Improve Plant Growth Research Articles

Promoting effect of biogenic AgNPs on Echinops macrochaetus for improving growth parameters and mitigating the toxic effect caused by salinity stress

Nanoparticles may serve as novel plant growth stimulators to improve plant growth as well as protect plants from abiotic stresses. In this study, biogenic silver nanoparticles (AgNPs) were synthesized using the aqueous extract of Fagonia bruguieri and characterized using UV-visible spectroscopy, Zeta potential, transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR). The synthesized AgNPs were employed on Echinops macrochaetus as seeds priming, and plants grown in pots were exposed to salinity stress to assess the ameliorating effects based on various parameters. The growth parameters (shoot length) and biomass (shoot, root and leaves weight) decreased in E. macrochaetus exposed to salinity stress alone (40, 80 and 120 mmol/L NaCl) for 90 days. However, seed priming with a low concentration of AgNPs (40 µmol/L) improved the growth of the plant in terms of biomass, shoot length and chlorophyll content alone as well as ameliorated the toxic effect caused by salinity stress. The mitotic index measured by flowcytometry (FCM) indicated genotoxic effects in plants grown at high concentrations of NaCl (80 and 120 mmol/L) as well as plants obtained with 80 µmol/L AgNPs seed priming and exposed to 120 mmol/L NaCl. Thus, an optimum concentration of AgNPs could be used in E. macrochaetus for production of more biomass by modulating the chlorophyll content, proline and antioxidant enzyme activity.

Wood Distillate Promotes the Tolerance of Lettuce in Extreme Salt Stress Conditions.

Soil salinization is an adverse phenomenon in agriculture that severely affects crop growth and yield. The use of natural products, such as wood distillate (WD, derived from the pyrolysis of woody biomass), could be a sustainable approach to enhance the tolerance of plants cultivated in the saline soils. Hence, this study aimed to evaluate the potential of WD, a foliar sprayed at 0.2% (v/v), in lettuce plants subjected to grow under both moderate and high soil sodium chloride (NaCl) concentrations (ranging from 0 to 300 mM). The changes in the physiological and biochemical responses of these plants to the varying salt stress conditions allowed the identification of a maximum tolerance threshold (100 mM NaCl), specific to lettuce. Beyond this threshold, levels related to plant defense antioxidant power (antiradical activity) were lowered, while those indicative of oxidative stress (malondialdehyde content and electrolyte leakage) were raised, causing significant losses in leaf fresh biomass. On the other hand, WD significantly improved plant growth, enabling plants to survive high salt conditions >200 mM NaCl. Collectively, these observations highlight that treatments with WD could be of paramount importance in coping with current environmental challenges to have better yields under soil conditions of high salt concentrations.

Serotonin improves plant growth, foliar functions and antioxidant defence system in Ethiopian mustard (Brassica carinata A. Br.)

Every year, high salinity reduces agricultural crop yields by a substantial amount due to osmotic and ionic impacts that prevent plants from absorbing the required water and promote the hyperaccumulation of ions, which enter the transpiration stream and injure plant cells. Thus, in general, the effects of salinity stress on plant physio-chemicals functions are well known, but little has been explored on how serotonin combats abiotic stress in Ethiopian mustard (Brassica carinata). In this study, the effect of serotonin (SR; 200 µmol L−1) on Ethiopian mustard under salt stress (SS; 0, 50, 100 and 150 mM) was examined. Results exhibited that all SS levels tested in this trial were able to offer a significant reduction of plant growth parameters, chlorophyll contents, gas exchange, water use efficiency, fv/fm and nitrate reductase activity (NR) and increased the antioxidants and proline contents. However, the foliar application of SR significantly ameliorated the influence of all SS levels by improving gas exchange parameters, chlorophyll contents, PSll photochemical efficiency, antioxidant activities, proline, NR, water use efficiency and growth parameters. Based on these results, it is recommended that SR application is useful to uplift the growth, yield and physio-chemical mechanisms of Ethiopian mustard. Furthermore, the SR application can be carried out on various traditional crops under different climate conditions for sustainable agriculture production.

