) and grain yield (4514 kg ha-1) were obtained by foliar spraying of two g amino acids per litre under normal irrigation conditions. According to the results, foliar spraying 2 g amino acids per liter had the most positive effect on the yield and yield components of oil rapeseed in all irrigation regimes (normal irrigation, withholding irrigation from 50% flowering stage, and withholding irrigation from pod forming). Therefore, upon approving in future research it could be recommended to use foliar spraying with 2 g amino acids per liter in oil rapeseed cultivation. [ABSTRACT FROM AUTHOR]

Rapid and efficient recovery from water deficit stress may be one of the key determinants of drought adaptation in plants. The present study was designed to investigate drought stress tolerance and recovery in promising lentil lines at the flowering stage. For this, a factorial experiment based on the completely randomized design was conducted with three replications. The factors included 6 lentil lines, drought stress (control (irrigation at 80% FC or 20% moisture depletion), medium stress (irrigation at 55% FC or 45% moisture depletion), and severe stress (irrigation at 30% FC or 70% moisture depletion)), and three sampling times (three and six days after drought, and recovery (two days after reirrigation)). Drought stress caused a decrease in chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, protein, yield, and yield components. The reduction of these traits was more remarkable at six days after stress. However, during the recovery time remarkable increase was observed in these traits. The results showed that the correlation between H2O2 and MDA was significant and positive. Furthermore, drought stress increased the amount of proline, H2O2, and MDA, which resulted in an increase in the activity of antioxidant enzymes (catalase, polyphenol oxidase, and peroxidase). An increase in the intensity and duration of the drought stress also caused an increase in H2O2 and MDA content and the activity of antioxidant enzymes. In addition, in the recovery conditions, a significant reduction in the destructive effects of stress (H2O2, MDA content) and the activity of antioxidant enzymes was visible. The results of the present study indicated that the effects of drought stress on lentil lines yield and yield components (seed number, number of pods, 100-seed weight, and seed yield) were varied. Drought stress at the flowering stage decreased the number of seeds and pods per plant, and 100-seed weight, which led to yield losses. Although line 2 had the highest yield under normal and drought stress conditions, line 1 exhibited the lowest yield under stress conditions. Based on the results of this experiment, line 2 seems to be a suitable line for culture in the regions challenged with water deficit stress. [ABSTRACT FROM AUTHOR]

The article discusses a study on the phenotypic differentiation of Norway spruce seedlings under different water regimes. The researchers conducted an experiment with drought-stressed and well-watered seedlings from five provenances of Norway spruce. They measured various physiological traits and genotyped the seedlings. The study found that there was inconsistent phenotypic differentiation between the drought-stressed and control plants, with only three traits showing signs of selection under both treatments. The researchers emphasize the importance of considering the environmental setup of the experiment and highlight the need for common gardens in adaptation research. The article also includes a list of references related to genetic diversity, climate change, and adaptation in tree species, providing valuable information for researchers studying these topics. [Extracted from the article]

Drought has severely affected the yield and quality of commercial crops. The BRI1 family plays an important role in plant response to drought stress, and BRL3 gene plays an important role in the study of drought in Arabidopsis thaliana. In this study, NtBRL3 was constructed as a vector and genetically transformed to obtain 'N. Tobacco K326' overexpression of NtBRL3. The enzyme activities of transgenic tobacco and wild-type tobacco were measured and transcriptome and metabolome analyses were performed. The results showed that the antioxidant enzymes of transgenic tobacco were more active under drought conditions, and 85 significantly differentially metabolites and 106 significantly differentially expressed genes were identified in the metabolome and transcriptome analyses, respectively. Transgenic tobacco NtBRL3ox demonstrated an excessive accumulation of droughtrelated metabolites, sugars such as sucrose and maltotetraose, and amino acids such as proline, compared with WT. We discovered drought-related differential genes in the root transcriptome, among which LOX6, RD22, WSD1, CCD8, and UGT were key genes which play an important role in plant response to drought stress. Our results demonstrate that NtBRL3 overexpression in K326 enhances drought resistance in transgenic tobacco. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum) is one of the most important vegetable crops in the world and abiotic stresses often cause serious problems in tomato production. It is thus important to identify new regulators in stress response and to devise new approaches to promote stress tolerance in tomato. Previous studies have shown that small secreted peptides (SSPs) are important signal molecules regulating plant growth and stress response by mediating intercellular communication. However, little is known about tomato SSPs, especially their roles in responding to abiotic stresses. Here we report the identification of 1,050 putative SSPs in the tomato genome, 557 of which were classified into 38 known SSP families based on their conserved domains. GO and transcriptome analyses revealed that a large proportion of SlSSPs might be involved in abiotic stress response. Further analysis indicated that stress response related cis-elements were present on the SlCEP promotors and a number of SlCEPs were significantly upregulated by drought treatments. Among the drought-inducible SlCEPs, SlCEP10 and SlCEP11b were selected for further analysis via exogenous application of synthetic peptides. The results showed that treatments with both SlCEP10 and SlCEP11b peptides enhanced tomato drought stress tolerance, indicating the potential roles of SlSSPs in abiotic stress response. [ABSTRACT FROM AUTHOR]

N6-methylated adenine (m6A) is an emerging epigenetic marker in eukaryotic organisms that plays an important role in biological functions and in enriching genetic information.m6A exerts these functions via the dynamic interplay among m6A writers, erasers, and readers. However, little is known about the underlying mechanisms of m6A in plant growth and stress responses. Here, we identified 276 masked m6A regulators from nine Rosaceae species (Pyrus bretschneideri, Pyrus betulifolia, Pyrus communis, Malus domestica, Fragaria vesca, Prunus avium, Prunus mume, Prunus persica, and Rubus occidentalis). We classified and named these genes in more detail based on phylogenetic and synteny analysis. The expansion ofm6A regulators in Maloideae was dated back to the recent whole-genome duplication (WGD) in Rosaceae. Based on the expression pattern analysis and gene structure analysis of m6A regulators, m6A was shown to be a significant factor in regulating plant development and resistance. In addition, PbrMTA1-silenced pear plants displayed significantly reduced drought tolerance and chlorophyll content, as well as increased electrolyte leakage and concentrations of malondialdehyde and H2O2. [ABSTRACT FROM AUTHOR]

