Root Length Research Articles

Identification of Potato StPIN Gene Family and Regulation of Root Development by StPIN4.

The growth hormone export PIN-FORMED (PIN) is an important carrier for regulating the polar transport of plant growth hormones and plays an important role in plant growth and development. However, little is known about the characteristics and functions of PINs in potatoes. In this study, 10 PIN members were identified from potatoes and named StPIN1, StPIN2, StPIN3, StPIN4, StPIN5, StPIN6, StPIN7, StPIN8, StPIN9, and StPIN10 according to their positions in the potato chromosome In addition, the expression of 10 StPINs was analyzed by qRT-PCR during potato root development. The results showed that the StPIN4 gene plays an important regulatory role in potato root development, and its tissue expression varied greatly. Several cis-regulatory elements related to growth factors were also detected in the promoter region of the StPIN gene. The transgenic overexpressing StPIN4 in potato showed suppressed growth in root length and lateral root number, and StPIN4-interfering plants showed the opposite. These results suggested that StPIN4 plays a key role in the regulation of the potato root architecture.

Hydroponic Lettuce Cultivation with Organic Liquid Fertilizer: Examining Bacterial Inhibition and Phosphate Solubilization

This study explores organic hydroponic cultivation as a sustainable alternative to chemical fertilizers amid global supply challenges. With rising costs and the depletion of conventional nitrogen sources, organic liquid fertilizers are gaining attention for their microbial enrichment processes (MEP) that convert organic matter into plant-accessible nutrients. This experiment focuses on lettuce cultivation using two organic liquid fertilizers, Power Fish and POF vol. 2, in controlled environments. The results show that there are significant differences in plant growth parameters such as leaf number, fresh weight, chlorophyll content, and root length across different fertilizer treatments. Key findings include that effective management practices, including pH control and regular nutrient application, are crucial for maintaining microbial activity and optimizing nutrient uptake efficiency. Additionally, Bacillus sp. and Xanthomonas sp. were isolated from these fertilizers and dual-cultured with rot fungi, Pythium sp. and Fusarium sp. This dual cultivation demonstrated inhibitory activity against these pathogens, showcasing the potential of these microorganisms in promoting biofilm-mediated disease resistance in organic hydroponic systems. The study also emphasizes the phosphate solubilization capabilities of isolated bacteria, essential for sustainable nutrient cycling. Overall, organic hydroponic systems present a promising strategy for sustainable agriculture, reducing dependency on chemical inputs while enhancing crop productivity and resilience to environmental stressors.

Evaluating the efficacy of endophytic bacteria in controlling rice sheath blight: In vitro and In vivo studies

Rice production is highly susceptible to various pathogens, including Rhizoctonia solani, Curvularia lunata, and Epicoccum rostratum, which are major threats in Asia. Exploring biological control methods using endophytic bacteria offers promising opportunities to enhance rice resilience against these lethal diseases. Using 16S RNA sequencing, we identified four endophytic isolates of Bacillus spp. from rice roots, stems, and leaves. We evaluated the antagonistic activity of these endophytic bacterial isolates against rice pathogens both in vitro and in vivo. These isolates inhibited the growth of C. lunata by 82 %, R. solani by 79 %, and E. rostratum by 88 % in vitro. The detached leaf assay for sheath blight (ShB) disease severity in strains ranged from 10.4 % to 73.3 %. In vivo results showed that B. amyloliquefaciens (R-19) exhibited the lowest disease intensity at 7.2 % and the highest disease suppression at 78.8 %. The fungicide propiconazole at 0.1 % treatment showed the lowest disease intensity of 7.7 % and the highest disease suppression of 73.4 %, compared to the infected control. Besides biocontrol efficacy, endophytic isolates enhance plant growth parameters, including shoot height, root length, fresh and dry weights, number of tillers, and grains per tiller. Plant hormones abscisic acid (ABA) and gibberellic acids (GA3) increased by 35 % and 53 %, respectively, due to B. subtilis (R-20) and B. amyloliquefaciens (R-19), while flavonoid and indole acetic acid (IAA) concentrations surged by 30%–80 %. Similarly, chlorophyll (a, b), carotenoids, antioxidant enzymatic activity, phenolic content, carbohydrates, and proline contents were higher compared to the control. This study provides a foundation for future studies on novel and eco-friendly biocontrol agents. In addition, our study recommends the integration of endophytic bacteria into sustainable agriculture for enhancing rice production and reducing disease impacts.

