Melatonin and KNO3 Application Improves Growth, Physiological and Biochemical Characteristics of Maize Seedlings under Waterlogging Stress Conditions

Waterlogging is one of the serious abiotic stresses that inhibits crop growth and reduces productivity. Therefore, investigating efficient waterlogging mitigation measures has both theoretical and practical significance. The objectives of the present research were to examine the efficiency of melatonin and KNO3 seed soaking and foliar application on alleviating the waterlogging inhibited growth performance of maize seedlings. In this study, 100 µM melatonin and different levels (0.25, 0.50 and 0.75 g) of potassium nitrate (KNO3) were used in seed soaking and foliar applications. For foliar application, treatments were applied at the 7th leaf stage one week after the imposition of waterlogging stress. The results showed that melatonin with KNO3 significantly improved the plant growth and biochemical parameters of maize seedlings under waterlogging stress conditions. However, the application of melatonin with KNO3 treatments increased plant growth characteristics, chlorophyll content, and the net photosynthetic rate at a variable rate under waterlogging stress. Furthermore, melatonin with KNO3 treatments significantly reduced the accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA), and it decreased the activity of pyruvate decarboxylase and alcohol dehydrogenase, while increasing enzymatic activities and soluble protein content of maize seedlings under waterlogging stress conditions. Overall, our results indicated that seed soaking with 100 µM melatonin and 0.50 g KNO3 was the most effective treatment that significantly improved the plant growth characteristics, chlorophyll content, photosynthetic rate, and enzymatic activity of maize seedling under waterlogging conditions.

Influence of Inorganic Metal (Ag, Cu) Nanoparticles on Biological Activity and Biochemical Properties of Brassica napus Rhizosphere Soil

Two separate forms of application of silver and copper nanoparticles (AgNP and CuNP in a nanocolloidal suspension) to winter oilseed rape seeds were used: (1) seed soaking (S) for 1 h at 20 °C in a NP suspension and (2) additional seed soaking and spraying plants 21-day-old seedlings (SP) with NP. The AgNP and CuNP colloidal suspensions in sterile distilled water were applied in three different NP concentrations (50, 100, 150 mg L−1). However, the changes in the biology and biochemistry of the Brassica napus rhizospheric soil after the application of CuNPs and AgNPs are not considerable, although mostly statistically significant, and the application of CuNPs is more beneficial for this activity than the application of AgNPs. The number of CFUs (colony–forming units) of the tested groups of culturable microorganisms (fungi and copiotrophic, oligotrophic, and siderophore-producing bacteria) indicates the following trend: the abundance of all the tested groups was slightly positively correlated with CuNPs and clearly negatively correlated with AgNPs in each version of application. The soil pH value and tested biochemical soil parameters (IAA: indole-3-acetic acid, PhC: phenolic compounds, FeCC: Fe–chelating compounds) were negatively correlated with AgNPs applied to the seeds (S) at all the tested concentrations and to the seeds and plants (SP) at the concentration of 50 mg L−1. In turn, these parameters were strongly positively correlated with CuNPs applied to the S and SP groups at the concentration of 50 mg L−1 as well as Ag applied to SP at 100 mg L−1. Decrease in dehydrogenase activity (DHA) was lower after the application of CuNPs and AgNPs in S than in the SP way, and the DHA activity was equal to the activity in the control sample after the CuNP application in 100 and 150 mg L−1 concentrations.

Reducing Phenanthrene Contamination in Trifolium repens L. With Root-Associated Phenanthrene-Degrading Bacterium Diaphorobacter sp. Phe15

Some root-associated bacteria could degrade polycyclic aromatic hydrocarbons (PAHs) in contaminated soil; however, their dynamic distribution and performance on root surface and in inner plant tissues are still unclear. In this study, greenhouse container experiments were conducted by inoculating the phenanthrene-degrading bacterium Diaphorobacter sp. Phe15, which was isolated from root surfaces of healthy plants contaminated with PAHs, with the white clover (Trifolium repens L.) via root irrigation or seed soaking. The dynamic colonization, distribution, and performance of Phe15 in white clover were investigated. Strain Phe15 could efficiently degrade phenanthrene in shaking flasks and produce IAA and siderophore. After cultivation for 30, 40, and 50 days, it could colonize the root surface of white clover by forming aggregates and enter its inner tissues via root irrigation or seed soaking. The number of strain Phe15 colonized on the white clover root surfaces was the highest, reaching 6.03 Log CFU⋅g–1 FW, followed by that in the roots and the least in the shoots. Colonization of Phe15 significantly reduced the contents of phenanthrene in white clover; the contents of phenanthrene in Phe15-inoculated plants roots and shoots were reduced by 29.92–43.16 and 41.36–51.29%, respectively, compared with the Phe15-free treatment. The Phe15 colonization also significantly enhanced the phenanthrene removal from rhizosphere soil. The colonization and performance of strain Phe15 in white clove inoculated via root inoculation were better than seed soaking. This study provides the technical support and the resource of strains for reducing the plant PAH pollution in PAH-contaminated areas.