Introduction The present research on Lycium depressum stocks aims to study the vegetative responses (leaf area, leaf specific weight, leaf specific area, dry weight ratio of root to shoot, dry weight of leaf, stem, and root) of the pasture shrub of Kam Tigh against drought stress and the effect of soil amendment on these responses. Materials and methods The experiment was conducted in a factorial design based on a completely randomized design, including the main irrigation treatment at four levels (100, 75, 50, and 25% of crop capacity) and subtreatment of soil conditioners under semi-controlled greenhouse conditions. The experiment involved five repetitions and 160 pots for each combined irrigation and soil amendment treatment. Subtreatments of soil conditioners, including Stacosorb hydrogel, were added at 3 grams per kilogram of soil in each pot in the lower part of the plant roots. Mineral Zeolite in 8 grams per pot was placed in the lower part of the plant roots. Nitrobacter was added in the amount of 3 cc in each pot in the upper root area of the plant. Mycorrhiza at 10 grams per pot was added to the lower plant roots. Results and discussion Generally, a significant difference (p<0.05) was observed in all irrigation levels between the treatments in each soil amendment material. In zeolite with mycorrhiza, the highest stem dry weight and leaf-specific weight were obtained at a 50% irrigation level. With the increase in leaf-specific gravity and drought stress, plant dry weight increased, and proline content decreased in Nitrobacter and mycorrhizal treatment, which differed from the treatment. Measurements of leaf area revealed that leaf area decreased from 1450 mm2 in 100% and 75% irrigation to 900 mm2 in 25% irrigation. This indicated the impact of drought stress on the leaf area. The highest specific weight of leaves at 25% irrigation was related to Nitrobacter with mycorrhiza. This modifier increased the specific weight of leaves from 0.0025 g/m2 at 100% irrigation level to 0.0028 g/m2 at 25% irrigation level. Leaf surface area in Nitrobacter treatment with mycorrhiza during 100% irrigation decreased from 400 mm2/g to 350 mm2/g during 25% irrigation. In hydrogel treatment without mycorrhiza, the dry weight ratio of root to shoot at 100% irrigation level declined from 2 grams to 1.4 grams in 25% irrigation. The dry weight of the leaf decreased from 1.4 g in 100% irrigation to 1.3 g in 25% irrigation. Conclusions Biofertilizers enhance plant resistance to drought stress by improving vegetative characteristics. Nitrobacter treatments without mycorrhiza, hydrogel, and zeolite with mycorrhiza are recommended for planting this plant due to improved growing conditions. Since the Kam Tig plant is considered a medicinal plant, it can be used as a soil conditioner in the pharmaceutical and medical industries. This will enable better cultivation of the species. All organizations related to the cultivation of Kam Tig species can use the results of this research to enhance cultivation projects. [ABSTRACT FROM AUTHOR]

Small ubiquitin-like modifier (SUMO) E3 ligases that facilitate the conjugation of SUMO proteins to target substrates contain an SP-RING domain which is like the RING domain found in ubiquitin E3 ligases. In this study, we isolated and characterized the Oryza sativa protein inhibitor of activated STAT like1 (OsPIAL1) containing SP-RING domains, as the rice homolog of Arabidopsis PIALs. OsPIAL1 interacts with OsSUMO proteins but does not interact with rice SUMO-conjugating enzymes (OsSCEs). An analysis of transgenic rice plant shows that OsPIAL1 is involved in SUMO conjugation to SCEs but not in SUMO conjugation to substrates. In addition, this OsPIAL1 activity requires drought stress conditions. Expression profiles show that the OsPIAL1 gene is induced by only drought stress in the leaves, whereas it is repressed by ABA and abiotic stresses in the roots. Salt stress leads to the fastest decrease in OsPIAL1 transcripts in the roots. Furthermore, the stress experiments indicate that the transgenic rice plants overexpressing OsPIAL1 exhibit a drought stress-tolerant phenotype but a salt stress hypersensitive phenotype. Our results and those from Arabidopsis pial mutants suggest that PIALs act as a positive regulator in the drought stress response but as a negative regulator in the salt stress response. [ABSTRACT FROM AUTHOR]

Objective: As a critical limitation of plant growing, drought stress has always received a lot of attention from botanical researchers. This study intends to investigate the role of salicylic acid and the Mycorrhiza and Azotobacter bio-fertilizer on Satureja hortensis L. under drought stress. Materials and Methods: Salicylic acid and bio-fertilizers have been shown to improve drought tolerance in growing plants. To evaluate the synergistic effect of salicylic acid, Azotobacter chroococcum bacteria, and arbuscular mycorrhizal fungi under drought stress (-3.5 atm: W1), (-6.5 atm: W2), and (-10 atm: W3), a 2-year (2016 to 2018) field experiment was organized based on split-plot factorial statistical in a randomized complete block design, with three replicates. Results: The main findings of this study showed that the combinable use of bio-fertilizers and salicylic acid diminished the disadvantageous effects of drought stress. Co-application of bio-fertilizers and salicylic acid significantly increased chlorophyll a and b (22% and 31.5%), carotenoid (30.7%) contents, aerial fresh (38.3%) and dry (64.1%) weights, root fresh (55.8%), and dry (45%) weights, auxin (15%), percentage of essential oil (30.7%) in S. hortensis while it decreased the proline content (48.8%) under severe stress as compared to the control groups, which confirmed the efficacy of this approach and its role in drought tolerance. Conclusion: The results demonstrated that this new suggested treatment could effectively alleviate drought stress symptoms and improve S. hortensis growth under spreading drought conditions and limited water resources. [ABSTRACT FROM AUTHOR]

