Photosynthetic efficiency and water retention in okra (Abelmoschus esculentus) contribute to tolerance to single and combined effects of drought and heat stress.

The co-occurrence of drought and heat significantly hampers plant productivity. Although their impacts are well studied, these studies have been based on the effects of individual stressors rather than their combined influence. Okra is crucial for food and nutritional security and livelihoods in many regions, yet it remains under-researched and unimproved.

Biochar addition and reduced irrigation modulates leaf morpho-physiology and biological nitrogen fixation in faba bean-ryegrass intercropping.

Intercropping legume with grass has potential to increase biomass and protein yield via biological N-fixation (BNF) benefits, whereas the joint effects of biochar (BC) coupled with deficit irrigation on intercropping systems remain elusive. A N isotope-labelled experiment was implemented to investigate morpho-physiological responses of faba bean-ryegrass intercrops on low- (550 °C, LTBC) or high-temperature BC (800 °C, HTBC) amended sandy-loam soil under full (FI), deficit (DI) and partial root-zone drying irrigation (PRD). LTBC and HTBC significantly reduced intrinsic water-use efficiency (WUE) by 12 and 14 %, and instantaneous WUE by 8 and 16 %, respectively, in faba bean leaves, despite improved photosynthetic (A) and transpiration rate (T), and stomatal conductance (g).

Rapid and low-cost screening for single and combined effects of drought and heat stress on the morpho-physiological traits of African eggplant (Solanum aethiopicum) germplasm.

Drought and heat are two stresses that often occur together and may pose significant risks to crops in future climates. However, the combined effects of these two stressors have received less attention than single-stressor investigations. This study used a rapid and straightforward phenotyping method to quantify the variation in 128 African eggplant genotype responses to drought, heat, and the combined effects of heat and drought at the seedling stage.

Trade-offs in carbon-degrading enzyme activities limit long-term soil carbon sequestration with biochar addition.

Biochar amendment is one of the most promising agricultural approaches to tackle climate change by enhancing soil carbon (C) sequestration. Microbial-mediated decomposition processes are fundamental for the fate and persistence of sequestered C in soil, but the underlying mechanisms are uncertain. Here, we synthesise 923 observations regarding the effects of biochar addition (over periods ranging from several weeks to several years) on soil C-degrading enzyme activities from 130 articles across five continents worldwide.

Spatiotemporal Winter Wheat Water Status Assessment Improvement Using a Water Deficit Index Derived from an Unmanned Aerial System in the North China Plain.

Agricultural droughts cause a great reduction in winter wheat productivity; therefore, timely and precise irrigation recommendations are needed to alleviate the impact. This study aims to assess drought stress in winter wheat with the use of an unmanned aerial system (UAS) with multispectral and thermal sensors. High-resolution Water Deficit Index (WDI) maps were derived to assess crop drought stress and evaluate winter wheat actual evapotranspiration rate (ET).

Nickel toxicity pretreatment attenuates salt stress by activating antioxidative system and ion homeostasis in tomato (Solanum lycopersicon L.): an interplay from mild to severe stress.

Plants antioxidative system is the first line of defense against oxidative stress caused secondarily by toxic ions under salinity. Plants with pre-activated antioxidative system can better adapt to salinity and can result in higher growth and yield. The current experiment was conducted to assess the adaptation of two tomato genotypes (Riogrande and Green Gold) with pre-activated antioxidative enzymes against salt stress.

Elevational shifts in foliar-soil δ N in the Hengduan Mountains and different potential mechanisms.

The natural abundance of stable nitrogen isotopes (δ N) provides insights into the N dynamics of terrestrial ecosystems, the determination of which is considered an effective approach for gaining a better understanding ecosystem N cycling. However, there is currently little information available regarding the patterns and mechanisms underlying the variation in foliar-soil δ N among mountain ecosystems. In this study, we examined the determinants of foliar-soil δ N in association with N transportation rates along an elevational gradient in the Hengduan Mountains.

Physiological and Growth Responses of Potato ( L.) to Air Temperature and Relative Humidity under Soil Water Deficits.