Study of Seed Soaking and Foliar Application of Ascorbic Acid, Citric Acid and Humic Acid on Growth, Yield and Active Components In Maize

Foliar application and seed soaking has been used as a means of supplying supplemental doses of nutrients, plant hormones, stimulants, and organic components. the effects of these applications have included yield increases, and improved drought tolerance, and enhanced crop quality, so A field experiment was carried out during spring seasons in 2019 and 2020 for styding Seed soaking and Foliar Application of Ascorbic acid, Citric acid and Humic acid on Growth, Yield and Active Components IN Maize. Randomized complete block design in split plots arrangement was used with three replicates. Main-plots were for seeds soaking with ascorbic, citric (100 mg l-1) frequently and humic at (1 ml l-1). Sub-plots were for vegetative parts nutrition with same acids above. Results showed a significant superiority of seeds soaking in humic acid for traits of ears number per plant (1.3 and 1.6), rows number per ear (16.6 and 17.5), grains number per row (39.3 and 45.3), grains number per ear (644.3 and 793.5), weight of 300 grains (75.3 and 100.6 g), total grain yield ( 6.0 and 8.3 ton ha-1), shelling ratio (79.3 and 85.1%), biological yield (20.7 and 26.8 ton ha-1), harvesting index (30.4 and 31.2%), in both seasons respectively. Effect of vegetative parts nutrition or interaction between studied factors was non-significant on most traits studied. It can be concluded that soaking maize seeds in humic acid improves yield and yield components.

Effect of Concentration and Period of Seed Soaking with Atonik on Some Quantitative Traits of Mung Bean

A field experiment was carried out during spring season of 2016 and 2017 in the field of the Department of Field Crops - College of Agriculture - University of Anbar (Alternative Site – Abu Ghraib), to study the effect of concentration and Period of seed soaking with the Atonik growth regulator on the some quantitative traits of the mung bean (Al-Khadhrawi variety). Split plots arrangement according to randomized complete block design (RCBD) at three replications was used. The concentrations of soaking with Atonik (0, 2.5, 5- and 7.5-ml L-1) were the main plots, while the soaking period (0, 2, 4 and 6 hours) occupied the sub plots. The results showed that the seeds soaking with Atonik growth regulator at a 7.5 ml L-1 recorded the highest plant height (54.05 and 47.10 cm), number of pods (15.83 and 11.58 pods plant-1) and number of seeds (10.81 and 8.48 seeds pod-1) for both seasons respectively, and number of branches (14.33 branch plant-1) in the first season only. The soaking period for 6 hours was significantly superior and gave the highest plant height (54.23 and 46.59 cm), number of branches (14.00 and 12.80 plant branch- 1), number of pods (16.75 and 14.08 pod plant-1) and number of seeds (10.80 and 8.80 seed pod-1) for both seasons respectively. The interaction between concentrations of soaking at 7.5 ml L-1 and soaking period for 6 hours had highest values for more the studied traits and both seasons. We can bw conclude that the quantitative characteristics of the mung It can be improved by using seed soaking treatment before planting with Atonik growth regulator.

Seed Invigoration with Paclobutrazol Improves Seedling Growth, Physiological, Biochemical Attributes and Fruit Yield in Okra

The production of okra is affected by improper seedling growth and abiotic factors like temperature and soil. This study was aimed to examine the effect of paclobutrazol (PBZ) seed priming on the growth, seedling vigor and yield of okra. A pot experiment was conducted in completely randomized design under natural conditions and seeds of two okra varieties were soaked in 0, 4, 8, 10 and 20 mg L-1 of PBZ solution. Results showed that PBZ seed soaking affected the germination rate and maximum reduction in germination rate was observed at 20 mg L-1 of PBZ. A gradual decrease in plant height was recorded in PBZ treated plants as compared to control. A decrease in plant height of PBZ treated plants was accompanied with an increase in plant biomass and number of branches. PBZ seed soaking resulted in darker green leaves with higher chlorophyll, protein and total free amino acid contents than control plants. The activity of antioxidant enzymes, peroxidase and superoxide dismutase was also higher in PBZ treated plants. The improvement in all vegetative and physiological parameters ultimately had a positive effect on yield. PBZ treated plants showed an increase in the number of pods and pod length while seed weight remained unaffected. Thus, seed priming with optimum doses of PBZ could improve the seedlings and yield of okra. © 2021 Friends Science Publishers