Phosphorus uptake and rhizosphere properties of alfalfa in response to phosphorus fertilizer types in sandy soil and saline-alkali soil.

Phosphorus (P) fertilizer is critical to maintain a high yield and quality of alfalfa (Medicago sativa L.). There are several fertilizer types and soil types in China, and the application of a single type of P fertilizer may not be suitable for present-day alfalfa production. In order to select the optimal combination of alfalfa and soil type and fertilizer type for improving P utilization efficiency. We conducted a greenhouse pot experiment, calcium superphosphate (SSP), diammonium phosphate (DAP), ammonium polyphosphate (APP), potassium dihydrogen phosphate (KP), and no-fertilizer control treatments were applied to alfalfa in sandy and saline-alkali soils. The response of alfalfa root morphology and rhizosphere processes to different P fertilizers was investigated. The results showed that shoot biomass of alfalfa was slightly higher in sandy soil than in saline-alkali soil. Shoot biomass of alfalfa increased by 223%-354% in sandy soil under P treatments compared with the control, and total root length increased significantly by 74% and 53% in DAP and SSP treatments, respectively. In saline-alkali soil, alfalfa shoot biomass was significantly increased by 229% and 275% in KP and DAP treatments, and total root length was increased by 109% only in DAP treatment. Net P uptake of alfalfa in DAP treatment was the highest in both soils, which were 0.73 and 0.54 mg plant-1, respectively. Alfalfa shoot P concentration was significantly positively correlated with shoot and root biomass (P < 0.05, 0.01 or 0.001) whereas negatively correlated with acid phosphatase concentration (P < 0.05). Improvement of plant growth and P uptake induced by P fertilizer application was greater in sandy soil than in saline-alkali soil. DAP and KP was the most efficient P fertilizers in both sandy soil and saline-alkali soil.

Synergy of plant growth promoting rhizobacteria and silicon in regulation of AgNPs induced stress of rice seedlings

Silver Nanoparticles (AgNPs), as an emerging pollutant, have been receiving significant attention as they deepen the concern regarding the issue of food security. Silicon (Si) and plant growth-promoting rhizobacteria (PGPR) are likely to serve as a sustainable approach to ameliorating abiotic stress and improving plant growth through various mechanisms. The present study aims to evaluate the synergistic effect of Si and PGPRs on growth, physiological, and molecular response in rice seedlings (Oryza sativa) under AgNPs stress. Data suggested that under AgNPs exposure, the root and shoot growth, photosynthetic pigments, antioxidant enzymes (CAT and APX), expression of antioxidant genes (OsAPX and OsGR), silicon transporter (OsLsi2), and auxin hormone-related genes (OsPIN10 and OsYUCCA1) were significantly decreased which accompanied with the overproduction of reactive oxygen species (ROS), nitric oxide (NO) and might be due to higher accumulation of Ag in plant cells. Interestingly, the addition of Si along with the AgNPs enhances the level of ROS generation, thus oxidative stress, which causes severe damage in all the above-tested parameters. On the other hand, application of PGPR alone and along with Si reduced the toxic effect of AgNPs through the improvement of growth, biochemical, and gene regulation (OsAPX and OsGR, OsPIN10 and OsYUCCA1). However, the addition of L-NAME along with PGPR and silicon drastically lowered the AgNPs induced toxicity through lowering the oxidative stress and maintained the overall growth of rice seedlings, which suggests the role of endogenous NO in Si and PGPRs mediated management of AgNPs toxicity in rice seedlings.

Transcriptional and physiological analyses uncover the mineralization and uptake mechanisms of phytic acid in symbiotically grown Vicia faba plants

