Improve Plant Growth Research Articles

Zeolite enhances leaf photosynthesis and fruit quality in tomato through greenhouse CO2 enrichment

Elevated CO2 concentration has been widely acknowledged as a leading factor to global climate change, while deficient CO2 serves as a crucial limiting factor in modern greenhouse production. Harnessing the existing excessive CO2 to promote agriculture production is significant but filled with challenges. To this end, we proposed a concentration gradient-regulated CO2 enrichment system for capturing CO2 into greenhouses, which requires suitable CO2 sorbents with sufficient CO2 desorption capacity and high hydrophobicity at ambient temperature and pressure. Zeolites with different framework types and cations were detected by CO2 desorption and cyclic stability test under simulated agricultural production conditions. The results indicate that larger pore volume cooperated with higher Si/Al ratio and weaker alkali cations may be critical determinants for balancing high CO2 adsorption-desorption capacities and hydrophobicity in crop-cultivated environments. H-SSZ-13 zeolite is identified as the potential sorbents and exhibits exceptional CO2 release abilities and cyclic stability in tomato-grown environment. Long-term application of H-SSZ-13 zeolite to tomato plants significantly stimulated photosynthetic processes, particularly the Calvin-Benson cycle, culminating in notable improvements in plant growth, fruit yield and quality. This investigation provides a promising solution to develop a carbon-neutral CO2 enrichment system for both sustainable and productive greenhouse production.

Arbuscular Mycorrhizal Fungi Inducing Tomato Plant Resistance and Its Role in Control of Bemisia tabaci Under Greenhouse Conditions.

Arbuscular mycorrhizal fungi (AMF) are one of the environment-friendly organisms that enhance plant performance. AMF affect the herbivorous insect community by indirectly modifying host plant nutrient uptake, growth, and defense, also known as priming. In the current study, under greenhouse conditions, the effects of inoculating tomato seedlings with four species of AMF, i.e., Funneliformis mosseae, Rhizophagus intraradices, Rhizophagus irregularis, and Glomus iranicus, were studied in relation to tomato plant growth parameters, plant defense enzymes, and total phenol content, and additionally, the life table of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) feeding on these plants was determined. The results demonstrated that the growth parameters of tomato plants, including plant height, stem diameter, number of leaves, root volume, leaf surface area, weight of the root, and aerial organs (containing the leaves and stem), were greater and larger in the AMF-inoculated plants compared to the non-inoculated plants. Furthermore, there were higher defense enzyme activities, including peroxidase, phenylalanine ammonia lyase and polyphenol oxidase, and also higher total phenol contents in the AMF-inoculated plants. The whitefly life table characteristics were decreased in the group feeding on the AMF-inoculated plants. All together, the AMF colonization made the tomato plants more resistant against B. tabaci by improving plant growth and increasing defense enzymes. The degree of priming observed here suggests the potential of AMF to have expansive applications, including their implementation in sustainable agriculture.

Modifying Rhizobacteria for Improved Plant Growth and Soil Health in Sustainable Agriculture

Modifying Rhizobacteria for Improved Plant Growth and Soil Health in Sustainable Agriculture

Epichloë bromicola Enhances Elymus dahucirus Plant Growth and Antioxidant Capacity under Cadmium Stress

Elymus dahucirus is an essential plant for ecological restoration in fragile ecological areas and mining area restoration. As lawn grass, it can quickly cover soil and prevent soil erosion, so it is commonly used as a pioneer grass for lawn greening and slope protection. In recent years, with the development of mineral resources, Qinghai–Tibet Plateau soil is facing the threat of heavy metal cadmium (Cd) pollution. E. dahuricus can host the filamentous fungus Epichloë bromicola. To make better use of the advantages that Epichloë bring to host plants to alleviate heavy metal pollution in soil, plant growth and antioxidant capacity effects on E. bromicola infected (E+) and uninfected (E−) E. dahuricus were determined under Cd stress. During Cd treatment, plant growth was decreased by Cd stress, while E+ plants exhibited equal or better growth compared to E− plants. Cd treatment induces a proline and antioxidant enzyme burst in infected plants, while malondialdehyde (MDA) increases. E. bromicola improved plant growth and antioxidant capacity. E. dahuricus breeding strategies could use the information here in efforts to improve the performance of E. dahuricus in both environmental protection and agronomic contexts.

