Plant Growth Traits Research Articles

Neem and Castor Oil–Coated Urea Mitigates Salinity Effects in Wheat by Improving Physiological Responses and Plant Homeostasis

Soil salinity is abiotic stress of growing concern, whose effects can be potentially mitigated by the use of suitable fertilisers. Based on this, an experiment was conducted to determine the role of vegetable oil–coated urea on the performance of wheat (Triticum aestivum) under salinity. Neem oil–coated urea (NOCU), castor oil–coated urea (COCU), and normal urea (NU) were compared in wheat plants growing in pots at three soil salinity levels (0, 6, and 12 dS m-1). Plant morphology, growth, element contents (Na, Cl, K, and N), and several traits were assessed at the flag leaf stage; biological yield, grain yield, and its components were assessed at maturity. Salinity stunted growth (approximately -50% yield with high salinity vs. control); boosted Na and Cl concentrations while abating K and N concentrations in plant organs; impaired leaf water status; reduced photosynthetic pigments and increased antioxidant activities and osmo-regulating compounds. NOCU and, to a lesser degree, COCU mitigated salinity effects by upgrading antioxidant activities, reducing oxidative stress markers, increasing leaf water status, photosynthetic pigments, and osmo-regulating compounds. However, NOCU under high salinity could only achieve the levels of NU under intermediate salinity. Lastly, NOCU and COCU restricted plant entry of adverse ions (Na and Cl) while increasing K and N accumulation. Vegetable oil–coated urea, namely NOCU, significantly contributed to improving wheat behaviour and final yield under salinity. These outcomes are associated with the two fertilisers’ properties of slow nitrogen release.

Proglacial slopes are protected against erosion by trait diverse and dense plant communities associated with specific microbial communities

Soil erosion is a severe threat for ecosystems and anthropogenic infrastructure. Glaciers are retreating rapidly due to global warming and the receding ice leaves unvegetated depositions of sediment, which are prone to mobilisation during precipitation events. Vegetation is known to serve as erosion protection, but how above- and belowground plant traits, vegetation cover and plant diversity on community level are jointly affecting erosion is unclear. Additionally, soil microbial communities may have effects on slope stability by promoting plant growth and function. We measured sediment transport on 30 plots of 2 × 3 m size on proglacial slopes of the Gepatschferner glacier (Kaunertal, Austria) over three years in a natural pristine high alpine environment. Vegetation cover, species abundances and relevant above- and belowground traits were measured for each occurring plant species on community level. Path model analysis revealed that dense and species-rich plant cover characterized by specific plant growth strategies and trait diversity was best suited to decrease erosion. Vegetation properties were also closely linked to the composition of soil microbial communities characterised by next generation amplicon sequencing, which may facilitate soil formation and further enhance the plants’ soil stabilising potential. Our study illustrates that erosion control may benefit from a high vegetation cover, which is facilitated by diverse plant communities with complementary morphological traits. These vegetation properties also affect soil microbiota, but their impact on slope protection in combination with the vegetation remains to be elucidated. Our findings may inform nature-based solutions against erosion such as revegetation of alpine slopes using specific seed mixtures.

Advances in the Application of Small Unoccupied Aircraft Systems (sUAS) for High-Throughput Plant Phenotyping

