Periods Of Deficit Research Articles

Physiological Characterization of Banana Germplasm of North East India for Tolerance against Moisture Deficit

Background: Water deficit stress is a serious environmental constrain to banana productivity in north east (NE) India. A field experiment was conducted to appraise the performance of 29 banana germplasm of NE India under moisture deficit condition of Assam that naturally prevails due to deficit rainfall every year during November to January. Methods: Randomized block design with five replications was the experimental design used. Irrigation was not applied during the crop growing season. Various physio-chemical parameters were measured in the main crop on 7th and 9th months after planting (MAP) that coincided with November and January. Result: Significant variations were observed in leaf relative water content, leaf area plant-1, leaf area index, total chlorophyll content, leaf proline content, lipid peroxidation, hands bunch-1 and bunch weight amongst germplasm studied. During moisture deficit period, germplasm Barjahaji, Bhimkal, Athiya and Bogimonahar could maintained better values in the physio-chemical traits studied except lipid peroxidation. The germplasm that showed superior values in the physio-chemical traits and lower value for lipid peroxidation registered the higher bunch weight. Significant positive correlation of bunch weight with leaf area (0.42 and 0.45 respectively for 7th and 9th MAP) and relative leaf water content (0.38 respectively for both 7th and 9th MAP) and significant negative correlation with lipid peroxidation (-0.45 and -0.49 respectively for 7th and 9th MAP) were observed at 5 per cent level of significant. Significant strong positive correlation between leaf chlorophyll content and proline content in leaf (0.85) was observed at 9th MAP. Germplasm Barjahaji, Bhimkal, Bogimanohar and Athiya are considered physiologically more tolerant to moisture deficit which can be used for future breeding programs and the physio-chemical parameters viz., leaf area, chlorophyll content, relative leaf water content and proline content can be considered as physiological indices for drought tolerance.

Electric vehicles coordination for grid balancing using multi-objective Harris Hawks Optimization

The rise of renewables coincides with the shift towards Electrical Vehicles (EVs) posing technical and operational challenges for the energy balance of the local grid. Nowadays, the energy grid cannot deal with a spike in EVs usage leading to a need for more coordinated and grid aware EVs charging and discharging strategies. However, coordinating power flow from multiple EVs into the grid requires sophisticated algorithms and load-balancing strategies as the complexity increases with more control variables and EVs, necessitating large optimization and decision search spaces. In this paper, we propose an EVs fleet coordination model for the day ahead aiming to ensure a reliable energy supply and maintain a stable local grid, by utilizing EVs to store surplus energy and discharge it during periods of energy deficit. The optimization problem is addressed using Harris Hawks Optimization (HHO) considering criteria related to energy grid balancing, time usage preference, and the location of EV drivers. The EVs schedules, associated with the position of individuals from the population, are adjusted through exploration and exploitation operations, and their technical and operational feasibility is ensured, while the rabbit individual is updated with a non-dominated EV schedule selected per iteration using a roulette wheel algorithm. The solution is evaluated within the framework of an e-mobility service in Terni city. The results indicate that coordinated charging and discharging of EVs not only meet balancing service requirements but also align with user preferences with minimal deviations. The assessment of the determined solutions’ quality and efficacy shows promising outcomes, with convergence after 100 iterations reflected in a generational distance of 0.35 and a Pareto front error of 1.01, while the distribution of solutions exhibits strong hypervolume thus covering a significant portion of the objective space.

Are the ecosystem-level evaporative stress indices representative of evaporative stress of vegetation?

Evaporative Stress Index (ESI), also sometimes referred as Evaporative Stress Ratio (ESR), has been widely used as an indicator of vegetation evaporative stress, and is often used to track forest and agriculture droughts. Lower the stress, higher is the value of ESI or ESR. The goal of this study is to assess the suitability of these indices for tracking vegetation evaporative stress. As the dynamics of water loss from vegetation through transpiration (T) can be different than that of evapotranspiration (ET) from the ecosystem, it is hypothesized that ESI or ESR may not be sufficiently representative of the vegetation evaporative stress. Using eddy covariance flux tower data of 518 site years, distributed across 49-sites and 9 land covers globally, our findings reveal underestimation of vegetation evaporative stress by ESI during periods of high vapor pressure deficit (VPD) and overestimation during dry, low-VPD periods. The results highlight the need to improve representativeness of ESI for monitoring vegetation evaporative stress. Notably, this may entail accurate estimation of ecosystem T in systems lacking in-situ data, a challenge that warrants further attention.

