Growth Of Seedlings Research Articles

Growth Promotion and In vitro Seed Germination of Lycium barbarum L. (Red Goji) Using Different Types of Cytokinins.

Lycium barbarum L., commonly known as red goji berry, is a widely recognized plant-based medicinal herb with nutritional and therapeutic properties. In this study, the effects of various cytokinins on the germination of L. barbarum seeds and the growth of seedlings were investigated under in vitro conditions. The berries were first surface sterilized and dissected, and the seeds were then cultured on Murashige and Skoog (MS) medium supplemented with different concentrations (0.5, 1.0, and 1.5 mg/L) of 6-benzylaminopurine (BAP), thidiazuron (TDZ), and kinetin (KIN) for 10 weeks at 25±2ºC with a photoperiod of 16 hours and a light intensity of 1000 lux. Upon observation after 10 weeks of culture, all cytokinin-treated cultures produced 100% seed germination as early as 7 days. KIN at 0.5 mg/L produced plantlets with the greatest height (8.40 ± 0.97 cm) with extensive rooting and the greatest total chlorophyll production. Besides, KIN at 1.5 mg/L resulted in the highest number of leaves per plantlet (6.90 ± 0.72), while 1.0 mg/L of TDZ led to the greatest biomass, i.e., fresh weight (FW) of 0.328 ± 0.05 gram and dry weight (DW) of 0.023 ± 0.003 gram. All cytokinins used in this experiment (BAP, TDZ, and KIN) promoted different in vitro growth promotion responses in L. barbarum. The effects of different types and concentrations of cytokinin on the height of plantlets, number of leaves per plantlet, fresh and dry weight, the extent of rooting, and the chlorophyll content were demonstrated to be statistically significant. This study provides valuable insights into optimizing in vitro cultivation techniques for goji berry propagation, which could contribute to developing superior cultivars and increased production of this superfruit in the future. For future perspectives, extended research in elucidating the underlying mechanism associated with cytokinin supplementation is imperative to understanding the roles of cytokinins and optimizing their effects on plant growth promotion.

Evaluation of Germination and Early Seedling Growth of Different Grasses Irrigated with Treated Mine Water

Coal mining is known to have negative impacts on the environment, necessitating land rehabilitation after mining activities. Amongst the problems associated with coal mining is the accumulation of acid mine drainage characterized by large amounts of heavy metals and high acidity. The impact of these environmental problems on the ecosystem around mining areas underscores a need to devise strategies that will ensure sustainable restoration of the ecosystem integrity to ensure environmental protection. Of these, treatment of acid mine drainage using calcium sulfate dihydrate, which is subsequently used for irrigation during phytoremediation, holds great promise for restoration of open-cast mines. However, although grasses are used for rehabilitation of coal mined areas, the impacts of treated mine water on the germination, seedling emergence, and plant growth of grasses are not well known. The aim of the study was to evaluate the germination and early seedling growth responses of different forage grasses to treated mine water. Seven forage grass species were selected, with four species represented by two varieties while others were represented by one variety, totaling 11 forage grasses. For each plant entry, 100 seeds were placed in J.R. Petri’s dishes lined with Whatman No. 2 filter paper and watered with distilled and mine water to assess germination. For the seedling establishment experiment, only five species were studied, in which twenty seeds per species were sown in pots containing mine soil and irrigated using distilled and treated mine water. The final germination percentage (FGP), germination rate index (GRI), corrected germination rate index (CGRI), and T50 were determined for the germination trail and total biomass was assessed for the seedling growth trail. The highest FGP for all grasses was attained under controlled conditions, using distilled water, ranging from 38–94%. All grasses germinated when watered using treated mine water and had a FGP ranging from 20–91%. Relative to distilled water, GRI and CGRI were highest only for L. multiflorum cv AgriBoost when seeds were watered using the treated mine water. All grasses watered with treated mine water produced high biomass for the first two weeks, after which biomass production started to decline. Two grasses, Eragrostis curvula cv Ermelo and Lolium multiflorum cv Archie, showed tolerance to treated mine water irrespective of its high electrical conductivity (557 mS∙m−1). Therefore, these grasses could be used in the rehabilitation of coal-mined areas irrigated with treated mine water.

