Reduced Water Potential Research Articles

Determining the effects of reduced water availability on seed germination of five bottomland hardwood tree species

Globally, floodplain forests are experiencing shifts in species composition associated with drier conditions and disruptions of flood pulse hydrology. The specific processes behind these shifts in composition are not fully understood, but differential effects of drought on regeneration processes such as seed germination may be partially responsible. To determine how reduced water availability impacts seed germination of different floodplain tree species, a lab-controlled germination experiment was conducted. Seeds from tree species common to floodplain forests of the southeastern and southcentral United States whose abundance have been altered by drier hydrogeomorphic conditions were examined. These seeds included desiccation resistant, or orthodox, seeds of sugarberry (Celtis laevigata) and green ash (Fraxinus pennsylvanica), and desiccation sensitive, or recalcitrant, acorns of overcup oak (Quercus lyrata), water oak (Quercus nigra), and willow oak (Quercus phellos). Seeds of each species were incubated with one of eight osmotically adjusted water solutions ranging in water potential from 0.0 MPa to −1.4 MPa. This reduction in water potential decreases the water available to the seeds for germination. After four weeks, seed germination of all species decreased with reduced water potential; however, desiccation tolerance did not correspond with the ability to germinate under lower water potential. Orthodox seeds only germinated in higher water potential treatments. Sugarberry reached 30 % germination in only the control 0.0 MPa treatment while green ash reached 30 % germination in treatments as low as −0.4 MPa. In contrast, recalcitrant acorns continued to germinate under lower water potentials. Water oak maintained 30 % or greater germination under all treatments and willow oak reached 30 % down to −0.8 MPa. Overcup oak was the only species to not respond to water potential treatment. With respect to maximum germination, sugarberry and green ash reached maximum germination an average of 9 days sooner than the oak species. The results of this study agree with others that demonstrate that seed germination success is sensitive to environmental water conditions and that species specific differences in germination traits are linked to broader life history strategies that are adaptive to common environmental conditions in their range.

Growth Performance of Sabia Grass Irrigated by Drippers Installed in Subsurface

Studies to improve the use of subsurface drippers in pasture formation are needed. Therefore, the objective of this study was to evaluate the germination and emergence of Sabia grass as a function of drippers installed at different depths. The study was conducted in pots in Viçosa, Minas Gerais State, Brazil. The experiment was conducted using a completely randomized design with four replicates. The experimental layout featured split plots over time, where the main plots consisted of three cultivation cycles and the subplots represented various dripper installation depths. The three sowing dates were 26 March, 12 April, and 29 April 2022. Drip tapes were installed at seven different depths: 0 (superficial), 5, 10, 15, 20, 25, and 30 cm. The results showed that the reduction in water potential, associated with increased temperature, resulted in lower performance of Sabia grass seeds. Seed germination and parameters related to germination speed were negatively impacted by the increase in dripper installation depth, with a 30–40% reduction in germination speed observed at depths greater than 15 cm. Drippers installed at 15–20 cm depth in clayey soil were ideal, providing a balance between reducing soil water evaporation and maintaining seedling emergence rates. Compared to surface installation, this depth improved seed performance by up to 25%, while enhancing operability and minimizing water loss. It is recommended to install drippers at a depth of 15–20 cm in subsurface drip irrigation systems in clayey soil areas to achieve benefits such as decreased soil water evaporation and improved operability compared to surface systems.

Apple vacuolar sugar transporters regulated by MdDREB2A enhance drought resistance by promoting accumulation of soluble sugars and activating ABA signaling

