Seedling Root Length Research Articles

Overexpression of ZmDUF1644 from Zoysia matrella enhances salt tolerance in Arabidopsis thaliana

The DUF1644 family is a highly conserved and functionally unknown protein family and it has been demonstrated that it significantly improved the salt tolerance of rice (non-halophytes). However, little is understood about the function of the DUF1644 gene in halophytes. This study aimed to investigate whether the DUF1644 gene has a similar function in non-halophytes as in halophytic species. The functions of ZmDUF1644 transferred from the halophytic Zoysia matrella into non-halophytic Arabidopsis thaliana were investigated under salt stress (150 mM NaCl). Phylogenetic analysis clustered ZmDUF1644 and OsSDIP361 in the same group, which function as salt-tolerant genes in rice. The obtained results exhibited that the ZmDUF1644 gene significantly alleviated the adverse effects of salt stress on transgenic Arabidopsis thaliana seedlings. The maximum root length, fresh weight, and photosynthetic pigment content of the transgenic seedlings were obviously better than that of the wild type. The relative electrolyte leakage rate, Na+ content, and Na+/K+ ratios were relatively lower in the transgenic line than in the wild type under salt stress. Moreover, the expression of AtSOS2 gene was also significantly higher than that of wild-type under salt stress. The study concluded that the ZmDUF1644 gene was significantly overexpressed in salt-stressed Arabidopsis thaliana, enhancing its salt tolerance. It is the first report on the functions of ZmDUF1644 from halophytic Zoysia matrella which has a similar function in glycophytic species or non-halophytic species.

Foliar application of 6-benzyladenine after pollination improves hybrid rice seed vigor through modulating antioxidant system

Application of plant growth regulators emerges as one of the most reliable methods to enhance crop productivity and quality. However, knowledge is limited in seed quality of hybrid rice subjected to exogenous 6-Benzyladenine (6-BA) application during seed development. A 2-year experiment was conducted to investigate the effects of 6-BA treatment after pollination on seed vigor and its underlying regulatory mechanisms. Results showed that 6-BA treatment increased germination potential (GP) and vigor index (VI) of hybrid rice irrespective of cultivar and year, particularly with 50 mg/L. Consistently, seedling quality including seedling height, root length and dry weight was significantly enhanced under 6-BA treatment with 50 mg/L. Based on the results above, 50 mg/L was considered as the optimal concentration. Additionally, 6-BA treatment with 50 mg/L increased catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) activities, and it strongly induced the expression of OsAPX1 and OsCSD3 related to antioxidant enzyme activity at the early stage of seed emergence. Therefore, spraying 6-BA with 50 mg/L after pollination could be recommended as an agronomic practice for hybrid rice seed production with high seed vigor.

Cold Plasma Treatment for Astragalus membranaceus Seed Germination and Seedling Growth Improvement

Background: Astragalus membranaceus seeds have dormant properties that not only limit germination but also negatively affect the growth of seedlings. We investigated the enhancing effect of cold plasma treatment on seed germination and the positive effect on seedling growth of Astragalus membranaceus by treating its seeds with cold plasma at different power levels. Method: The Astragalus membranaceus seeds were treated with cold plasma at power levels of 40, 60, 80, 100, 120, 140, 160, 180, 200, 220 and 240 W for 15 seconds with helium gas and seeds without any treatment were used as control. Results: The Astragalus membranaceus seeds were treated with cold plasma, which not only improved seed germination, but also had a positive effect on seedling growth, with the best results for the 80 W power cold plasma treatment. The 80 W power cold plasma treatment increased the germination rate, germination index and vigor index of Astragalus membranaceus seeds by 26.8%, 12.4% and 39.8%, respectively; increased root length, CAT activity and SOD activity of Astragalus membranaceus seedlings by 24.5%, 99.7% and 7.1%, respectively and decreased the relative conductivity and MDA content of Astragalus membranaceus seedlings by 6.6% and 17.6%, respectively; compared with that of the control group.

