[Effects of soil relative water content on growth characteristics of Armillaria spp. and seedling production of Gastrodia elata f. glauca].

The seedling survival rate, yield, and individual weight of Gastrodia elata is closely related to the soil relative water content(RWC) and the growth characteristics of the associated fungi Armillaria spp. This study explored the effects of the soil RWC on the growth characteristics of Armillaria spp. and the seedling production of G. elata f. glauca, aiming to provide guidance for breeding G. elata f. glauca and selecting elite strains of Armillaria. According to the growth characteristics on the medium for activation, thirty strains of Armillaria were classified into 4 clusters. Two strains with good growth indicators were selected from each cluster and cultiva-ted with immature tuber(Mima) and the branches of the broad-leaved trees in a water-controlled box. The results showed that the Armillaria clusters with uniaxial branches of rhizoid cords, such as clusters Ⅲ and Ⅳ, were excellent clusters in symbiosis with G. elata f. glauca. The soil RWC had significant effects on the growth characteristics of Armillaria strains and the seedling survival rate, yield, and individual weight of G. elata f. glauca. The growth characteristics of Armillaria strains and the seedling survival rate, yield, and individual weight of G. elata f. glauca in the case of the soil RWC being 75% were significantly better than those in the case of other soil RWC. Cultivating Mima with elite strains of Armillaria, together with branches of broad-leaved trees, in the greenhouses with the artificial control of the soil RWC, can achieve efficient seedling production and Mima utilization of G. elata f. glauca.

Do the expected heatwaves pose a threat to lichens?: Linkage between a passive decline in water content in thalli and response to heat stress.

Being poikilohydric, lichens are inherently exposed to alternating desiccation and hydration cycles. They can exhibit extraordinary resistance to extreme temperatures in a dehydrated state but thermal thresholds for hydrated lichens are lower. The ability of the lichen Cetraria aculeata to recovery after high temperature treatment (40°C, 60°C) at different air humidity levels (relative humidity [RH]: <15%, 25%, 50%, 75%, ≅100%) was examined to find a linkage between passive dehydration of the lichen and its physiological resistance to heat stress. The response to heating was determined by measuring parameters related to photosynthesis and respiration after 2- and 24-h recovery. A higher RH level resulted in a slower decline in relative water content (RWC) in hydrated thalli. In turn, the stress resistance of active thalli depended on the ambient humidity and associated RWC reduction. Elevated temperature had a negative impact on bioenergetic processes, but only an unnatural state of permanent full hydration during heat stress resulted in a lethal effect. Hydrated lichen thalli heated at 40°C and 50% relative humidity (RH) tended to be least susceptible to stress-induced damage. Although atypical climatic conditions may lead lichens to lethal thresholds, the actual likelihood of deadly threat to lichens due to heat events per se is debatable.

Individual and interactive effects of amino acid and paracetamol on growth, physiological and biochemical aspects of Brassica napus L. under drought conditions.

Drought stress poses a significant threat to Brassica napus (L.), impacting its growth, yield, and profitability. This study investigates the effects of foliar application of individual and interactive pharmaceutical (Paracetamol; 0 and 250 mg L-1) and amino acid (0 and 4 ml/L) on the growth, physiology, and yield of B. napus under drought stress. Seedlings were subjected to varying levels of drought stress (100% field capacity (FC; control) and 50% FC). Sole amino acid application significantly improved chlorophyll content, proline content, and relative water contents, as well as the activities of antioxidative enzymes (such as superoxide dismutase and catalase) while potentially decreased malondialdehyde and hydrogen peroxide contents under drought stress conditions. Pearson correlation analysis revealed strong positive correlations between these parameters and seed yield (R2 = 0.8-1), indicating their potential to enhance seed yield. On the contrary, sole application of paracetamol exhibited toxic effects on seedling growth and physiological aspects of B. napus. Furthermore, the combined application of paracetamol and amino acids disrupted physio-biochemical functions, leading to reduced yield. Overall, sole application of amino acids proves to be more effective in ameliorating the negative effects of drought on B. napus.