Abstract Soluble sugars are not only an important contributor to fruit quality, but also serve as the osmotic regulators in response to abiotic stresses. Early drought stress promotes sugar accumulation, while specific sugar transporters govern the cellular distribution of the sugars. Here, we show that apple plantlets accumulate soluble sugars in leaf tissues under drought stress. Transcriptional profiling of stressed and control plantlets revealed differential expression of several plasma membrane- or vacuolar membrane-localized sugar transporter genes. Among these, four previously identified vacuolar sugar transporter (VST) genes (MdERDL6–1, MdERDL6–2, MdTST1 and MdTST2) showed higher expression under drought, suggesting their roles in response to drought stress. Promoter cis-elements analyses, yeast one-hybrid and dual-luciferase tests confirmed that the drought-induced transcription factor MdDREB2A could promote the expression of MdERDL6–1/−2 and MdTST1/2 by binding to their promoter regions. Moreover, overexpressing of each of these four MdVSTs alone in transgenic apple or Arabidopsis plants accumulated more soluble sugars and abscisic acid, and enhanced drought resistance. Furthermore, apple plants overexpressing MdERDL6–1 also showed reduced water potential, facilitated stomatal closure and reactive oxygen species scavenging under drought condition compared to control plants. Overall, our results suggest a potential strategy to enhance drought resistance and sugar accumulation in fruits through manipulating the genes involved in vacuolar sugar transport.

Models of osmotic stress as a tool for proteomics and metabolomics of legume seeds

Drought poses a significant challenge to the sustainable development of modern agriculture and to the achievement of high crop yields. Water deficit causes osmotic stress and triggers plant physiological responses characterized by reduced water potential, diminished stomatal conductance, and decreased photosynthetic efficiency. Long-term adaptation to osmotic stress entails intricate metabolic rearrangements, leading to the accumulation of osmoprotectants, activation of antioxidant systems, and increased biosyntheses of stress-protective proteins. The severity and duration of drought, along with plant genotype and developmental stage, influence the plant response to stress, consequently affecting crop yield and quality. Particularly in the context of legumes, which are crucial for human and animal nutrition, understanding adaptive strategies to water deficit is essential for the cultivation of drought-resistant genotypes, primarily because these crops predominantly thrive in semi-arid regions. Proteomics and metabolomics approaches, in turn, serve as valuable tools, offering critical insights into the molecular dynamics governing plant responses to drought stress. Furthermore, the use of reliable drought simulation models is imperative for the effective evaluation of legume response to water scarcity, aiding the cultivation of drought-tolerant varieties. This review highlights the perspectives of utilizing different osmotic stress models to investigate proteome and metabolome alteration within seeds of food legumes.

Germination Performance of Physalis peruviana L. Seeds under Thermal and Water Stress Conditions

Physalis peruviana holds significant economic value, making it crucial to determine optimal cultivation conditions, particularly concerning seed germination under varying water and temperature conditions. Therefore, this study aimed to assess the impacts of heat and water stress on the germination and vigor of P. peruviana seeds. The study was divided into two trials: the first examined the effect of constant temperatures of 10, 15, 20, 25, 30, 35, and 40 °C and alternating temperatures of 20 °C during the dark period and 30 °C during the light period (control) on seed germination and vigor. The second trial investigated germination and vigor under different water and thermal conditions using various osmotic potentials (0; −0.3; −0.6; and −0.9 MPa) and two temperatures (constant 30 °C and alternating 20 °C during the dark period and 30 °C during the light period). Both trials used a 16 h photoperiod. The germination tests revealed optimal (30 °C), moderate (20/30 °C), minimal (20 °C), and inhibited (40 °C) temperatures for the species’ germination. It was found that the first germination count could be conducted on the seventh day after sowing. Low water availability had negative effects on seed germination and vigor, especially at osmotic potentials below −0.45 and −0.61 MPa, combined with temperatures of 30 and 20/30 °C, respectively. Severe water stress, with osmotic potentials equal to or below −0.9 MPa, completely inhibited seed germination and vigor. Reduction in water potential and increased temperature resulted in a significant decrease in the percentage, speed, and quality of P. peruviana germination. These findings indicate that the species does not tolerate extreme temperatures, whether low (less than 15 °C) or high (greater than 35 °C), nor water stress with osmotic potentials lower than −0.45 MPa, much less the combination of these factors.