Effect of different concentrations of soil and foliar applied zinc, boron and iron fertilizers on seedling growth, chlorophyll content and productivity of chickpea seedlings under semi-arid environment

The effectiveness of zinc (Zn), boron (B), and iron (Fe) is reduced in semi-arid regions, which can lead to a deficiency of these nutrients and inhibit chickpea productivity. In this work, three field experiments were executed over two years where soil and foliar applications of Zn, B, and Fe were carried out, including controls (Zn0, B0, and F0), soil application at 4.125 kg/ha (Zn-1, B1, and F1) and 8.25 kg/ha (Zn-2, B2, and F2), and foliar spay at 0.3% at flowering initiating (Zn-3, B3, and F3) and one week after flowering initiation (Zn-4, B4, and F4, respectively). The results indicate that the deficiency of these nutrients inhibited chickpea growth and yield, leading to a reduction in the pigment contents. Nonetheless, soil and foliar application of Zn, B, and Fe significantly improved growth, chlorophyll contents, and yield, showing a dose-dependent effect. The best results were recorded for Zn-3, B2, and F2 treatments which significantly (P<0.05) increased shoot length (20.96-85.19%), root length (42.85-93.65%), shoot fresh (23-76%) and root fresh weight (45-90.32%), compared with the control treatment. Chlorophyll parameters, including chlorophyll a and b contents, showed similar trends. Zn-3, B2, and F2 treatments significantly increased biological and grain yields, which were associated with higher values of the number of pods per plant and the number of seeds per pod. In a nutshell, we suggest that Zn foliar application at 0.3% at flowering initiation and soil application of B and Fe at 25 kg/ha are beneficial for improving the growth, pigment content, and overall productivity of chickpea.

Study on the synergistic effects of siderophore bacteria and arbuscular mycorrhizal fungi on the improvement of iron nutrition in Cinnamomum camphor

Iron, an essential micronutrient for plant growth, is often found in insoluble forms in alkaline soils, leading to inadequate absorption, poor plant growth, and iron deficiency chlorosis. This study explores the effects of co-inoculation with the siderophore bacteria Lysinibacillus fusiformis (S5) and Arbuscular mycorrhizal fungi (AMF) on the iron uptake and growth of Cinnamomum camphora seedlings. The experiment included four treatment groups: a control with plain water, AMF only, S5 only, and a combined AMF+S5 group, over a three-month pot experiment. Compared to the control, the combined AMF+S5 treatment significantly enhanced root mycorrhizal colonization and spore density by 15.6% and 31.8%, respectively. Additionally, there were increases in stem thickness, plant height, and root length by 34.7%, 15.6%, and 80.3%, respectively. In terms of photosynthetic physiology, the combined treatment improved the net photosynthetic rate and stomatal conductance by 37.5% and 46.7%, respectively, while reducing intercellular CO2 concentration by 8.7%. Furthermore, total iron content in Cinnamomum camphora increased by 11%, and root-available iron content (FCR) by 26.6%. These results demonstrate that co-inoculation with AMF and siderophore bacteria significantly promotes growth and iron absorption in seedlings, effectively mitigating symptoms of iron deficiency chlorosis, providing a scientific basis for developing efficient microbial co-inoculation techniques.

An Enhanced Interaction of Graft and Exogenous SA on Photosynthesis, Phytohormone, and Transcriptome Analysis in Tomato under Salinity Stress.