Drought stress is a serious threat to the germination of plant seeds and the growth of seedlings. Melatonin has been proven to play an important role in alleviating plant stress. However, its effect on seed germination under drought conditions is still poorly understood. Therefore, we studied the effects of melatonin on rice seed germination and physiological characteristics under drought stress. Rice seeds were treated with different concentrations of melatonin (i.e., 0, 20, 100, and 500 µM) and drought stress was simulated with 5% polyethylene glycol 6000 (PEG6000). The results showed that 100 µM melatonin can effectively improve the germination potential, rate and index; the vigor index of rice seeds; and the length of the shoot and root. In addition, that treatment also increased the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and reduced the content of malondialdehyde (MDA). The grey relational grade between the shoot MDA content and the melatonin seed-soaking treatment was the highest, which could be useful for evaluating the effect of melatonin on drought tolerance. Two-way analysis of variance showed that the effect of single melatonin treatment on rice seeds was more significant than that of single drought stress and interaction treatment of drought and melatonin (p < 0.05). The subordinate function results showed that 100 µM melatonin significantly improved the germination and physiological indexes of rice seeds and effectively alleviated the adverse effects of drought stress on rice seedlings. The results helped to improve the understanding of the morphological and physiological involvement of melatonin in promoting seed germination and seedling development under drought stress. [ABSTRACT FROM AUTHOR]

Drought is a severe environmental constraint, causing a significant reduction in crop productivity across the world. Salicylic acid (SA) is an important plant growth regulator that helps plants cope with the adverse effects induced by various abiotic stresses. The current study investigated the potential effects of SA on drought tolerance efficacy in two barley (Hordeum vulgare) genotypes, namely BARI barley 5 and BARI barley 7. Ten-day-old barley seedlings were exposed to drought stress by maintaining 7.5% soil moisture content in the absence or presence of 0.5, 1.0 and 1.5 mM SA. Drought exposure led to severe damage to both genotypes, as indicated by phenotypic aberrations and reduction of dry biomass. On the other hand, the application of SA to drought-stressed plants protected both barley genotypes from the adverse effects of drought, which was reflected in the improvement of phenotypes and biomass production. SA supplementation improved relative water content and proline levels in drought-stressed barley genotypes, indicating the osmotic adjustment functions of SA under water-deficit conditions. Drought stress induced the accumulation of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2) and superoxide (O2 •-), and the lipid peroxidation product malondialdehyde (MDA) in the leaves of barley plants. Exogenous supply of SA reduced oxidative damage by restricting the accumulation of ROS through the stimulation of the activities of key antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX). Among the three-applied concentrations of SA, 0.5 mM SA exhibited better mitigating effects against drought stress considering the phenotypic performance and biochemical data. Furthermore, BARI barley 5 showed better performance under drought stress than BARI barley 7 in the presence of SA application. Collectively, our results suggest that SA played a crucial role in improving water status and antioxidant defense strategy to protect barley plants from the deleterious effects of water deficiency. [ABSTRACT FROM AUTHOR]

Allium senescens, is an important economic and ecological grassland plant with drought-resistant characteristics. A TCP protein transcription factor is important in the regulation of plant development and adverse responses. However, the mechanism by which TCP transcription functions in drought resistance in Allium senescens is still not clear. Here, we obtained a total of 190,305 transcripts with 115,562 single gene clusters based on RNA-Seq sequencing of Allium senescens under drought stress. The total number of bases was 97,195,096 bp, and the average length was 841.06 bp. Furthermore, we found that there were eight genes of the TCP family that showed an upregulated expression trend under drought stress in Allium senescens. We carried out an investigation to determine the evolution and function of the AsTCP family and how they produce an effect in drought resistance. The 14 AsTCP genes were confirmed and divided into class I and class II containing CIN and CYC/TBI subfamilies, respectively. We also found that the expression of AsTCP17 was remarkably upregulated with drought treatment. Besides, the transformation of AsTCP17 in Arabidopsis revealed that the protective enzymes, namely polyphenol oxidase (POD) and superoxide dismutase (SOD), were increased by 0.4 and 0.8 times, respectively. Chlorophyll content was also increased, while the H2O2 and malondialdehyde (MDA) contents were decreased. Staining assays with 3,3'-diaminobenzidine (DAB) also suggested that the AsTCP17 downregulates reactive oxygen species (ROS) accumulation. In addition, overexpression of the AsTCP17 affected the accumulation of drought-related hormones in plants, and the synthesis of ABA. The expression of AtSVP and AtNCED3, related ABA synthesis pathway genes, indicated that the level of expression of AtSVP and AtNCED3 was obviously enhanced, with the overexpression of line 6 showing a 20.6-fold and 7.0-fold increase, respectively. Taken together, our findings systematically analyze the AsTCPs family at the transcriptome expression level in Allium senescens, and we also demonstrated that AsTCP17 protein, as a positive regulator, was involved in drought resistance of Allium senescens. In addition, our research contributes to the comprehensive understanding of the drought stress defense mechanism in herbaceous plants. [ABSTRACT FROM AUTHOR]

Herbaceous peony (Paeonia lactiflora Pall.), as a high-end cut flower in the international market, has high ornamental and medicinal values. But in Northern China, drought is a major environmental factor influencing the growth and development of P. lactiflora. Quantitative real-time polymerase chain reaction (qRT-PCR) can evaluate gene expression levels under different stress conditions, and stable internal reference is the key for qRT-PCR. At present, there is no systematic screening of internal reference for correcting gene expressions of P. lactiflora in response to drought stress. In this study, 10 candidate genes [ubiquitin (UBQ2), UBQ1, elongation factor 1-α (EF-1α), Histidine (His), eukaryotic initiation factor (eIF), tubulin (TUB), actin (ACT), UBQ3, ACT2, RNA polymerase II (RNA Pol II)] were chosen, and 4 analysis methods were used to compare the stabilities for these 10 genes coping with drought stress. Due to the difference of operation methods, the results of different analysis were distinct, and the final comprehensive analysis indicated that EF-1α was a relatively stable internal reference gene for P. lactiflora under drought stress. Also, UBQ1 and UBQ2 were the best reference gene combination according to GeNorm analysis. This study will lay a foundation for screening the key genes of P. lactiflora in response to drought stress. [ABSTRACT FROM AUTHOR]