OsSTP1 mediates sucrose allocation to regulate rice responses to different nitrogen supply levels

Improving the nitrogen use efficiency is an effective way to increase the yield of rice, and maintaining carbon-nitrogen balance is essential for the normal growth and development of rice. To investigate the impact of the sucrose transporter protein OsSTP1 on nitrogen absorption in rice, in this study, we constructed transgenic lines overexpressing the sucrose transporter gene OsSTP1 (OsSTP1-OE1, OsSTP1-OE2) and mutant transgenic lines (osstp1-1, osstp1-2) from the wild type TB309. Further, we conducted a hydroponic experiment with four nitrogen supply levels of free nitrogen (FN, 0 mg/L), low nitrogen (LN, 10 mg/L), normal nitrogen (NN, 40 mg/L), and high nitrogen (HN, 80 mg/L) to study the responses of each line to different nitrogen supply levels during the seedling stage. The results showed that compared with the wild type and mutant lines in the LN group, the OsSTP1-overexpressing lines exhibited significantly increased biomass, root length, and plant height, decreased soluble sugar content in the leaves, and increased soluble sugar content in the roots. The results indicate that the soluble sugars produced by leaf photosynthesis are transported to the roots through the phloem to promote root growth and nitrogen uptake, thus increasing the aboveground biomass. This study has identified that OsSTP1 can affect the long-distance transport of carbohydrates from source to sink to promote root growth, ultimately influencing rice's absorption and accumulation of nitrogen, improving nitrogen use efficiency and providing reference for reducing nitrogen fertilizer application.

Uni- and Multivariate Analyses for the Characterization of Popcorn Inbred Lines for Drought Tolerance at Seedling and Vegetative Stages

Water deficit is the main limiting factor in rainfed agricultural production, negatively affecting germination and vegetative development. The objectives of this work were to characterize inbred lines for drought tolerance, to identify the most important root and shoot morphological traits for discriminating genotypes, to compare the efficiency of identifying contrasting inbred lines using uni- and multivariate methods, and to evaluate the effectiveness of identifying drought-tolerant genotypes at seedling and vegetative stages. We assessed 28 popcorn inbred lines and three maize single crosses, two drought-tolerant and one drought-sensitive. At the seedling stage, drought was induced on germitest paper moistened with polyethylene glycol 6000. At the vegetative stage, we applied water stress using lysimeters. We measured root and shoot morphological traits under water stress and no stress and processed the relative values. Uni- and multivariate methods, alone or in combination, were equally efficient for identifying contrasting inbred lines for drought tolerance. The confidence interval and Dunnett’s test worked very well when contrasting controls were included. Principal component analysis allowed to discriminate genotypes and identify the most important traits for discriminating them. At the seedling stage, inbred line 22-1824-2 was the most drought-tolerant and 22-1877-3 the most sensitive. At the vegetative stage, inbred lines 22-1920-1 and 22-1867-4 were the most tolerant and 22-1860-5 was the most sensitive. Root length, volume, dry weight, and surface area, as well as water content, were the most important traits for discriminating genotypes. Due to distinct tolerance mechanisms, drought tolerance should be assessed at both stages.

Isolation, Identification, and Application of Endophytic Fungi from Lavandula stoechas L.: Mitigating Salinity Stress in Hydroponic Winter Cereal Fodder

Soil and irrigation water salinity is a growing global problem affecting farmland, due to poor agricultural practices and climate change, leading to reduced crop yields. Given the limited amount of arable land and the need to boost production, hydroponic systems offer a viable solution. Additionally, endophytic fungi have been shown to mitigate salinity effects through symbiosis with plants. This study evaluated three endophytic fungi isolated from Lavandula stoechas L. in the grasslands of Extremadura (i.e., Diplodia corticola L11, Leptobacillium leptobactrum L15, and Cladosporium cladosporioides L16) for their ability to improve hydroponic forage production under saline conditions. In vitro experiments were conducted assessing plant growth promotion and fungal growth under salinity, followed by research evaluating the impact of fungal inoculation on hydroponic wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) forages irrigated with NaCl solutions (0, 100, and 200 mM). The results showed improved fungal growth and production of plant growth-promoting substances, which could explain the improved plant germination, shoot and root length, fresh and dry weight, and yield of inoculated plants growing under salinity. Plants inoculated with L15 or L16 showed the best performance overall. L15 demonstrated broader bioactivity in vitro, potentially explaining its superior performance in both wheat and barley growth. Conversely, L16 was more effective in barley, while L11 was beneficial in wheat but detrimental in barley. This study provides a preliminary exploration of the capabilities of these fungi and their optimization for hydroponic forage production.