Germination of Lolium perenne and Medicago Species under the Conditions of Drought and Silicon Application as Well as Variable pH and Medicago sativa Root Extracts

Drought and allelopathic conditions impact the germination of seeds of grass and legume species used in mixtures on grassland. This study evaluated the effects of drought and Medicago sativa root extracts at different pH levels on the germination and characteristics of seedlings of Lolium perenne and selected Medicago species. Two experiments were carried out: the first explored the effects of drought induced by PEG solutions (0.0, -0.3, and -0.6 MPa) under silicon (Si) application; the second studied the influence of Medicago sativa root extracts (12 and 24 g/100 mL H2O) and variable pH solutions (control, 5.0, and 6.5) on seed germination. Germination was carried out on Petri dishes for individual species and in two-species mixtures. The drought conditions did not affect the germination capacity of seeds, but it increased the dry weight of the seedlings of the tested species. The application of silicon decreased the root length of the seedlings of all species, independent of the germination conditions. The higher concentration of M. sativa root extract combined with the studied pH solutions had an inhibitive impact on the germination capacity of L. perenne. Our findings revealed that the lower concentration of M. sativa root extract had a beneficial effect on the morphological features (length of roots and leaves, fresh and dry weight) of the seedlings when germination was carried out separately for both species. In the mixture, the effect was especially marked for L. perenne (only in terms of the root length and fresh weight of seedlings). The applied root extracts in combination with the acidic pH conditions limited the germination capacity and growth of the seedlings of L. perenne the most when germination was performed separately. It was concluded from this study that silicon application did not improve the germination capacity of seeds under drought conditions, whereas the germination of L. perenne seeds in a mixture with M. sativa mitigated the negative allelopathic effects of M. sativa root extracts on the seed germination capacity and morphological features of seedlings of L. perenne.

Phytotoxicity of Quillaja lancifolia Leaf Saponins and Their Bioherbicide Potential.

Weeds are major threats to the integrity of agricultural and natural environments due to their invasive and competing potential. Bioherbicides are substances based on natural compounds that are biodegradable and often have low residual effects. Plant species able to produce and release phytotoxic compounds may represent effective bioherbicide sources. Leaves of Quillaja lancifolia D.Don (formerly Q. brasiliensis (A.St.-Hil. & Tul.) Mart.) produce water-soluble specialized metabolites of the saponin class that could be evaluated for phytotoxic activity and potential as natural herbicides. This study was conducted to examine the impacts of Q. lancifolia total saponins aqueous extract (AE) at 4 and 10% (w/v) and of two combined reverse-phase chromatography purified saponin fractions (QB) at 1 and 2% (w/v) on morpho-physiological parameters of Lactuca sativa (lettuce) and Echinochloa crus-galli (barnyardgrass) in pre- and post-emergence bioassays. QB was only tested in pre-emergence assays. In pre-emergence bioassays, the germination rate and germination kinetics were determined. Post-emergence evaluations included effects on seedling morphology, root and shoot length, dry mass, and chlorophyll content. Osmotic potential and pH analyses ruled out roles for these factors in the observed responses. AE had a high inhibitory impact on the germination of both lettuce and barnyardgrass. QB at 1% and 2% (w/v) significantly decreased the growth of lettuce seedlings germinated in its presence by more than 10-fold. Phytotoxic effects on the post-emergence growth of lettuce, especially at the highest concentration tested of AE (10% w/v), was also observed. The presence of quillaic acid-based triterpene saponins in AE and QB was confirmed using different analytical methods. Therefore, both saponin-enriched fraction and aqueous extracts of Q. lancifolia inhibited tested plant growth and development. The water solubility of saponins and the availability of a sustainable source of these molecules from the leaves of cultivated young Q. lancifolia plants make them attractive candidates for use as bioherbicides.

Drought alleviation efficacy of a galactose rich polysaccharide isolated from endophytic Mucor sp. HELF2: A case study on rice plant.