Legume-rhizobia symbiosis requires high phosphorus (P) in the form of ATP to convert atmospheric nitrogen (N) into ammonia. The fixed ammonia is converted to NH4+ by H+-ATPase via protonation. To the best of our knowledge, most of these research works resort to using only inorganic P (Pi) to the neglect of the organic P (Po) counterpart. As it stands, the potential regulating roles of plasma membrane (PM) H+-ATPases during legume-rhizobia symbiosis in response to phytic acid supply and how it alters and modulates the regulation of PM H+-ATPases remain obscure. To contribute to the above hypothesis, we investigate the mechanisms that coordinately facilitate the growth, uptake, and transcript expression of PM H+-ATPase gene isoforms in response to different P sources when hydroponically grown Vicia faba plants were exposed to three P treatments, viz., low- and high-Pi (2.0 and 200 μM KH2PO4; LPi and HPi), and phytic acid (200 μM; Po) and inoculated with Rhizobium leguminosarum bv. viciae 384 for 30 days. The results consistently reveal that the supply of Po improved not only the growth and biomass, but also enhanced photosynthetic parameters, P uptake and phosphatase activities in symbiotically grown Vicia faba relative to Pi. The supply of Po induced higher transcriptional expression of all PM H+-ATPase gene isoforms, with possible interactions between phosphatases and H+-ATPase genes in Vicia faba plants when exclusively reliant on N derived from nodule symbiosis. Overall, preliminary results suggest that Po could be used as an alternative nutrition in symbiotic crops to improve plant growth.

Meticulously designed red emission carbon dots as efficient and stable luminescent species for rapid latent fingerprint recognition and light emitting diodes

The preparation of carbon dots (CDs) emitting long wavelength has attracted more attentions due to their unique advantages in biological and optoelectronic fields, including the wide absorption, long PL lifetime and deep-tissue penetration. Herein, we prepare the nitrogen and sulfur co-doped red emission carbon dots (R-CDs) from the 2,4-diaminodiphenylamine (DDA) and thiourea via a solvothermal reaction, which exhibit reliable red emission at 613 nm and possess a high quantum yield (QY) of 34 %. Meanwhile, the structural analysis and theoretical calculation reveal that the sulfur doping from thiourea increases the nitrogen and oxygen content of CDs, leading to the red emission observed in R-CDs. Subsequently, we design an integrated fingerprints recognition system based on the R-CDs phosphors for the imaging of latent fingerprints (LFPs) and fast LFPs recognition, expanding the application of biometric identification and comparison technology based on fluorescence. Finally, we successfully apply the R-CDs into red and white light-emitting diodes, improving plant growth efficiency. As a result, this work provides a new in-depth insight of red emission CDs and expands the application in latent fingerprint recognition and light-emitting diodes.

Heavy metals immobilization and bioavailability in multi-metal contaminated soil under ryegrass cultivation as affected by ZnO and MnO2 nanoparticle-modified biochar

Pollution by heavy metals (HMs) has become a global problem for agriculture and the environment. In this study, the effects of pristine biochar and biochar modified with manganese dioxide (BC@MnO2) and zinc oxide (BC@ZnO) nanoparticles on the immobilization and bioavailability of Pb, Cd, Zn, and Ni in soil under ryegrass (Lolium perenne L.) cultivation were investigated. The results of SEM–EDX, FTIR, and XRD showed that ZnO and MnO2 nanoparticles were successfully loaded onto biochar. The results showed that BC, BC@MnO2 and BC@ZnO treatments significantly increased shoots and roots dry weight of ryegrass compared to the control. The maximum dry weight of root and shoot (1.365 g pot−1 and 4.163 g pot−1, respectively) was reached at 1% BC@MnO2. The HMs uptake by ryegrass roots and shoots decreased significantly after addition of amendments. The lowest Pb, Cd, Zn and Ni uptake in the plant shoot (13.176, 24.92, 32.407, and 53.88 µg pot−1, respectively) was obtained in the 1% BC@MnO2 treatment. Modified biochar was more successful in reducing HMs uptake by ryegrass and improving plant growth than pristine biochar and can therefore be used as an efficient and cost effective amendment for the remediation of HMs contaminated soils. The lowest HMs translocation (TF) and bioconcentration factors were related to the 1% BC@MnO2 treatment. Therefore, BC@MnO2 was the most successful treatment for HMs immobilization in soil. Also, a comparison of the TF values of plant showed that ryegrass had a good ability to accumulate all studied HMs in its roots, and it is a suitable plant for HMs phytostabilization.