Mitigation of cadmium toxicity stress by magnetopriming during germination of soybean

Cadmium (Cd) is a highly toxic heavy metal that poses a significant threat to food safety and agricultural production worldwide. Its solubility enables easy entry into plants, leading to reductions in seed germination, growth and crop yield. Thus, it is crucial to discover methods to alleviate the harmful impact of Cd on plant growth. Magnetopriming (MP) is a non-invasive and cost-effective technique that has been proposed to improve plant growth under abiotic stress conditions. The current study investigated the potential of MP to improve the seed germination, early seedling growth and biochemical responses of soybean under Cd toxicity. Soybean seeds were magnetoprimed with static magnetic field (SMF) strength of 200 mT for 1 hour before germination. The unprimed and magnetoprimed seeds were grown under different concentrations of cadmium chloride (0, 25, 50, 75, 100, 200 and 300 μM CdCl2) in Petri plates for five days in the dark at 25 + 1°C. The results revealed that Cd toxicity significantly reduced the germination percentage and inhibited the seedling growth parameters and increased oxidative stress, as determined by malondialdehyde (MDA) content in soybean seedlings from unprimed seeds. The inhibitory effect was increased with increasing concentration of Cd. However, MP remarkably increased the germination percentage, seedling growth parameters, activities of total amylase and protease, and hydrogen peroxide (H2O2) content and decreased MDA and proline content in germinating soybean seedlings at all concentrations of Cd. These findings suggest that MP can alleviate the adverse effects of Cd stress in soybean seedlings and increase the tolerance index towards Cd toxicity by enhancing the activity of amylotic and proteolytic enzymes and reducing oxidative stress.

Grafting in Tomato for Improving Abiotic Stress Tolerance, Yield and Quality Traits

Tomato (Solanum lycopersicum L.) is a major vegetable crop worldwide, however, its production is adversely affected by a wide range of abiotic and biotic stresses at various stages of its cultivation. Abiotic stresses, such as drought, salinity, flooding, extreme temperatures and heavy metals can cause morphological, physiological and biochemical changes in the plant, which ultimately affect crop growth, yield and quality. Among various mitigation strategies, grafting technology has emerged as an effective and alternative tool to slow breeding programs to alleviate various biotic and abiotic stresses. Various studies indicated that increased osmolytes accumulation, synthesis of antioxidant enzymes, improved photosynthesis and vigorous root architecture in grafted tomatoes confer tolerance towards abiotic stresses, besides improving plant growth and fruit yields. Moreover, tomato grafting on suitable rootstocks has also a positive effect on the nutritional qualities of fruits, such as, lycopene, β-carotene, ascorbic acid, proteins, etc.). In this review, we have tried to summarize the adverse effects of abiotic stresses in tomatoes and include all possible recent references related to the response of grafted tomatoes using different intra-and/ or inter-specific rootstocks on improving plant growth, yield and quality and alleviation in various abiotic stresses.

Evaluating the Impact of Plant Growth on Different Varieties of Wheat and Barley Treated With Biofertilizers

Purpose: Biofertilizers have gained recognition as a crucial element in integrated plant nutrient management, contributing to sustainable agriculture. Biofertilizers are natural products that contain living microorganisms capable of enhancing plant growth and improving soil fertility. This study aims to assess the impact of different biofertilizers on the growth of various varieties of wheat and barley. The primary objective of this research is to evaluate the efficacy of biofertilizers as an alternative to chemical fertilizers for promoting the growth of wheat and barley crops.
 Methodology: The experiment involves treating multiple cultivars of wheat and barley with biofertilizers, while a control group is administered traditional chemical fertilizers for comparison. The growth parameters, including plant height, leaf area, root development, and yield, are carefully monitored and recorded throughout the experiment. The study is conducted under controlled environmental conditions to ensure consistency across all plant samples. Collected data is subjected to statistical analysis to determine any significant disparities in growth between the biofertilizer-treated group and the control group.
 Findings: The utilization of biofertilizers resulted in remarkable growth improvements in the plants as opposed to conventional fertilizers. The plants treated with biofertilizers exhibited noticeable enhancements in various parameters, including increased plant height, expanded leaf area, elongated root length, and greater biomass accumulation. Among the different crop varieties, certain ones showcased a more pronounced response to biofertilizer treatments. Specifically, varieties W1 and W2 of wheat displayed the highest levels of growth enhancement when treated with biofertilizers, while barley varieties B1 and B2 showed significant improvements as well. Furthermore, the application of biofertilizers led to higher grain weight and increased yield per unit area in the crops compared to traditional fertilizers. Notably, the biofertilizer-treated crops also exhibited notable enhancements in quality attributes, such as improved nutritional content and reduced pesticide residues.
 Unique contributor to theory, policy and practice: The utilization of biofertilizers demonstrated significant advantages over traditional fertilizers, resulting in improved plant growth, increased yield, and enhanced quality attributes in various crop varieties.