Drought stress is the main limiting plant growth factor in arid and semiarid regions. The Lanzhou lily (Lilium davidii var. unicolor) is the only sweet-tasting lily grown in these regions of China that offers highly edible, medicinal, health, and ornamental value. The Tresor lily is an ornamental flower known for its strong resistance. Plants were grown under three different drought intensity treatments, namely, being watered at intervals of 5, 15, and 25 d (either throughout the study or during specific growth stages). We measured the biomass, leaf area, photosynthetic response, chlorophyll content (SPAD value), and osmoregulation of both the Lanzhou lily and the Tresor lily (Lilium 'Tresor'). Additionally, we employed RNA sequencing (RNA-Seq) and qRT-PCR to investigate transcriptomic changes of the Lanzhou lily in response to drought stress. Results showed that under drought stress, the decreasing rate in the Lanzhou lily bulb weight was lower than the corresponding Tresor lily bulb rate; the net photosynthetic rate, transpiration rate, and stomatal conductance of the Lanzhou lily were all higher compared to the Tresor lily; osmoregulation constituents, such as glucose, fructose, sucrose, trehalose, and soluble sugar, in the Lanzhou lily were comparatively higher; PYL, NCED, and ERS genes were significantly expressed in the Lanzhou lily. Under moderate drought, the biosynthesis of flavonoids, circadian rhythms, and the tryptophan metabolism pathway of the Lanzhou lily were all significant. Under severe drought stress, fatty acid elongation, photosynthetic antenna protein, plant hormone signal transduction, flavone and flavonol biosynthesis, and the carotenoid biosynthesis pathway were all significant. The Lanzhou lily adapted to drought stress by coordinating its organs and the unique role of its bulb, regulating photosynthesis, increasing osmolyte content, activating circadian rhythms, signal transduction, fatty acid elongation metabolism, and phenylalanine and flavonoid metabolic pathways, which may collectively be the main adaptation strategy and mechanisms used by the Lanzhou lily under drought stress. [ABSTRACT FROM AUTHOR]

Background: Ongoing climate change is anticipated to increase the frequency and intensity of drought events, thereby affecting forest recovery dynamics and elevating tree mortality. The drought of 2018, with its exceptional intensity and duration, had a significant adverse impact on tree species throughout Central Europe. However, our understanding of the resistance to and recovery of young trees from drought stress remains limited. Here, we examined the recovery patterns of native deciduous tree sapling species following the 2018 drought, and explored the impact of soil depth, understory vegetation, and litter cover on this recovery. Methods: A total of 1,149 saplings of seven deciduous tree species were monitored in the understory of old-growth forests in Northern Bavaria, Central Germany. The vitality of the saplings was recorded from 2018 to 2021 on 170 plots. Results: Fagus sylvatica was the most drought-resistant species, followed by Betula pendula, Acer pseudoplatanus, Quercus spp., Corylus avellana, Carpinus betulus, and Sorbus aucuparia. Although the drought conditions persisted one year later, all species recovered significantly from the 2018 drought, albeit with a slight decrease in vitality by 2021. In 2018, the drought exhibited a more pronounced adverse effect on saplings in deciduous forests compared to mixed and coniferous forests. Conversely, sapling recovery in coniferous and mixed forests exceeded that observed in deciduous forests in 2019. The pivotal factors influencing sapling resilience to drought were forest types, soil depth, and understory vegetation, whereas litter and forest canopy cover had a negative impact. Conclusion: Long-term responses of tree species to drought can be best discerned through continuous health monitoring. These findings demonstrate the natural regeneration potential of deciduous species in the context of climate change. Selective tree species planting, soil management practices, and promoting understory diversity should be considered when implementing adaptive management strategies to enhance forest resilience to drought events. [ABSTRACT FROM AUTHOR]

Drought stress impairs crop growth and productivity. Stress-associated proteins (SAPs), a class of zinc finger proteins containing the A20/AN1 domain, function in various stress responses in plants. However, little is known about the function of SAPs in drought-stress responses in soybean, an oil and protein crop. We report that a GmSAP5 protein confers drought tolerance by increasing sensitivity to abscisic acid (ABA) and reducing stomatal aperture. Overexpression and RNA interference of GmSAP5 in soybean hairy roots resulted in elevated resistance and sensitivity to drought stress, respectively. ABA and proline contents increased in GmSAP5-overexpressing plants under water-deficit conditions. Lower water loss rates and higher relative water contents were observed in GmSAP5-overexpressing plants, resulting in increased drought-stress resistance. A yeast one-hybrid assay and luciferase transient transcriptional activity assay showed that GmAREB3, an AREB/ABF transcription factor, could bind to the promoter of GmSAP5 and activate its expression. These results suggest that GmSAP5 acts downstream of GmAREB3 and improves drought-stress resistance by mediating ABA signaling. [ABSTRACT FROM AUTHOR]

This research was 2016-2017 years of the Selcuk University Faculty of Agriculture Department of Horticulture Research and practice was carried out in the greenhouse. Study the Yalova Atatürk Central Horticultural Research Institute, Ata-77, Bolverim-77, Doruk-77, Dorukhan-77, Eren-77, Erenoğlu-77, and Hilal-77 strawberry varieties. After the planted strawberry seedlings reached the 56 leaf stage, after irrigation at field capacity, drought application was made until the plants lost their leaf turgor. After implementation of the varieties of drought with healing and drought period of watering again losses to determine. In strawberry cultivars, significant decreases occurred in the amount of protein with the application of drought. In the recovery period after the drought, the protein amounts increased again. Drought treatment significantly increased proline content in all cultivars compared to control. Catalase enzyme activity in all strawberry cultivars increased significantly as a result of drought application in both years. There was a slight decrease in the recovery period. In both years of the study, drought application increased the peroxidase enzyme activity in all strawberry cultivars compared to the control, and a slight decrease occurred in the recovery period compared to the drought application. Drought application in cultivars increased the superoxide dismutase enzyme activity a little compared to the control, while the activity decreased to the control level during the recovery period. [ABSTRACT FROM AUTHOR]