Drought stress often occurs concurrently with heat stress, yet the interacting effect of high vapor pressure deficit (VPD) and soil drying on the physiology of potato plants remains poorly understood. This study aimed to investigate the physiological and growth responses of potatoes to progressive soil drying under varied VPDs. Potato plants were grown either in four separate climate-controlled greenhouse cells with different VPD levels (viz.

Interactions between biochar, arbuscular mycorrhizal fungi and photosynthetic processes in potato (Solanum tuberosum L.).

Pyrolyzed biomass, generating biochar for use as soil amendment, is recognized as a promising strategy for carbon sequestration. Current understanding of the interactions between biochar, arbuscular mycorrhizal (AM), and plant photosynthesis, in terms of biochemical processes and CO uptake, is fragmentary. The aim of this study was to investigate the effects on photosynthesis in potato including maximum rate of carboxylation by Rubisco (V), maximum rate of electron transport rate for RuBP-regeneration (J), mesophyll conductance (g) and other plant traits.

Biochar and alternate wetting-drying cycles improving rhizosphere soil nutrients availability and tobacco growth by altering root growth strategy in Ferralsol and Anthrosol.

Biochar has been advocated as a sustainable and eco-friendly practice to improve soil fertility and crop productivity which could aid in the mitigation of climate change. Nonetheless, the combined effects of biochar and irrigation on tobacco growth and soil nutrients in diverse soil types have been incompletely explored. We applied a split-root experiment to investigate the impacts of amendment with 2% softwood- (WBC) and wheat-straw biochar (SBC) on growth responses and rhizosphere soil nutrients availability of tobacco plants grown in a Ferralsol and an Anthrosol.

Domestic wastewater infiltration process in desert sandy soil and its irrigation prospect analysis.

Although domestic wastewater and its reclaimed water are alternative water resources in arid region, investigation of their negative effect must be done to prevent environmental pollution. In this paper, a short-term column experiment was conducted to simulate the infiltration process of wastewater in desert soil. Alfalfa was planted and irrigated with fresh water for control (CK), tertiary treated domestic wastewater (TTW), secondary treated domestic wastewater (STW) and raw domestic wastewater untreated (RW).

New Rootsnap Sensor Reveals the Ameliorating Effect of Biochar on Root Growth Dynamics of Maize in Sandy Soil.

We investigated if subsoil constraints to root development imposed by coarse sand were affected by drought and biochar application over two seasons. Biochar was applied to the subsoil of pots at 20-50 cm depth in concentrations of 0%, 1%, 2%, and 3% (B0, B1, B2, and B3). Maize was grown in the same pots 1 week and 12 months after biochar application.

Plants with lengthened phenophases increase their dominance under warming in an alpine plant community.

Predicting how shifts in plant phenology affect species dominance remains challenging, because plant phenology and species dominance have been largely investigated independently. Moreover, most phenological research has primarily focused on phenological firsts (leaf-out and first flower dates), leading to a lack of representation of phenological lasts (leaf senescence and last flower) and full phenological periods (growing season length and flower duration). Here, we simultaneously investigated the effects of experimental warming on different phenological events of various species and species dominance in an alpine meadow on the Tibetan Plateau.

Rice yield estimation based on forecasting the future condition of groundwater salinity in the Caspian coastal strip of Guilan Province, Iran.

Irrigation water salinity is one of the factors that reduces agricultural production. Guilan Province is one of the most important rice-producing areas in Iran where groundwater is used for irrigation. The temporal and spatial variations of groundwater salinity were studied in the coastal strip covering 4285 km of the province using data from 73 wells, as well as its estimated effect on the rice yield.

Integrated modelling of crop production and nitrate leaching with the Daisy model.

An integrated modelling strategy was designed and applied to the Soil-Vegetation-Atmosphere Transfer model Daisy for simulation of crop production and nitrate leaching under pedo-climatic and agronomic environment different than that of model original parameterisation. The points of significance and caution in the strategy are: •Model preparation should include field data in detail due to the high complexity of the soil and the crop processes simulated with process-based model, and should reflect the study objectives. Inclusion of interactions between parameters in a sensitivity analysis results in better account for impacts on outputs of measured variables.