A meta-analysis of photosynthetic efficiency and stress mitigation by melatonin in enhancing wheat tolerance

BackgroundOur meta-analysis examines the effects of melatonin on wheat under varying abiotic stress conditions, focusing on photosynthetic parameters, chlorophyll fluorescence, leaf water status, and photosynthetic pigments. We initially collected 177 publications addressing the impact of melatonin on wheat. After meticulous screening, 31 published studies were selected, encompassing 170 observations on photosynthetic parameters, 73 on chlorophyll fluorescence, 65 on leaf water status, 240 on photosynthetic pigments.ResultsThe analysis revealed significant heterogeneity across studies (I² > 99.90%) for the aforementioned parameters and evidence of publication bias, emphasizing the complex interaction between melatonin application and plant physiological responses. Melatonin enhanced the overall response ratio (lnRR) for photosynthetic rates, stomatal conductance, transpiration rates, and fluorescence yields by 20.49, 22.39, 30.96, and 1.09%, respectively, compared to the control (no melatonin). The most notable effects were under controlled environmental conditions. Moreover, melatonin significantly improved leaf water content and reduced water potential, particularly under hydroponic conditions and varied abiotic stresses, highlighting its role in mitigating water stress. The analysis also revealed increases in chlorophyll pigments with soil drenching and foliar spray, and these were considered the effective application methods. Furthermore, melatonin influenced chlorophyll SPAD and intercellular CO2 concentrations, suggesting its capacity to optimize photosynthetic efficiency.ConclusionsThis synthesis of meta-analysis confirms that melatonin significantly enhances wheat’s resilience to abiotic stress by improving photosynthetic parameters, chlorophyll fluorescence, leaf water status, and photosynthetic pigments. Despite observed heterogeneity and publication bias, the consistent beneficial effects of melatonin, particularly under controlled conditions with specific application methods e.g. soil drenching and foliar spray, demonstrate its utility as a plant growth regulator for stress management. These findings encourage focused research and application strategies to maximize the benefits of melatonin in wheat farming, and thus contributing to sustainable agricultural practices.

A seed-borne endophyte mediates plant drought responses and intergenerational effects on seed characteristics

Global warming is expected to increase drought severity in diverse environments, impacting plant performance. Plants acclimate to drought by mechanisms like stomatal closure and osmotic adjustment. Maternally inherited symbiotic microorganisms with capacity to regulate these mechanisms have the potential to influence intergenerational plant drought responses. We studied how a seedborne endophyte affects maternal drought effects on seed germination water requirements and specialized metabolites. Isotopic analysis of seed cellulose indicated that drought led to improved water use efficiency (WUE; higher δ13C) in endophyte-free mother plants, seemingly without affecting stomatal conductance (non-significant δ18O change). Alternatively, endophyte-symbiotic plants did not exhibit a change in WUE but apparently an increase in stomatal conductance (significant δ18O decrease). Regardless of the symbiosis, drought reduced seed production but not seed size. Endophyte symbiosis improved the seed concentration of mannitol and sorbitol, but this increment was higher under drought. Maternal plant responses to drought did not increase seed germination under reduced water potential but induced dormancy in seeds from endophyte-free but not endophyte-symbiotic plants. Our findings suggest that although differential accumulation of metabolites in seeds results from how endophyte-symbiotic plants perceive and respond to drought, this response may not form part of a mechanism that would enhance seed performance of progeny under drought.

Polysome-bound mRNAs and translational mechanisms regulate drought tolerance in rice

Plants evolved several acquired tolerance traits for drought stress adaptation to maintain the cellular homeostasis. Drought stress at the anthesis stage in rice affects productivity due to the inefficiency of protein synthesis machinery. The effect of translational mechanisms on different pathways involved in cellular tolerance plays an important role. We report differential responses of translation-associated mechanisms in rice using polysome bound mRNA sequencing at anthesis stage drought stress in resistant Apo and sensitive IR64 genotypes. Apo maintained higher polysomes with 60 S-to-40 S and polysome-to-monosome ratios which directly correlate with protein levels under stress. IR64 has less protein levels under stress due to defective translation machinery and reduced water potential. Many polysome-bound long non-coding RNAs (lncRNA) were identified in both genotypes under drought, influencing translation. Apo had higher levels of N6-Methyladenosine (m6A) mRNA modifications that contributed for sustained translation. Translation machinery in Apo could maintain higher levels of photosynthetic machinery-associated proteins in drought stress, which maintain gas exchange, photosynthesis and yield under stress. The protein stability and ribosome biogenesis mechanisms favoured improved translation in Apo. The phytohormone signalling and transcriptional responses were severely affected in IR64. Our results demonstrate that, the higher translation ability of Apo favours maintenance of photosynthesis and physiological responses that are required for drought stress adaptation.