Salt stress can adversely affect global agricultural productivity, necessitating innovative strategies to mitigate its adverse effects on plant growth and yield. This study investigated the effects of exogenous salicylic acid (SA), grafting (G), and their combined application (GSA) on various parameters in tomato plants subjected to salt stress. The analysis focused on growth characteristics, photosynthesis, osmotic stress substances, antioxidant enzyme activity, plant hormones, ion content, and transcriptome profiles. Salt stress severely inhibits the growth of tomato seedlings. However, SA, G, and GSA improved the plant height by 22.5%, 26.5%, and 40.2%; the stem diameter by 11.0%, 26.0%, and 23.7%; the shoot fresh weight by 76.3%, 113.2%, and 247.4%; the root fresh weight by 150.9%, 238.6%, and 286.0%; the shoot dry weight by 53.5%, 65.1%, and 162.8%; the root dry weight by 150.0%, 150.0%, and 166.7%, and photosynthesis by 4.0%, 16.3%, and 32.7%, with GSA presenting the most pronounced positive effect. Regarding the osmotic stress substances, the proline content increased significantly by more than 259.2% in all treatments, with the highest levels in GSA. Under salt stress, the tomato seedlings accumulated high Na+ levels; the SA, G, and GSA treatments enhanced the K+ and Ca2+ absorption while reducing the Na+ and Al3+ levels, thereby alleviating the ion toxicity. The transcriptome analysis indicated that SA, G, and GSA influenced tomato growth under salt stress by regulating specific signaling pathways, including the phytohormone and MAPK pathways, which were characterized by increased endogenous SA and decreased ABA content. The combined application of grafting and exogenous SA could be a promising strategy for enhancing plant tolerance to salt stress, offering potential solutions for sustainable agriculture in saline environments.

Germination success of seeds ingested by Saguinus bicolor

ABSTRACT Frugivory and seed dispersal are fundamental ecological interactions influencing plant population dynamics and distribution. Still, understanding how the ingestion of seeds by fruit-eating animals affects seedling emergence performance remains poorly documented. Seed dispersal through animal ingestion can either promote or hinder germination. In this study, we assessed how seed ingestion by Saguinus bicolor, a critically endangered primate from the Brazilian Amazon, affects germination rate and germinability. As primate seed ingestion often improves seed germination, we predicted that germination rate and germinability would be higher in seeds defecated by the tamarins if compared to hand-extracted seeds. Of the 23 species, five did not germinated in either the control or gut-passage treatments. Among the ones that germinated, nine had an average increase in germinability, two decreased in germinability, and seven had a neutral effect. The germination rate increased in four species, reduced in eight species and had a neutral effect in six of the species. Most of the seeds that passed through the tamarins' digestive tract successfully germinated, demonstrating that seed ingestion by pied tamarins can benefit the plant populations by dispersing viable seeds through the landscape.

Application of 28.1 kDa Alginate Oligosaccharide Improves the Yield and Quality of Grain in Rice

AbstractWe conducted a phase‐wise study to evaluate the efficacy of the gamma ray‐produced oligosaccharides of alginate and chitosan in enhancing the yield in rice. Initially, we irradiated the dry powder of alginate and chitosan with 200–500 kGy dose of gamma ray to produce their oligosaccharides. Subsequently, we assessed efficiency of the aqueous solution (50–400 ppm) of these oligosaccharides to stimulate the growth in rice seedling. The elicitors which stimulated the seedling growth were later tested in the field for their ability to enhance the growth and yield in rice under six different treatment regimens. In the next two seasons we evaluated the elicitor and treatment regimen, which enhanced the yield and yield contributing factors, at a larger scale. The observations suggest that 200 ppm of alginate oligosaccharide (28.1 kDa) produced by 500 kGy of gamma ray enhances the yield in rice by 13% and improves the seed quality when sprayed during seedling, pre‐flowering and grain‐filling stages. Such treatment improves the overall growth and development of the plant, which probably enhances the yield and grain quality of the produce.