High-throughput plant phenotyping (HTPP) involves the application of modern information technologies to evaluate the effects of genetics, environment, and management on the expression of plant traits in plant breeding programs. In recent years, HTPP has been advanced via sensors mounted on terrestrial vehicles and small unoccupied aircraft systems (sUAS) to estimate plant phenotypes in several crops. Previous reviews have summarized these recent advances, but the accuracy of estimation across traits, platforms, crops, and sensors has not been fully established. Therefore, the objectives of this review were to (1) identify the advantages and limitations of terrestrial and sUAS platforms for HTPP, (2) summarize the different imaging techniques and image processing methods used for HTPP, (3) describe individual plant traits that have been quantified using sUAS, (4) summarize the different imaging techniques and image processing methods used for HTPP, and (5) compare the accuracy of estimation among traits, platforms, crops, and sensors. A literature survey was conducted using the Web of ScienceTM Core Collection Database (THOMSON REUTERSTM) to retrieve articles focused on HTPP research. A total of 205 articles were obtained and reviewed using the Google search engine. Based on the information gathered from the literature, in terms of flexibility and ease of operation, sUAS technology is a more practical and cost-effective solution for rapid HTPP at field scale level (>2 ha) compared to terrestrial platforms. Of all the various plant traits or phenotypes, plant growth traits (height, LAI, canopy cover, etc.) were studied most often, while RGB and multispectral sensors were most often deployed aboard sUAS in HTPP research. Sensor performance for estimating crop traits tended to vary according to the chosen platform and crop trait of interest. Regardless of sensor type, the prediction accuracies for crop trait extraction (across multiple crops) were similar for both sUAS and terrestrial platforms; however, yield prediction from sUAS platforms was more accurate compared to terrestrial phenotyping platforms. This review presents a useful guide for researchers in the HTPP community on appropriately matching their traits of interest with the most suitable sensor and platform.

Deciphering the Potential of Sulphur-Oxidizing Bacteria for Sulphate Production Correlating with pH Change.

Sulphur, available in the form of sulphate, is one of the essential nutrients that is required by plants. Bacteria capable of oxidizing reduced forms of sulphur to sulphate play an important role in sulphur nutrition for plants. The present study was conducted to isolate, screen, and characterize sulphur-oxidizing bacteria from different soil samples collected from mustard rhizosphere and fly ash mixed soil. A total of 33 sulphur-oxidizing bacterial isolates (HMSOB1-33) were retrieved from soil and further screened for sulphur-oxidizing ability. Maximum solubilization index (3.76), pH reduction (3.93), and sulphate production (173.61µg/ml) were observed for the isolate HMSOB2 which on the basis of 16S rDNA sequencing was identified as Pantoea dispersa with sequence similarity 98.22%. Four other selected bacterial isolates were identified as Bacillus megaterium, Bacillus tropicus, Bacillus velezensis, and Bacillus cereus. Sulphate solubilization index (SSI) correlated positively (r = 0.91) with sulphate production; however, pH showed negative correlation (r = - 0.82) with SSI as well as sulphate production after 120h of incubation. These promising bacterial isolates could be further explored as bioinoculant after assessing plant growth traits.

Plant-growth promoting activity of three fungal endophytes isolated from plants living in dehesas and their effect on Lolium multiflorum

Endophytic fungi have been demonstrated to produce bioactive secondary metabolites, some of which promote plant growth. Three endophytic fungi isolated from healthy plants living in dehesas of Extremadura (Spain) were identified and evaluated for their ability to produce phytohormone-like substances, antioxidant activity, total polyphenol content, phosphate solubilization ability and siderophore and ammonia production. The filtrates and extracts produced by the three endophytes were applied to Lolium multiflorum seeds and seedlings under both in vitro and greenhouse conditions, to analyse their influence on plant growth traits such as germination, vigour index, chlorophyll data, number and length of leaves and roots, and dry weight. All three endophytes, which were identified as Fusarium avenaceum, Sarocladium terricola and Xylariaceae sp., increased the germination of L. multiflorum seeds by more than 70%. Shoot and root length, plant dry weight and the number of roots were positively affected by the application of fungal filtrates and/or extracts, compared with controls. The tentative HPLC–MS identification of phytohormone-like substances, such as gibberellin A2 and zeatin, or the antioxidant acetyl eugenol, may partially explain the mechanisms of L. multiflorum plant growth promotion after the application of fungal filtrates and/or extracts.

Host filtering, not competitive exclusion, may be the main driver of arbuscular mycorrhizal fungal community assembly under high phosphorus