IMPACT OF AGRI-ENVIRONMENTAL ECOSYSTEM SERVICES ON FARM LANDSCAPES

More than a third of the Earth's total land area is used for agriculture and grazing, leading to alarming rates of land conversion and habitat loss for a variety of plant and animal species. Conventional agricultural production, in both methods and practice, is responsible for high rates of biodiversity degradation, soil erosion, reduced water potential, and impacts on a range of ecosystem services. In Bulgaria, research on economic and other issues related to agroecosystem services is at an early stage. With few exceptions, there is a virtual lack of research on the dominant forms of agroecosystem services management in the country. This paper aims to investigate the impact of implementing ecosystem services on the shaping of the landscape on farms. As well as to further the understanding of the impact of multiple agroecological ecosystem services in farm landscapes.

Effect of Short-Term Water Deficit on Some Physiological Properties of Wheat (Triticum aestivum L.) with Different Spike Morphotypes

Water deficit is one of the most important stress factors affecting yield and production quality. Breeders are focusing on breeding wheat cultivars and crop lines that are more resistant to water deficit, so there is a possibility that plants with changes in their ear morphologies, such as long chaff and multi-rowed varieties, will be more resistant to water deficit. Therefore, our research focused on the study of changes in the physiological parameters of wheat cultivar ‘Bohemia’ (normal cob) with an altered morphotype (genotypes ‘284-17’ (long chaff) and genotype ‘29-17’ (multirow cob)), in relation to the duration of the water deficit. The experiment was set up as a container experiment under partially controlled greenhouse conditions. The experimental design included four treatments. The control (C) variant was irrigated regularly. The other treatments were stressed by water deficit, which was induced through the method of gradually drying the substrate: treatment D1 involved 10 days without irrigation, 4 days of watering, 10 days with a re-induced water deficit and 4 days of watering; treatment D2 involved 10 days of watering, and then stress was induced via water deficit until the end of the experiment; treatment D3 involved 10 days of stress and then irrigation until the end of the experiment. The pigment content, gas exchange rate, chlorophyll fluorescence and water potential were monitored in the juvenile wheat plants. The obtained results showed that the contents of photosynthetically active pigments (chlorophyll a and b and carotenoids) were influenced by the gene type. The chlorophyll and carotenoid content were higher in genotype ‘29-17’ (0.080 and 1.925 nM cm−2, respectively) and lowest in cultivar ‘Bohemia’ (0.080 and 0.080 nM cm−2, respectively). The chlorophyll content decreased due to water deficit most significantly in the D2 variant (0.071 nM cm−2), compared to the control (0.138 nM cm−2). The carotenoid content significantly decreased due to water deficiency in the cultivar ‘Bohemia’, D2 (0.061 nM cm−2) and the genotype ‘284-17’ (0.075 nM cm−2) and non-significantly decreased in ‘29-17’ (1.785 nM cm−2). In the control plants, the carotenoid content decreased in the following order: genotype ‘29-17’ (1.853 nM cm−2) > genotype ‘284-17’ (0.088 nM cm−2) > cv. ‘Bohemia’ (0.087 nM cm−2). Wheat plants had a decreased photosynthetic rate due to the closure of stomata and reduction in substomatal CO2 levels, which were caused by water deficit. The above effect was observed in genotype ‘29-17’ and cultivar ‘Bohemia’. The transpiration rate increased by 0.099 mM m−2 s−1 (5.69%) in the variety ‘Bohemia’, due to water deficit. On the other hand, the transpiration rate of genotype ‘29-17’ and genotype ‘284-17’ decreased by 0.261 mM m−2 s−1 (88.19%) and 0.325 mM m−2 s−1 (81.67%), respectively, compared to the control. Among the genotypes studied, genotype ‘29-17’ showed higher photosynthesis and transpiration rates, compared to genotype ‘284-17’ and the variety ‘Bohemia’. The effect of genotype and water deficit on chlorophyll fluorescence parameters was also shown. In all genotypes studied, there was a significant decrease in water potential due to water deficit, most significantly in the Bohemia variety, then in the genotype ‘284-17’, and the least significant decrease in water potential was seen in the genotype ‘29-17’. Genotype ‘29-17’ appears promising with respect to drought tolerance and photosynthetic rate, despite increased transpiration and reduced water potential; it also appears promising for better water management, with respect to reduced water potential in aboveground organs. On the other hand, the variety Bohemia appears to be less suitable for dry areas, since, despite its relative plasticity, it shows not only high water potential values in the water deficit region but also the most significant decrease in water potential.