Aquaporin mediated silicon-enhanced root hydraulic conductance is benefit to cadmium dilution in tobacco seedlings.

Numerous studies shown that silicon (Si) enhanced plants' resistance to cadmium (Cd). Most studies primarily focused on investigating the impact of Si on Cd accumulation. However, there is a lack of how Si enhanced Cd resistance through regulation of water balance. The study demonstrated that Si had a greater impact on increasing fresh weight compared to dry weight under Cd stress. This effect was mainly attributed to Si enhanced plant relative water content (RWC). Plant water content depends on the dynamic balance of water loss and water uptake. Our findings revealed that Si increased transpiration rate and stomatal conductance, leading to higher water loss. This, in turn, negatively impacted water content. The increased water content caused by Si could ascribe to improve root water uptake. The Si treatment significantly increased root hydraulic conductance (Lpr) by 131 % under Cd stress. This enhancement was attributed to Si upregulation genes expression of NtPIP1;1, NtPIP1;2, NtPIP1;3, and NtPIP2;1. Through meticulously designed scientific experiments, this study showed that Si enhanced AQP activity, leading to increased water content that diluted Cd concentration and ultimately improved plant Cd resistance. These findings offered fresh insights into the role of Si in bolstering plant resistance to Cd.

A Solanum lycopersicum polyamine oxidase contributes to the control of plant growth, xylem differentiation, and drought stress tolerance.

Polyamines are involved in several plant physiological processes. In Arabidopsis thaliana, five FAD-dependent polyamine oxidases (AtPAO1 to AtPAO5) contribute to polyamine homeostasis. AtPAO5 catalyzes the back-conversion of thermospermine (T-Spm) to spermidine and plays a role in plant development, xylem differentiation, and abiotic stress tolerance. In the present study, to verify whether T-Spm metabolism can be exploited as a new route to improve stress tolerance in crops and to investigate the underlying mechanisms, tomato (Solanum lycopersicum) AtPAO5 homologs were identified (SlPAO2, SlPAO3, and SlPAO4) and CRISPR/Cas9-mediated loss-of-function slpao3 mutants were obtained. Morphological, molecular, and physiological analyses showed that slpao3 mutants display increased T-Spm levels and exhibit changes in growth parameters, number and size of xylem elements, and expression levels of auxin- and gibberellin-related genes compared to wild-type plants. The slpao3 mutants are also characterized by improved tolerance to drought stress, which can be attributed to a diminished xylem hydraulic conductivity that limits water loss, as well as to a reduced vulnerability to embolism. Altogether, this study evidences conservation, though with some significant variations, of the T-Spm-mediated regulatory mechanisms controlling plant growth and differentiation across different plant species and highlights the T-Spm role in improving stress tolerance while not constraining growth.

Physio-Biochemical Insights into the Cold Resistance Variations among Nectarine (Prunus persica (L.) Batsch var. nectarina) Cultivars.

Cold stress occurs in late winter and early spring threatens greatly the nectarine industry. In this study, the semi-lethal low temperature (LT50) and thirteen cold resistance related parameters of five nectarine cultivars, including 'Nonglehong little princess' (LP), 'Luyou No. 5' (LY), 'Nonglehong No. 6' (NL), 'Zhongyou No. 20' (ZY) and 'Qiuhongzhu' (QH), were determined. Based on these parameters, they were categorized into high-(HR, including NL and LP), moderate-(MR, including QH) and low-cold resistant (LR, including ZY and LY) groups. The relative water (RW), proline (PRO), soluble sucrose (SS) and soluble protein (SP) contents, and superoxide dismutase (SOD) and peroxidase (POD) activities of HR cultivars were higher while their relative electronic conductivity (RE), malondialdehyde (MDA) and gibberellin acid (GA3) contents and catalase (CAT) activity were lower than other cultivars during natural overwintering. Redundancy analysis revealed that the lowest temperature in a day (LT) and LT50 significantly explains 69.8% and 10.9% of these physiological variables, respectively. Moreover, GA3 and indoleacetic acid (IAA) contents and CAT activity were positively correlated, while PRO, SS, ABA and RW contents were negatively correlated with both LT and LT50. Our study will be helpful in understanding the cold resistance variations of nectarine germplasm resources.