Genetic Diversity of Maize (Zea mays L.) Genotypes under Low Level of Nitrogen

Maize (Zea mays L.) is India's second most significant crop, behind rice. As a cross-pollinated crop, hybrid vigour is commonly used to achieve the best production potential. The selection of various genotypes is a primary goal in the maize hybrid breeding programme. Maize is a voracious feeder and requires a lot of fertiliser. The biggest limits on maize production in India are low soil nitrogen and high fertiliser costs. Jharkhand consumes only 82.5 kg of total fertiliser nutrients per acre. In order to discover genetically varied maize genotypes for nitrogen usage efficiency, the current study evaluated 121 maize genotypes in a randomised block design with two replications at low nitrogen levels. Plant height, days to 50% pollen shed, days to 50% silk, anthesis-silking interval (ASI), days to75% maturity, number of leaves per plant, root length, stover yield per plant, grain yield per plant, and harvest index were all recorded. Statistical analysis was performed using the morphological trait data. Analysis of variance revealed substantial (p≤0.05) variations in morphological features between maize genotypes. For statistical analysis, a clustering method was used to locate various genotypes with greater genetic distance in order to develop good heterotic combinations. One hundred twenty one genotypes were divided into six clusters using the dendogram-by-ward minimum variance approach. Cluster III and V had the greatest inter-cluster distance (79.26), followed by cluster III and VI (74.77) and cluster II and III (73.80). The many heterotic combinations developed from these clusters can be employed in subsequent breeding programmes to produce low nitrogen-requiring hybrids with a low yield penalty.

Production of organic melon seedlings under different growing medias and doses of aqueous humic extract

Aiming to determine the viability of organic compost (OC) as a component of commercial growing media (CGM), as its potential in the formulation of humic extract (HE), an experiment was developed with organic melon seedlings. A completely randomized design with 4x5 factorial arrangement and four replicates was adopted. The treatments consisted of four compost proportions (0, 10, 20 and 30%), mixed to the growing media (v:v), associated with the application of five doses of aqueous extract obtained from the same compost (0, 5, 10, 15 and 20%). The following variables were evaluated: total percent emergence (TPE), emergence rate index (ERI), emergence rate (ER), leaf area (LA), number of leaves (NL), dry and fresh mass of shoot and root (SDM, SFM, RDM and RFM); length (RL) and volume of root (RV); and shoot (SDMC) and root dry matter content (RDMC). Only NL provided interaction between the analyzed factors. ER, RFM, RDM, and RDMC showed no statistically significant differences across the various concentrations of OC and HE. SFM and SDM presented a negative quadratic term in relation to OC increase. SDMC and LA had inferior results at greater OC amount. OC is not recommended as a conditioner for growing media, at the conditions and variables analyzed in this study.

Short-Term Effects of Incorporation Depth of Straw Combined with Manure During the Fallow Season on Maize Production, Water Efficiency, and Nutrient Utilization in Rainfed Regions

Diminishing soil fertility and crop productivity due to traditional intensive cultivation has prompted the use of straw and manure to improve soil health in Northeast China. However, few comparative studies have explored the influence of varying straw and manure incorporation depths on crop growth. A field experiment in the rainfed black soil regions of Gongzhuling and Keshan assessed the effects of deep (30 cm) and shallow (15 cm) incorporations of straw and manure on soil fertility, maize root growth, and maize productivity. Deep incorporations, via subsoiling tillage (DST) and deep-plow (DDT) tillage, enhanced soil water storage of 30–100 cm soil layer during periods of low rainfall, improved the availability of nutrients (nitrogen, phosphorus, and potassium) and soil organic matter content, especially in deeper soil, compared to shallow incorporation using rotary tillage (SRT). Both DST and DDT induced a larger rooting depth and a higher fine root (diameter class 0–0.5 mm) length density by 31.0% and 28.9%, respectively, accompanied by reduced root turnover. Furthermore, the sub-surface foraging strategies of roots under the DST and DDT treatments boosted the total nitrogen, phosphorus, and potassium uptake (6.5–17.9%) and achieved a higher dry mass accumulation during the later growth period, thus leading to notable improvements in the 100-kernel weight and yield (16.1–19.7%) and enhancing water- and nutrient-use efficiencies by 2.5–20.5%. Overall, compared to shallow incorporation, deep incorporation of straw and manure significantly enhances root growth and spatial distribution of soil water and nutrients, which has great potential for increasing maize yield in rainfed agricultural areas.