Low-temperature leaf photosynthesis of a Miscanthus germplasm collection correlates positively to shoot growth rate and specific leaf area.

Background And Aims: The C4 perennial grass miscanthus has been found to be less sensitive to cold than most other C4 species, but still emerges later in spring than C3 species. Genotypic differences in miscanthus were investigated to identify genotypes with a high cold tolerance at low temperatures and quick recovery upon rising temperatures to enable them to exploit the early growing season in maritime cold climates. Suitable methods for field screening of cold tolerance in miscanthus were also identified.

Cytosolic glutamine synthetase is important for photosynthetic efficiency and water use efficiency in potato as revealed by high-throughput sequencing QTL analysis.

WUE phenotyping and subsequent QTL analysis revealed cytosolic GS genes importance for limiting N loss due to photorespiration under well-watered and well-fertilized conditions. Potato (Solanum tuberosum L.) closes its stomata at relatively low soil water deficits frequently encountered in normal field conditions resulting in unnecessary annual yield losses and extensive use of artificial irrigation.

Interactive effect of biochar and plant growth-promoting bacterial endophytes on ameliorating salinity stress in maize.

The objective of this work was to study the interactive effect of biochar and plant growth-promoting endophytic bacteria containing 1-aminocyclopropane-1-carboxylate deaminase and exopolysaccharide activity on mitigating salinity stress in maize (Zea mays L.). The plants were grown in a greenhouse under controlled conditions, and were subjected to separate or combined treatments of biochar (0% and 5%, w/w) and two endophytic bacterial strains (Burkholderia phytofirmans (PsJN) and Enterobacter sp.

Ionic and photosynthetic homeostasis in quinoa challenged by salinity and drought - mechanisms of tolerance.

Quinoa (Chenopodium quinoa Willd.) grown under field conditions was exposed to five irrigation water salinities (0, 10, 20, 30 and 40dSm-1; 4:1 NaCl:CaCl2 molar ratio) from flowering, and divided between full irrigation and progressive drought (PD) during seed filling. Quinoa demonstrated homeostatic mechanisms which contributed to quinoa's extraordinary tolerance.

Leaching of human pathogens in repacked soil lysimeters and contamination of potato tubers under subsurface drip irrigation in Denmark.

The risk for contamination of potatoes and groundwater through subsurface drip irrigation with low quality water was explored in 30 large-scale lysimeters containing repacked coarse sand and sandy loam soils. The human pathogens, Salmonella Senftenberg, Campylobacter jejuni and Escherichia coli O157:H7, and the virus indicator Salmonella Typhimurium bacteriophage 28B, were added weekly through irrigation tubes for one month with low irrigation rates (8 mm per week). In the following six months lysimeters were irrigated with groundwater free of pathogens.

Physiological responses of potato (Solanum tuberosum L.) to partial root-zone drying: ABA signalling, leaf gas exchange, and water use efficiency.

The physiological responses of potato (Solanum tuberosum L. cv. Folva) to partial root-zone drying (PRD) were investigated in potted plants in a greenhouse (GH) and in plants grown in the field under an automatic rain-out-shelter.

Pod set related to photosynthetic rate and endogenous ABA in soybeans subjected to different water regimes and exogenous ABA and BA at early reproductive stages.

Background And Aims: The physiological reasons for reduced pod set in soybean (Glycine max) caused by drought during anthesis are not established. The objective of this study was to investigate the involvement of photosynthetic rate (A), pod endogenous abscisic acid (ABA) and exogenously applied ABA and 6-benzylaminopurine (BA) in regulating pod set in soybean during drought.

Methods: Two pot experiments were done in a controlled-environment glasshouse.

Loss of pod set caused by drought stress is associated with water status and ABA content of reproductive structures in soybean.

Drought stress occurring during flowering and early pod expansion decreases pod set in soybean (Glycine max L. Merr.).

Hydraulic and chemical signals in the control of leaf expansion and stomatal conductance in soybean exposed to drought stress.

Both hydraulic and chemical signals are probably important in regulating leaf growth and stomatal conductance of soybean (Glycine max L. Merr.) under drought stress.