Physiological and biochemical effects of 24-Epibrassinolide on drought stress adaptation in maize (Zea mays L.).

Maize production and productivity are affected by drought stress in tropical and subtropical ecologies, as the majority of the area under maize cultivation in these ecologies is rain-fed. The present investigation was conducted to study the physiological and biochemical effects of 24-Epibrassinolide (EBR) as a plant hormone on drought tolerance in maize. Two maize hybrids, Vivek hybrid 9 and Bio 9637, were grown under three different conditions: (i) irrigated, (ii) drought, and (iii) drought+EBR. A total of 2 weeks before the anthesis, irrigation was discontinued to produce a drought-like condition. In the drought+EBR treatment group, irrigation was also stopped, and in addition, EBR was applied as a foliar spray on the same day in the drought plots. It was observed that drought had a major influence on the photosynthesis rate, membrane stability index, leaf area index, relative water content, and leaf water potential; this effect was more pronounced in Bio 9637. Conversely, the activities of antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) increased in both hybrids under drought conditions. Specifically, Vivek hybrid 9 showed 74% higher CAT activity under drought conditions as compared to the control. Additionally, EBR application further enhanced the activity of this enzyme by 23% compared to plants under drought conditions. Both hybrids experienced a significant reduction in plant girth due to drought stress. However, it was found that exogenously applying EBR reduced the detrimental effects of drought stress on the plant, and this effect was more pronounced in Bio 9637. In fact, Bio 9637 treated with EBR showed an 86% increase in proline content and a 70% increase in glycine betaine content compared to untreated plants under drought conditions. Taken together, our results suggested EBR enhanced tolerance to drought in maize hybrids. Hence, pre-anthesis foliar application of EBR might partly overcome the adverse effects of flowering stage drought in maize.

New Hybrid Ethylenediurea (EDU) Derivatives and Their Phytoactivity.

Natural and synthetic phytohormones are widely used in agriculture. The synthetic cytokinin ethylenediurea (EDU) induces protection in plants against ozone phytotoxicity. In our study, new hybrid derivatives of EDU were synthesized and tested for phytoactivity. The germination potential (Gp), germination of seeds (G), and relative water content in leaves (RWC), characterizing the drought resistance of plants, were determined. The results of laboratory studies showed that EDU and its hybrid derivatives have a positive effect on root length, the growth and development of shoots, as well as the ability of plants to tolerate stress caused by a lack of water.

Photosynthetic acclamatory response of Panicum antidotale Retz. populations to root zone desiccation stress / Reação fotossintética aclamatória de Panicum antidotale Retz. populações submetidas ao estresse da dessecação da zona radicular

Abstract Growth of plants is severely reduced due to water stress by affecting photosynthesis including photosystem II (PSII) activity and electron transport. This study emphasised on comparative and priority targeted changes in PSII activity due to progressive drought in seven populations of Panicum antidotale (P. antidotale) collected from Cholistan Desert and non-Cholistan regions. Tillers of equal growth of seven populations of P. antidotale grown in plastic pots filled with soil were subjected progressive drought by withholding water irrigation for three weeks. Progressive drought reduced the soil moisture content, leaf relative water content, photosynthetic pigments and fresh and dry biomass of shoots in all seven populations. Populations from Dingarh Fort, Dingarh Grassland and Haiderwali had higher growth than those of other populations. Cholistani populations especially in Dingarh Grassland and Haiderwali had greater ability of osmotic adjustment as reflected by osmotic potential and greater accumulation of total soluble proteins. Maximum H2O2 under water stress was observed in populations from Muzaffargarh and Khanewal but these were intermediate in MDA content. Under water stress, populations from Muzaffargarh and Dingarh Fort had greater K+ accumulation in their leaves. During progressive drought, non-Cholistani populations showed complete leaf rolling after 23 days of drought, and these populations could not withstand with more water stress condition while Cholistani populations tolerated more water stress condition for 31 days. Moreover, progressive drought caused PSII damages after 19 days and it became severe after 23 days in non-Cholistani populations of P. antidotale than in Cholistani populations.