Abstract A major goal in ecology is understanding the factors which determine the diversity and distribution of organisms. The outcome of the symbiotic relationship between plants and arbuscular mycorrhizal (AM) fungi is strongly influenced by soil phosphorus (P) availability. Despite this knowledge, there is still much to uncover about how soil P status can shape the taxonomic and phylogenetic assembly of root‐colonising AM fungi. Additionally, there is a paucity of understanding about the implications of these changes for the outcome of the AM symbiosis in terms of plant growth, nutrient status and defence traits. We conducted a factorial pot experiment where sorghum (Sorghum bicolor) was grown under three different P treatments (low, medium and high), in the presence or absence of a natural AM fungal community. By analysing the diversity and community structure of the fungal community colonising roots, we aimed to determine if and how soil P influences the relatedness of these communities and whether competitive exclusion or environmental filtering play a more significant role in their assembly. Additionally, we evaluated the concomitant outcomes for plant growth, nutrient acquisition and defensive chemistry (phenolics). Increasing P availability reduced AM fungal richness and increased community evenness. Root‐colonising AM fungal communities under the high P treatment had significantly reduced phylogenetic diversity and comparatively lower mean pairwise distances among all treatments. This indicated that AM fungal communities became more closely related (phylogenetically clustered) with increasing soil P. The mycorrhizal growth and mycorrhizal P responses of plants were positive under low and medium P, but this was lost under high P, however, plant phenolics were increased. Our results suggest that under high P conditions, environmental filtering plays an important role in AM fungal community assembly as host plants alter their selectivity of fungal functional groups prioritising those associated with enhancing plant stress resistance and defences, rather than nutrient acquisition. Here we demonstrated how soil P status can shape taxonomic and phylogenetic assembly of AM fungi and the associated functional outcomes for the host. Read the free Plain Language Summary for this article on the Journal blog.

Arbuscular Mycorrhizal Fungi and Compost-Based Biostimulants Enhance Fitness, Physiological Responses, Yield, and Quality Traits of Drought-Stressed Tomato Plants.

Climate change-driven water resource constraints cause tomatoes to suffer from drought. The use of biostimulants has emerged as an important approach to enhancing resilience to drought. However, the roles of biostimulants in the physicochemical characteristics of tomatoes in response to drought are poorly understood. In this study, we evaluated the ability of arbuscular mycorrhizal fungi (AMF) and compost (versus NPK application) to improve the agro-physiology, yield, and fruit quality of tomato plants and their tolerance to drought by comparing them with conventional chemical fertilizers (NPK). Under drought conditions, plant growth traits associated with yield and fruit bioactive compounds (carotenoids: 73%; lycopene: 53%; polyphenols: 310%; and flavonoids: 158%) were increased in the AMF-tomato treatment. Compost significantly enhanced sugars (ca. 60%) and protein contents (ca. 20%). Moreover, AMF protected the photosynthetic apparatus from drought-induced oxidative stress, improved photosynthetic efficiency, leaf water potential, and osmolytes, and reduced malondialdehyde (MDA) and hydrogen peroxide (H2O2) accumulation by increasing peroxidase (POX) (140%) and polyphenol oxidase (PPO) (340%) activities compared to their controls. Our findings revealed that NPK is an important nutrient-based fertilizer for plant growth and development. However, its efficiency as a fertilizer is quite low. In addition, we highlighted different mechanisms mediated by AMF and compost, inducing drought tolerance in tomato plants.

Growing ‘Genovese’ and ‘Valentino’ Basil in Pots Using Peat Substrate Combined with Phytoremediated Sediment: Effects on Yield and Nutraceutical Content

Climate change is causing a decline in the availability of crucial resources such as water and fertile soil, leading to a detrimental impact on crop yields. Basil (Ocimum basilicum L.), an annual aromatic plant used worldwide for culinary, cosmetic, and medicinal purposes, is especially at risk due to its high water demand and specific growing requirements typical of the Mediterranean climate. In Italy, basil is an essential part of any herb garden and is also commonly found in households as a potted plant. Nowadays, the conventional practice of growing basil in pots with peat as the primary medium is not environmentally sustainable, which underscores the need for alternative and sustainable cultivation techniques to ensure the continued growth of this majestic king of herbs. A greenhouse factorial experiment was conducted to study the impact of peat replacement and reduced water supply on the growth and biochemical traits of basil plants. The study included two cultivars (‘Genovese’ and ‘Valentino’), three substrate mixes with phytoremediated dredged sediment (TS) at varying volume percentages (0%, 12.5%, and 25%), and three levels of water irrigation (normal, reduced by 25%, and reduced by 37.8%). Increasing the TS percentage resulted in higher germination rates and greater biomass production in both cultivars compared with the control. ‘Valentino’ potted plants produced a higher yield than those of ‘Genovese’, while the latter had higher pigment contents due to its genetic characteristics. All combinations of substrates mixed with the highest water amounts of irrigation positively impacted seed germination and biomass-based outputs, while control peat with reduced water availability led to lower plant yields and germination capacity. Substrates with TS had suitable physicochemical characteristics for plant development. Our findings suggest that using peat–TS mixtures can produce quality results comparable to or even better than conventional soilless culture using only peat. Thus, replacing peat with moderate percentages of TS can be an effective and sustainable practice for recycling phytoremediated sediments.