ASSESSMENT OF PHYSICAL FITNESS OF MATURE WOMEN WITH DIFFERENT TYPES OF POSTURE

Relevance of the research topic. The systematization and generalization of a wide layer of both theoretical developments and practical achievements in the field of physical culture and sports serve as a basis for stating that maturity is the longest period of ontogenesis, characterized by the tendency for a person to achieve the optimal level of development of his spiritual, intellectual and physical potential. Against this background, the age of maturity in women, according to numerous data from representatives of the scientific community, is a period of motor deficit. The consequences of the latter include, first of all, the gradual unfolding of involutional processes, negative changes in the hormonal background, the appearance of excess weight, a decrease in the elasticity of connective tissue, the appearance of the first signs of structural and functional disorders of the spine and joints. The purpose of the article is to determine the level of physical fitness of women aged 36-40 with different types of posture. Methods. Theoretical analysis of special scientific and methodical literature, pedagogical testing, methods of mathematical statistics. The results of the work. The assessment of physical fitness of women in the second half of mature age showed the following. Firstly, it was found that according to tests of strength, endurance and flexibility, women aged 36-38 were more physically fit, performing pull-ups in a lying position mainly at an average level, tilting the torso forward from a sitting position and lifting the torso in a sitting position at a sufficient level. In contrast, the physical fitness of women aged 39-40 years was much worse, in particular, most of them performed lying pull-ups at a low level, torso bending forward from a sitting position and lifting the torso in a sitting position at an average level. Secondly, the comparison of groups of women aged 36-38 and 39-40 years, taking into account the type of their posture, did not reveal any differences in pairs of different ages of each type. At the same time, it was found that women with normal posture performed much better than the other groups in exercises such as flexion and extension of the arms in a lying position, pull-ups in a lying position, and women aged 36-38 years were superior in the test of lifting the torso into a seated position. Accordingly, women with a round, flat back and scoliotic posture were less physically prepared to perform these exercises.

Water Carrying Capacity on Small Islands Tourism: Case Study of the Tidung Islands, Jakarta

This study examines the water carrying capacity of the Tidung Islands, a popular small island tourism destination in Jakarta, Indonesia. The research aims to measure the availability of water resources and assess the balance between water supply and demand, focusing on both domestic and tourism needs. Using a water balance approach, the study analyzes seasonal fluctuations in precipitation, evapotranspiration, runoff, and changes in water storage. The results indicate that while Tidung Islands currently have a surplus of water resources, projected increases in population and tourism will lead to periods of water deficit by 2040. The study highlights the critical need for sustainable water management practices, including rainwater harvesting, efficient water use, and community involvement in conservation efforts. Implementing these strategies is essential to ensure long-term water security and support the continued growth of tourism and local development in Tidung Islands.

Multidimensional forecasting of precipitation and potential evapotranspiration in the Paranapanema river basin using neural network time series

Spatial and temporal forecasts of the hydrological cycle compartments aiming projections of extreme drought scenarios represent a challenge for the planning, management and monitoring of water resources in order to mitigate potential impacts on the natural environment, civil society and wildlife under climate change. Machine Learning (ML) methods can help in this task, combining constant updating of model information and further scenarios evaluation. This study investigated the application of multidimensional forecast of precipitation and potential evapotranspiration at the Paranapanema River Basin (PRB) for the years 2023–2025. PRB is a region that provides hydrological, energy and agricultural resources, located in the southeast of Brazil that has suffered several problems related to water deficit and stress as well as droughts in the last 10 years. For these reasons, geospatial technologies such as remote sensing and Geographic Information Systems (GIS) were applied to generate time series between 2001 and early 2023 for a total of 22 Hydrological Planning Units (HPUs) in the PRB. Subsequently, a Neural Network Auto Regression (NNAR) was used to forecast precipitation and potential evapotranspiration of the HPUs in the period 2023–2025, finding for the months of May, June, July and August of 2024 and later in 2025 possible periods of water deficit in the central and northern regions. Finally, a comparative analysis of possible impacts on the agricultural, energy and social sectors based on the forecast developed by the NNAR network is presented, showing possible scenarios for short and mid-term water planning in the PRB.