Exogenous MgH2-derived hydrogen alleviates cadmium toxicity through m6A RNA methylation in rice

Cadmium (Cd) contamination poses a substantial threat to crop yields and human health. While magnesium hydride (MgH2) has been reported as a hydrogen (H2) donor that promotes plant growth under heavy metal contamination, its role in rice remains elusive. Herein, seedlings of Oryza sativa L. Japonica variety Zhonghua 11 (ZH11) were selected and exposed to 20 µL of 1-mol/L cadmium chloride (CdCl2) solution via hydroponics to simulate Cd stress. Meanwhile, 0.1 mg of MgH2 was used to slow-release H2 to the experimental group to explore its potential effects on rice over a 2-week period. The results indicated that Cd exposure severely inhibited the growth and development of ZH11 rice seedlings. However, the exogenous slow-release of H2 from MgH2 effectively mitigated this inhibitory effect by restoring the balance of reactive oxygen species (ROS), maintaining endogenous H2 homeostasis, and supporting the photosynthetic system. High-performance liquid chromatography analysis revealed that exogenous H2 reduces m6A RNA methylation levels in mRNA under Cd stress. Consequently, MeRIP-seq was conducted to investigate the effect of Cd exposure in rice in the presence and absence of H2. The m6A modifications were enriched at the start codon, stop codon, and 3′ UTR. By integrating RNA-seq data, 118 transcripts were identified as differentially methylated and expressed genes under Cd stress. These gene annotations were associated with ROS, biological stress, and hormonal responses. Notably, 297 differentially methylated and expressed genes were identified under Cd stress in the presence of H2, linked to heavy metals, protein kinases, and calcium signaling regulation. Cd strongly activates the MAPK pathway in response to stress. Exogenous H2 reduces Cd accumulation as well as enhances plant tolerance and homeostasis by lowering m6A levels, thereby decreasing the mRNA stability of these genes. Our findings indicate that MgH2, by supplying H2, regulates gene expression through m6A RNA methylation and confers Cd tolerance in rice. This study provides potential candidate genes for studying the remediation of heavy metal pollution in plants.

Copper mitigates salinity stress by regulating water status, photosynthetic pigments and ion homeostasis and increases the yield of Eggplant (Solanum melongena)

Eggplant (Solanum melongena) is moderately sensitive to salinity. Seed priming and exogenous supplementation are technique that enhances germination, growth, and crop yield by overcoming salt stress. Therefore, this study was designed to understand the role of seed priming and copper (Cu) supplementation in modulating salt tolerance in eggplant. When exposed to salt stress, eggplant seedlings showed significantly higher Na+ content, an increased Na/K ratio, prolonged mean germination time, higher relative water loss, more days to flower bud initiation and first flowering, along with decreased germination rate, growth factors, water content, photosynthetic pigments, ionic contents (K+, Ca2+, Mg2+), and yield. The results demonstrated that the germination rate, final germination percentage, germination index, germination energy, and seed vigor index significantly improved, while the mean germination time decreased in Cu-primed seeds. The results also revealed that Cu supplementations increased seedling traits, leaf water content, photosynthetic pigment contents, ionic contents (K+, Ca2+, and Mg2+), and yield while decreasing the contents of Na+, and Na/K ratio, mean germination time, relative water loss, days to flower bud initiation, and days to 1st flowering under salt stress. Germination of seeds, seedlings growth traits, plant water status, plant pigments, yield, and ionic contents with the NaCl and Cu treatments were found to substantially interact with each other according to both hierarchical clustering and PCA. Overall, Cu seed priming and exogenous supplementation emerged as a promising strategy to enhance salt tolerance and promote germination, growth, and yield by regulating water status, photosynthetic pigments, and ion homeostasis in eggplant seedlings under NaCl stress. These findings provide valuable insights into the mechanisms of Cu-mediated stress alleviation in eggplant, with implications for sustainable crop production in saline environments.