Genomic Insights into the Symbiotic and Plant Growth-Promoting Traits of "Candidatus Phyllobacterium onerii" sp. nov. Isolated from Endemic Astragalus flavescens.

A novel strain of Gram-negative, rod-shaped aerobic bacteria, identified as IY22, was isolated from the root nodules of Astragalus flavescens. The analysis of the 16S rDNA and recA (recombinase A) gene sequences indicated that the strain belongs to the genus Phyllobacterium. During the phylogenetic analysis, it was found that strain IY22 is closely related to P. trifolii strain PETP02T and P. bourgognense strain STM 201T. The genome of IY22 was determined to be 6,010,116 base pairs long with a DNA G+C ratio of 56.37 mol%. The average nucleotide identity (ANI) values showed a range from 91.7% to 93.6% when compared to its close relatives. Moreover, IY22 and related strains had digital DNA-DNA hybridization (dDDH) values ranging from 16.9% to 54.70%. Multiple genes (including nodACDSNZ, nifH/frxC, nifUS, fixABCJ, and sufABCDES) associated with symbiotic nitrogen fixation have been detected in strain IY22. Furthermore, this strain features genes that contribute to improving plant growth in various demanding environments. This study reports the first evidence of an association between A. flavescens and a rhizobial species. Native high-altitude legumes are a potential source of new rhizobia, and we believe that they act as a form of insurance for biodiversity against the threats of desertification and drought.

Plant biomarkers as early detection tools in stress management in food crops: a review.

Plant Biomarkers are objective indicators of a plant's cellular state in response to abiotic and biotic stress factors. They can be explored in crop breeding and engineering to produce stress-tolerant crop species. Global food production safely and sustainably remains a top priority to feed the ever-growing human population, expected to reach 10 billion by 2050. However, abiotic and biotic stress factors negatively impact food production systems, causing between 70 and 100% reduction in crop yield. Understanding the plant stress responses is critical for developing novel crops that can adapt better to various adverse environmental conditions. Using plant biomarkers as measurable indicators of a plant's cellular response to external stimuli could serve as early warning signals to detect stresses before severe damage occurs. Plant biomarkers have received considerable attention in the last decade as pre-stress indicators for various economically important food crops. This review discusses some biomarkers associated with abiotic and biotic stress conditions and highlights their importance in developing stress-resilient crops. In addition, we highlighted some factors influencing the expression of biomarkers in crop plants under stress. The information presented in this review would educate plant researchers, breeders, and agronomists on the significance of plant biomarkers in stress biology research, which is essential for improving plant growth and yield toward sustainable food production.

The Function of Root Exudates in the Root Colonization by Beneficial Soil Rhizobacteria.

Soil-beneficial microbes in the rhizosphere play important roles in improving plant growth and health. Root exudates play key roles in plant-microbe interactions and rhizobacterial colonization. This review describes the factors influencing the dynamic interactions between root exudates and the soil microbiome in the rhizosphere, including plant genotype, plant development, and environmental abiotic and biotic factors. We also discuss the roles of specific metabolic mechanisms, regulators, and signals of beneficial soil bacteria in terms of colonization ability. We highlight the latest research progress on the roles of root exudates in regulating beneficial rhizobacterial colonization. Organic acids, amino acids, sugars, sugar alcohols, flavonoids, phenolic compounds, volatiles, and other secondary metabolites are discussed in detail. Finally, we propose future research objectives that will help us better understand the role of root exudates in root colonization by rhizobacteria and promote the sustainable development of agriculture and forestry.