Drought is a serious challenge that causes significant crop loss worldwide. The developmental processes of plants are regulated by phytohormones and signaling molecules that crosstalk together in signaling cascades. We suppose that nitric oxide (NO) is a secondary messenger of the JAs signaling pathway, as 10−7 M methyl jasmonate (MeJA) pretreatment regulates NO accumulation in wheat plants under drought stress, modulated by 12% polyethylene glycol (PEG), and in control plants. This study aimed to compare 2 × 10−4 M nitric oxide donor sodium nitroprusside (SNP) and MeJA pretreatments in regulating growth and water balance parameters at the vulnerable initial first-leaf stage of wheat growth. The application of 12% PEG decreased transpiration intensity twofold, relative water content (RWC) by 7–9%, and osmotic potential of cell sap by 33–40% compared with those of control plants. Under drought, MeJA- and SNP-pretreated plants decreased transpiration intensity by 20–25%, RWC by 3–4%, and osmotic potential of cell sap by 16–21% compared with those of control plants, and enhanced the proline content by 25–55% compared with MeJA- and SNP-untreated plants. Our results suggest that pretreatment with MeJA as well as SNP could mitigate drought stress in wheat plants. Similarities in MeJA- and SNP-induced shifts in plant water balance suggested that NO is a mediator of MeJA-induced regulation of wheat water content during water deficit. [ABSTRACT FROM AUTHOR]

Introduction: Drought stress is known to change biochemical activities resulting in altered plant growth and development. Objective: Due to the shortage of research evidence in a certain taxa of basil, it is imperative to examine the relationship between drought stress and morphological changes as well as essential oil accumulation. Methods: An open field experiment was conducted in 2020 to determine the effects of drought stress on the morphological and biochemical responses of selected Ocimum species. Five basil species, namely O. basilicum 'Genovese', O. basilicum 'Ohre', O. × africanum, O. americanum, O. selloi, and O. sanctum 'Krishna' were grown under irrigated (control) and non-irrigated (drought stress treatment) plots with two block replications. Results: The result showed that irrigation had a positive effect on production. Consequently, fresh and dry biomass yields were higher on irrigated plots by 39% and 33%, respectively. No significant changes were detected between the treatments in essential oils (EO) yield and EO composition of major compounds. However, a slight increase in camphor (O. × africanum), nerol (O. americanum), and trans-β-caryophyllene (O. sanctum 'Krishna') ratios were observed under irrigation treatments. On the other hand, drought stress increased EO content, polyphenol content, and antioxidant capacity. Furthermore, drought stress had a positive effect on the ratios of 1,8-cineole (O. × africanum), and eugenol (O. sanctum 'Krishna'). There is only a slight increase in EO content under drought stress, which is not comparable to the significant yield reduction recorded. Morphological and biochemical variations were also detected among basil species. Accordingly, higher biomass (616.33 g/plant) and EO yield (3.72 ml/100 g) among the species were obtained from O. basilicum 'Genovese' and O. × africanum, respectively. Conclusion: Irrigation is imperative for maximizing biomass and EO yield of tested basil species. [ABSTRACT FROM AUTHOR]

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Proline accumulation has been shown to occur in plants in response to various environmental stresses. Although proline metabolismrelated genes have been functionally characterized, the inter-organ transport of proline in stressed plants remains unclear. In this study, free proline was detected with significant accumulations in the roots, stems, and leaves of watermelon drought-tolerant germplasm M08 and drought-susceptible line Y34 under drought stress. Expression profiling and enzyme activity measurements revealed that ClP5CS1 gene, rather than its paralog ClP5CS2, mainly contributes to the proline synthesis in leaves via the Glu pathway. Additionally, over-expression of the ClP5CS genes significantly enhanced the drought tolerance of transgenic Arabidopsis lines. Furthermore, we confirmed that proline is mainly synthesized in leaves and transported to roots in watermelon under drought stress. Transcriptome and expression analyses revealed that the genes involved in proline metabolism exhibited different expression levels. Specifically, ClP5CS1 was upregulated in leaves and roots, while ClP5CS2 was downregulated under drought stress. Also, 415 and 362 differently expressed TFs were identified in roots and leaves, respectively, with the majority upregulated in the former. Ultimately, a model for proline metabolism was proposed. The findings of this study provided new insights into the biosynthesis, transport, and regulatory mechanism of drought-induced proline in plants. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Slovenica is the property of Biotechnical Faculty of the University of Ljubljana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tea plants are sensitive to soil moisture deficit, with the level of soil water being a critical factor affecting their growth and quality. Arbuscular mycorrhizal fungi (AMF) can improve water and nutrient absorption, but it is not clear whether AMF can improve the photosynthetic characteristics of tea plants. A potted study was conducted to determine the effects of Claroideoglomus etunicatum on plant growth, leaf water status, pigment content, gas exchange, and chlorophyll fluorescence parameters in Camellia sinensis cv. Fuding Dabaicha under well-watered (WW) and drought stress (DS) conditions. Root mycorrhizal colonization and soil hyphal length were significantly reduced by the eightweek DS treatment. AMF inoculation displayed a significant increase in shoot and root biomass production. The relative water content, leaf water potential, nitrogen balance index, pigment content, maximum photometric effect (Fv/Fm, QY_max), and steady-state photometric effect Y (II) (QY_Lss) decreased dramatically, while the leaf water saturation deficit and steady-state non-photochemical fluorescence quenching (NPQ_Lss) generally increased under DS conditions. Mycorrhizal treatment induced significantly higher relative water content, leaf water potential, nitrogen balance index, pigment (chlorophyll, flavonoid, and anthocyanin) content, net photosynthesis rate, transpiration rate, stomatal conductance, intercellular CO2 concentration, QY_max, and QY_Lss; however, it resulted in a lower leaf water saturation deficit and NPQ_Lss under both WW and DS conditions, as compared with nonmycorrhizal plants. These results imply that AMF promoted tea plant growth and alleviated negative effects of DS by promoting gas exchange, regulating the water status of leaves, and regulating photosynthetic parameters. [ABSTRACT FROM AUTHOR]