Biochar-based phosphate fertilizer improve phosphorus bioavailability, microbial functioning, and citrus seedling growth

Phosphorus is essential for plant growth but often becomes immobilized in soils, reducing its availability to plants. This study explored the enhancement of phosphorus bioavailability through the co-pyrolysis of rice straw with magnesium oxide (MgO) at 800 °C, resulting in a novel biochar-based phosphate fertilizer, termed MRS8-P. The treatment involved enriching biochar with MgO to increase phosphorus loading and evaluating its effects on soil physicochemical properties and citrus seedling growth. Soil analysis revealed improved physicochemical properties, including increased available phosphorus (AP), enhanced soil pH, higher electrical conductivity (EC), and rapidly increased available potassium (RAK); however, a temporary immobilization of alkaline hydrolytic nitrogen (AHN) was noticed by biochar application. Notably, soil microbiota dynamics shifted with an increase in beneficial taxa, such as Proteobacteria and Actinobacteria, which enhanced phosphorus solubilization and organic matter decomposition, and a decrease in taxa, such as Methylomirabilota and Desulfobacterota. These microbial changes significantly contribute to soil fertility and nutrient availability. The application of MRS8-P significantly enhanced nitrogen, phosphorus, and potassium (NPK) uptake in citrus seedlings, as demonstrated by increased growth metrics, such as plant height, stem coarseness, and chlorophyll content measured by the SPAD index. These findings underscore the potential of MRS8-P in reducing reliance on traditional phosphate fertilizers, which are linked to environmental degradation through runoff and pollution. The study confirms that biochar-based phosphate fertilizers, such as MRS8-P, can promote more sustainable agricultural practices and improve crop health and soil management while minimizing environmental impacts.

Effects of Water-Deficit Stress on the Growth and Physiological Characteristics of Chloranthus spicatus Seedlings

Effects of Water-Deficit Stress on the Growth and Physiological Characteristics of Chloranthus spicatus Seedlings

Combination of silicon and plant growth promoting rhizobacteria consortia promoted the growth of melon seedlings under salt stress

Combination of silicon and plant growth promoting rhizobacteria consortia promoted the growth of melon seedlings under salt stress

Mycorrhizal fungi as critical biotic filters for tree seedling establishment during species range expansions

AbstractGlobal warming has been shifting climatic envelopes of many tree species to higher latitudes and elevations across the globe; however, unsuitable soil biota may inhibit tree migrations into these areas of suitable climate. Specifically, the role of mycorrhizal fungi in facilitating tree seedling establishment beyond natural species range limits has not been fully explored within forest ecosystems. We used three experiments to isolate and quantify the effects of mycorrhizal colonization and common mycorrhizal networks (CMN) on tree seedling survival and growth across (within and beyond) the elevational ranges of two dominant tree species in northeastern North America, which were associated with either arbuscular mycorrhiza (AMF, Acer saccharum) or ectomycorrhiza (EMF, Fagus grandifolia). In order to quantify the influence of mycorrhiza on seedling establishment independent of soil chemistry and climate, we grew seedlings in soils from within and beyond our study species ranges in a greenhouse experiment (GE) as well as in the field using a soil translocation experiment (STE) and another field experiment manipulating seedling connections to potential CMNs (CMNE). Root length colonized, seedling survival and growth, foliar nutrients, and the presence of potential root pathogens were examined as metrics influencing plant performance across species' ranges. Mycorrhizal inoculum from within species ranges, but not from outside, increased seedling survival and growth in a greenhouse setting; however, only seedling survival, and not growth, was significantly improved in field studies. Sustained potential connectivity to AMF networks increased seedling survival across the entire elevational range of A. saccharum. Although seedlings disconnected from a potential CMN did not suffer decreased foliar nutrient levels compared with connected seedlings, disconnected AM seedlings, but not EM seedlings, had significantly higher aluminum concentrations and more potential pathogens present. Our results indicate that mycorrhizal fungi may facilitate tree seedling establishment beyond species range boundaries in this forested ecosystem and that the magnitude of this effect is modulated by the dominant mycorrhizal type present (i.e., AM vs. EM). Thus, despite changing climate conditions beyond species ranges, a lack of suitable mutualists can still limit successful seedling establishment and stall adaptive climate‐induced shifts in tree species distributions.