Pomegranate (Punica granatum L.) growth and biochemical alterations in response to meloidogyne incognita infection, minerals, and nano-fertilizers

The effects of four inoculum levels (500, 1,000, 2,000, or 4,000 second-stage juveniles (J2) per plant) of the root-knot nematode, Meloidogyne incognita, on two pomegranate cultivars (‘Manfalouty’ and ‘Wonderful’) were investigated under greenhouse conditions in response to plant inorganic and organic chemical concentrations. Furthermore, the effects of six commercial chemical fertilizers (inorganic fertilizers and nano-fertilizers) on plant growth and nematode reproduction were also studied. Both cultivars recorded the highest gall formation, embedded stages, and final nematode population at the inoculum dosage of 2,000 J2/plant. The highest reproductive rate was achieved with 500 J2/plant, while the lowest rate was observed with 4,000 J2/plant on both cultivars. ‘Wonderful’, at all M. incognita inoculum levels, was more sensitive to nematode infestation than ‘Manfalouty’. ‘Wonderful’ showed a greater reduction in fresh and dry plant weights than ‘Manfalouty’ at 2,000 and 4,000 J2/plant. In both cultivars, the concentrations of N, P, and K decreased with increasing nematode inoculum levels. This decline was more pronounced in ‘Manfalouty’ than in ‘Wonderful’. The nano-fertilizers, Hyper Feed®, and Hyper Feed Solo® reduced all nematode parameters but only in ‘Wonderful’. Treatment with Hyper Feed® resulted in the highest percentage increases in all plant growth parameters in ‘Wonderful’. Total carbohydrate concentration was increased in ‘Manfalouty’ treated with the nano-fertilizers, especially with Hyper Feed®. Also, concentrations of total phenols and tannins increased in ‘Wonderful’ when treated with either nano-fertilizer. Generally, both nano-fertilizers showed an increase in plant N levels. We recommend using nano-fertilizers in integrated pest management (IPM) programs on pomegranate where they improved plant growth parameters and reduced nematode multiplication parameters more markedly than inorganic fertilizers.

Sensitivity of microbial bioindicators in assessing metal immobilization success in smelter-impacted soils

While plant toxicity reduction remains the primary metric for judging the success of metal immobilization in soil, the suitability of microorganisms as universal indicators of its effectiveness in various contaminated soils remains a point of contention. This study assessed the sensitivity of microbial bioindicators in monitoring metal immobilization success in smelter-impacted soils. It compared plants and microorganisms as indicators of the efficiency of natural Fe–Mn nodules from the Gulf of Finland in immobilizing metals in soils contaminated by a Ni/Cu smelter, on the Kola Peninsula, Murmansk region, Russia. Perennial ryegrass (Lolium perenne) was grown on nodule-amended and control soils. Plant responses in the smelter-impacted soils proved to be sensitive and robust indicators of successful metal immobilization. However, microbial responses exhibited a more complex story. Despite the observed reductions in soluble metal concentrations, shoot metal contents in ryegrass, and significant improvements in plant growth, certain microbial bioindicators were unresponsive to metal immobilization success brought about by the addition of Fe–Mn nodules. Among microbial bioindicators studied, community-level physiological profiling, microbial biomass carbon, and basal respiration were sensitive indicators of metal immobilization success, whereas the number of saprotrophic, oligotrophic, and Fe-oxidizing bacteria and fungi, the biomass of bacteria and fungi, and enzymatic activity were less robust indicators. Interestingly, the correlations between different microbial responses measured were weak or even negative. Some microbial responses also exhibited negative correlations with plant biomass. These findings underscore the need for further research on comparative evaluations of plants and microorganisms as reliable indicators of metal immobilization efficacy in polluted environments.