Arabidopsis transcription factor STOP1 directly activates expression of NOD26-LIKE MAJOR INTRINSIC PROTEIN5;1, and is involved in the regulation of tolerance to low-boron stress.

Transcriptional regulation is a crucial component of plant adaptation to numerous different stresses; however, its role in how plants adapt to low-boron (B) stress remains unclear. In this study, we show that the C2H2-type transcription factor SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1) in Arabidopsis is essential for improving plant growth under low-B conditions. STOP1 and the boric acid-channel protein NOD26-LIKE MAJOR INTRINSIC PROTEIN5;1 (NIP5;1) were found to co-localize in root epidermal cells, and STOP1 binds to the 5´-untranslated region of NIP5;1 to activate its expression and enhance B uptake by the roots. Overexpression of STOP1 increased tolerance to low-B stress by up-regulating NIP5;1 transcript levels. Further genetic analyses revealed that STOP1 and NIP5;1 function together in the same pathway to confer low-B tolerance. These results highlight the importance of the STOP1-NIP5;1 module in improving plant growth under low-B conditions.

Effectiveness of Rhizobium tropici sp. Strain UD5 Peat Biofertilizer Inoculant on Growth, Yield, and Nitrogen Concentration of Common Bean

Common bean (Phaseolus vulgaris L.) ranks among the most produced and consumed legume crops and contains essential macro- and micronutrients. Grain yield of the food crop is markedly decreased by poor management, especially a lack of additional essential nutrient elements through the application of fertilizers. In addition to the application of fertilizers, scholarly research and crop farmers have shown that the use of biofertilizer inoculants improves the yield of legume crops. The objective of this research study was to assess the effectiveness of peat-based Rhizobium tropici sp. UD5 on the growth, yield, and nitrogen concentration of common bean. The peat inoculant contained 6.5 × 109 viable cells/g. The experiment was conducted in two climatic zones, as described by the Koppen–Gieger climatic classification system. Treatments involved the peat-based inoculant Rhizobium tropici (T0 = 0 g without inoculation, T1 = 250 g of peat inoculant of strain UD5 for 50 kg seeds, T2 = 500 g of inoculant of strain UD5, and T3 = 200 g of comparative peat inoculant). The results indicated that common-bean-inoculated formulation of R. tropici sp. strain UD5 increased the following parameters compared to the controls: plant height (T1 = 18.22%, T2 = 20.41%, and T3 = 19.93% for bioclimatic zone 1; T1 = 16.78%, T2 = 20.71%, and T3 = 19.93% for bioclimatic zone 2), root length (T1 = 13.26%, T2 = 21.28%, and T3 = 19.38% for zone 1; T1 = 15.06%, T2 = 23.70%, and T3 = 19.20% for zone 2), number of nodules (T1 = 1162.57%, T2 = 1166.36%, and T3 = 1180.30% for zone 1; T1 = 1575%, T2 = 1616.5%, and T3 = 1608.25% for zone 2), size of nodules (T1 = 224.07%, T2 = 224.07%, and T3 = 208.33% for zone 1; T1 = 166.4%, T2 = 180%, and T3 = 140% for zone 2), and yield (T1 = 40.49%, T2 = 47.10%, and T3 = 45.45% for zone 1; T1 = 62.16%, T2 = 54.05%, and T3 = 58.55% for zone 2). R. tropici sp. UD5 peat inoculant formulation also increased the nitrogen concentration in leaves compared to the control (T1 = 3.75%, T2 = 1.12%, and T3 = 8.72%) in both bioclimatic zones. The findings of this study provide significant information on the positive effect of R. tropic UD5 strain peat inoculant application in the improvement of plant growth, development, and yield through the formation of nodules.