The crop mined phosphorus nutrition via modifying root traits and rhizosphere micro‐food web to meet the increased growth demand under elevated CO2

AbstractElevated CO2 (eCO2) stimulates productivity and nutrient demand of crops. Thus, comprehensively understanding the crop phosphorus (P) acquisition strategy is critical for sustaining agriculture to combat climate changes. Here, wheat (Triticum aestivum L) was planted in field in the eCO2 (550 µmol mol−1) and ambient CO2 (aCO2, 415 µmol mol−1) environments. We assessed the soil P fractions, root morphological and physiological traits and multitrophic microbiota [including arbuscular mycorrhizal fungi (AMF), alkaline phosphomonoesterase (ALP)‐producing bacteria, protozoa, and bacterivorous and fungivorous nematodes] in the rhizosphere and their trophic interactions at jointing stage of wheat. Compared with aCO2, significant 20.2% higher shoot biomass and 26.8% total P accumulation of wheat occurred under eCO2. The eCO2 promoted wheat root length and AMF hyphal biomass, and increased the concentration of organic acid anions and the ALP activity, which was accompanied by significant decreases in calcium‐bound inorganic P (Ca‐Pi) (by 16.7%) and moderately labile organic P (by 26.5%) and an increase in available P (by 14.4%) in the rhizosphere soil. The eCO2 also increased the growth of ALP‐producing bacteria, protozoa, and bacterivorous and fungivorous nematodes in the rhizosphere, governed their diversity and community composition. In addition, the eCO2 strengthened the trophic interactions of microbiota in rhizosphere; specifically, the eCO2 promoted the associations between protozoa and ALP‐producing bacteria, between protozoa and AMF, whereas decreased the associations between ALP‐producing bacteria and nematodes. Our findings highlighted the important role of root traits and multitrophic interactions among microbiota in modulating crop P‐acquisition strategies, which could advance our understanding about optimal P management in agriculture systems under global climate changes.

Enhancing salt tolerance in rice genotypes through exogenous melatonin application by modulating growth patterns and antistress agents

Melatonin is a bioactive molecule with an important role in plants responding to various abiotic and biotic stresses. This study aims to determine the role of melatonin in rice under salt stress. This study used a factorial completely randomized design. The first factor was local rice varieties (IR64 and Silaun), and the second factor was plant treatments (control, 1 µM melatonin, 150 mM NaCl, 150 mM NaCl + 1µM melatonin). This study shows that exogenous melatonin can increase plant growth, such as plant height, root length, stem length, leaf length, leaf area, and plant biomass under salt stress compared to treatment without melatonin. Exogenous melatonin can increase the total chlorophyll content, relative water content, and proline content, reduce the total sodium content, and increase potassium absorption under conditions of salinity stress. Melatonin is also able to scavenge ROS in plants, resulted the decrease in ROS and MDA content. In terms of gene expression, OsAPX1 and cytosolic APX exhibited the highest expression in IR64 under combined salt and melatonin treatment, while GPOD, Mn-SOD, and Cu/Zn-SOD were upregulated under various conditions in both varieties. Additionally, OsLEA showed high expression in both varieties under control conditions, and CAT was significantly upregulated under salt stress. Our findings indicate that exogenous melatonin has the potential to enhance various factors under salt stress and helping in the recovery of rice plants from sodium (Na+) damage.

Isolation and Characterization of Arsenic-Tolerable Bacteria from Groundwater and Their Implementation on Rice Seedling's Shoot and Root Enhancement.