Endophytes play a vital role in plant growth under biotic and abiotic stress conditions. In the present investigation, a Galactose-Rich Heteropolysaccharide (GRH) with a molecular weight of 2.98 × 105 Da was isolated from endophytic Mucor sp. HELF2, a symbiont of the East Indian screw tree Helicteres isora. OVAT (One Variable at A Time) experiment coupled with RSM (Response Surface Methodology) study exhibited 1.5-fold enhanced GRH production (20.10 g L-1) in supplemented potato dextrose broth at a pH of 7.05 after 7.5 days of fermentation in 26°C. GRH has alleviated drought stress (polyethylene glycol induced) in rice seedlings (Oryza sativa ssp. indica MTU 7093 swarna) by improving its physicochemical parameters. It has been revealed that spray with a 50-ppm dosage of GRH exhibited an improvement of 1.58, 2.38, 3, and 4 times in relative water contents and fresh weight of the tissues, root length, and shoot length of the rice seedlings, respectively "in comparison to the control". Moreover, the soluble sugars, prolines, and chlorophyll contents of the treated rice seedlings were increased upto 3.5 (0.7 ± 0.05 mg/g fresh weight), 3.89 (0.57 ± 0.03 mg/g fresh weight), and 2.32 (1,119 ± 70.8 μg/gm of fresh weight) fold respectively, whereas malondialdehyde contents decreased up to 6 times. The enzymatic antioxidant parameters like peroxidase and superoxide dismutase and catalase activity of the 50 ppm GRH treated seedlings were found to be elevated 1.8 (720 ± 53 unit/gm/min fresh weight), 1.34 (75.34 ± 4.8 unit/gm/min fresh weight), and up to 3 (100 ppm treatment for catalase - 54.78 ± 2.91 unit/gm/min fresh weight) fold, respectively. In this context, the present outcomes contribute to the development of novel strategies to ameliorate drought stress and could fortify the agro-economy of India.

Gasotransmitter ammonia accelerates seed germination, seedling growth, and thermotolerance acquirement in maize

ABSTRACT Ammonia (NH3), as an intermediate product of nitrogen metabolism, is recognized as a novel gasotransmitter (namely gaseous signaling molecule), its signaling role being revealed in plants. NH3 exists in two different chemical forms, namely the weak base (free molecule: NH3) and the weak acid (ammonium: NH4 +), which are generally in equilibrium with each other in plants. However, the effect of NH3 on seed germination, seedling growth, and thermotolerance acquirement in maize remains unclear. Here, maize seeds were imbibed in the different concentrations of NH3·H2O (NH3 donor), and then germinated and calculated seed germination rate at the various time points. Also, the 60-h-old seedlings were irrigated in the different concentrations of NH3·H2O, and then subjected to heat stress and counted survival rate. The data implied that the appropriate concentrations (6, 9, and 12 mM) of NH3·H2O accelerated seed germination as well as increased seedling height and root length compared with the control without NH3 treatment. Also, the suitable concentrations (2 and 4 mM) of NH3·H2O improved tissue vitality, relieved an increase in malondialdehyde content, and enhanced survival rate of maize seedlings under heat stress compared with the control. These results firstly suggest that NH3 could accelerate seed germination, seedling growth, and thermotolerance acquirement in maize.

Efek Perendaman Biji dalam PGPR terhadap Pertumbuhan Semai Cabai Rawit (Capsicum frutescens L.)

The process of cayenne pepper seedling begins with soaking the seeds in liquid to break the dormancy of the seeds. The effect of soaking cayenne pepper seeds using PGPR solution obtained from the root system of cultivated plants, namely cayenne pepper (Capsicum frutescens L.), maize (Zea mays L.), peanuts (Arachys hypogaea L.), and rice (Oryza sativa L.) which had been harvested was the purpose of this study. Cayenne pepper seeds were soaked overnight using PGPR, then the seeds were sown in a planting medium mixed with soil, manure, compost and husk charcoal in a ratio of 2:1:1:1. Cayenne pepper seedling plantations were observed for 4 WAP. Using one-way ANOVA test for research data. Soaking cayenne pepper seeds using PGPR had a significant effect on seedling growth in terms of height, number of leaves, and stem diameter parameters with optimal treatment of 50% concentration. Meanwhile, PGPR immersion for seedling root length parameters did not have a significant effect.

OsGLP participates in the regulation of lignin synthesis and deposition in rice against copper and cadmium toxicity.