Biochar and vermicompost modulated Pb toxicity in summer savory (Satureja Hortensis L.) plants through inducing physiological and biochemical changes

The primary environmental factor affecting the biochemical attributes of plants is soil pollution by heavy metals. The detrimental effects of heavy metals on plants can be lessened by soil amendments. The goal of the current research was to determine the potential of biochar (BC) and vermicompost (VC) as soil amendments in reducing Pb toxicity in summer savory (Satureja HortensisL.) though physiological and biochemical modifications. Therefore, the pot experiment was conducted with Pb toxicity (control (non-Pb), 300, and 600 mg kg soil-1) and soil amendments (control, 2% BC, 10% VC, and 1% BC+5% VC) based on a completely randomized design. The results showed that Pb toxicity at 600 mg kg soil-1 led to significant decreases in shoot weight (41%), root weight (25%), leaf relative water content (20%), and chlorophyll content (39%) compared to the control. However, it resulted in increases in malondialdehyde (61%) and electrolyte leakage (49%) when BC and VC were not applied. The results showed that Pb toxicity at 600 mg kg soil-1 led to decreases in shoot weight (41%), root weight (25%), leaf relative water content (20%), and chlorophyll content (39%), but increases in malondialdehyde (61%), and electrolyte leakage (49%) compared to the control in the treatments without BC and VC application. However, BC and VC, particularly their combination were more effective in improving plant growth. The interaction of Pb at 300 mg kg-1 and combined BC and VC resulted in higher total phenolic content, total flavonoid content, essential oil (EO) content, and EO yield with 29, 62, and 39, and 35% raises compared with the control. Agglomerative hierarchical clustering revealed that Pb at 300 and 600 mg kg soil-1 differed from the control, and that combined VC and BC significantly varied from their individual values. Combining BC and VC is more effective than using them separately in alleviating Pb toxicity, as it enhances plant growth and secondary metabolite production. The results have the potential to benefit the improvement of summer savory resistance in Pb-polluted soils.

Application of Trichoderma harzianum and Bacillus thuringiensis in increasing plant growth of Aceh patchouli (Pogostemon cablin Benth)

Aceh Patchouli (Pogostemon cablin Benth), an essential oil crop, has been famous for a long time. The best quality patchouli producing area in Indonesia is Aceh Province. Trichoderma harzianum is one of the PGPFs that has been successfully used on a commercial scale while Bacillus thuringiensis as a plant growth-promoting rhizobacteria (PGPR). Improving plant growth, one of its roles, especially seed germination, and shoot elongation. The use of these two microbes indicates that plants grow well and healthy, this is part of the efficiency of plant disease management. In connection with the large number of patchouli plants in Blang Tingkeum Village, Mukim Lamteuba, Seulimum District, Aceh Besar, it is necessary to know whether Application of T. harzianum and B. thuringiensis in the field can increase the growth of aceh patchouli plants (Pogostemon cablin Benth), Plant height, number of shoots, and crown width were observed. The study used a non-factorial Randomized Group Design with 3 treatments and 7 blocks. PGPR and PGPF from both microbes are concluded to play a role in increasing plant growth and production based on the parameters mentioned above.

Comparative Response of Arbuscular Mycorrhizal Fungi versus Endophytic Fungi in Tangor Citrus: Photosynthetic Efficiency and P-Acquisition Traits

Citrus plants are prone to phosphorus (P) deficiency, especially in acidic soil, making them more dependent on root-associated endophytic fungi for growth and development. Beni-Madonna, a hybrid of Citrus nanko × C. amakusa, is a citrus known as “tangor” that is highly popular in China and other parts of the world due to its deep red color and jelly-like flesh. In this study, the inoculation response to two arbuscular mycorrhizal fungi (Diversispora versiformis, Dv; Funneliformis mosseae, Fm) and an endophytic fungus (Serendipita indica, Si) with regard to the growth, leaf gas exchange, light energy efficiency, P levels, acid phosphatase activity, and expression of the purple acid phosphatase (PAP) and phosphate transporter (PT) genes through a potted experiment using Beni-Madonna (tangor) citrus plants grafted on trifoliate orange (Poncirus trifoliata) was studied. Two years following inoculation, the root fungal colonization rates of inoculated plants were significantly increased, accompanied by an increase in plant height and stem diameter, with Si presenting the best effect. Fungal inoculations also significantly increased the leaf chlorophyll index, nitrogen-balance index, photosynthesis rate, stomatal conductance, transpiration rate, photosynthetic efficiency, and quantum yield of PSII, while it reduced photoinhibition and heat dissipation, with Si having the best effect on light energy efficiency. Si significantly increased leaf and root P levels, as well as root CsPAP1‒3, CsPT2, CsPT3, and CsPT7 expression and soil acid phosphatase activity; Fm in mycorrhizal fungi significantly increased leaf and root P levels, as well as root CsPT1 and CsPT7 expression and root/soil acid phosphatase activity. These observations suggested an advantage of Si over the other two AMF in terms of improved plant growth and P acquisition, while Fm displayed prominent effects on increased photosynthetic efficiency.