Effect of Different Growing Media and Polybag Sizes on Seeds Germination & Root System of Rough Lemon (Citrus jambhiri Lush.) in Nursery Condition

Aims: The study aimed to evaluate the different growing media & polybag size for seedling growth of rough lemon rootstock. Study Design: The experiment used a Complete Randomized Design (CRD) with three replications. Place and Duration of Study: The study "Effect of Growing Media and Polybag Size on Rough Lemon Seedling Growth" took place in an insect-proof net house at CCS Haryana Agricultural University during the 2021-2022 academic year. Methodology: It comprising of 30 treatment combination i.e., ten different growing media: T1: garden soil; T2: soil: sand (1:1); T3: soil: sand: leafmold (1:1:1); T4: soil: cocopeat (1:1); T5: sand: cocopeat (1:1); T6: soil: sand: cocopeat (1:1:1); T7: soil: FYM (1:1); T8: sand: FYM (1:1); T9: soil: sand: FYM (1:1:1); T10: soil: sand: FYM: cocopeat (1:1:1:1), and the polybags S1: large (30 x 18 cm), S2: medium (21 x 18 cm) & S3: small size (17 x 16 cm) bags. Results: The study found that adding cocopeat to growing media (T4, T5, T6) resulted in earlier germination and higher rates (87-89%) Whereas, T4 to T10 media consists of either FYM, cocopeat for both resulted into more germination 87-89% as compared to controls (T1, T2, T3). The most of the root growth parameters i.e., diameter of tap root(2.45mm), fresh root weight (4.63g) & dry root weight (1.21g) & root: shoot ratio (0.61) improved with the media sand: FYM, soil: FYM, sand: soil: FYM, sand: soil: FYM: cocopeat in equal proportion. However, when media supplemented with cocopeat (T4, T5 & T6 ) also showed appreciable results as compared to soil, sand: soil & soil: sand: leafmold. However, sand: FYM, sand: cocopeat treatments were best in respect of number of primary roots (61.22), root volume (6.44ml). Whereas, sand: soil showed very poor results in all growth aspects. Among polybags sizes, large size (30 x 18cm) bags performed best in most of the germination & root growth parameters. Conclusion: Media enriched with organic matter outperformed sole media across all parameters, while larger polybags produced significantly better results than medium and small sizes.

Optimizing mycorrhizal fungi application for improved nutrient uptake, growth, and disease resistance in cardamom seedlings (Elettaria cardamomum (L.) Maton)

This study evaluated the impact of various doses (5, 10, 15 g) and application sequences (1, 2, or 3 times at monthly intervals) of arbuscular mycorrhizal (AM) fungal inoculum on cardamom seedlings over two years (2020–2021 and 2021–2022). The results indicated that the dosage of AM inoculum had a more substantial effect on the seedlings than the application sequence. A 10 g dose significantly increased shoot length and dry weight, while three applications of 5 g each improved the number of fibrous roots. Although potassium uptake was not affected, phosphorus and calcium uptake were highest with the 10 g dose. Arbuscular mycorrhizal inoculation also enhanced phosphatase activity in the rhizosphere, with 5 g improving acid phosphatase and 10 g improving alkaline phosphatase activity. Disease incidence, including seedling rot was lower with the 10 g dose, and additional sequential applications did not further reduce disease. Structural equation modeling (SEM) revealed that AM colonization positively influenced dry weight through the number of fibrous roots, showing a strong relationship between AM dose, colonization, spore count, and mycorrhizal dependency. This study indicates that applying a 10 g dose of AM fungal inoculum can be particularly beneficial in agroecosystems for improving cardamom seedling growth, nutrient uptake, and disease resistance.