Copper (Cu) and cadmium (Cd) are common heavy metal pollutants. When Cd and excessive Cu accumulate in plants, plant growth is reduced. Our previous study showed that Germin-like proteins (GLPs), which exist in tandem on chromosomes, are a class of soluble glycoproteins that respond to Cu stress. In this study, hydroponic cultures were carried out to investigate the effect of GLP on Cd and Cu tolerance and accumulation in rice. The results showed that knockout of a single OsGLP8-2 gene or ten OsGLP genes (OsGLP8-2 to OsGLP8-11) resulted in a similar sensitivity to Cd and Cu toxicity. When subjected to Cu and Cd stress, the glp8-2 and glp8-(2-11) mutants displayed a more sensitive phenotype based on the plant height, root length, and dry biomass of the rice seedlings. Correspondingly, Cu and Cd concentrations in the glp8-2 and glp8-(2-11) mutants were significantly higher than those in the wild-type (WT) and OsGLP8-2-overexpressing line. However, Cu and Cd accumulation in the cell wall was the opposite. Furthermore, we determined lignin accumulation. The overexpressing-OsGLP8-2 line had a higher lignin accumulation in the shoot and root cell walls than those of the WT, glp8-2, and glp8-(2-11). The expression of lignin synthesis genes in the OsGLP8-2-overexpressing line was significantly higher than that in the WT, glp8-2, and glp8-(2-11). The SOD activity of OsGLP8-2, Diaminobe-nzidine (DAB), propidium iodide (PI) staining, and Malondialdehyde (MDA) content determination suggested that OsGLP8-2 is involved in heavy metal-induced antioxidant defense in rice. Our findings clearly suggest that OsGLPs participate in responses to heavy metal stress by lignin deposition and antioxidant defense capacity in rice, and OsGLP8-2 may play a major role in the tandem repeat gene clusters of chromosome 8 under heavy metal stress conditions.

Boron sources and rates on soybean seed physiological quality and root system volume

Abstract: Soybean has shown increasing performance in terms of yield in recent years. However, despite this growth, the lack of quality control and knowledge about the effects of the nutritional status of plants has compromised the germination and vigor of a significant proportion of seeds. The aim of this study was to evaluate the physiological performance of seeds and root growth of soybean cultivated with boron (B) sources with different solubilities incorporated into the soil. The experimental design was completely randomized in a 2×5 factorial arrangement, with two B sources (boric acid and ulexite) and five B rates (0, 2, 4, 8, and 16 mg.kg-1). 100-seed weight (100SW), germination, seedling shoot length (SSL), seedling root length (SRL), accelerated aging (AA), root protrusion (RP), lignin content in the seed coat (LCSC), and root volume (RV) were evaluated. The B sources and rates showed a significant interaction with increases in RV, RP, SSL, SRL, and 100SW, while the LCSC decreased with increasing rates with no interaction effect, indicating a reduction of seed quality with rates up to 8.0 mg.kg-1, regardless of the B source used.

Activated charcoal alleviates fluoride stress by restricting fluoride uptake and counteracting oxidative damages in the rice cultivar MTU1010

This work was aimed to explore the efficacy of activated charcoal (5 mg g-1 soil) in abating fluoride (25 mg L-1 NaF) stress in rice seedlings, since the protective role of charcoal is widely reported against other forms of abiotic stress. Application of NaF solution reduced germination rate, dry and fresh weight, and shoot and root length of seedlings. Extensive fluoride accumulation lowered the chlorophyll level along with higher electrolyte leakage and formation of H2 O2 , malondialdehyde, and methylglyoxal. Administration of activated charcoal lowered the extent of oxidative damages by inhibiting the uptake of fluoride ions. Exogenous application of activated charcoal also restored the activity of Kreb's cycle enzymes, i.e. PDH, IDH, MDH, and SDH, thereby overcoming the burden of carbon utilization and energy depletion occurring during stress. Additionally, the osmolyte (soluble sugar, proline, glycine-betaine, and amino acid) level was further escalated in presence of activated charcoal. The inhibition in catalase activity in fluoride-stressed seedlings was also restored. The activity of a range of enzymatic antioxidants (guaiacol peroxidase, superoxide dismutase, and ascorbate peroxidase) along with the glyoxalase system associated-enzymes (glyoxalase I and II) was further triggered in stressed seedlings treated with activated charcoal. The enhanced level of carotenoids, ascorbic acid, and total phenolics also enabled efficient scavenging of reactive oxygen species, thereby reducing cellular necrosis in the leaves. Based on the current investigation, it can be concluded that activated charcoal application appears a promising strategy to improve growth and mitigate damages in rice plants, growing in fluoride-polluted soil.

Maturation and harvest time of Ateleia glazioveana Baill. seeds.