Arsenic exerts detrimental impacts on primary metabolism in plants, leading to reduced crop yield. Some arsenic-resistant plant growth-promoting bacteria (PGPB) help plants by providing some plant hormones to sustain their growth and development under arsenic stress. Here, seven different species of Bacillus were isolated from arsenic-contaminated groundwater of West Bengal, India. Those species were capable of growing in the presence of > 3.12g/L arsenate (AsV) and > 0.65g/L arsenite (AsIII) salts and also resist different heavy metals like Cu2+, Fe2+, Co2+, Zn2+, Pb2+, etc. They were susceptible to multiple groups of antibiotics like beta-lactam, aminoglycosides, etc. All species were capable of detoxifying arsenite and influenced rice seedlings' growth in the presence of arsenic salts by their capabilities likenitrogen-fixing ability, phosphate solubilization, indole 3-acetic acid (IAA), gibberellic acid (GA), proline production, etc. Most species helped enhance root and shoot lengths under arsenic stress. These primary findings suggest that those Bacillus spp. could be used as potential bio-fertilizers in arsenic-contaminated agricultural fields.

Invasive plants and their root traits are linked to the homogenization of soil microbial communities across the United States

Although the impacts of invasive plants on soil ecosystems are widespread, the role and impacts of invader root traits in structuring microbial communities remain poorly understood. Here, we present a macroecological study investigating how plant invaders and their root traits affect soil microbial communities, spanning data from 377 unique plots across the United States sampled multiple times, totaling 632 sampling events and 94 invasive plant species. We found that native and invasive plants harbor different root traits on average, with invasive plants possessing higher specific root lengths and native plants having higher root tissue density. We also show that soil microbial communities experiencing heavy plant invasions were more similar to each other in composition across ecosystem types and geographical regions than plots with higher proportions of native plants, which displayed highly variable microbial communities across the continent. Root traits of invasive plants in highly invaded plots explained two times more variation in microbial composition than native plants. This work represents an important step toward understanding macroscale and cross-scale patterns of the relationship between plant invasions, root traits, and soil microbial composition. Our findings provide insights into how invasive plants may impact ecosystem functioning at the macroscale via their homogenizing influence on microbial communities.

RrWRKY1, a Transcription Factor, Is Involved in the Regulation of the Salt Stress Response in Rosa rugosa.

Salt stress has become a major environmental problem affecting plant growth and development. Some WRKY transcription factors have been reported to be involved in the salt stress response in plants. However, there are few studies on the involvement of WRKYs in the salt stress response in Rosa rugosa. In this study, we isolated a salt tolerance gene, RrWRKY1, from R. rugosa. RrWRKY1 was found to belong to Group I of the WRKY family, and it was specifically expressed in leaves and petals. RrWRKY1 expression was upregulated under NaCl stress in rose leaves. After silencing RrWRKY1 in R. rugosa, transgenic plants showed dry leaves and black and brown veins, indicating sensitivity to salt stress. At the same time, the transcription levels of the salt tolerance-related genes RrNHX1, RrABF2, RrRD22, RrNCED1, and RrHKT1 also changed significantly. The superoxide dismutase (SOD) and peroxidase (POD) activities decreased, the proline content decreased, and the malondialdehyde (MDA) content in the gene-silenced plants increased, indicating that RrWRKY1 regulates the salt tolerance of R. rugosa. In addition, the overexpression of RrWRKY1 in Arabidopsis thaliana improved the germination rate and the average of the main root and lateral root lengths, and the transgenic plants had a larger number of lateral roots than the WT plants under salt stress. This study provides candidate gene resources for salinity tolerance breeding and a theoretical basis for analyzing the salinity tolerance mechanism of the WRKY gene.

Modeling Root Development of Rice (Oryza sativa L) under Varying Drought Stress

In the current era, where drought occurrences are frequent and devastating, extensive study on drought tolerance mechanisms is imperative. Root growth under water stress is a key indicator of drought tolerance. Modeling a crop's root-length under such conditions aids in predicting seminal root length (SRL) and, consequently, its tolerance level. Under consecutive stress using Poly-ethylene-glycol (PEG), root length of a landrace originating from the drought-prone area of West Bengal, India was measured through image analysis and then mathematically modulated using an equation. The highest root length under stress was predicted at 6% PEG stress which aligned with the experimental readings. On the 15th day of stress, predicted SRL values were 104.67mm and experimental values were 90.00mm. Despite some over and underestimations with a low root mean square error of 14.68 mm, the equation provides insight into root elongation trends under various stress levels, offering a basis for predicting SRL and yield capabilities under water stress for diverse crop species.