Pseudoxanthomonas sp. JBR18, a halotolerant endophytic bacterium, improves the salt tolerance of Arabidopsis seedlings

Salinization of land is globally increasing due to climate change, and salinity stress is an important abiotic stressor that adversely affects agricultural productivity. In this study, we assessed a halotolerant endophytic bacterium, Pseudoxanthomonas sp. JBR18, for its potential as a plant growth-promoting agent with multiple beneficial properties. The strain exhibited tolerance to sodium chloride concentration of up to 7.5 % in the R2A medium. In vitro evaluation revealed that strain JBR18 possessed proteolytic, protease (EC 3.4), and cellulase (EC 3.2.1.4) activities, as well as the ability to produce indole-acetic acid, proline, and exopolysaccharides. Compared with the controls, co-cultivation of Arabidopsis seedlings with the strain JBR18 improved plant growth, rosette size, shoot and root fresh weight, and chlorophyll content under salinity stress. Moreover, JBR18-inoculated seedlings showed lower levels of malondialdehyde, reactive oxygen species, and Na+ uptake into plant cells under salt stress but higher levels of K+. Additionally, seedlings inoculated with JBR18 exhibited a delayed response time and quantity of salt-responsive genes RD29A, RD29B, RD20, RD22, and KIN1 under salt stress. These multiple effects suggest that Pseudoxanthomonas sp. JBR18 is a promising candidate for mitigating the negative impacts of salinity stress on plant growth. Our findings may assist in future efforts to develop eco-friendly strategies for managing abiotic stress and enhancing plant tolerance to salt stress.

Foliar application of natural zeolites affects the growth and productivity of processing tomato

The foliar application of zeolites has been proven to positively affect plant physiology suggesting that it could improve plant growth, however, this topic has been little studied. Two field trials were carried out (in 2021 and 2022) to study the potential beneficial effect of natural zeolite particle films on processing tomato crops. Natural zeolites i) clinoptinolite + and mordenite (CubZeo) and ii) micronized clinoptinolite (BigZeo) were sprayed onto the plants six times in the central crop cycles. In both trials, BigZeo promoted leaf and fruit dry mass (DM) accumulation, and leaf area from the early crop stage compared to the water-sprayed plants (Control). The final aerial DM of BigZeo plants enhanced more in the year with favourable (+39.2%) (2022) than in that with more stressing thermal conditions (2021) (+12.1%). Concurrently, the marketable yield was improved by + 36% in both years with positive effects also on fruit total soluble solids. Under heat stress, the CubZeo crop showed even lower aerial DM than the Control, however, the marketable yield remained similar due to higher fruit DM and higher incidence of blossom-end-rot (BER) in untreated plants. In 2022, CubZeo promoted DM accumulation, leaf expansion and yield even if to a lesser extent than the BigZeo treatment. In the fruits the concentrations of K, Ca, and Mg rose in zeolite-treated plants. The improved Ca level in the fruits can explain the lower occurrence of BER in the zeolite-treated plants, particularly with CubZeo. Si was observed at the highest level in fruits and stems of BigZeo-treated plants, followed by CubZeo and Control ones. The accumulation of Si could explain the best crop responses elicited by BigZeo, whereas the observed responses did not appear to involve changes in the photosynthetic machinery. However, further and comprehensive investigations are needed to define the zeolite film particle characteristics and the related physiological and nutritional changes in the plants.