Ateleia glazioveana Baill. is a pioneer, rustic and can be used for forest recovery. This work aimed to study the process of physiological maturation of this species. The research was carried out in the city of Alegre - ES, the trees were identified in the floral anthesis and accompanied during the filling of the fruits and development of the seeds until the complete maturation. The fruits were harvested at the following stages 7, 14, 21, 28, 35 and 42 days after anthesis, and characterized according to: morphometry, moisture, fresh and dry mass of fruits and seeds, germination, germination speed index, shoot and root length and dry mass of seedlings. The regression equations were adjusted for the main characteristics analyzed as a function of the harvest period. The point of physiological maturity of timbó occurred at 42 days after anthesis.

Semente de milho crioula promove incremento nos aspectos produtivos e nutricionais da forragem hidropônica

ABSTRACT The aimed of this study to assess the productivity and nutritional characteristics of hydroponic corn forage derived from bico de ouro creole seeds and AL-Bandeirante. Two treatments (T), each representing a corn seed variety, were randomly allocated to beds filled with a wood sawdust substrate: T1 (n=5) - bico de ouro creole seed variety, and T2 (n=5) - AL-Bandeirante hybrid seed variety. On the 13th day, forage was collected to assess seedling biometry, green and dry mass production, and bromatological analyses. The data were subjected to statistical analysis, with a 5% significance level. The creole seed variety yielded higher seedling height (17.53 cm), root length (10.19 cm), stem (5.37 cm), leaf (12.17 cm), and greater production of green mass (7.22 kg/m²) and dry matter (2.05kg/m²) (P<0.05). The AL-Bandeirante corn forage had higher dry matter content (39.18%), mineral matter (2.33%), non-fiber carbohydrate (31.88%), and estimated total digestible nutrients (68.14%) (P<0.05), while the creole corn forage had higher organic matter content (99.45%), ethereal extract (19.53%), neutral detergent fiber (45.56%), and cellulose (15.46%) (P<0.05). Crude protein, acid detergent fiber, and lignin were similar between the treatments (P>0.05). Despite the AL-Bandeirante variety yielding a higher concentration of certain nutrients, its forage productivity was significantly low. Therefore, under the conditions of this study, the use of the creole seed variety is recommended.

24-epibrassinolide improves cadmium tolerance and lateral root growth associated with regulating endogenous auxin and ethylene in Kentucky bluegrass

The application of phytohormones is a viable technique to increase the efficiency of phytoremediation in heavy metal-contaminated soils. The objective of this study was to determine how the application of 24-epibrassinolide (EBR), a brassinosteroid analog, could regulate root growth and tolerance to cadmium (Cd) stress in Kentucky bluegrass. As a result, the number of lateral root primordia and total root length in the Cd-treated seedlings decreased by 33.1 % and 56.5 %, respectively. After the application of EBR, Cd accumulation in roots and leaves, and the negative effect of Cd on root growth were reduced under Cd stress. Additionally, the expression of the brassinosteroid signaling gene PpBRI1 was significantly upregulated by exogenous EBR. Moreover, exogenous EBR upregulated the expression of genes encoding antioxidant enzymes and improved the activity of antioxidant enzymes, thereby reduced oxidative stress in roots. Finally, targeted hormonomics analysis highlighted the utility of the application of EBR to alleviate the effect of Cd on the reduction in auxin (IAA) content and the increase in ethylene (ACC) content. These were known to be associated with the upregulation in the expression of auxin biosynthesis gene PpYUCCA1 and downregulation in the expression of ethylene biosynthesis gene PpACO1 in the roots treated with Cd stress. Overall, the application of EBR alleviated Cd-induced oxidative stress in addition to improving root elongation and lateral root growth crosstalk with auxin and ethylene in Kentucky bluegrass subjected to Cd stress. This study further highlights the potential role of brassinosteroids in improving the efficiency of phytoremediation for Cd-contaminated soils.