Amending clayey and sandy soils with nano - bio phosphorous for regulating tomato growth, biochemical, and physiological characteristics

Phosphorus is a critical nutrient that significantly enhances tomato production, so maintaining an adequate level of phosphorus plays an essential role in enhancing the growth of tomato by being present in the soil. This study assessed the impact of soil texture and phosphorus content on tomato plant properties using a factorial, complete, randomized design with four replications. Treatments included clayey and sandy soils with varying phosphorus sources: non-phosphorus (P0), calcium phosphate (CaP1 and CaP2), and nano-hydroxyapatite (PN1 and PN2), where 1 indicates a concentration of 0.12 g and 2 indicates a concentration of 0.23 g per 5-kilogram pot of fertilizer. Results indicated that treatments significantly influenced yield parameters such as average fruit weight, juice content, antioxidant activity, and fruit volume. In the clayey soil, CaP2 treatment had a superior effect on yield, average fruit weight, and shoot fresh weight. In comparison with sandy conditions, CaP2 produced a 50% increase in fruit number, 29% increase in average fruit weight, and 91% increase in fruit yield. The treatments then impacted the shoot fresh weight and root length, while the phosphorus concentration appeared to be more dependent on soil type than on phosphorus sources. Similar to the CaP1 and CaP2 treatments, the PN1 treatment in clay soil also resulted in the highest fresh and dry weights of tomato shoots when compared with the control group. Generally, the findings from this study suggest that the use of CaP2 can serve as a reliable method to improve the growth, yield, and fruit quality of tomatoes, especially in clayey soil environments. However, nano-based phosphorous sources need to be tested more to see if they can improve tomato performance in a range of soil conditions. Also, further research should look into the long-term effects of phosphorous interventions on soil health and sustainability.

Effect of Green Synthesized Silver and Zinc Nanoparticles on Seed Quality OF Maize

Nanotechnology is an emerging science and has wide applications in agriculture. Green synthesized nanoparticles are safer, cost effective and eco-friendly over chemical and physical synthesis. The laboratory experiment was conducted to investigate the effectiveness of green-synthesized silver and zinc nanoparticles on seed quality of maize hybrid (GH-150125) during 2023-24 at the Department of Seed Science and Technology, University of Agricultural Sciences, Dharwad. Green synthesis of silver and zinc nanoparticles were mediated through neem (Azadirachta indica) leaf extract is as reducing and capping agent. The standardization for effective concentration and priming duration for silver and zinc nanoparticles were standardized from different concentrations of (250 ppm, 500 ppm, 750 ppm and 1000 ppm). For priming effective duration were standardized from six, eight and twelve hours inclusive of hydropriming and control (untreated). The effective concentrations of 250-750 ppm and duration of 8 h and 6 h from AgNPs and ZnNPs recorded higher respectively as compared to control and hydropriming. In laboratory, the seed treated with zinc nanoparticles at 750 ppm for 6 h recorded significantly higher germination percentage of (97 %), shoot length (21.53 cm), root length (20.17cm) and seedling vigour index I (4045) compared to control. Hence, the results conclude that ZnNPs at 750 ppm for 6 hours was superior as seed treatment in maize to enhance seed germination and seedling growth than other treatments.

Effect of Modified Atmospheric Storage on Seed Longevity of Soybean [Glycine max (L.) Merr.

Seed quality is crucial for boosting seed production and productivity. However, soybean seeds are inherently short lived, quickly loses viability even under optimal storage conditions. Therefore, maintaining their quality during storage is of prime importance. Keeping these in view a laboratory experiment was conducted to study the effect of modified atmospheric storage on seed quality of soybean (cv. DSb 34). The freshly harvested seeds with initial moisture content of 7.6% were stored in different modified atmospheric gaseous combinations for nine months from November 2023- August 2024. Results indicated that the seeds stored with gaseous combination of 90 % CO2: 4 % O2: 6 % N2 in 700 gauge polyethylene bag maintained better seed quality in terms of germination (86.77%), shoot length (14.49 cm), root length (12.58 cm), dry weight(0.995g/ 10 seedlings), seedling vigour index I (2349) and II (86.34) upto the end of nine months storage period by recording higher total dehydrogenase (0.438 OD value), α- amylase (10.72 µmol of maltose released min-¹ ml-1 of enzyme) and catalase activity (1.364 µmol H₂O₂ decomposed minˉ¹gˉ¹ protein) compared to all other gaseous combinations and control. Hence, this technique can be used to maintain seed longevity with little deterioration, ensuring the quality of seeds even after extended storage period.