The definition of relatively stable expressed internal reference genes is essential in both traditional blotting quantification and as a modern data quantitative strategy. Appropriate internal reference genes can accurately standardize the expression abundance of target genes to avoid serious experimental errors. In this study, the expression profiles of ten candidate genes, ACT1, ACT2, GAPDH, eIF1, eIF2, a-TUB, ß-TUB, TBP, RNA Pol II and RP II, were calculated for a suitable reference gene selection in Paeonia ostii T. Hong et J. X. Zhang leaves under various drought stress conditions. Data were processed by the four regularly used evaluation software. A comprehensive analysis revealed that RNA Pol II was the most stable gene and eIF2 was the least stable one. In addition, the geNorm program provided the optimal choice of two reference gene combination, RNA Pol II and ß-TUB, for qRT-PCR normalization in P. ostii subjected to different drought stress levels. Our research provided convenience for gene expression analysis in P. ostii under drought stress and promoted research of effective methods to alleviate P. ostii drought stress in the future. [ABSTRACT FROM AUTHOR]

Drought is considered one of the leading abiotic constraints to agricultural crop production globally. Present study was conducted to assess the effects of different drought treatments (viz. Control, 10% PEG, and 20% PEG) on seed germination, germination indices, seedling traits, and drought tolerance indices of sesame. Our results showed that maximum reduction in the studied parameters was observed at higher PEG concentration (i.e., 20% PEG). As compared to control, the drought treatments viz. 10% and 20% PEG decreased the values for germination indices, such as germination percentage, coefficient of variation of germination time, germination index, and seedling vigor index. Similarly, for seedling traits, the values were decreased for root length, shoot length, root shoot ratio, root fresh weight, shoot fresh weight, root dry weight and shoot dry weight under 10% and 20% PEG treatments significantly in comparison with control. Furthermore, relative to control, the values for drought tolerance indices, such as germination drought tolerance index, root length drought tolerance index, shoot length drought tolerance index, total seedling length drought tolerance index, root fresh weight drought tolerance index, shoot fresh weight drought tolerance index, total fresh weight drought tolerance index, root dry weight drought tolerance index, shoot dry weight drought tolerance index and total dry weight drought tolerance index were also reduced under 10% and 20% PEG treatments, respectively. Our results confirms that drought impact on seed germination and seedling traits could be quantified by using different indices which can further help to design drought adaptation and mitigation strategies. Based on these results it can be concluded that germination indices, seedling traits, and drought tolerance indices have great potential to simulate drought stress impacts on different crop traits thus they should be used in all kinds of stress related studies. [ABSTRACT FROM AUTHOR]

In order to study the effect of drought stress seven bread wheat (Triticum aestivum L.) cultivars (Acheloos, Apollonia, Generoso, Doirani, Nestos, Strimonas, and Orpheas) and seven durum wheat (Triticum durum L.) cultivars (Sifnos, Anna, Elpida, Thraki, Papadakis, Athos, Mexikali 81) were evaluated at three levels of drought treatment using polyethylene glycol in a randomized complete block design with 10 replications. For this purpose, seedlings of the aforementioned genotypes were cultured in pots with three different concentrations of polyethylene glycol (5, 10% and 15% PEG 8000) whereas irrigation without PEG was used as control. During the experiment, the length of spike with awns, the length of spike, the plants height, the number of tillering per plant, and the concentration of proline in the plants treated were measured. The drought treatment reduced the length of spike and the plant height of the cultivars studied, whereas it increased the length of spike with awns in bread wheat cultivars. It was concluded that there are considerable differences in drought resistance between the genotypes studied. The drought stress, caused by the polyethylene glycol, increased the concentration of proline in the cultivars tested. The highest value of proline was estimated in plants of bread wheat cultivar Strimonas and in plants of durum wheat cultivar Sifnos. So consequently, we can conclude that Strimonas and Sifnos were the most tolerant cultivars of the two species. Orpheas (bread wheat) and Thraki (durum wheat) had the lowest concentration of proline, so Orpheas and Thraki were considered the most sensitive cultivars. [ABSTRACT FROM AUTHOR]

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The physiological and biochemical role of the γ-aminobutyric acid (GABA) shunt pathway in green pea seedlings (Pisum sativum L.) was studied in response to soil water holding capacity levels: 80%, 60%, 40%, 20%, and 10% grown under continuous light at 25 ◦C for 7 days and 14 days, separately. Characterization of seeds germination pattern, seedlings growth (plant height, fresh and dry weight, and chlorophyll contents), GABA shunt metabolite (GABA, glutamate, and alanine) levels, total protein and carbohydrate levels, and oxidative damage (MDA level) were examined. Data showed a significant effect of drought stress on seed germination, plant growth, GABA shunt metabolites level, total protein and carbohydrate contents, and MDA level. A significant decline in seed germination percentage was recorded at a 20% drought level, which indicated that 20% of soil water holding capacity is the threshold value of water availability for normal germination after 14 days. Seedling fresh weight, dry weight, and plant height were significantly reduced with a positive correlation as water availability was decreased. There was a significant decrease with a positive correlation in Chl a and Chl b contents in response to 7 days and 14 days of drought. GABA shunt metabolites were significantly increased with a negative correlation as water availability decreased. Pea seedlings showed a significant increase in protein content as drought stress was increased. Total carbohydrate levels increased significantly when the amount of water availability decreased. MDA content increased slightly but significantly after 7 days and sharply after 14 days under all water stress levels. The maximum increase in MDA content was observed at 20% and 10% water levels. Overall, the significant increases in GABA, protein and carbohydrate contents were to cope with the physiological impact of drought stress on Pisum sativum L. seedlings by maintaining cellular osmotic adjustment, protecting plants from oxidative stress, balancing carbon and nitrogen (C:N) metabolism, and maintaining cell metabolic homeostasis and cell turgor. The results presented in this study indicated that severe (less than 40% water content of the holding capacity) and long-term drought stress should be avoided during the germination stage to ensure proper seedling growth and metabolism in Pisum sativum L. [ABSTRACT FROM AUTHOR]

With the global climate anomalies and the destruction of ecological balance, the water shortage has become a serious ecological problem facing all mankind, and drought has become a key factor restricting the development of agricultural production. Therefore, it is essential to study the drought tolerance of crops. Based on previous studies, we reviewed the effects of drought stress on plant morphology and physiology, including the changes of external morphology and internal structure of root, stem, and leaf, the effects of drought stress on osmotic regulation substances, drought-induced proteins, and active oxygen metabolism of plants. In this paper, the main drought stress signals and signal transduction pathways in plants are described, and the functional genes and regulatory genes related to drought stress are listed, respectively. We summarize the above aspects to provide valuable background knowledge and theoretical basis for future agriculture, forestry breeding, and cultivation. [ABSTRACT FROM AUTHOR]