Screening and identification of Paenibacillus polymyxa GRY-11 and its biological control potential against apple replant disease.

Apple replant disease (ARD) is a significant factor restricting the healthy development of the apple industry. Biological control is an important and sustainable method for mitigating ARD. In this study, a strain of Paenibacillus polymyxa GRY-11 was isolated and screened from the rhizosphere soil of healthy apple trees in old apple orchards in Shandong Province, China, and the effects of strain GRY-11 on soil microbial community and ARD were studied. The result showed that P. polymyxa GRY-11 could effectively inhibit the growth of the main pathogenic fungi that caused ARD, and the inhibition rates of the strain against Fusarium moniliforme, Fusarium proliferatum, Fusarium solani, and Fusarium oxysporum were 80.00%, 71.60%, 75.00%, and 70.00%, respectively. In addition, the fermentation supernatant played an active role in suppressing the growth of pathogenic fungi. The results of the pot experiment showed that the bacterial fertilizer of the GRY-11 promoted the growth of Malus hupehensis seedlings, improved the activity of protective enzymes in plant roots, enhanced the soil enzyme content, and optimized the soil microbial environment. In general, the GRY-11 can be used as an effective microbial preparation to alleviate ARD. Our study offers novel perspectives for the prevention of ARD.

Response of Leaf Traits and Photosynthetic Fluorescence Characteristics of Fraxinus malacophylla Seedlings to Rainfall Patterns During Dry and Rainy Seasons in Southwestern China.

Global climate change has led to a shift in rainfall patterns. And as water is an essential ingredient for plant photosynthesis, shifts in rainfall patterns will inevitably affect plant growth. This study was conducted in Kunming, southwest China. In this study, the response of leaf traits and photosynthetic fluorescence properties of Fraxinus malacophylla seedlings to rainfall patterns during the dry and rainy seasons was investigated using a natural rainfall interval of 5 days (T) and an extended rainfall interval of 10 days (T+) as rainfall interval treatments and a monthly average rainfall as a control (W), with the corresponding rainfall treatments of a 40% increase in rainfall (W+) and a 40% decrease in rainfall (W-). The results showed that Pn, Gs, and Tr basically all tended to increase and then decrease with increasing rainfall in the dry season and generally reached the highest under the W treatment; Pn, Gs, Ci, and Tr mostly remained high at 5 days relative to 10 days; PI was overall higher under the W treatment throughout the dry season. Extending the rainfall interval at the beginning of the rainy season significantly reduced Fm; throughout the rainy season, Gs, Ci, and Tr basically showed a decreasing trend with increasing rainfall, reaching the highest under the W-treatment and mostly higher at 5 days than at 10 days. These results suggest that natural rainfall intervals and natural rainfall amounts are more favorable to the growth of Fraxinus malacophylla seedlings in the dry season; reduced rainfall and multiple rainfalls in the rainy season tend to promote photosynthesis in Fraxinus malacophylla. This study reflects the different survival strategies of Fraxinus malacophylla under different rainfall patterns, as well as provides a theoretical basis for understanding how Fraxinus malacophylla can grow better under rainfall variability and for future management.

Effects of Light Intensity, Water Content, and the Application of Biochar Nanoparticles on the Growth and Development of Tomato Seedlings