Ultrasound application for the decontamination of roselle (Hibiscus sabdariffa L.) seeds: Influence on fungal inhibition and seed quality

Seed decay is a major problem caused by pathogens that adversely affect seed yield and quality in agricultural production. Herein, the effect of 28 KHz ultrasound treatment for 20, 40 and 60 min and 1.5% sodium hypochlorite solution for 20 min was assessed for the decontamination of roselle (Hibiscus sabdariffa L.) seeds. In addition, seed germination indices, seedling growth traits, total phenolic content and the activity of defense-related enzymes, viz. peroxidase, superoxide dismutase, catalase and malondialdehyde were measured in the treated seeds. An isolate of Fusarium solani was obtained from roselle seeds and identified as the causal agent of roselle seed rot based on morphological and molecular characteristics. After six days of seed storage, the microbial infection caused the highest seed rot in the control seeds on the average of 56.67%, whereas ultrasound treatment for 60 min could remarkably reduce the seed decay by 3.33%. At the end of seed storage, the fungal load showed the highest (7.72 Log CFU ml−1) and lowest (6.99 Log CFU ml−1) rates in the control and ultrasound treatment for 60 min, respectively. Total phenolic content was significantly increased in ultrasound treatment for 60 min compared to control and sodium hypochlorite treatments. Moreover, the activity of peroxidase, superoxide dismutase and catalase was noticeably improved in ultrasound treatment for 60 min. Furthermore, ultrasound treatment did not show any adverse effects on seed germination indices and seedling growth traits of the roselle plants. Overall, ultrasound treatment for 60 min could effectively decrease roselle seed decay and the fungal load without changing seed and seedling quality.

Performance of Plant-Growth-Promoting Rhizobacteria (PGPR) Isolated from Sandy Soil on Growth of Tomato (Solanum lycopersicum L.).

The plant-growth-promoting rhizobacteria (PGPR) in the rhizosphere affect plant growth, health, and productivity, as well as soil-nutrient contents. They are considered a green and eco-friendly technology that will reduce chemical-fertilizer usage, thereby reducing production costs and protecting the environment. Out of 58 bacterial strains isolated in Qassim, Saudi Arabia, four strains were identified by the 16S rRNA as the Streptomyces cinereoruber strain P6-4, Priestia megaterium strain P12, Rossellomorea aquimaris strain P22-2, and Pseudomonas plecoglossicida strain P24. The plant-growth-promoting (PGP) features of the identified bacteria involving inorganic phosphate (P) solubilization, the production of indole acetic acid (IAA), and siderophore secretion were assessed in vitro. Regarding the P solubilization, the previous strains' efficacy reached 37.71%, 52.84%, 94.31%, and 64.20%, respectively. The strains produced considerable amounts of IAA (69.82, 251.70, 236.57, and 101.94 µg/mL) after 4 days of incubation at 30 °C. Furthermore, the rates of siderophore production reached 35.51, 26.37, 26.37, and 23.84 psu, respectively, in the same strains. The application of the selected strains in the presence of rock phosphate (RP) with tomato plants under greenhouse conditions was evaluated. The plant growth and P-uptake traits positively and significantly increased in response to all the bacterial treatments, except for some traits, such as plant height, number of leaves, and leaf DM at 21 DAT, compared to the negative control (rock phosphate, T2). Notably, the P. megaterium strain P12 (T4), followed by R. aquimaris strain P22-2 (T5), revealed the best values related to plant height (at 45 DAT), number of leaves per plant (at 45 DAT), root length, leaf area, leaf-P uptake, stem P uptake, and total plant P uptake compared to the rock phosphate. The first two components of the PCA (principal component analysis) represented 71.99% (PCA1 = 50.81% and PCA2 = 21.18%) of the variation at 45 DAT. Finally, the PGPR improved the vegetative-growth traits of the tomato plants through P solubilization, IAA, and siderophore production, and ameliorated the availability of nutrients. Thus, applying in PGPR in sustainable agriculture will potentially reduce production costs and protect the environment from contamination by chemical fertilizers and pesticides.