Response of strawberry (Fragaria ananassa L.) to chilling and potassium supply from inorganic and amino acid-complexed sources

There is growing evidence that plants need higher potassium (K) when subjected to environmental stresses i.e., chilling in order to tolerate oxidative damages provided by stress. In this work, influence of potassium (K) foliar spray from different fertilizer sources including K2SO4 and lysine (Lys)- and methionine (Met)-complexed K on physiological and antioxidative responses of strawberry (Fragaria ananassa ‘Gavieta’) to chilling (6 h d−1 at 4 °C for 3 consecutive days) was investigated. Chilling of control, Lys, and K-Lys-strawberry plants to 4 °C increased ion leakage and malondialdehyde (MDA) concentration. In contrast, chilling was ineffective on the amount of ion leakage and MDA in the plants supplied by K2SO4, K-Met, and only Met. The leaf chlorophyll concentration was found to reduce by chilling in both control (free of K and amino acid) and Lys-treatments, however, the chill-treatment leaf chlorophyll concentration remained unchanged in the plants supplied with K-Met, K2SO4, and only Met. The chilling at 4 °C resulted in between 0.58 % to 5.2-fold rise in strawberry leaf CAT, APX, and SOD activities, the largest increase was found at K-Met-treatment. Chilling substantially increased leaf proline concentration (on average 99.5 %), the largest increase was found at the K-Met-treatment. Chilling caused significant reduction in water potential (ΨL) and relative water content (RWC) of control and only Lys-and Met-strawberry plants but it had no effect on these water relations of K-fed plants. According to the results, foliar fertilization of K particularly from K-Met-complex was effective in alleviating the destructive effect of chilling on cell membrane of plant leaves. The protective effect of K and Met-fertilization against chilling-induced injuries was in part related to a substantial rise in leaf activity of CAT, APX, and SOD and leaf proline concentration.

Penilaian Indeks Kinerja Sistem Irigasi (Studi Kasus Daerah Irigasi Cirompang Kabupaten Garut Jawa Barat)

Irrigation is an effort to provide, regulate and distribute irrigation water. The Cirompang Irrigation Area is located in Bungbulang District, Garut Regency, West Java Province, with a functional area of 847 Ha, covering the service area of 4 (four) villages, namely Cihikeu Village, Bungbulang Village, Margalaksana Village and Hanjuang Village, Bungbulang District. The location of the Cirompang Irrigation Area Weir is in the village of Cintarasa, Samarang sub-district. The availability of water in the upstream, downstream and main network areas during the planting season I to planting season III is felt to be sufficient but in the middle areas the availability of water is reduced or it can be said to be non-existent due to reduced water potential and there are damaged irrigation networks and accumulation of sedimentation which results in obstruction of water flow. The Cirompang secondary canal experienced moderate to moderate damage, there was accumulation of mud or sedimentation which affected the flow of water and besides that there was also a lack of personal O&M officers in the field such as irrigation officers, weir operation officers, water gate officers and workers who have so far relied on participation. water user farmers (P3A/GP3A). The research method was carried out by direct observation in the field, interviews and secondary data analysis. Calculation of the real need for operation and maintenance is needed to determine the O&M funding and priority recommendations proposed to increase the value of irrigation system performance appraisal (IKSI). The results of the IKSI assessment for the Cirompang irrigation area, the combined index value is in the bad criteria, namely with a weight value of 48.14%, meaning that the irrigation network requires rehabilitation of the irrigation system and needs immediate treatment. 117,626,150.00 In addition, O&M financing in Cirompang for the last 3 years is still far from ideal conditions, namely an average of only 10% of AKNOP. Efforts to increase the water discharge, it is suggested for the Public Works and Spatial Planning Office of Garut Regency is to increase the budget allocation, empower the participation of water-using farmers and rehabilitate irrigation networks.