Ajuste osmótico y rendimiento de dos variedades de palta (Persea americana), Hass y Fuerte, con sistema de riego por goteo, en zona andina del Perú

The cultivation of avocado (Persea Americana) is not only essential from an economic point of view, but also plays a crucial role in the nutrition, health and well-being of populations around the world. The study was carried out in Ayacucho -Peru (latitude: 12° 53' 57'' S, longitude: 74° 16' 55'' W and altitude: 2596 masl), with the objective of evaluating the effect of the use of the technical drip irrigation system on the production and yield of two varieties of avocado, Hass and Fuerte. The study was based on the use of an irrigation system with programming by treatment with avocado plants installed in plots of 500 m² in 6 sectors, with a density of 5 x 5 m, whose age was between 5 to 16 years, of the which were considered 12 plants (6 plants with drip irrigation and 6 plants as a control with gravity irrigation). Irrigation was carried out right at the flowering and production stage, guaranteeing adequate water supply in periods of water deficit, between February and June 2022. The experimental design was a complete randomized block, with six blocks of 20 plants each. The harvest carried out reported yields of 67.96 ± 8.8 t/ha under technical irrigation and 26.42 ± 4.93 t/ha under gravity irrigation, an increase of 157% with respect to the latter. As for the varieties, the Fuerte avocado had the highest yield 49.38 ± 23.06 t/ha compared to the Hass variety (45.0 ± 21.14 t/ha), the maximum yield occurred with drip irrigation for the Fuerte variety (71.09 ± 8.38 t/ha), this is explained by the energy expenditure in the osmotic adjustment potential which drastically decreases the yield potential with traditional gravity irrigation, obtaining a minimum yield in Hass of 25.18 ± 4.44 t/ha.

Modeling the impacts of hot drought on forests in Texas

IntroductionUnder climate change, drought is increasingly affecting forest ecosystems, with subsequent consequences for ecosystem services. An historically exceptional drought in Texas during 2011 caused substantial tree mortality. We used 2004–2019 Forest Inventory and Analysis (FIA) data and state-wide weather data to examine the climatic conditions associated with this elevated tree mortality.MethodsWe measured moisture extremes (wet to dry) using the Standardized Precipitation Evapotranspiration Index (SPEI) at two timescales (12- and 36-month). We quantified heat wave severity using the Heat Wave Magnitude Index daily (HWMId) over the same period. We performed statistical modeling of the relationship between tree mortality and these indices across four Texas regions (Southeast, Northeast, North Central, and South) and for prominent tree genera (Pinus, Juniperus, Quercus, Liquidambar, Prosopis, and Ulmus) as well as selected species: Quercus stellata, Q. virginiana, and Q. nigra.ResultsThe highest tree mortality was observed between 2011 and 2013. We found similarity in the trends of the 12- and 36-month SPEI, both of which exhibited more extreme negative intensities (i.e., drought) in 2011 than other years. Likewise, we found that the extreme heat experienced in 2011 was much greater than what was experienced in other years. The heat waves and drought were more intense in East (i.e., Southeast and Northeast) Texas than Central (i.e., North Central and South) Texas. In gradient boosted regression models, the 36-month SPEI had a stronger empirical relationship with tree mortality than the 12-month SPEI in all regions except South Texas, where HWMId had more influence than SPEI at either timescale. The correlations between moisture extremes, extreme heat, and tree mortality were high; typically, mortality peaked after periods of extreme moisture deficit rather than surplus, suggesting that the mortality was associated with hot drought conditions. The effects of extreme heat outweighed those of SPEI for all tree genera except oaks (Quercus). This was also true for oak species other than water oak (Q. nigra). In generalized additive models, the median trend showed tree mortality of Prosopis was higher during conditions of moderate drought (SPEI36 ∼ –1) or worse, but for Pinus and Quercus, mortality started to become apparent under mild drought conditions (SPEI36 ∼ –0.5). The impacts of extreme heat on the mortality of Juniperus occurred when heat wave magnitude reached the ultra extreme category (HWMId > 80) but occurred at lower magnitude for Liquidambar.DiscussionIn summary, we identified risks to Texas forest ecosystems from exposure to climate extremes. Similar exposure can be expected to occur more frequently under a changing climate.