Effect of Bio-Fertilizer and Potassium Spraying on the Growth and Yield of Potatoes for Autumn Season

The experiment was conducted in the fields of a farmer in the Al-Dila area / south of Babylon provainc, at a longitude of 44.39 E and a latitude of 32.3 N, 17 km south of the Hilla city. To study the effect of biofertilizer and potassium source on improving the performance, growth and production of potatoes, the experiment was designed according to a split plot-System using a randomized complete block design with three replicates. The results of the experiment were statistically analyzed according to the method of analysis of variance and according to the significant differences between the treatments at the probability level of 0.05 using the least significant difference LSD. The results showed that there were significant differences when adding bio-fertilizer in most of the vegetative, quantitative and qualitative traits of potato plants, as the addition of bio-fertilizer Fulzyme (12 kg. ha-1) was significantly excelled in plant height, number of stems, number of leaves, number of total tubers and number of marketable tubers, As for the qualitative traits, it gave the highest rate in the percentage of protein and carbohydrates. The results of spraying with potassium source indicated that there were significant differences in most of the vegetative, quantitative and qualitative traits, where the spraying treatment with potassium sulfate at a concentration of (3 ml. L-1) was achieved. Significantly excelled in the number of main stems, the average marketing weight of the tuber, and the treatment of spraying with nano-potassium at a concentration (2 g. L-1) was significantly excelled in the total plant yield amounting to (1.069 kg. plant-1 and 56.44 tons. ha-1), the yield marketable (54.26 tons. ha-1), the percentage of carbohydrates in the tubers, While the spraying treatment with potassium silicate at a concentration of (3 ml. L-1) achieved significantly excelled in plant height, number of leaves, number of total and marketable tubers, and the percentage of protein in tubers. The two interactions showed a significant effect on most of the vegetative, quantitative and qualitative growth traits of potato plants. The bi-interaction treatment, adding Fulzyme + spraying with potassium silicate, achieved a significantly excelled in the traits of the total yield per ton, which amounted to (61.56 tons. ha-1) and the marketable yield per ton reached(59.41 tons. ha-1).

Comparison of the effect of two categories of Arthrospira platensis polysaccharides (exo and endopolysaccharides) on tomato growth: Effect on morphological, histological and biochemical plant growth traits

Comparison of the effect of two categories of Arthrospira platensis polysaccharides (exo and endopolysaccharides) on tomato growth: Effect on morphological, histological and biochemical plant growth traits

Reversing Precipitation Largely Reverses Soil Microbial Communities in Desert Steppe

Photo 1. The current study site on a desert steppe in Damao County, Inner Mongolia, China. The vegetation in this arid ecosystem mainly consists of native grasses, including Stipa tianschanica var. klemenzii, Cleistogenes squarrosa, Neopallasia pectinata, and Erodium stephanianum. Photo credit: Zhenzhu Xu. Photo 2. The experimental facility in field. We applied rainout shelters to achieve 50% and 25% precipitation reduction by changing the number of V-shaped acrylic strips. A steel pipe frame was used to support the V-shaped acrylic bands (92% light transmittance). For the precipitation addition treatments, four and eight V-shaped steel sheets were uniformly located outside the plots for the 25% and 50% addition treatments, respectively. Photo credit: Quanhui Ma. Photo 3. A 50% precipitation reduction treatment by covering the number of V-shaped acrylic strips. Photo credit: Quanhui Ma. Photo 4. Plant growth and physiologic traits were measured in a plot. Photo credit: Zhenzhu Xu. Photo 5. A group photo of the study team during field survey and measurement work (16 August 2018). From left to right: Hongying Yu, Miao Qi, Wenjuan Wu, Zhenzhu Xu, Xiaodi Liu, Lang Li, Quanhui Ma. Photo credit: Quanhui Ma. These photographs illustrate the article “Soil microbial responses to large changes in precipitation with nitrogen deposition in an arid ecosystem” by Hongying Yu, Lang Li, Quanhui Ma, Xiaodi Liu, Yibo Li, Yuhui Wang, Guangsheng Zhou, and Zhenzhu Xu published in Ecology. https://doi.org/10.1002/ecy.4020