Physio-morphological trait and bioactive constituents of Ocimum species under drought stress

The genus Ocimum, which belongs to the Lamiaceae family, encompasses a wide variety of herbs and shrubs, with over 60 species originating from tropical regions. These plants are widely cultivated for their essential oils, which are used in culinary, medicinal, and aromatic applications. However, prolonged exposure to water scarcity can negatively impact the growth and essential oil production of Ocimum species. There is limited information available on how Ocimum basilicum ‘Ohře’ and O. americanum respond to drought stress. Consequently, two-year studies (2021 and 2022) were conducted to investigate the physiological, morphological, and biochemical changes occurring in those two basil plants under three different soil water regimes (70%, 50%, and 30% of soil water capacities ‘SWC’). The findings of these studies demonstrated that drought stress significantly affected physiological indicators, hindered the growth and development of the examined Ocimum species, and altered their essential oil production. Due to severe drought stress both basil plants lost over 14% of their leaf relative water content and more than 60% reduction in water potential. Consequently, basil plants lost over 45% of their biomass (dry and fresh) and essential oil yield when the soil became drier (30% SWC). Conversely, dry soil conditions enhanced water use efficiency, SPAD value, glandular hair density (increased by over 60%), essential oil concentration (increased by 10%), and phenol concentration. Additionally, the essential oil constituents were mildly affected, with the effects dependent on factors such as species, production year, drought intensity, and specific essential oil compounds. In conclusion, these studies have demonstrated that prolonged exposure to water scarcity limits growth and alters the biochemical constituents of both Ocimum species. Therefore, to secure maximum biomass and essential oil yield under protected cultivation, it is recommended to maintain at least 70% soil water capacity.

Effects of Drought and Flooding on Growth and Physiology of Cinnamomum camphora Seedlings

In the context of climate change, future patterns of precipitation are expected to increase the intensity and frequency of drought and flooding stress. This is also likely to result in more frequent flooding–drought alternation events. Drought and flooding stress can have negative effects on tree morphology, physiology, and biochemistry, which can potentially pose long-term threats to tree survival and further disrupt the stability of forest ecosystems. However, it remains unclear how trees would cope with these stressors and their alternations through growth and physiology responses. Potted seedlings of C. camphora were grown under a rainout shelter in the field with four water treatments for 40 days: well-watered (WW), drought stress (DS), flooding stress (FS) and flooding–drought alternation (FDF). Growth, leaf gas exchange, water potential, and biochemical traits were measured. Results show different seedling growth patterns under drought and flooding stress. Drought increased the root-to-shoot ratio (+25%) but flooding favored leaf growth (+33%). Decreases in photosynthesis under drought and flooding were mainly related to stomatal limitations, accompanied by abscisic acid accumulation under drought but not under flooding. Drought reduced water potential, and flooding–drought alternation only decreased water potential in its drought phase. Flooding treatment had no effect on water potential. Drought treatment increased the proline concentrations (+74%) and carbon isotopic composition (+3.7%), but all treatments had no effect on the concentrations of elements in leaves. Drought stress led to carbon depletion in both stem and root, whereas flooding stress primarily induced carbon depletion in the root. Flooding–drought alternation was accompanied by complex physiological responses, including physiological recovery when the stress (flood, drought) was relieved. Our results have shown the different effects of drought and flooding on the growth and physiology of C. camphora seedlings, emphasizing the need to consider specific water stress conditions in future studies and providing a theoretical basis for better management of this tree species in urban areas under variable rainfall patterns.

Graphene-Cu Nanocomposites Induce Tolerance against Fusarium oxysporum, Increase Antioxidant Activity, and Decrease Stress in Tomato Plants.