Resumo O crescimento das plantas é severamente reduzido devido ao estresse hídrico, afetando a fotossíntese, incluindo a atividade do fotossistema II (PSII) e o transporte de elétrons. Este estudo enfatizou as mudanças comparativas e prioritárias na atividade do PSII devido à seca progressiva em sete populações de Panicum antidotale (P. antidotale) coletadas no Deserto do Cholistão e regiões fora do Cholistão. Perfilhos de igual crescimento de sete populações de P. antidotale cultivadas em vasos de plástico cheios de solo foram submetidos à seca progressiva, retendo a irrigação com água por três semanas. A seca progressiva reduziu o teor de umidade do solo, teor de água relativo nas folhas, pigmentos fotossintéticos e biomassa fresca e seca dos brotos em todas as sete populações. Populações de Dingarh Fort, Dingarh Grassland e Haiderwali tiveram maior crescimento do que as de outras populações. As populações de Cholistani, especialmente em Dingarh Grassland e Haiderwali, apresentaram maior capacidade de ajuste osmótico, refletido pelo potencial osmótico e maior acúmulo de proteínas solúveis totais. H2O2 máximo sob estresse hídrico foi observado em populações de Muzaffargarh e Khanewal, mas estas foram intermediárias no conteúdo de MDA. Sob estresse hídrico, as populações de Muzaffargarh e Dingarh Fort tiveram maior acúmulo de K+ em suas folhas. Durante a seca progressiva, as populações não cholistanesas mostraram rolagem completa das folhas após 23 dias de seca, e essas populações não conseguiram suportar mais condições de estresse hídrico, enquanto as populações cholistani toleraram mais condições de estresse hídrico por 31 dias. Além disso, a seca progressiva causou danos ao PSII após 19 dias e tornou-se severa após 23 dias em populações não cholistanesas de P. antidotale do que em populações cholistanesas.

Photosynthetic acclamatory response of Panicum antidotale Retz. populations to root zone desiccation stress

Abstract Growth of plants is severely reduced due to water stress by affecting photosynthesis including photosystem II (PSII) activity and electron transport. This study emphasised on comparative and priority targeted changes in PSII activity due to progressive drought in seven populations of Panicum antidotale (P. antidotale) collected from Cholistan Desert and non-Cholistan regions. Tillers of equal growth of seven populations of P. antidotale grown in plastic pots filled with soil were subjected progressive drought by withholding water irrigation for three weeks. Progressive drought reduced the soil moisture content, leaf relative water content, photosynthetic pigments and fresh and dry biomass of shoots in all seven populations. Populations from Dingarh Fort, Dingarh Grassland and Haiderwali had higher growth than those of other populations. Cholistani populations especially in Dingarh Grassland and Haiderwali had greater ability of osmotic adjustment as reflected by osmotic potential and greater accumulation of total soluble proteins. Maximum H2O2 under water stress was observed in populations from Muzaffargarh and Khanewal but these were intermediate in MDA content. Under water stress, populations from Muzaffargarh and Dingarh Fort had greater K+ accumulation in their leaves. During progressive drought, non-Cholistani populations showed complete leaf rolling after 23 days of drought, and these populations could not withstand with more water stress condition while Cholistani populations tolerated more water stress condition for 31 days. Moreover, progressive drought caused PSII damages after 19 days and it became severe after 23 days in non-Cholistani populations of P. antidotale than in Cholistani populations.