Appropriate Application Methods for Salicylic Acid and Plant Nutrients Combinations to Promote Morpho-Physiological Traits, Production, and Water Use Efficiency of Wheat under Normal and Deficit Irrigation in an Arid Climate

Freshwater shortage and inadequate nutrient management are the two major challenges for sustainable wheat production in arid agro-ecosystems. Relatively little is known about the positive roles of the application methods for the combination of salicylic acid (SA) and plant nutrients in sustaining wheat production under arid climatic conditions. A two-year field study was undertaken to assess the impact of seven treatments for the integrated application of SA, macronutrients, and micronutrients on the morpho-physiological traits, yield, and irrigation water use efficiency (IWUE) of wheat subjected to full (FL) and limited (LM) irrigation regimes. The results showed that the LM regime caused a significant reduction in different plant growth traits, relative water content, chlorophyll pigments, yield components, and yield, while a significant increase was observed in IWUE. The sole application of SA or co-application with micronutrients through soil did not significantly affect the studied traits under the FL regime, while they achieved some improvement over untreated plants under the LM regime. Based on the different multivariate analyses, the soil and foliar applications for the combinations of SA and micronutrients, as well as a foliar application for the combinations of SA, macronutrients, and micronutrients were identified as an efficient option for mitigating the negative impacts of water deficit stress and enhancing the growth and production of wheat under normal conditions. In conclusion, the results obtained herein indicated that the co-application of SA and macro- and micronutrients is an effective option to greatly enhance and improve the growth and production of wheat crops in water-scarce countries of arid regions, such as Saudi Arabia, while an appropriate application method for this combination was required for positive effects.

ORYZALIN-INDUCED TARO (COLOCASIA ESCULENTA L.) TETRAPLOID AND DIPLOID ASSESSMENT FOR GROWTH AND AGRONOMIC TRAITS

Taro (Colocasia esculenta L. cv. Pontianak) is a popular and widely cultivated cultivar in the Indonesian farming community. In taro Pontianak, manipulating the ploidy level by chromosome doubling can enhance its genetic diversity. The latest study aimed to evaluate the oryzalin-induced polyploid taro cv. Pontianak compared with its diploid in terms of growth, anatomical, cytological, morphological, and agronomic traits in the greenhouse and the field. In vitro shoots of taro cv. Pontianak were soaked using a liquid medium supplemented with oryzalin with a concentration of 30 and 60 μM for one day. After five times of subcultures, flow cytometry analysis proceeded to determine their ploidy levels. The diploid (2n = 2x) and tetraploid (2n = 4x) plantlets were then acclimatized in the greenhouse for six to eight weeks and hardened for two months before planting in the field for 10 months. Squashing the root tip to ensure the ploidy levels of taro seedlings helped measure the chromosome numbers. Observing the growth, anatomical, and agronomic traits of diploid and tetraploid plants occurred during the hardening process until harvest time. The 30 μM oryzalin treatment produced tetraploid and mixoploid shoots; none from the 60 μM treatment. Oryzalininduced tetraploid taro exhibited some morphological characteristics of tetraploid plants, such as, longer stomata size and low density. Tubers of tetraploid plants tended to have increased protein, ash, and water content compared with their diploid counterpart. However, tetraploid taro showed a slower growth rate both in the greenhouse and the field. Additionally, it gave lower yields than diploids in some agronomic characteristics, including delayed flowering time, lower plant fresh weight, and smaller tubers. This study provides information that oryzalin-induced tetraploid taro could exhibit increasing and decreasing nutritional-agronomic traits (as mentioned above) compared with its diploid.