The tomato crop is susceptible to various types of stress, both biotic and abiotic, which affect the morphology, physiology, biochemistry, and genetic regulation of plants. Among the biotic factors, is the phytopathogen Fusarium oxysporum f. sp. lycopersici (Fol), which can cause losses of up to 100%. Graphene-Cu nanocomposites have emerged as a potential alternative for pathogen control, thanks to their antimicrobial activity and their ability to induce the activation of the antioxidant defense system in plants. In the present study, the effect of the Graphene-Cu nanocomposites and the functionalization of graphene in the tomato crop inoculated with Fol was evaluated, analyzing their impacts on the antioxidant defense system, the foliar water potential (Ψh), and the efficiency of photosystem II (PSII). The results demonstrated multiple positive effects; in particular, the Graphene-Cu nanocomposite managed to delay the incidence of the "vascular wilt" disease and reduce the severity by 29.0%. This translated into an increase in the content of photosynthetic pigments and an increase in fruit production compared with Fol. In addition, the antioxidant system of the plants was improved, increasing the content of glutathione, flavonoids, and anthocyanins, and the activity of the GPX, PAL, and CAT enzymes. Regarding the impact on the water potential and the efficiency of the PSII, the plants inoculated with Fol and treated with the Graphene-Cu nanocomposite responded better to biotic stress compared with Fol, reducing water potential by up to 31.7% and Fv/Fm levels by 32.0%.

The Effect of Sodium Ions on the Anatomical Structure and Growth of Early Simmondsia chinensis (Link) C.K. Schneid. Roots under Reduced Water Potential and Temperature

The Effect of Sodium Ions on the Anatomical Structure and Growth of Early Simmondsia chinensis (Link) C.K. Schneid. Roots under Reduced Water Potential and Temperature

Shading minimizes the effects of water deficit in Campomanesia xanthocarpa (Mart.) O. Berg seedlings.

The objective of this study was to evaluate the activity of antioxidant enzymes, the functioning of the photosystem II and quality of C. xanthocarpa seedlings cultivated under intermittent water deficit and shading levels and the influence of shading on recovery potential after suspension of the stress conditions. The seedlings were subjected to three levels of shading (0, 30, and 70%), six periods of evaluation (start: 0 days; 1st and 2nd photosynthesis zero: 1st and 2nd P0; 1st and 2nd recovery: 1stand 2nd REC; and END), and two forms of irrigation (control: periodically irrigated to maintain 70% substrate water retention capacity, and intermittent irrigation: suspension of irrigation). The plants subjected to intermittent irrigation conditions at 0% shading showed a reduction in water potential (Ψw) and potential quantum efficiency of photosystem II (Fv/Fm) and maximum efficiency of the photochemical process (Fv/F0) and an increase in basal quantum production of the non-photochemical processes (F0/Fm). Superoxide dismutase (SOD) activity was higher in the leaves than in the roots. The C. xanthocarpa is a species sensitive to water deficit but presents strategies to adapt to an environment under temporary water restriction, which are more temporary are most efficient under shading. The seedlings with water deficit at all levels of shading exhibited higher protective antioxidant activity and lower quality at 0% shading. The shading minimizes prevents permanent damage to the photosystem II and after the re-irrigation, the evaluated characteristics showed recovery with respect to the control group, except POD and SOD activities in the leaves.

Economic vulnerability assessment in the water sector with a focus on electricity production in hydropower plants: Case of Montenegro

The aim of our paper is economic vulnerability assessment in the water sector of Montenegro, with a focus on electricity production in hydropower plants. The absence of an officially defined methodology in Montenegro, as well as in the region of South-East Europe represents a kind of challenge for research of this type especially for the assessment of economic damage caused by climate change and in the future period. In our paper, we treated negative impacts in the water sector as additional costs for the import of electricity due to reduced electricity production caused by the reduction of water potential due to climate change. After collecting, processing and analyzing data on electricity production in Montenegro, we prepared a projection of this production in the future period for the basic scenario - “without climate change”. This was followed by an assessment of the quantitative damage, in accordance with the determined climate scenarios. After analyzing electricity prices in the European market, we defined future unit were defined as a basis for damage assessment. We conclude the paper with the calculation and projection of economic damages caused by climate change in the Montenegrin energy sector. The basic variant of the analysis would be the existing price of electricity imports for 2022, in the amount of 200 EUR per MWh. The other two variants would be one higher and one lower electricity import prices (250 and 150 EUR per MWh, respectively), in order to gain an overview of the future price fluctuations in a certain way.