Resumo O crescimento das plantas é severamente reduzido devido ao estresse hídrico, afetando a fotossíntese, incluindo a atividade do fotossistema II (PSII) e o transporte de elétrons. Este estudo enfatizou as mudanças comparativas e prioritárias na atividade do PSII devido à seca progressiva em sete populações de Panicum antidotale (P. antidotale) coletadas no Deserto do Cholistão e regiões fora do Cholistão. Perfilhos de igual crescimento de sete populações de P. antidotale cultivadas em vasos de plástico cheios de solo foram submetidos à seca progressiva, retendo a irrigação com água por três semanas. A seca progressiva reduziu o teor de umidade do solo, teor de água relativo nas folhas, pigmentos fotossintéticos e biomassa fresca e seca dos brotos em todas as sete populações. Populações de Dingarh Fort, Dingarh Grassland e Haiderwali tiveram maior crescimento do que as de outras populações. As populações de Cholistani, especialmente em Dingarh Grassland e Haiderwali, apresentaram maior capacidade de ajuste osmótico, refletido pelo potencial osmótico e maior acúmulo de proteínas solúveis totais. H2O2 máximo sob estresse hídrico foi observado em populações de Muzaffargarh e Khanewal, mas estas foram intermediárias no conteúdo de MDA. Sob estresse hídrico, as populações de Muzaffargarh e Dingarh Fort tiveram maior acúmulo de K+ em suas folhas. Durante a seca progressiva, as populações não cholistanesas mostraram rolagem completa das folhas após 23 dias de seca, e essas populações não conseguiram suportar mais condições de estresse hídrico, enquanto as populações cholistani toleraram mais condições de estresse hídrico por 31 dias. Além disso, a seca progressiva causou danos ao PSII após 19 dias e tornou-se severa após 23 dias em populações não cholistanesas de P. antidotale do que em populações cholistanesas.

Nitric Oxide (NO) Improves Wheat Growth under Dehydration Conditions by Regulating Phytohormone Levels and Induction of the Expression of the TADHN Dehydrin Gene.

Nitric oxide (NO) is a universal signaling molecule with important regulatory functions in the plant's life cycle and adaptation to a wide spectrum of environmental stresses including drought. The effect of pre-sowing seed treatment with the donor of NO sodium nitroprusside (SNP, 200 µM) on wheat Triticum aestivum L. plants subjected to dehydration (PEG-8000, 12%) was investigated. SNP pretreatment stimulated germination and seedling growth in normal conditions and protected them under dehydration. These effects were confirmed by percentage of seed germination, changes in fresh and dry weight of 5-6-day-old seedlings, as well as by seedlings' linear dimensions, visual appearance, and mitotic index of the root apical meristem. Assessment of the transpiration intensity (TI) and relative water content (RWC) showed that SNP pretreatment helped to maintain the water status of seedlings subjected to dehydration stress. The data obtained by enzyme-linked immunosorbent assay (ELISA) suggested that the positive effects of SNP may be due to its influence on the phytohormonal system. SNP pretreatment induced an increase in the level of indolylacetic acid (IAA) and especially cytokinins (CK), while essential changes in ABA content were not detected. Water deficiency caused a substantial increase in ABA content and a decrease in the levels of CK and IAA. Pre-sowing SNP treatment decreased stress-induced fluctuations in the content of all studied phytohormones. Using reverse-transcription PCR (RT-PCR), we obtained data on the increase in expression of the TADHN dehydrin gene in SNP-pretreated seedlings under normal and, especially, under dehydration conditions. These findings may indicate the participation of dehydrins in NO-induced defense reactions in wheat plants under water stress. Furthermore, exogenous NO had a stabilizing effect on membrane cellular structures, as evidenced by the reduction of electrolyte leakage (EL) levels and malondialdehyde (MDA) content in dehydrated wheat seedlings under the influence of pre-sowing SNP treatment.

Role of WSOCs and pH on Ammonium Nitrate Aerosol Efflorescence: Insights into Secondary Aerosol Formation.