Background: Apple is one of the oldest and most valuable fruits. Water restriction is one of the major problems in the production of this fruit in some planting areas. Methods: Effects of kaolin spray treatments were studied on two early apple cultivars of Golab and Shafi-Abadi under sustained deficit irrigation (SDI) in Alborz province, Iran during 2017 and 2018. Irrigation treatments were 100%, 85%, and 70% ETc and kaolin application were concentrations of 0, 3 and 6% in 2017 and 0, 1.5 and 3% in 2018. Results: Results showed that 85% ETc treatment compared to other irrigation treatments improved apple tree crown volume in 2017. Deficit irrigation treatments significantly reduced fruit weight in both years. Application with 6% kaolin resulted in 33.3% increase in apple fruit weight compared to non-kaolin treatment at 100% ETc irrigation in the first year. Severe deficit irrigation (70% ETc) significantly reduced apple fruit length in both years, but 6% kaolin increased fruit length in both apple cultivars in 2017. Severe deficit irrigation treatment increased the firmness of apple fruit compared to control and mild deficit irrigation (85% ETc) in the first year of experiment. There was no significant difference between irrigation treatments for apple fruit firmness in the second year of experiment. Kaolin treatments of 1.5% and 3% at full irrigation increased the soluble solids content of apple fruit by 36.6% and 44.1% in 2018, respectively. Deficit irrigation treatments significantly increased leaf proline content compared to control in both years. In the first year, kaolin treatments increased leaf proline but in the second year, leaf proline was not significant. Deficit irrigation treatment of 70% ETc and 6% kaolin had the highest amount of glycine betaine content, malondialdehyde and hydrogen peroxide in apple leaf in the first year of experiment. Conclusions: Severe deficit irrigation stress (70% ETc) increased the activity of nonenzymatic defense systems of apple trees. Kaolin as a drought stress reducing agent can be recommended in apple orchards of Golab and Shafi-Abadi cultivars as an effective and inexpensive method to improve tolerance to drought stress conditions. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the genetic diversity of 140 barley advanced lines, using Selection Index of Ideal Genotype (SIIG) and Adjusted Selection Index of Ideal Genotype (ASIIG) indicators for introduction and cultivation of suitable lines in rainfed conditions. The highest coefficient of variation was related to the type of spike, flag leaf area, seeds per spike, peduncle length, flag leaf width, and early growth vigor. The stepwise regression showed that the early growth vigor, 1000-seeds weight, spike type, days to heading, plant height, number of seeds per spike, and flag leaf length were the most critical components, which affect the grain yield under the rainfed conditions. The results of SIIG showed that lines 4, 43, 47, 40, 70, 96, 137, 3, 57, and 45 were the best lines with the highest SIIG values. The SIIG index divided all lines into seven groups; the average grain yield of lines in groups I and II were higher than the average grain yield of control cultivars and the other groups. According to ASIIG plots, lines 47, 3, 43, 45, 137, 96, and 40 were placed in the ideal quarter. Finally, the SIIG and ASIIG were compatible in selecting the best lines. ASIIG was more suitable for separating the ideal lines, because it participated all traits commensurate with their importance in the end product quantity and quality. [ABSTRACT FROM AUTHOR]

An automated method of determining tree water status would enable tree fruit growers, foresters and arborists to reduce water consumption, reduce orchard maintenance costs and improve fruit quality. Automated measurements could also be used to irrigate based on need rather than on fixed schedules. Numerous automated approaches have been studied; all are difficult to implement. Electromagnetic sensors that measure volumetric water content can be inserted in tree trunks to determine relative changes in tree water status. We performed automated measurements of dielectric permittivity using four commercially available electromagnetic sensors in fruit tree trunks over the 2016 growing season. These sensors accurately measure the ratio of air and water in soils, but tree trunks have minimal air-filled porosity. The sensors do respond, however, to bound and unbound water and the relative change in the output of the sensors thus provides an indication of this ratio. Sapwood is the hydro-dynamically responsive component of trunk anatomy and is nearest the bark. Sensor response improved when the waveguides were exposed to a greater percentage of sapwood. Irrigation-induced increases of approximately 0.5 MPa in stem water potential were associated with 0.5 unit increases in dielectric permittivity. Electromagnetic sensors respond to bound water in trees and thus have the potential to indicate tree water status, especially when the sensor rods are in contact with sapwood. Sensor modifications and/or innovative installation techniques could enable automated measurements of tree water status that could be used to precision irrigate trees. [ABSTRACT FROM AUTHOR]

A factorial experiment with Randomized Complete Block Design was carried out in the plastic house of Diyala Agriculture Department (Baquba Agricultural Nursery) for the winter season 2018 to study the effect of drought stress and spraying with arginine in chlorophyll, carbohydrates, proline and plant yield. The experiment was conducted with three replicates using two levels of stress S1, S2 and three levels of arginine (0,1000,2000) mg l-1. The results showed a significant increase in the level of stress S1 in the average concentration of total chlorophyll, reaching 2.91 mg g 1 and the plant yield 1114.8 g, while the concentration of carbohydrate was significantly reduced to 18.02 mg g 1 and propylene 1.34 mg 1 compared with S2 2073 mg 1, 788.5 g, 1, 20.70 mg and 1.43 mg respectively. The effect of arginine significantly increased the mean of total chlorophyll concentration, carbohydrate, proline and plant yield, with the highest values of spray treatment with a concentration of 2000 mg per 1 liter, reaching 3.62 mg 1, 21.93 mg 1, 1.79 mg 1, 1081 g respectively, With a concentration of O 1 mg per liter, at 2.10 mg 1, 17.03 mg 1, 0.96 mg and 820.5 grespectively. [ABSTRACT FROM AUTHOR]