THE EFFECT OF ROOTING MEDIA ON THE GROWTH OF MALAY APPLE (Syzygium malaccense L.) SEEDLINGS FROM STEM CUTTINGS

This study aims to determine the effect of the type of planting medium in the propagation of Malay apple cuttings. The research design used is random design non-factorial grouping that consist of 5 levels of treatment for cuttings rooting media types, i.e. soil (1), soil + compost (1:1), soil + compost + chaff charcoal (1:1:1), sand + compost + chaff charcoal (1:1:1), and compost (1) with 5 repetitions and each replication consists of 25 experimental units, and each experimental unit consists of 15 samples and 3 spare plants, so there are 450 plants. The research was conducted from February to July 2022. The parameters observed include the time of shoot emergence, sprout percentage, root length, seed height, root volume, and the percentage of life. Data analysis used ANOVA (analysis of variance) and if there was an effect, then continued with the tukey’s HSD (Honestly Significant Difference) test with a level of 5%. The results showed that rooting media mixed with soil + compost + chaff charcoal or mixed media of sand + compost + chaff charcoal could increase the percentage of survival, seedling height, root length, and root volume of malay apple seedlings from stem cuttings.

AgNPs-Triggered Seed Metabolic and Transcriptional Reprogramming Enhanced Rice Salt Tolerance and Blast Resistance

Seeds are facing harsher environments due to the changing climate. Improving seeds' stress resilience is critical to reduce yield loss. Here, we propose that using ROS-generating nanoparticles (NPs) to prestimulate seeds would enhance the stress resilience of seeds and seedlings through triggering stress/immune responses. We examined this hypothesis by exposing AgNPs-primed rice (Oryza sativa L.) seeds under salt conditions (NaCl). The results showed that primed seeds exhibit accelerated germination speed, increased seedling vigor (from 22.5 to 47.6), biomass (11%), and root length (83%) compared to seeds with hydropriming treatment. Multiomics (metabolomics and transcriptomics) analyses reveal that AgNPs-priming triggered metabolic and transcriptional reprogramming in rice seeds. Signaling metabolites, such as salicylic acid, niacinamide, and glycerol-3-phosphate, dramatically increased upon AgNPs-priming. KEGG pathway analysis reveals that AgNPs-priming activated stress signaling and defense related pathways, such as plant hormone signal transduction, glutathione metabolism, flavone and flavonol biosynthesis, MAPK signaling pathway, and plant-pathogen interaction. These metabolic and transcriptional changes indicate that AgNPs-priming triggered stress/immune responses. More importantly, this "stress memory" can last weeks, providing protection to rice seedlings against salt stress and rice blast fungus (Magnaporthe oryzae). Overall, we show that prestimulated seeds with ROS-generating AgNPs not only enable faster and better germination under stress conditions, but also increase seedling resistance to biotic and abiotic stresses. This simple nanobiostimulant-based strategy may contribute to sustainable agriculture by maintaining agricultural production and reducing the use of pesticides.

Endophytic Pseudomonas sp. from Agave palmeri Participate in the Rhizophagy Cycle and Act as Biostimulants in Crop Plants.

Plant growth-promoting bacteria are generating increasing interest in the agricultural industry as a promising alternative to traditional chemical fertilizers; however, much of the focus has been on rhizosphere bacteria. Bacterial endophytes are another promising source of plant growth-promoting bacteria, and though many plants have already been prospected for beneficial microbes, desert plants have been underrepresented in such studies. In this study, we show the growth-promoting potential of five strains of endophytic Pseudomonas sp. isolated from Agave palmeri, an agave from the Sonoran Desert. When inoculated onto Kentucky bluegrass, clover, carrot, coriander, and wheat, endophytic Pseudomonas sp. increased seedling root lengths in all hosts and seedling shoot lengths in Kentucky bluegrass, carrot, and wheat. Transformation of the Pseudomonas sp. strain P3AW to express the fluorescent protein mCherry revealed that Pseudomonas sp. becomes endophytic in non-native hosts and participates in parts of the rhizophagy cycle, a process by which endophytic bacteria cycle between the soil and roots, bringing in nutrients from the soil which are then extracted through reactive oxygen-mediated bacterial degradation in the roots. Tracking of the Pseudomonas sp. strain P3AW also provided evidence for a system of endophyte, or endophyte cell content, transport via the vascular bundle. These results provide further evidence of the rhizophagy cycle in plants and how it relates to growth promotion in plants by biostimulant bacteria.

Polystyrene microplastics protect lettuce (Lactuca sativa) from the hazardous effects of Cu(OH)2 nanopesticides.