Efflorescence of ammonium nitrate (AN) aerosols significantly impacts atmospheric secondary aerosol formation, climate, and human health. We investigated the effect of representative water-soluble organic compounds (WSOCs) (sucralose (SUC), glycerol (GLY), and citric acid (CA) on AN:WSOC aerosol efflorescence using vacuum Fourier transform infrared spectroscopy. Combining efflorescence relative humidity (ERH) measurements, heterogeneous nucleation rates, and model predictions, we found that aerosol viscosity, correlating with molecular diffusion, effectively predicted ERH variations among the AN:WSOC aerosols. WSOCs with higher viscosity (SUC and CA) hindered efflorescence, while GLY with a lower viscosity showed a minor effect. At a low AN:CA molar ratio (10:1), CA promoted ERH, likely due to CA crystallization. Increasing the droplet pH inhibited AN:CA aerosol efflorescence. In contrast, for AN:SUC and AN:GLY aerosols, efflorescence is pH-insensitive. With the addition of trivial sulfate, AN:SUC droplets exhibited two-stage efflorescence, coinciding with ammonium sulfate and AN efflorescence. Given the atmospheric abundance, the morphology, phase, and mixing state of nitrate aerosols are significant for atmospheric chemistry and physics. Our results suggest that AN:WSOCs aerosols can exist in the amorphous phase in the atmosphere, with efflorescence behavior depending on the aerosol composition, viscosity, pH, and the cation and anion interactions in a complex manner.

Assessment of air pollution tolerance potential of selected dicot tree species for urban forestry.

Air pollution is one of the killers of our age especially for the urban areas. Urban forestry which involves planting more trees has been considered as one of the prominent strategies to mitigate air pollution. Identification of trees tolerant to air pollution is important for plantation drives being organized across the country. The present study aimed to compare the air pollution tolerance potential of 46 tree species growing in Guru Nanak Dev University (GNDU) campus, Amritsar, using two indices, viz., Air Pollution Tolerance Index (APTI) and Anticipated Performance Index (API). APTI is based on four biochemical parameters, viz., relative water content, leaf extract pH, total chlorophyll, and ascorbic acid contents of leaf samples, whereas API takes into consideration morphological and socioeconomic values of plant species along with their APTI. Based on APTI values calculated for 46 tree species, only 2 tree species, viz., Psidium guajava (46.26) and Cassia fistula (41.83), were found to be tolerant to air pollution, while 25 species showed intermediate tolerance. API scores revealed one tree species, namely, P. guajava, as an excellent performer, 8 species as very good performers, and 28 species as moderate to good performers against air pollution. In conclusion, tree species like Alstonia scholaris, C. fistula, Ficus tsjakela, Grevillea robusta, Kigelia africana, Mangifera indica, Melia azedarach, P. guajava, Pongamia pinnata, Pterospermum acerifolium, Putranjiva roxburghii, Syzygium cumini, Terminalia arjuna, and Toona ciliata can be considered as most desirable for plantations in areas around GNDU campus.

The Effects of Seed Pretreatment with Endophytic Bacteria Bacillus subtilis on the Water Balance of Spring and Winter Wheat Seedlings under Short-Time Water Deficit.

We investigated the effect of pre-sowing seed treatment with endophytic Bacillus subtilis 10-4 (B. subtilis) on spring and winter wheat (Triticum aestivum L.; cultivars Ekada-70 (Ek) and Scepter (Sc), respectively) growth and tolerance under 1-24 h of drought stress, modulated by 12% polyethylene glycol 6000 (PEG). The results showed that drought decreased transpiration intensity (TI), root relative water content (RWC), osmotic potential (Ψπ) of cell sap, and induced proline accumulation and electrolyte leakage (EL) in both wheat cultivars. It was revealed that Sc was more responsive to PEG and B. subtilis treatments than Ek. Under drought, Ek did not significantly change root length, shoot height, or dry biomass. The pretreatment of wheat plants with B. subtilis performed significantly better under drought conditions through the enhanced TI, RWC, and Ψπ of the cell sap in comparison with the plants treated with 12% PEG alone. B. subtilis also reduced stress-caused EL, especially in the Sc cultivar. Under water deficit wheat seedlings, pretreated with B. subtilis, have a higher proline accumulation in comparison to untreated stressed plants. Taken together, our results demonstrate the crucial role of endophytic B. subtilis in ameliorating the adverse effects of water stress on the water balance of both winter and spring wheat cultivars.

Air mapping during COVID-19 and association between air pollutants and physiochemical parameters of the plants using structural equal modeling: a case study.