Radiation, Air Temperature, and Soil Water Availability Drive Tree Water Deficit Across Temporal Scales in Canada's Western Boreal Forest

AbstractChanges are projected for the boreal biome with complex and variable effects on forest vegetation including drought‐induced tree mortality and forest loss. With soil and atmospheric conditions governing drought intensity, specific drivers of trees water stress can be difficult to disentangle across temporal scales. We used wavelet analysis and causality detection to identify potential environmental controls (evapotranspiration, soil moisture, rainfall, vapor pressure deficit, air temperature and photosynthetically active radiation) on daily tree water deficit and on longer periods of tree dehydration in black spruce and tamarack. Daily tree water deficit was controlled by photosynthetically active radiation, vapor pressure deficit, and air temperature, causing greater stand evapotranspiration. Prolonged periods of tree water deficit (multi‐day) were regulated by photosynthetically active radiation and soil moisture. We provide empirical evidence that continued warming and drying will cause short‐term increases in black spruce and tamarack transpiration, but greater drought stress with reduced soil water availability.

Mapping the race between crop phenology and climate risks for wheat in France under climate change.

Climate change threatens food security by affecting the productivity of major cereal crops. To date, agroclimatic risk projections through indicators have focused on expected hazards exposure during the crop's current vulnerable seasons, without considering the non-stationarity of their phenology under evolving climatic conditions. We propose a new method for spatially classifying agroclimatic risks for wheat, combining high-resolution climatic data with a wheat's phenological model. The method is implemented for French wheat involving three GCM-RCM model pairs and two emission scenarios. We found that the precocity of phenological stages allows wheat to avoid periods of water deficit in the near future. Nevertheless, in the coming decades the emergence of heat stress and increasing water deficit will deteriorate wheat cultivation over the French territory. Projections show the appearance of combined risks of heat and water deficit up to 4years per decade under the RCP 8.5 scenario. The proposed method provides a deep level of information that enables regional adaptation strategies: the nature of the risk, its temporal and spatial occurrence, and its potential combination with other risks. It's a first step towards identifying potential sites for breeding crop varieties to increase the resilience of agricultural systems.

ANALISIS NERACA AIR DI TITIK BENDUNG TEMPANG DAERAH IRIGASI PANASEN HULU KABUPATEN MINAHASA

This study aims to conduct a water balance analysis at the Tempang weir point, which is part of the Panasen Hulu Irrigation Area in Minahasa Regency. The Panasen River is the main source of water to meet the irrigation needs in this area. Given the complexity of the dry season period which is difficult to predict, water balance analysis needs to be carried out to calculate the availability and demand of water in the Upper Panasen Irrigation Area, to improve the optimization of water resource management of the Panasen River. Water balance analysis is carried out by calculating the ratio between water availability and water demand. To calculate water availability, the NRECA Modified method is used with available data, namely rainfall data, evapotranspiration, and watershed parameters to calculate the mainstay discharge Q80% and water availability for maintenance of the Q95% River. The calculated water needs are for water needs in the Upper Panasen Irrigation Area. The results of the water balance analysis show periods of water deficit in which water demand exceeds water availability, causing difficulties in meeting irrigation needs. However, there are also periods of surplus water that can be utilized for more effective management of water resources.

Increasingly frequent co-occurrence of drought or pluvial in multiple tributaries of the Yangtze River basin

Drought and pluvial respectively represent a region experiencing a period of water deficit and surplus relative to its normal state. The co-occurrence of drought and pluvial across numerous tributaries of a large river would trigger widespread water shortage and extreme flooding. However, little is known about such spatially concurrent hydrological extremes within large river basins throughout historical periods. Here, we select ten tributaries of the Yangtze River basin (YRB) and employ the VineCopula model to assess the probability of simultaneous drought and pluvial using precipitation observations during 1960–2019 from the perspective of dry and rainy seasons. From 1960 to 1989 to 1990–2019, the probability of two or more tributaries with simultaneous drought decreases from 37.7% to 25.3% during the dry season while increases from 26.6% to 27.3% during the rainy season. For the case of simultaneous pluvial, the probability increases in both dry (from 19.2% to 36.7%) and rainy (from 26.2% to 29.6%) seasons. The notable shifts in the probabilities of concurrent drought and pluvial within YRB highlight an escalating threat of widespread water scarcity and heightened risks of severe flooding. These changes necessitate immediate attention and proactive measures to address the imminent challenges faced by both natural and societal systems along the Yangtze River.