Genotypic Difference in Growth and Physiological Indices of Grain Amaranth Species under Salinity Stress

The present experiment was conducted during October to February of year 2019−20, to investigate the effect of salinity on morpho-physiological traits and identify the genotype have higher salt tolerance among ten genotypes belongs to three grain Amaranth species. Plant growth traits viz., plant height, shoot and root dry weight decreases with increase in the salinity stress level (EC of 5 and 10 dS m-1) in all the genotypes, however significant (p<0.01) genotypic difference were present among genotypes and GA-5 maintained the maximum growth under salinity. Percent decrease in SDW and RDW was lowest (10.61−23.86 and 10.37 and 26.59) in A. hypochondriachus while in A. cruentus (15.10-29.55 and 12.78-33.09) and A. caudatus (15.15−28.84 and 16.62-34.90). Salinity significantly (p<0.01) decreases the membrane stability, relative water content and leaf potassium content while, leave sodium content increases. As compared to other genotype GA-5 have maximum membrane stability (53.30), relative water content (85.40%), K+ accumulation and minimum Na+ accumulation in leaves.Morpho-physiological traits of grain Amaranthus species are significantly positively correlated with dry shoot biomass (0.649), MSI (0.770), RWC (0.768), chlorophyll (0.908), carotenoid (0.883) and leaf potassium (0.883). It might be concluded that among studied genotypes GA-5 maintained the growth and have higher physiological efficiency results into maximum salt tolerance index also morpho-physiological traits like dry weight, RWC, MSI, Chlorophyll, Carotenoid and leaf potassium content might be utilised for selection of salt tolerant Amaranth genotypes.

Enrichment of keystone fungal taxa after flue gas desulphurization gypsum application drives reclamation of the saline‐sodic soil

AbstractSoil salinization is a major threat to sustainable agriculture in the western part of Songnen Plain, Northeast China. Flue gas desulphurization gypsum (FGDG) is commonly used for reclaiming of saline soils due to its high efficiency and cost‐effectiveness. However, the responses of soil and root‐associated fungi after FGDG amendment and the keystone fungal taxa in determining soil reclamation effect remain elusive. In this study, a long‐term field experiment was conducted to explore the effect of different levels of one‐time FGDG application on the soil reclamation and the herbage (Leymus chinensis) growth. Our results showed that the FGDG application greatly reduced soil salinity level, increased soil fertility and fungal diversity, and promoted aboveground biomass of L. chinensis, whereas reduced FGDG dose to 60% of gypsum requirement (GR) exhibited non‐significant difference on these characters compared with 100% GR treatment. We further discovered that both soil and root fungal communities were greatly changed after FGDG application, with root fungal community more sensitive than soil fungi. Through applying the Random Forest model, the arbuscular mycorrhizal fungi Glomeromycota was identified as the keystone taxa in predicting the soil salinity, soil fertility, and plant growth trait. Intriguingly, some Glomeromycota‐affiliated ZOTUs were consistently enriched in the FGDG application treatments, and acted as keystone hubs in the co‐occurrence network of fungal communities. Together, our study provides new insights that the enrichment of keystone Glomeromycota after FGDG application determines the reclamation of the saline‐sodic soil, which would guide the microbial‐based strategy for the development of degraded ecosystems.

Exogenous Melatonin Application Induced Morpho-Physiological and Biochemical Regulations Conferring Salt Tolerance in Ranunculus asiaticus L.

This study presents the effects of exogenous melatonin application at different concentrations (50, 100, and 200 μM) on the morphological, physiological, and antioxidant defense systems of the buttercup plant under salinity stress (4.5 and 5.5 dS·m−1 EC). Expectedly, the salinity stress negatively affected the plant growth parameters, cell membrane stability, and POX enzyme activity of R. asiaticus compared to non-stressed plants. However, in a dose-dependent manner, exogenous melatonin foliar application decreased the salt stress-induced symptoms of retarded vegetative growth, physiological characteristics, and oxidative stress level. The results obtained, revealed the significant effectiveness of exogenous melatonin treatment at 200 μM concentration under salt stress conditions by enhancing the plant growth traits such as chlorophyll and carotenoids content, relative water content, proline content, peroxidase enzyme activity (POD), and by the decreased electrolyte leakage rate, and Na+ content, as well as delaying the emergence of flower buds under salinity stress. The salt tolerance index percentages (STI%) for all estimated characters are also calculated for all studied parameters. This study uncovered the beneficial effect of melatonin in reducing salt stress symptoms that can be used to reduce the salinity effect in ranunculus plant production.