This study investigates the effects of light intensity, water content, and the application of biochar nanoparticles (BNPs) on the growth and development of tomato seedlings to provide valuable insight into tomato cultivation. BNPs were prepared using rice straw. In this experiment, the light intensity was set at 350 μmol ·m−2 · s−1 (L1), 300 μmol ·m−2 · s−1 (L2), and 250 μmol ·m−2 · s−1 (L3). The irrigation amount was set at 150 mL/plant (W1) and 100 mL/plant (W2). The contents of BNPs were set at 0% BNPs (N1) and 5% BNPs (N2). L2W2N2 was used as the control. A total of 12 groups were included in the study. Groups D, E, F, J, K, and L did not use BNPs, while the remaining six groups used 5% BNPs. We found that BNPs exhibit significant aggregation with spherical morphology. As the pH increased, the particle size of BNPs showed a trend of initial increase, followed by a decrease and subsequent increase. Carbon elements existed in three different forms and possessed distinct chemical bonds, resulting in different relative contents. The relative content of C═O accounted for 26.40%, which was significantly higher than that of C—O by approximately 15%. Under the W1 treatment, the height of the tomato plant in L1N2 was 31.7 cm, which is higher by 0.4 cm than that in L1N1. Under L2W1N1 treatment, the net photosynthetic rate, transpiration rate, stomatal conductivity, and intercellular CO2 concentration of tomatoes were 9.68 μmoL ·m2 · s−1, 1.223 mmoL ·m2 · s−1, 0.071 μmoL ·m2 · s−1, and 626 ppm, respectively, which are significantly higher than the control. In conclusion, this research provides a foundation for growing tomatoes.

Plant growth-promoting Bacillus cereus MCC3402 facilitates rice seedling growth under arsenic-spiked soil

Microorganisms can solve the global problem of arsenic (As) contamination in soil and water, by eliminating the hazardous metalloid from contaminated habitats. A native As-resistant PMM6 strain was isolated from the tainted agricultural field in Durgapur, India. Following phenotypic investigations, fatty acid methyl ester analysis, and 16S rDNA sequence-based homology, it was identified as Bacillus cereus. Various analytical techniques such as atomic absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy studies revealed a positive correlation between the strain's resistance properties against arsenate (75 mM) and arsenite (25 mM) and the biosorption and bioaccumulation of arsenic. The strain exhibited several important plant growth-promoting traits, including indole-3-acetic acid production (110.0±0.33μg/mL), 1-aminocyclopropane-1-carboxylate deaminase activity (2334.2±1.90 nm α-ketobutyrate/mg protein/h), phosphate solubilization, and siderophore production (68.0±2%). These traits facilitated the growth augmentation of rice seedlings under As stress, both in terms of physiological and biochemical parameters. Compared to uninoculated soil, the use of strain PMM6 helped to reduce As mobilization and oxidative stress in rice seedlings growing in As-spiked soil. Therefore, strain PMM6 holds the potential as bioremediator to restore As-contaminated agricultural lands while also promoting the growth of rice seedlings. It could thus be utilized in the bioremediation of As-contaminated agricultural lands in the near future.

Soil properties of overburden and topsoil in limestone mining area: A preliminary study

Limestone mining removes topsoil and produces overburden piles, which is improper for plant growth. The objectives of this study were to compare the texture, certain chemical properties, and bacterial population of overburden to the topsoil and to observe the effects of compost amendment on the growth of corn seedlings on the potted overburden. The overburden characterization was performed using a quantitative descriptive method with purposive sampling. Samples were taken from a 6-month-old overburden pile and a pine-vegetable agroforestry ecosystem. The data were further analyzed by using the Student’s t-test. A bioassay was set up in a randomized block design with various concentration compost treatments and five replications. The results showed significant differences between texture, chemical characteristics, and bacterial counts of overburden and topsoil were recorded. The topsoil was more acidic and had higher organic carbon, potential phosphorus, potential potassium, and cation exchange capacity, while the overburden had higher levels of calcium; however, the total N and Magnesium content in topsoil and overburden was similar. The bacterial population of the overburden was lower than in the topsoil. A total of 16 gram-negative and one gram-positive bacteria have been identified from both samples. Applying huge amounts of compost enhanced corn seedlings' growth in the overburden. The study suggested that overburden was more unfertile compared to the topsoil. Therefore, the improvement of overburden properties by compost amendment is needed to green the area.