Olive-tree physiological response to biotic and abiotic stress fruit yield, oil quality and tolerance to Anthracnose: Doctoral thesis abstract

The olive tree is highly tolerant to water deficit and in humid climate regions, such as Uruguay, the need to irrigation is questioned. However, Uruguay's climate is characterized by high interannual variability, resulting in periods of water deficit. In the event of a water deficit, plants trigger a series of defense mechanisms to maintain cellular homeostasis, including increased antioxidant enzyme activity and cuticle thickening to prevent transpiration. These responses are common during abiotic stress and biotic stress caused by pathogen infections. Anthracnose, caused by the Colletotrichum complex, is a major disease in olive trees, leading to reduced fruit yield and oil quality. Mild drought stress has been found to activate the basal defense response, enhancing plant tolerance to pathogen infections. Therefore, the hypothesis was that exposing olive plants to moderate water deficit during the lipogenesis stage would trigger the basal defense response, increasing fruit tolerance to biotic stress caused by Colletotrichum acutatum. The study also examined whether this response was sustained under moderate water deficit. Results showed that water deficit induced anatomical and biochemical changes in olive fruits, promoting anthracnose tolerance with reduced incidence and severity of C. acutatum infection both in vitro and in vivo. Fruit weight and pulp/pit ratio decreased in response to water deficit, while cuticle thickness and fruit polyphenol content increased. An induction of enzymes related to hydrogen peroxide scavenging were observed, in particular PER and CAT. This enzymatic activity was induced by the pathogen inoculation treatment and was higher in the non-irrigated treatment. Severe water deficit resulted in significant reductions in fruit weight and oil content, but the fruits exhibited enhanced tolerance to anthracnose infection.

Effects of meteorological factors and groundwater depths on sap flow density of Populus euphratica in a desert oasis, Taklamakan Desert, China.

Accurate estimation of desert vegetation transpiration is key to regulating desert water resources of desert ecosystems. Sap flow density (SFD) can indirectly reflect a tree's transpiration consumption, and it has been affected by climate warming and groundwater depths in desert ecosystems. Sap flow responses to meteorological conditions and groundwater depths are further affected by tree of different sizes. However, how meteorological factors and groundwater depths affects tree sap flow among tree sizes remains poorly understand. In this study, a 50 × 50 m P. euphratica stand was selected as a sample plot in the hinterland of the Taklamakan Desert, and the SFD of P. euphratica of different sizes was measured continuously using the thermal diffusion technique from May to October of 2021 and 2022. The results showed that SFD of large P. euphratica was consistently higher than that of small P. euphratica in 2021 and 2022. and the SFD of P. euphratica was significantly and positively correlated with solar radiation (Rad) and vapor pressure deficit (VPD), and the correlation was higher than that of the air temperature (Ta) and relative humidity (RH), and also showed a strong non-linear relationship. Analysis of the hour-by-hour relationship between P. euphratica SFD and VPD and Rad showed a strong hysteresis. Throughout the growing season, there was no significant relationship between SFD of P. euphratica and groundwater depth, VPD and Rad were still the main controlling factors of SFD in different groundwater depths. However, during the period of relative groundwater deficit, the effect of groundwater depth on the SFD of P. euphratica increased, and the small P. euphratica was more sensitive, indicating that the small P. euphratica was more susceptible to groundwater changes. This study emphasized that Rad and VPD were the main drivers of SFD during the growing season, as well as differences in the response of different sizes of P. euphratica to groundwater changes. The results of the study provide a scientific basis for future modeling of transpiration consumption in P. euphratica forests in desert oases, as well as the regulation and allocation of water resources.