Bio-stimulants from medicinally and nutritionally significant plant extracts mitigate drought adversities in Zea mays through enhanced physiological, biochemical, and antioxidant activities

Drought stress poses a substantial threat to global plant productivity amid increasing population and rising agricultural demand. To overcome this problem, the utilization of organic plant growth ingredients aligns with the emphasis on eco-friendly farming practices. Therefore, the present study aimed to assess the influence of 30 botanical extracts on seed germination, seedling vigor, and subsequent maize plant growth under normal and water deficit conditions. Specifically, eight extracts showed significant enhancement in agronomical parameters (ranging from ∼2 % to ∼ 183 %) and photosynthetic pigments (ranging from ∼21 % to ∼ 195 %) of seedlings under drought conditions. Extended tests on maize in a greenhouse setting confirmed that the application of six extracts viz Moringa oleifera leaf (MLE), bark (MBE), Terminalia arjuna leaf (ALE), bark (ABE), Aegel marmelos leaf (BLE), and Phyllanthus niruri leaf (AmLE) improved plant growth and drought tolerance, as evident in improved physio-biochemical parameters. GC-MS analysis of the selected extracts unveiled a total of 51 bioactive compounds, including sugars, sugar alcohols, organic acids, and amino acids, and might be playing pivotal roles in plant acclimatization to drought stress. In conclusion, MLE, MBE, BLE, and ABE extracts exhibit significant potential for enhancing seedling establishment and growth in maize under both normal and water deficit conditions.

Seaweed Polysaccharides as Potential Biostimulants in Turnip Greens Production

Seaweed polysaccharides can act as substitutes for synthetic compounds present in commercial stimulants and fertilizers used in agriculture to improve crop yields and vigor. In this study, three different polysaccharides (alginate, agar, and carrageenan) were extracted from one brown seaweed, Saccorhiza polyschides, and two red seaweeds, Gracilaria gracilis and Chondrus crispus, respectively, and applied to potted turnip greens (Brassica napus L.), with the intention to analyze their impact on plant growth, development, and metabolism. Turnip greens treated with polysaccharides, especially carrageenan of C. crispus, showed the best results in improving the crop productivity in terms of plant length and weight, number of leaves, nutrient and pigment content, and soil fertility compared with turnip greens from the negative control or those treated with a commercial leaf fertilizer. λ-carrageenan extracted from the tetrasporophyte generation of C. crispus had the highest bioactivity and positive effect on turnip greens among all treatments. λ-carrageenan has been shown to improve plant growth; increase the plant’s biomass (plant leaves: CC(T) (40.80 ± 5.11 g) compared to the positive control (15.91 ± 15.15 g)) and root system; enhance photosynthetic activity; increase the uptake of soil nutrients; and protect plants against abiotic and biotic stresses, stimulating the production of secondary metabolites and managing its defense pathways. Seaweed-extracted polysaccharides have the potential to be used in sustainable agriculture.

Photosynthesis promotion mechanisms of artificial humic acid depend on plant types: A hydroponic study on C3 and C4 plants

It is feasible to improve plant photosynthesis to address the global climate goals of carbon neutrality. The application of artificial humic acid (AHA) is a promising approach to promote plant photosynthesis, however, the associated mechanisms for C3 and C4 plants are still unclear. In this study, the real-time chlorophyll synthesis and microscopic physiological changes in plant leave cells with the application of AHA were first revealed using the real-time chlorophyll fluorescence parameters and Non-invasive Micro-test Technique. The transcriptomics suggested that the AHA application up-regulated the genes in photosynthesis, especially related to chlorophyll synthesis and light energy capture, in maize and the genes in photosynthetic vitality and carbohydrate metabolic process in lettuce. Structural equation model suggested that the photodegradable substances and growth hormones in AHA directly contributes to photosynthesis of C4 plants (0.37). AHA indirectly promotes the photosynthesis in the C4 plants by upregulating functional genes (e.g., Mg-CHLI and Chlorophyllase) involved in light capture and transformation (0.96). In contrast, AHA mainly indirectly promotes C3 plants photosynthesis by increasing chlorophyll synthesis, and the Rubisco activity and the ZmRbcS expression in the dark reaction of lettuce (0.55). In addition, Mg2+ transfer and flux in C3 plant leaves was significantly improved by AHA, indirectly contributes to plant photosynthesis (0.24). Finally, the AHA increased the net photosynthetic rate of maize by 46.50 % and that of lettuce by 88.00 %. Application of the nutrients- and hormone-rich AHA improves plant growth and photosynthesis even better than traditional Hoagland solution. The revelation of the different photosynthetic promotion mechanisms on C3 and C4 plant in this work guides the synthesis and efficient application of AHA in green agriculture and will propose the development of AHA technology to against climate change resulting from CO2 emissions in near future.