A predictive method for selecting the most appropriate level of water potential for Thymus daenensis ssp. daenensis Cleak seed priming with respect to the severity of salinity or drought stress

Thymus daenensis ssp. daenensis Cleak is an aromatic medicinal plant belonging to Lamiaceae family. Seed priming is a practical method to alleviate salinity and drought stress over germination stage. The objective of this study was to determine the most appropriate water potential level of seed priming solution according to the level of the salinity or drought stress of the medium which T. daenensis seeds will be sown. A factorial completely randomized design with four replications was conducted, one for salinity stress by using NaCl and another for drought stress by using PEG 6000. The first factorial design consisted of five seed medium water potential levels including 0, − 0.3, − 0.6, − 0.9 and − 1.2 MPa and the second was six seed priming treatments, including unprimed (UP), hydroprimed (HP, 0 MPa), − 0.3, − 0.6, − 0.9 and − 1.2 MPa water potential solutions. Priming efficacy (PE) is suggested in this study as a new characteristic for evaluation of the efficiency of priming. The PE values revealed that priming increases the germination percentage in all treatments; based on the obtained values of PE, the most effective priming treatment was the hydropriming in − 9 MPa of PEG. The final percentage germination (FPG), germination speed (GS), and root and shoot length (RL and SL) were reduced by decreasing the water potential levels of NaCl and PEG iso-osmotic solutions at 0, − 0.3, − 0.6, − 0.9 and − 1.2 MPa. All the traits were higher in NaCl than in PEG at the same water potential. Priming was helpful in overcoming the negative effects imposed by reduced water potential upon seed germination. The severity of salinity or drought stress determined the level of water potential would be better suited for seed priming. The highest germination percentage for the seed medium with Ψ-0.3 and Ψ-0.9 solutions was achieved by the priming solution of − 0.9 (96%) and − 0.3 (56%) MPa for NaCl treatments, respectively; and − 0.6 (94%) and 0 (35%) MPa for PEG treatments. There were second or third-order polynomial relationships between water potentials in seed germination medium and priming solutions according to the germination characteristics. Consequently, predictive equations were derived for each characteristic to show the suitable priming treatment regarding to the seed germination water stress level. The results showed that higher water potential treatments should be chosen for priming if germination is expected to occur under lower water potential and vice versa. This achievement can be used in rehabilitation of the degraded lands of T. daenensis by seed dispersal or when irrigating with saline water is required under cultivated fields.

Screening Bambara Groundnut (Vigna subterranea L. Verdc) Genotypes for Drought Tolerance at the Germination Stage under Simulated Drought Conditions.

Bambara groundnut (Vigna subterranean L. Verdc) is grown by smallholders and subsistence farmers in the marginal parts of sub-Saharan Africa. This legume is native to Africa and is cultivated throughout semi-arid sub-Saharan Africa. It is hardy and has been recognized as a nutritious food source in times of scarcity. Drought can negatively affect the germination or establishment of seedlings in the early stages of crop growth. Drought can limit the growing season of certain crops and create conditions that encourage the invasion of insects and diseases. Drought can also lead to a lack of crop yield, leading to rising food prices, shortages, and possibly malnutrition in vulnerable populations. A drought-tolerant genotype can be identified at the germination stage of Bambara groundnut by screening for drought-tolerance traits, and this knowledge can be applied to Bambara crop improvement programs to identify drought-tolerant traits during early growth phases. As an osmolyte, polyethylene glycol (PEG 6000) reduced water potential and simulated drought stress in Bambara groundnut seeds of different genotypes. Osmolytes are low-molecular-weight organic compounds that influence biological fluid properties. In this study, 24 Bambara groundnut genotypes were used. Data were collected on seed germination percentage (G%), germination velocity index (GVI), mean germination time (MGT), root dry mass (RDM), root fresh mass (RFM), and seven drought tolerance indices: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), stress susceptibility index (SSI), yield index (YI), yield stability index (YSI), stress tolerance index (STI) as well as seed coat color measurements. The data were applied to the mean observation of genotypes under simulated drought conditions (Ys) and the mean observation of genotypes under controlled conditions (Yp). Germination%, germination velocity index (GVI), mass germination time (MGT), and root fresh mass (RFM) differed significantly (p < 0.001) between the two stress conditions. Bambara genotypes Acc 82 and Acc 96 were found to be the most drought-tolerant.