The Coupling Effects of PGPR Inoculation and Foliar Spraying of Strigolactone in Mitigating the Negative Effect of Salt Stress in Wheat Plants: Insights from Phytochemical, Growth, and Yield Attributes

Salt stress has detrimental effects on wheat plants at several physiological, biochemical, and molecular levels. This stress leads to suppressed growth, reduced grain yield, and poor quality of harvested grains. However, two approaches have shown promise for improving wheat salt tolerance: using a synthetic strigolactone analog called GR24 and applying plant growth-promoting rhizobacteria (PGPR). GR24 plays a vital role in regulating plant growth and development and in defense against various stresses. Conversely, PGPR are beneficial bacteria that colonize the rhizosphere of plants and promote their growth through multiple mechanisms. In our study, we investigated the effects of salinity on the growth and yield traits of two different wheat cultivars and explored the combined role of PGPR and GR24 in mitigating the impact of salt stress. We created three different salinity levels using NaCl in pots (original, 5 dS m−1, and 10 dS m−1) and inoculated wheat seeds with a salt-tolerant Bacillus velezensis UTB96 strain. In addition, we applied 10 μM GR24 via foliar application during the pollination stage. Our observations showed that salt stress negatively affected wheat’s growth, yield, and phytochemical properties compared to the control. However, both single and combined applications of PGPR and GR24 mitigated the adverse effects of salinity. The combined treatment had a more substantial impact than either alone in inducing and improving biochemical and ionic characteristics. These included decreasing Na+ content in both leaves and roots, and EL, H2O2, and MDA content in leaves while increasing K+ content in both leaves and roots, growth and yield-related traits, RWC, chlorophyll pigments, total protein, soluble sugar, starch, proline, GB, and antioxidant enzyme activity (APX, POX, and CAT) of leaves. In conclusion, integrating PGPR and GR24 can efficiently induce salt tolerance and improve plant growth under stressed conditions. This combined approach has the potential for broad applicability in supporting plant growth in the presence of salt stress.

The Impact of Aboveground Epichloë Endophytic Fungi on the Rhizosphere Microbial Functions of the Host Melica transsilvanica.

In nature, the symbiotic relationship between plants and microorganisms is crucial for ecosystem balance and plant growth. This study investigates the impact of Epichloë endophytic fungi, which are exclusively present aboveground, on the rhizosphere microbial functions of the host Melica transsilvanica. Using metagenomic methods, we analyzed the differences in microbial functional groups and functional genes in the rhizosphere soil between symbiotic (EI) and non-symbiotic (EF) plants. The results reveal that the presence of Epichloë altered the community structure of carbon and nitrogen cycling-related microbial populations in the host's rhizosphere, significantly increasing the abundance of the genes (porA, porG, IDH1) involved in the rTCA cycle of the carbon fixation pathway, as well as the abundance of nxrAB genes related to nitrification in the nitrogen-cycling pathway. Furthermore, the presence of Epichloë reduces the enrichment of virulence factors in the host rhizosphere microbiome, while significantly increasing the accumulation of resistance genes against heavy metals such as Zn, Sb, and Pb. This study provides new insights into the interactions among endophytic fungi, host plants, and rhizosphere microorganisms, and offers potential applications for utilizing endophytic fungi resources to improve plant growth and soil health.

AMF symbiosis drives the rhizosphere microbiome to synergistically improve herbage growth in saline–alkaline soils

AbstractPlant–microbe interactions are essential in shaping plant performance and overall ecosystem functioning. However, the regulatory mechanisms underlying plant–microbe interactions mediated by mycorrhizal symbiosis in saline–alkaline soils are still not fully understood. Here, we aimed to clarify the synergistic regulatory mechanism through which arbuscular mycorrhizal fungi (AMF) symbiosis drives the rhizosphere microbiome to improve perennial herbage growth in saline–alkaline soils and evaluate phytoremediation efficiency. This study revealed that Funneliformis mosseae inoculation (i) strongly promoted the growth of all three herbage species (with values ranging from 21.62% to 233.33%), Na+ accumulation in plants (with values ranging from 24.63% to 188.89%), and decreased soil electrical conductivity (with values ranging from 7.68% to 12.87%), potentially suggesting improved phytoremediation efficiency with AMF symbiosis; (ii) increased nutritional content and decreased C:P and N:P ratios (with values ranging from 27.20% to 92.87%) and improved K+/Na+ and P/Na+ ratios (with values ranging from 2.60% to 302.96%); (iii) increased the abundance of some beneficial bacterial taxa and strengthened the significant strong relationships among most of these bacteria and plant biomass, ion homeostasis as well as stoichiometric ratio constants, and AMF inoculation treatments also consisted the higher proportion of differential genera significantly correlated with these plant factors as well as plant nutrient contents, potentially reflecting that AMF mediated the enrichment process of beneficial bacterial taxa and may strength functional interaction between plant and bacterial taxa, which may be importance for the enhancement of saline–alkaline tolerance of plants; and (iv) enhanced stability of the rhizosphere bacterial community and complexity of interaction networks, and the related indictors also established significant correlations with plant/soil factors, suggesting that the improvement of stability and functional complexity driven by AMF may also be beneficial for enhancing phytoremediation efficiency. These findings indicate that AMF inoculation plays its own beneficial role by simultaneously activating the potential of beneficial rhizosphere bacterial taxa and that their synergistic interaction is more beneficial for enhancing plant growth in salt‐affected soils and enhancing phytoremediation efficiency. This study helps to elucidate the underlying mechanisms through which AMF‐mediated rhizosphere bacterial community improve plant growth and tolerance to saline–alkaline stresses, and provides evidence that effective ecological restoration of saline–alkaline degraded grasslands can be achieved via the use of mycorrhizal symbiosis herbage.