Highlights • The modulation of elevated CO 2 on stomatal response to progressive drought was studied in tomato plants. • Elevated CO 2 retarded the response of photosynthesis and stomatal conductance to soil water deficits. • The responsiveness of stomatal conductance to ABA was unaffected by CO 2 environment. • Elevated CO 2 enhanced both water use efficiency and nitrogen use efficiency in tomato plants. Abstract The objective of this study was to investigate the response of leaf gas exchange of tomato plant to progressive drought stress under ambient (a [CO 2 ], 400 ppm) and elevated (e [CO 2 ], 800 ppm) atmospheric CO 2 concentration. The fraction of transpirable soil water (FTSW) was used to evaluate soil water status in the pots. The results showed that stomatal conductance (g s) and transpiration rate (T r) were significantly lower while the net photosynthetic rate (A n) was significantly higher in plants grown under e [CO 2 ] than those under a [CO 2 ] at onset of drought stress. Along with soil drying, the FTSW thresholds at which g s and A n started to decrease were significantly lower in plants grown under e [CO 2 ] as compared to plants grown under a [CO 2 ]. The intrinsic water use efficiency and instantaneous water use efficiency of plants grown under e [CO 2 ] was significantly higher than those under a [CO 2 ]. Under e [CO 2 ], the drought-stressed plants had greater leaf area, dry matter and water use efficiency than those grown under a [CO 2 ]. e [CO 2 ] notably enhanced shoot C concentration while decreased shoot N concentration hereby increased the C:N ratio. With the decrease of FTSW, the concentration of abscisic acid in leaf ([ABA] leaf) and xylem sap ([ABA] xylem) increased exponentially. When FTSW > 0.2, under both CO 2 environments, g s decreased linearly with increasing [ABA] leaf and [ABA] xylem ; and similar slopes but different intercepts were noticed for the regression lines, indicating that the responsiveness of g s to ABA was unaffected by CO 2. In conclusion, CO 2 elevation retarded the response of leaf gas exchange to progressive soil drying in tomato plants. This result provides novel knowledge for more precise prediction of plant response to drought stress in a future CO 2 -enriched environment. [ABSTRACT FROM AUTHOR]

Abstract Drought is a common environmental factor that limits plant growth, development and productivity. To understand the effect of drought on the perennial grass Bothriochloa ischaemum , we applied high-throughput Illumina sequencing technology and analyzed the transcriptional expression profile of Bothriochloa ischaemum leaves and roots under drought and normal growth conditions. Compared to the controls, drought-treated samples had 7989 differentially expressed genes in leaves and 15,675 differentially expressed genes in roots. Of these, 4489 and 5010 genes were up-regulated genes in leaves and roots, respectively. Of the 2012 differentially expressed genes that were shared between leaves and roots, 1068 were up-regulated. We identified common and distinct biological processes and metabolic pathways involved in drought stress between the two tissues. Most notably, there was a dramatic up-regulation of genes involved in plant hormone signal transduction especially ABA signal transduction components and flavonoid biosynthesis enzymes or regulation factors in drought stress treated leaves. Therefore, these two cellular processes likely confer resistance to drought stress in Bothriochloa ischaemum. Overall, our findings provided new insights into a mechanism involving the synergistic interaction between ABA signaling and secondary metabolism during the drought adaptation of Bothriochloa ischaemum. Highlights • We analyzed the effect of drought on B. ischaemum by transcriptome sequencing. • ABA signal transduction may confer resistance to drought stress in B. ischaemum. • Flavonoid biosynthesis likely confers resistance to drought stress in B. ischaemum. [ABSTRACT FROM AUTHOR]

Abstract This research was conducted to address the influence of foliage-applied sodium nitroprusside (SNP; 0, 50, 100 and 150 μM) on resistance against reduced irrigation by 80, 60 and 40% Field Capacity (FC), in two drought tolerant thyme (Thymus serpyllum Serpolet) and drought susceptible thyme (T. Vulgaris L.). Non-SNP treated resistant specie showed 55.17% higher plant growth rate than drought susceptible thyme under severe water deficit (40% FC). However, SNP treatment caused drought susceptible specie to show higher growth rate compared with those of resistant one under non- water stressed conditions (80% FC). Intensified drought, while significantly enhancing malondialdehyde (MDA), H 2 O 2 and electrolyte leakage of both specie, caused marked reduction in chlorophyll content, ratio of variable to maximum fluorescence (Fv/Fm) and relative water content. The essential oil yield of both specie increased with the decrease in irrigation from 80 to 60% FC, and decreased with the water deficit increase to 40% FC. Spraying Thymus specie with all three levels of SNP further increased the essential oil yield and improved physiological attributes of both specie, being more pronounced in drought resistant one. The compensatory effect of SNP in mitigating the negative impact of reduced irrigation was due to increase of proline accumulation and reduction of some antioxidant activities which increased drought tolerance of Thymus. [ABSTRACT FROM AUTHOR]

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Copyright of Acta Agriculturae Slovenica is the property of Biotechnical Faculty of the University of Ljubljana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • Water deficits in Michigan asparagus production have increased linearly since 1997. • Irrigation reduced losses due to drought stress for one of two cultivars. • Cultivar differences in drought tolerance were likely due to differences in rooting depth. Abstract Increasing temperatures and rainfall variability in the Midwestern U.S. have spurred interest in strategies to reduce risks of heat and drought stress in traditionally rainfed crops including asparagus. A long-term field experiment was conducted on sandy soils in Western Michigan from 2010-17 to evaluate the effects of three levels of irrigation (none, overhead or sub-surface drip) and two asparagus cultivars (Guelph Millennium [GM] and Jersey Supreme [JS]) for reducing these risks. Overhead irrigation during the fern growth period resulted in cumulative yield improvements of 10% for GM during the 2012-17 growing seasons, with the largest yield benefits (21%) occurring in 2012, following hot, dry conditions the previous summer. In contrast, cumulative yields of JS were unaffected by irrigation, and yield reductions of 13% due to irrigation were observed in 2017, following wet conditions the previous late summer and fall. Estimates of cultivar water-use by depth suggest that JS was better able to tolerate drought due to a deeper root system compared to GM. However, our results suggest that JS may also be more sensitive than GM to excessive soil moisture during fall senescence. Yield response did not vary with delivery system, but sub-surface drip used less water than overhead irrigation. These results demonstrate the important role of both genetics and management practices in mitigating drought risk. [ABSTRACT FROM AUTHOR]