Morphophysiological changes in Bauhinia cheilantha (Bong.) Steud. (Fabaceae) caused by water deficit

Drought-induced alterations often result in plant acclimation responses, though the extent to which these traits adjust, and their true significance remain species-specific and subject to debate. In order to discern which traits exhibit plasticity and essentiality for the species' survival, we studied the morpho-physiological responses of Bauhinia cheilantha seedlings subjected to varying water regimes. We examined modifications in growth patterns, resource allocation and partitioning, morphological traits, organic solute synthesis, relative water content in leaves and roots, and the plasticity index for each trait under different water supply levels. Several traits linked to plant growth were reduced under stress, but those changes were not considered to be plastic. The concentration of organic solutes increased under stress and exhibited a reversible behavior by reducing their levels after re-irrigation. These alterations underscored the significance of such compounds for survival during water deficit periods and the high degree of adaptability. B. cheilantha exhibits morpho-physiological plasticity, as demonstrated by alternating high levels of plasticity in physiological and morphological features, which are associated with moderate drought stress. The study discusses how these changes affect the growth and survival of the species.

KI Increases Tomato Fruit Quality and Water Deficit Tolerance by Improving Antioxidant Enzyme Activity and Amino Acid Accumulation: A Priming Effect or Relief during Stress?

A water deficit can negatively impact fruit yield and quality, affecting critical physiological processes. Strategies to mitigate water deficits are crucial to global food security. Iodine (I) may increase the efficiency of the antioxidant system of plants, but its role against water deficits is poorly understood. This study aimed to evaluate the effectiveness of I in attenuating water deficits and improving fruit quality, investigating whether metabolic responses are derived from a “priming effect” or stress relief during water deficits. Tomato plants were exposed to different concentrations of potassium iodide (KI) via a nutrient solution and subjected to a water deficit. A water deficit in tomatoes without KI reduced their yield by 98%. However, a concentration of 100 μM of KI increased the yield under a water deficit by 28%. This condition is correlated with increased antioxidant activity, photosynthetic efficiency improvement, and malondialdehyde reduction. In addition, the concentration of 100 μM of KI promoted better fruit quality through antioxidant capacity and a decline in the maturation index. Therefore, KI can be an alternative for attenuating water deficits in tomatoes, inducing positive responses during the water deficit period while at the same time improving fruit quality.

Factors and processes controlling hydrochemistry and evaporitic deposits in hypersaline wetland‐shallow lake systems

AbstractThree wetland‐shallow lakes were studied with the aim of analysing the processes and factors that control hydrochemistry and evaporite deposits in them in basins of the Pampean Plain, Argentina. In this sense, water balances and analysis of the water content of the lakes with normalized water difference index were made, and geologic‐geomorphological characteristics and groundwater flows were defined. Groundwater, surface water and evaporite samples were taken, along with sediment samples from wetland‐shallow lakes and surroundings. In situ pH, electrical conductivity and temperature, and laboratory chemical determinations of major ions of the water were measured. x‐ray diffraction (XRD) and scanning electron microscope (SEM)‐energy dispersive spectroscopy (EDS) analyses of evaporite and sediment samples were carried out. The results obtained allow the identification of two different systems. One of them is represented by Leubucó wetland‐lake basin, which is topographically higher and smaller than the other system, with Na‐HCO3 and Na‐Cl/SO4 groundwater inflows, with high concentrations of Ca2+ and Mg2+. In periods of high evaporation, the regional water table drops, and due to its topographic position, the lake dries. These determine the formation of thick layers of halite associated with magnesium salts on surface, and gypsum layers interbedded with clastic sediments. The other system involves de la Sal and Chasilauquen wetland‐lake basins, which have larger extensions. They receive Na‐HCO3 and Na‐Cl/SO4 groundwater inflow, but with low Mg2+ and Ca2+. Their lower topographic position determines that even during deficit periods, the water table intercepts the lakes surface and therefore, lakes have a shallow surface water level almost all the year, which is hypersaline, Na‐Cl type. These systems only have thin evaporite crusts, composed of halite and thenardite at the edges of the lakes, and the formation of Ca‐Mg sulfates is not observed. It is concluded that topographic position, basins size, geology, groundwater inflow and evaporation are the main processes and factors controlling hydrochemistry and evaporitic deposits.