Cocopeat supplementation negates lunar soil simulant-induced baneful phenotypic and biochemical changes in crop seedlings

Lunar exploration has captivated significant attention in recent times through programs such as Artemis. To establish long-term sustenance on the moon, astronauts have to grow their food on-site. While a key substrate for plant production – lunar regolith can induce baneful effects, supplementation with organic amendments could alleviate this inherent toxicity and significantly improve plant growth. In the present study, we examined the suitability of cocopeat (CP) as an amendment to ISRO's lunar soil simulant (LSS), LSS-ISAC-1. We assessed the germination and seedling growth response of four crops—wheat, tomato, groundnut, and cotton to LSS and Cocopeat supplementation. As anticipated, all four crops grew very well on earth soil (ES) and CP per se compared to the LSS. However, due to acidic pH, low electric conductivity (EC), and severe nutrient deficiency in LSS, we observed significantly low germination, stunted seedling growth, and altered associated oxidative stress indicators. To mitigate these pernicious effects, LSS supplemented with varied CP proportions – 3.125, 6.25, 12.50, 25, 50, and 100 %. The resultant data revealed that LSS supplemented with 6.25 % CP in wheat and tomato; 3.125 % CP in groundnut, and 25 % CP in cotton significantly improved phenotypic and biochemical traits in seedlings. Collectively, this study suggests the utility of CP as a novel augmenting agent to boost ISRU strategy for crop growth in moon regolith.

Significant Effect Of Amended Soil On Microbial Flora Of Soil And Plant Growth In Comparison With Natural Low Nutritive Soil

Soil chemical properties, such as Carbon and Nitrogen levels, are crucial for fulfilling the basic needs of plants. The presence of secondary and tertiary nutrients plays a vital role in constructing soil structure, influencing the survival of normal microbial flora, seeds, and later plant growth. The use of chemical fertilizers addresses nutritional deficiencies, but reports indicate that only 40% is utilized by plants, leading to soil issues like salinity and drought logging. When soil lacks essential nutrients, external amendments are necessary, impacting plant growth and crop yield by enhancing normal microbial flora i.e. Plant growth-promoting rhizobacteria (PGPRs). Recognizing the significance of both chemical nutrients and physical properties for healthy plant growth, a soil amendment called "Fertisol soil" was developed. This involved adding basic and secondary nutrients to the soil. The amended soil underwent analytical characterization and was compared with natural soil through chemical analysis and microbial growth assessments. Comparative studies using the amended soil showed improved plant growth and flowering capacity compared to control plants in terms of height and flowering. This highlights the positive impact of balanced nutrient amendments on soil health and overall plant performance.

Experimental evidence that root-associated fungi improve plant growth at high altitude.