Impact of Piriformospora indica on various characteristics of tomatoes during nickel nitrate stress under aeroponic and greenhouse conditions.

As an essential nutrient for plant growth, nickel's (Ni) requirement is very low, and its augmented level causes environmental pollution and toxicity. Being a root endophytic fungus, Piriformospora indica (P. indica) can be beneficial to many plants under stress and non-stress conditions, particularly in terms of their improved growth performance. P. indica, as evidenced, enhances tolerance and resistance in most plants once they experience a range of stresses caused by biotic and abiotic factors, e.g., diseases and heavy metals. Against this background, the positive effects of P. indica on the tomato plants under Ni-induced stress (300, 600, and 900 mg L-1) were analyzed in three experiments at labs, at greenhouses, and via aeroponics in this study. The growth traits of the tomato plants, such as root length (RL) and root dry weight (RDW), were accordingly found to be positively boosted in the cases treated with P. indica compared to the non-treated ones. Treating with P. indica also thwarted the negative effects of Ni on some biochemical traits, including anthocyanin (Anth), proline (Pro), catalase (CAT), and glutathione peroxidase (GPx), while significantly minimizing the adverse impacts of this heavy metal at different levels on hydrogen peroxide (H2O2). Despite this, the Ni-stressed plants indicated much better traits in the presence of this fungus, compared with the non-treated ones, in most of the cases measured. Moreover, the photosynthetic pigments, i.e., chlorophyll a and b (Chl a & b) and carotenoid content (Carrot), were significantly higher in the tomato plants treated with P. indica under high Ni-induced stress as compared with the non-treated ones under non-Ni conditions, in which these pigments were low. The pro-production was further observed all through the P. indica inoculation, which could aid the treated plants in becoming Ni-stress-tolerant. Finally, the current study contributed to a better understanding of how to use the P. indica symbiosis to induce heavy metal tolerance in tomato plants, such as Ni, to meet the goals of sustainable agriculture.

Ecklonia maxima-derivate seaweed extract supply as mitigation strategy to alleviate drought stress in chicory plants

Extreme climatic conditions have a severe repercussion on agriculture and on food availability. Ecological means to overcome drought are important to improve agroecosystems sustainability and resilience. The use of an Ecklonia maxima-derivate seaweed extract (SwE) as a tool to mitigate drought constrain in chicory plants grown in greenhouse was evaluated. Plants were cultivated in plastic pots filled with peat and subjected to drought stress by retaining moisture range at 90–100% of water holding capacity (WHC) [well-watered (WW)], 60–70% WHC [moderate drought stress (MDS)] or 30–40% WHC [severe drought stress (SDS)]. Drought stress decreased plant growth traits and yield. However, in plants supplied with SwE, head fresh mass was 7.6% higher than control. Water constrain reduced relative water content (RWC), whereas, SwE improved RWC when plants were exposed to drought. Moreover, water use efficiency (WUE) increased as drought intensity increased and plants exposed to drought significantly improved WUE when supplied with SwE. Drought stress intensity linearly reduced nitrogen use efficiency (NUE) in plants exposed to MDS and SDS, compared with WW plants. SwE application enhanced NUE by 7.7% compared with control plants. Exposing chicory plants to drought stress resulted in a significantly higher N and Mg concentration compared to WW plants. Conversely, drought reduced P and K in leaf tissues. SwE supply increased P, K, Ca and Mg content, whereas reduced N. Chlorophyll was reduced by drought, while SwE supply increased its concentration. Sugars increased as drought stress intensity increased. Water constrain enhanced malondialdehyde, especially in SwE non-treated plants. Drought stress improved proline and total polyphenols in plants supplied with SwE. Biostimulated plants grown under WW or MDS conditions showed higher ascorbic acid level than those exposed to SDS and non-biostimulated. The study proved that SwE application is a useful practice to mitigate drought in chicory plants, safeguarding yield and quality features.