Photosynthetic and hydraulic changes caused by water deficit and flooding stress increase rice’s intrinsic water-use efficiency

Effects of water deficit and flooding stress on rice’s intrinsic water-use efficiency (iWUE) and how iWUE variations are linked to stress-induced physiological changes are poorly understood. Here, we proposed a model-based approach to analyze iWUE across datasets and its relationship with physiological changes, using only leaf gas exchange data and plant hydraulic vulnerability parameters. We applied this approach to a leaf gas exchange dataset of rice, measured during the post-stress period of water deficit and flooding experiments. Results show that water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period, and that these physiological changes altered the relationship between photosynthetic rate and stomatal conductance, leading to an increase in iWUE. Nevertheless, improved iWUE cannot avoid the yield reduction. Interestingly, the stress-induced decrease in Vcmax25 was significantly correlated with the decline in Kmax. The Vcmax25-Kmax relationship was significantly different between the water deficit and flooding treatments, with the slope of the latter being closer to 1:1. Model predicts that stress-induced disproportionate Vcmax25-Kmax co-reduction improved iWUE while maintaining a relatively high intercellular to atmosphere CO2 concentration ratio; this may represent optimal coordination between photosynthetic and hydraulic traits in response to stress. Our work has important implications for using leaf gas exchange data to diagnose variations in iWUE, and for improving our understanding of crop physiological responses to environmental stresses.

Starch-Based Superabsorbent Enhances the Growth and Physiological Traits of Ornamental Shrubs

Periods of heat and water deficit often occur together and are especially dangerous for plants grown in pots, where the substrate volume for roots is limited. The purpose of the present research was to understand the response of shrubs planted in containers to the addition of a starch-based superabsorbent to their growing medium. The growth parameters, physiological conditions, and oxidative stress of Cornus alba ’Aurea’, Hydrangea paniculata ‘Limelight’, and Physocarpus opulifolius ‘Red Baron’ were assessed by adding a hydrogel (1, 2, or 3 g·dm−3) to their growing medium. The use of the superabsorbent improved the stomatal conductance and photosynthetic rate, resulting in better growth parameters. The application of 1 g·dm−3 hydrogel increased the chlorophyll content in hydrangea and ninebark leaves (8%) and increased the content of total soluble sugars in these plants (12% and 15%, respectively). The highest increase in reducing sugars was caused by a dosage of 3 g·dm−3. The lowest dose of hydrogel resulted in a decrease in hydrogen peroxide content in the leaves of all the taxa. The relationship between the contents of biologically active components and oxidative stress proved ambiguous for all the taxa. Oxidative stress was reduced, as evidenced by lower hydrogen peroxide and an increase in pigment content. In summary, a hydrogel dosage of 2 g·dm−3 in the medium could be optimal in pot nursery production using 3 dm3 pots.

Integrating GIS and remote sensing for land use/land cover mapping and groundwater potential assessment for climate-smart cocoa irrigation in Ghana

Although Ghana is a leading global cocoa producer, its production and yield have experienced declines in recent years due to various factors, including long-term climate change such as increasing temperatures and changing rainfall patterns, as well as drought events. With the increasing exposure of cocoa-producing regions to extreme weather events, the vulnerability of cocoa production is also expected to rise. Supplemental irrigation for cocoa farmers has emerged as a viable adaptation strategy to ensure a consistent water supply and enhance yield. However, understanding the potential for surface and groundwater irrigation in the cocoa-growing belt remains limited. Consequently, this study aims to provide decision-support maps for surface and groundwater irrigation potential to aid planning and investment in climate-smart cocoa irrigation. Utilizing state-of-the-art geospatial and remote sensing tools, data, and methods, alongside in-situ groundwater data, we assess the irrigation potential within Ghana's cocoa-growing areas. Our analysis identified a total area of 22,126 km2 for cocoa plantations and 125.2 km2 for surface water bodies within the cocoa-growing regions. The multi-criteria analysis (MCA) revealed that approximately 80% of the study area exhibits moderate to very high groundwater availability potential. Comparing the MCA output with existing borehole locations demonstrated a reasonable correlation, with about 80% of existing boreholes located in areas with moderate to very high potential. Boreholes in very high potential areas had the highest mean yield of 90.7 l/min, while those in low groundwater availability potential areas registered the lowest mean yield of 58.2 l/min. Our study offers a comprehensive evaluation of water storage components and their implications for cocoa irrigation in Ghana. While groundwater availability shows a generally positive trend, soil moisture and surface water have been declining, particularly in the last decade. These findings underline the need for climate-smart cocoa irrigation strategies that make use of abundant groundwater resources during deficit periods. A balanced conjunctive use of surface and groundwater resources could thus serve as a sustainable solution for maintaining cocoa production in the face of climate change.