Unravelling how species communities change along environmental gradients requires a dual understanding: the direct responses of the species to their abiotic surroundings and the indirect variation of these responses through biotic interactions. Here, we focus on the interactive relationships between plants and their symbiotic root-associated fungi (RAF) along stressful abiotic gradients. We investigate whether variations in RAF community composition along altitudinal gradients influence plant growth at high altitudes, where both plants and fungi face harsher abiotic conditions. We established a translocation experiment between pairs of Bistorta vivipara populations across altitudinal gradients. To separate the impact of shifting fungal communities from the overall influence of changing abiotic conditions, we used a root barrier to prevent new colonization by RAF following translocation. To characterize the RAF communities, we applied DNA barcoding to the root samples. Through the utilization of joint species distribution modelling, we assessed the relationship between changes in plant functional traits resulting from experimental treatments and the corresponding changes in the RAF communities. Our findings indicate that RAF communities influence plant responses to stressful abiotic conditions. Plants translocated from low to high altitudes grew more when they were able to associate with the resident high-altitude RAF compared to those plants that were not allowed to associate with the resident RAF. We conclude that interactions with RAF impact how plants respond to stressful abiotic conditions. Our results provide experimental support that interactions with RAF improve plant stress tolerance to altitudinal stressors such as colder temperatures and less nutrient availability.

Isolation of endophytic fungi from wild rice species for disease management and growth promotion in cultivated rice (Oryza sativa L.)

ABSTRACT The focus of plant health management is shifting from synthetic chemicals to bio-agents, and endophytes are beneficial for this purpose. In the present study, we isolated eleven endophytic fungi from seven wild rice species. Independent treatment of endophytic fungi in rice showed significant improvements in plant growth, higher tillering and percent fertility, panicle number/hill and filled grain number in endophyte-inoculated plants compared to control plants. Growth promotion activities of two endophytes Curvularia lunata (NRRI EF-11) and Hypocreals sp. (NRRI EF-8) were recorded with increased rice yield. These isolates also exhibited higher plant growth promoting chemicals namely, Indole acetic acid (IAA) and Inorganic phosphate (IP) which was realised into better growth promotion in rice. The biocontrol efficacy of endophytic fungi was highest in NRRI EF-11among all isolates as indicated by inhibition of radial growth of pathogens by 76.98–77.06% and in NRRI EF-8 by 74.81–76.61%, which is due to higher production of prussic acid. Defense induction was confirmed by analyzing the expression of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) defense enzymes, where expression of CAT, POD and SOD increased by 19.44–25.86, 2.70–3.16, 11.14–12.95 Units g−1 in treated NRRI EF-11 plants and 18.39–25.84, 2.16–2.94, 10.96–12.62 Units g−1 in treated NRRI EF-8 plants, respectively. These two endophytes have the potentiality to manage crop health in a sustainable way.

Glutathione‐induced hydrogen sulfide enhances drought tolerance in sweet pepper (Capsicum annuum L.)

AbstractGlutathione (GSH) has been studied for its potential to enhance stress tolerance in plant systems, but the role of hydrogen sulfide (H2S) in GSH‐induced water stress tolerance in sweet pepper (Capsicum annuum L.) is still under investigation. This study explores how H2S and GSH modulate water stress tolerance in pepper plants, addressing a research gap. The joint effect of sodium hydrosulfide (NaHS), a donor of H2S, and GSH on water stress tolerance was determined through pre‐treatment with the H2S scavenger 0.1 mM hypotaurine (HT). Pepper seedlings were sprayed with 1.0 mM GSH or GSH + 0.2 mM NaHS once a week, with soil moisture content set at 80% and 40% for full irrigation and water stress conditions for a duration of 2 weeks. The results showed that water stress significantly reduced total plant dry weight, chlorophyll a and b content, Fv/Fm, leaf water potential, and relative water content by 50%, 56%, 33%, 27%, 52%, and 34%, while increasing hydrogen peroxide (H2O2), proline, and H2S levels by 152%, 134%, and77%, respectively. Treatment with GSH and NaHS reduced water stress‐induced H2O2 production and improved plant growth, photosynthetic traits, proline, and the activity of L‐cysteine desulfhydrase (L‐DES), leading to the generation of H2S content. GSH reduced NADPH oxidase (NOX), superoxide dismutase (SOD), and H2O2 but increased glutathione peroxidase (GPX) activities. The interaction of NaHS and GSH led to further reductions in NOX, SOD, and H2O2 values but increased GPX activity. The combined GSH and NaHS treatment increased nitric oxide (NO) production but decreased the activity of S‐nitrosoglutathione reductase (GSNOR), potentially accelerating S‐nitrosylation. Hypotaurine negated the positive impacts of GSH on water stress tolerance by reducing H2S concentration in pepper plants, but this was corrected by the concurrent application of NaHS and GSH + HT. Therefore, water stress tolerance requires H2S.