Copper-based nanopesticides are released into the environment during foliar spray application, and they could, on their own or in combination with microplastics (MPs), pose threats to environmental safety and human health. In this study, Cu(OH)2 nanowires greatly decreased the vigor of lettuce seeds (p< 0.01) and the root length of lettuce seedlings (p< 0.01) and significantly altered the lettuce antioxidant defence system and MDA content (p< 0.05). Released Cu2+ played a critical role in the toxicity mechanism of Cu(OH)2 nanowires in lettuce seedlings, as evidenced by the substantial accumulation of Cu in the seedling roots (p< 0.01) rather than in the leaves. Polystyrene (PS) MPs (1 mg/L) stimulated lettuce seedling growth, as shown by the (highly) significant increase in root and leaf length and in the seed vigor index (p< 0.01 or 0.05). Notably, PS MPs (1 mg/L) neutralized the hazardous effects of 1 mg/L Cu(OH)2 nanowire treatment on lettuce growth, as reflected by the vitality and root length of the seedlings returning to normal levels. The PS MPs (1 mg/L) absorbed on middle root surfaces and strongly hindered Cu accumulation in lettuce roots, which was the predominant mechanism by which PS MPs suppressed the hazardous effects of the Cu(OH)2 nanowires. This study strengthens the understanding of the toxicity and toxicity mechanisms of Cu(OH)2 nanowires with or without PS MPs in the environment.

Fermentation as a Promising Tool to Valorize Rice-Milling Waste into Bio-Products Active against Root-Rot-Associated Pathogens for Improved Horticultural Plant Growth

In this study, water extracts from fermented (F), ultrasonicated (US), and enzyme-hydrolyzed (E) rice bran (RB) were evaluated against sixteen fungal plant stem and root-rot-associated pathogens. The effects of pre-treated RB additives on plant growth substrate (PGS) on bean and tomato seed germination, stem height and root length of seedlings, and chlorophyll concentration in plants were analyzed. The results showed that US-assisted pre-treatments did not affect protein content in RB, while 36 h semi-solid fermentation (SSF) reduced protein content by 10.3–14.8%. US initiated a 2.9- and 2-fold increase in total sugar and total phenolics (TPC) contents compared to the untreated RB (3.89 g/100 g dw and 0.61 mg GAE/g dw, respectively). Lactic acid (19.66–23.42 g/100 g dw), acetic acid (10.54–14.24 g/100g dw), propionic acid (0.40–1.72 g/100 g dw), phenolic compounds (0.82–1.04 mg GAE/g dw), among which phenolic acids, such as p-coumaric, cinnamic, sinapic, vanillic, and ferulic, were detected in the fermented RB. The RBF extracts showed the greatest growth-inhibition effect against soil-born plant pathogens, such as Fusarium, Pythium, Sclerotinia, Aspergillus, Pseudomonas, and Verticillium. Beans and tomatoes grown in RBUS+E- and RBF-supplemented PGS increased the germination rate (14–75%), root length (21–44%), and stem height (25–47%) compared to seedlings grown in PGS. The RB additives increased up to 44.6–48.8% of the chlorophyll content in both plants grown under greenhouse conditions. The results indicate that the biological potential of rice-milling waste as a plant-growth-promoting substrate component can be enhanced using solid-state fermentation with antimicrobial LABs and US processing.

Arbuscular mycorrhizal fungi and common mycorrhizal networks benefit plants through morphological, physiological and productive traits and soil quality

The extraradical hyphae of arbuscular mycorrhizal fungi (AMF) of one plant root system forage for the soil nutrients and induce the root colonization of the nearby plants, which leads to the formation of common mycorrhizal networks (CMNs) that interconnect roots. Inoculation with AMF can increase the root length, surface area and volume of seedlings in nutrient-limited karstic soils. Mycorrhizal symbioses can secrete glomalin to help promoting soil aggregates for water and nutrients storage, through an extended hyphae to absorb water and nutrients from long distances. AMF can boost rhizosphere soil enzyme activities, and may help to drive carbon sequestration. AMF also improve plant growth by advancing soil quality through influencing its structure and texture. As a result, AMF and CMNs benefit plants through improving soil quality and enhancing morphological (e.g., hyphal length, tillering, number of stolons per individual), physiological (e.g., water use efficiency) and productive (e.g., fresh and dry shoot and root weights) traits.