Rice Under Dry Cultivation-Maize Intercropping Improves Soil Environment and Increases Total Yield by Regulating Belowground Root Growth.

Under the one-season-a-year cropping pattern in Northeast China, continuous cropping is one of the main factors contributing to the degradation of black soil. Previous studies (on maize-soybean, maize-peanut, and maize-wheat intercropping) have shown that intercropping can alleviate this problem. However, it is not known whether intercropping is feasible for maize and rice under dry cultivation, and its effects on yield and soil fertility are unknown. A three-year field-orientation experiment was conducted at Jilin Agricultural University in Changchun city, Jilin Province, China, consisting of three cropping regimes, namely rice under dry cultivation-maize intercropping (IRM), sole rice under dry cultivation (SR), and sole maize (SM). All straw was fully returned to the field after mechanical harvesting. Rice under dry cultivation-maize intercropping with a land-equivalent ratio of 1.05 (the average of three years values) increased the total yield by 8.63% compared to the monoculture system. The aggressivity (A), relative crowding coefficient (K), time-area-equivalent ratio (ATER), and competition ratio (CR) value were positive or ≥1, also indicating that the rice under dry cultivation-maize intercropping had a yield advantage of the overall intercropping system. This is because the intercropped maize root length density (RLD) increased by 33.94-102.84% in the 0-40 cm soil layer, which contributed to an increase in the soil porosity (SP) of 5.58-10.10% in the 0-30 cm soil layer, an increase in the mean weight diameter of soil aggregates (MWD) of 3.00-15.69%, an increase in the geometric mean diameter of soil aggregates (GMD) of 8.16-26.42%, a decrease in the soil bulk density (SBD) of 4.02-7.35%, and an increase in the soil organic matter content (SOM) of 0.60-4.35%. This increased the water permeability and aeration of the soil and facilitated the absorption of nutrients and water by the root system and their transportation above ground, and the plant nitrogen, phosphorus, and potassium accumulation in the intercropping system were significantly higher than that in monoculture treatment, further promoting the total yield of intercropping. This suggests that rice under a dry cultivation-maize intercropping system is feasible in Northeast China, mainly because it promotes belowground root growth, improves the soil environment, and increases the total yield of intercropping.

Relationship between root characteristics and saturated hydraulic conductivity in a grassed clayey soil

Soil saturated hydraulic conductivity plays a crucial role in the fields of hydrology, geotechnical and geological engineering. This study investigated the relationship between root characteristics and soil saturated hydraulic conductivity in a grassed soil. The saturated hydraulic conductivity of soil specimens with varying soil dry densities and planting densities were experimentally determined. Root parameters of each specimen were measured, and the relationship between root parameters and soil saturated hydraulic conductivity was determined through the stepwise multiple regression analysis. Experimental results show that both soil dry density and planting density significantly influence root growth and the saturated hydraulic conductivity of the grassed soil. Root length ratio (>4 cm), root length, and root weight density exhibit a positive correlation with planting density, while root length density and root length ratio (>4 cm) are negatively correlated with dry density. Higher dry density leads to lower soil saturated hydraulic conductivity and the permeable effects become more pronounced with increased planting density. When planting density is higher, roots create more preferential flow channels in the soil, resulting in increased soil saturated hydraulic conductivity. Root length density exerts the most significant effect on soil saturated hydraulic conductivity (|r| = 0.82, p＜0.01), followed by root length ratio (>4 cm) and root weight density. This study provides insights into the relationship between root parameters and soil saturated hydraulic conductivity, and identifies key root parameters that govern the saturated hydraulic conductivity of soil. These findings hold significant implications for enhancing the understanding of slope protection using vegetation.