In urban areas around the world, air pollution introduced by vehicular movement is a key concern. However, restricting vehicular traffic during the COVID-19 shutdown improved air quality to some extent. This study was conducted out in the smart city of Bhubaneswar, which is also the state capital of Odisha, India. The study has tried to map Bhubaneswar by collecting the air quality data before, during, and after the COVID lockdown of six air quality monitoring stations present in Bhubaneswar established under "National Ambient Air Monitoring Program" (NAMP). Furthermore, plants, which are the most vulnerable to air pollution, can show a variety of visible changes depending on their level of sensitivity. Moreover, leaves of Mangifera indica, Monoon longifolium, Azadirachta indica, Millettia pinnata, Aegle marmelos were collected from nearby of six air monitoring stations to assess the "Air Pollution Tolerance Index." M. indica was found to be intermediately tolerant, and all of the other species were found to be sensitive. The structural equation modeling results also revealed a significant relationship between total chlorophyll content, relative water content, ascorbic acid content, leaf extract pH, APTI with species, air quality index, and PM10.

Effects of Salicylic Acid and Macro- and Micronutrients through Foliar and Soil Applications on the Agronomic Performance, Physiological Attributes, and Water Productivity of Wheat under Normal and Limited Irrigation in Dry Climatic Conditions.

Ensuring food security with severe shortages of freshwater and drastic changes in climatic conditions in arid countries requires the urgent development of feasible and user-friendly strategies. Relatively little is known regarding the impacts of the co-application (Co-A) of salicylic acid (SA), macronutrients (Mac), and micronutrients (Mic) through foliar (F) and soil (S) application strategies on field crops under arid and semiarid climatic conditions. A two-year field experiment was designed to compare the impacts of seven (Co-A) treatments of this strategy, including a control, FSA + Mic, FSA + Mac, SSA + FMic, SSA + FSA + Mic, SSA + Mic + FSA, and SSA + Mic + FMac + Mic on the agronomic performance, physiological attributes, and water productivity (WP) of wheat under normal (NI) and limited (LMI) irrigation conditions. The results reveal that the LMI treatment caused a significant reduction in various traits related to the growth (plant height, tiller and green leaf numbers, leaf area index, and shoot dry weight), physiology (relative water content and chlorophyll pigments), and yield components (spike length, grain weight and grain numbers per spike, thousand-grain weight, and harvest index) of wheat by 11.4-47.8%, 21.8-39.8%, and 16.4-42.3%, respectively, while WP increased by 13.3% compared to the NI treatment. The different Co-A treatments have shown a 0.2-23.7%, 3.6-26.7%, 2.3-21.6%, and 12.2-25.0% increase in various traits related to growth, physiology, yield, and WP, respectively, in comparison to the control treatment. The SSA+ FSA + Mic was determined as the best treatment that achieved the best results for all studied traits under both irrigation conditions, followed by FSA + Mic and SSA + Mic + FSA under LMI in addition to FSA + Mac under NI conditions. It can be concluded that the Co-A of essential plant nutrients along with SA accomplished a feasible, profitable, and easy-to-use strategy to attenuate the negative impacts of deficit irrigation stress, along with the further improvement in the growth and production of wheat under NI conditions.

Potential application of spectral indices for olive water status assessment in (semi-)arid regions: A case study in Khuzestan Province, Iran.

Spectral indices can be used as fast and non-destructive indicators of plant water status or stress. It is the objective of the present study to evaluate the feasibility of using several spectral indices including water index (WI) and normalized spectral water indices 1-5 (NWI 1-5) to estimate water status in olive trees in arid regions in Iran. The experimental treatments involved two olive cultivars (Koroneiki and T2) and four irrigation regimes (irrigated with 100%, 85%, 70%, and 55% estimated crop evapotranspiration [ETc]). The results obtained showed that olive trees subjected to the different irrigation regimes of 85%, 70%, and 55% ETc experienced soil water content (SWC) deficits by 4.5%, 12%, and 20.5% that of the control, respectively. Significant differences were observed among the treatments with respect to measured relative water content (RWC), SWC, and the spectral indices of WI and NWI 1-5. The normalized spectral indices combining NIR and NIR wavelengths were found more effective in tracking changes in RWC and SWC than those that combine NIR and VIS or VIS and VIS wavelengths, respectively. Spectral indices were closely and significantly associated with RWC (.63**

Rhizobacterial inoculation to improve the responses of olive cultivars to drought stress.