Plant growth-promoting rhizobacteria (PGPR) improve the growth and quality of several crops

Plant growth-promoting rhizobacteria (PGPR) are known to have the effect of promoting plant growth. In this paper, three PGPR strains were selected from the previous work, which had plant growth-promoting activities such as phosphate solubilization, nitrogen fixation, phosphorus mobilization, etc. These strains named FJS-3(Burkholderia pyromania), FJS-7(Pseudomonas rhodesiae), and FJS-16(Pseudomonas baetica), respectively, were prepared into solid biological agents. Three widely planted commercial crops (tea plant, tobacco, and chili pepper) were selected for PGPR growth promotion verification. The results showed that the new shoots of tea seedlings under PGPR treatment were much more than the control. We also used tobacco, another important crop in Guizhou, to test the growth-promoting effect of individual bacteria, and the results showed that each of them could promote the growth of tobacco plants, and FJS-3(Burkholderia pyrrocinia) had the best effect. In addition, we carried out experiments on tobacco and pepper using multi-strain PGPR, the tobacco plants' height, fresh, and root weight increased by 30.15 %, 37.36 %, and 54.5 %, respectively, and the pepper plants' increased by 30.10 %, 56.38 % and 43.18 %, respectively, which both showed significantly better effects than that of a single strain. To further test the field performance, field trials were carried out in a mature Longjing43 tea plantation in Guizhou. There were four treatments: no fertilization (T1), combined application of PGPR biological agent and compound fertilizer (T2), only application of PGPR (T3), and only application of compound fertilizer (T4). In terms of yield, grouped with or without PGPR, there was a 15.38 % (T2:T4) and 92.31 % (T3:T1) increase between them, respectively. The tea's yield and tea flavor substances such as tea polyphenols, caffeine, and theanine were detected, and the T2 showed the most significant positive effect on both sides. Especially, an important indicator of Matcha green tea is the color, chlorophyll content was then tested, and PGPR application increased it and improved the appearance. All these results demonstrated that the PGPR we screened could significantly promote plant growth and quality improvement, and had good application potential in crop planting, which could contribute to environmental protection and economic growth.

Foliar Application of Moringa Seed Extract Alone or in Combination with Salicylic Acid Enhanced Growth, Bioactive, and Phytohormone Compositions of Cancer Bush Plants under Heat Stress

Cancer bush (Lessertia frutescens L.) is an important medicinal plant that is rich in health beneficial compounds. It is commonly used in traditional medicine and as an ornamental plant. Heat stress is the most threatening abiotic factor restricting plant growth, thus causing crop yield and economic losses worldwide. The application of plant-derived biostimulant is as an innovative and promising approach for improving plant growth and productivity. The study was aimed to investigate the effect of moringa (Moringa oleifera Lam.) seed extract (MSE; 5%) either alone or in combination with salicylic acid (SA; 40 mg/L) on the growth, bioactive, and phytohormone attributes of cancer plants subjected to heat stress (38 °C for 2 hours for 5 days). Plants that were not treated were used as control. Plant pots were arranged in a randomized complete block design (RCBD) for treatments (MSE, SA, and MSE + SA) at 7-day intervals during the experiment. Both MSE and MSE + SA foliar application effectively increased plant growth characteristics and total carotenoids contents, and reduced electrolyte leakage and had no symptoms of wilting compared with SA and control. Plants treated with MSE showed higher number of branches and concentrations of abscisic acid (ABA), jasmonic acid (JA), and indole-3-acetic acid (IAA), and lower superoxide and hydrogen peroxide compared with other treatments and control. Also, plants treated with MSE + SA showed higher total chlorophylls and glutathione concentrations compared with other treatments and control. Overall, the application of MSE either alone or in combination with SA enhanced plant growth and productivity of heat-stressed cancer bush plants.