Tunisia is known as an underprivileged country in water resources, and water scarcity is evident in certain regions. In the long term, this situation could become more exacerbated, considering the increased risk of aridity. In this context, this work was carried out to study and compare the ecophysiological behavior of five olive cultivars facing drought stress and to evaluate the contribution of rhizobacteria to mitigate the effects of drought stress on these cultivars. The results showed a significant decrease in the relative water content (RWC) with the lowest percentage recorded for the 'Jarboui' cultivar (RWC = 37%), and the highest percentage was registered for the 'Chemcheli' cultivar (RWC = 71%). In addition, the performance index (PI) decreased for all the five cultivars and it reached the lowest values for 'Jarboui' and 'Chetoui' with 1.51 and 1.57, respectively. For the SPAD index, a decrease was registered for all the cultivars, except 'Chemcheli' (SPAD index = 89). Furthermore, the bacterial inoculation treatment improved the responses of cultivars to water stress. In fact, for all of the studied parameters, it was found that rhizobacterial inoculation significantly attenuated the effects of drought stress with variability dependent on the level of tolerance of the tested cultivars. This response improvement was noted especially in susceptible cultivars like 'Chetoui' and 'Jarboui'.

Sensitivity of the Photosynthetic Apparatus in Maize and Sorghum under Different Drought Levels.

Drought is one of the main environmental stress factors affecting plant growth and yield. The impact of different PEG concentrations on the photosynthetic performance of maize (Zea mays L. Mayflower) and sorghum (Sorghum bicolor L. Foehn) was investigated. The activity of the photosynthetic apparatus was assessed using chlorophyll fluorescence (PAM and JIP test) and photooxidation of P700. The data revealed that water deficiency decreased the photochemical quenching (qP), the ratio of photochemical to nonphotochemical processes (Fv/Fo), the effective quantum yield of the photochemical energy conversion in PSII (ΦPSII), the rate of the electron transport (ETR), and the performance indexes PItotal and PIABS, as the impact was stronger in sorghum than in maize and depended on drought level. The PSI photochemistry (P700 photooxidation) in sorghum was inhibited after the application of all studied drought levels, while in maize, it was registered only after treatment with higher PEG concentrations (30% and 40%). Enhanced regulated energy losses (ΦNPQ) and activation of the state transition under drought were also observed in maize, while in sorghum, an increase mainly in nonregulated energy losses (ΦNO). A decrease in pigment content and relative water content and an increase in membrane damage were also registered after PEG treatment. The experimental results showed better drought tolerance of maize than sorghum. This study provides new information about the role of regulated energy losses and state transition for the protection of the photosynthetic apparatus under drought and might be a practical approach to the determination of the drought tolerance of plants.

Investigating the Biochemical Responses in Wheat Cultivars Exposed to Thermal Power Plant Emission.

The current study aimed to assess how high concentrations of ozone (O3) and suspended particulate matter (SPM) alter biochemical properties of high yielding wheat cultivars (i.e., HD3086 and HD2967) grown under 10 km radius in 8 villages, located around Thermal Power Plant (TPP), Auraiya, Uttar Pradesh, India. Significant foliar damage was brought on by O3 and SPM exposure in both wheat cultivars and noted for consecutive 2 years as per emission patterns, air movement and biochemical defense capabilities. The detected air pollutants at the chosen experimental site ranged from 34 to 46 ppb O3 and 139-189 µg/m3 SPM. Range of biochemical parameter for both cultivars are as pH 6.6-7.1, relative water content (RWC) 44-62%, chlorophyll 0.23-0.35 mg/g, ascorbic acid (AA) 54-68 mg/g and air pollution tolerance index (APTI) 47-72. It has been observed that SPM deposition had a meaningful impact (P-value = 0.05) on the chlorophyll, pH, RWC and APTI.