Growth Of Maize Seedlings Research Articles

Melatonin and Nitrogen Applications Modulate Early Growth and Related Physio-biochemical Attributes in Maize Under Cd Stress

Melatonin is effective in modulating plant metabolism under stress conditions whereas nitrogen (N) is essential for plant growth. To explore the effects of melatonin and N applications on early growth, associated physiological and biochemical traits, and cadmium (Cd) uptake in maize under Cd stress, a pot experiment was conducted. Two melatonin levels, i.e., 0 and 200 μM, and two N levels, i.e., 1/4 N and full N dose of Kimura nutrient solution, were employed on two widely cultivated maize varieties, i.e., Yuecainuo 2 and Yuebaitiannuo 7, under Cd stress (150 μM). Results showed that melatonin application improved plant biomass and seedling growth, especially in low N treatment which further activated antioxidant defense system in terms of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) while melatonin application variably affected activities of antioxidants under Cd stress. In addition, melatonin application and low N treatment activated enzymes involved in N metabolism in Yuecainuo 2 as well as resulted in higher Cd concentration in shoot and root of maize seedlings in both maize varieties. Overall, short-term low N treatment showed marginal decrease in early growth of maize with higher Cd accumulation, while melatonin application could accelerate the growth of maize seedlings and further improve the Cd absorption in maize seedlings.

Klebsiella jilinsis 2N3 promotes maize growth and induces resistance to northern corn leaf blight

The northern corn leaf blight (NCLB) is one of the most damaging diseases of maize and is caused by the hemibiotrophic ascomycete fungal pathogen Setosphaeria turcica. Previously, we reported that Klebsiella jilinsis 2N3 is a bacterium that can degrade sulfonylurea herbicides. Interestingly, we found that 2N3 can also promote maize growth and induce resistance to NCLB. 2N3 can grow in a nitrogen-free environment, dissolve inorganic phosphorus and potassium, and produce indoleacetic acid and a siderophore. To further evaluate its potential use in agriculture, the ability to promote maize growth and inhibit NCLB were determined by pot experiments. 2N3 significantly promoted the growth of maize seedlings and their chlorophyll content. After challenge inoculation for 14 days with S. turcica, the causal agent of NCLB, 2N3-treated maize plants showed a 67.44% decrease in the disease index. 2N3 enhanced the activities of catalase, phenylalanine ammonia lyase, peroxidase, superoxide dismutase, polyphenol oxidase, and chitinase in maize leaves. The mechanism of induction of resistance appeared to be primarily owing to the enhancement of the transcript levels of the marker genes of systemic acquired resistance (ZmPR1, ZmPR5, ZmOPR2, and ZmPAL) and the activation of the salicylic acid signaling pathway.

Effects of exogenous silicon on maize seed germination and seedling growth

As the global population continues to increase, global food production needs to double by 2050 to meet the demand. Given the current status of the not expansion of cultivated land area, agronomic seedlings are complete, well-formed and strong, which is the basis of high crop yields. The aim of this experiment was to study the effects of seed germination and seedling growth in response to silicon (from water-soluble Si fertilizer). The effects of Si on the maize germination, seedling growth, chlorophyll contents, osmoprotectant contents, antioxidant enzyme activities, non-enzymatic antioxidant contents and stomatal characteristics were studied by soaking Xianyu 335 in solutions of different concentrations of Si (0, 5, 10, 15, 20, and 25 g·L−1). In this study, Si treatments significantly increased the seed germination and per-plant dry weight of seedlings (P < 0.05), and the optimal concentration was 15 g·L−1. As a result of the Si treatment of the seeds, the chlorophyll content, osmotic material accumulation and antioxidant defence system activity increased, reducing membrane system damage, reactive oxygen species contents, and stomatal aperture. The results suggested that 15 g·L−1 Si significantly stimulated seed germination and promoted the growth of maize seedlings, laying a solid foundation for subsequent maize growth.

Nitric oxide as a way to mitigate copper (Cu) toxicity in the emergence and initial growth of maize seedling (Zea mays L.)

The aim of this study is to assess the effect of sodium nitroprusside-NPS (nitric oxide donor) on the emergence and initial growth of maize seedlings (Zea mays L.) subjected to different copper concentrations. The study followed a completely randomized design at 4 x 3 factorial arrangement, with 12 treatments and 8 repetitions, totally 96 trays with 25 seedlings per repetition. Seedlings were soaked in sodium nitroprusside (SNP) solution (0.75 and 150 µM - donor), sodium ferrocyanide (SF) (0.75 and 150 µM - compensator) and deionized water (control) on Germitest paper for 48 hours. Next, they were placed on sand saturated with CuSO4.5H2O at concentrations of 0, 100 and 200 µM. The results showed that SNP doses were not capable of mitigating copper toxicity in seedling emergence, influencing emergence speed coefficient and prolonging the mean emergence time of plants subjected to copper concentrations of 100 µM and 200 µM. Copper concentrations rose the number of abnormal seedlings and had negative influence on plant biometrics and biomass. Copper concentration of 200 µM increased proline content in the roots. NPS and sodium ferrocyanide application had effect on emergence speed index, shoot and root dry mass and on proline content in the shoot and roots. This outcome highlights that such effects were caused by treatments related to release of cyanide found in sodium nitroprusside (SNP), rather than to nitric oxide (NO)

Effects of Root Zone Temperature Increase on Physiological Indexes and Photosynthesis of Different Genotype Maize Seedlings

This experiment investigated the effects of different degrees of warming of the root zone on the antioxidant enzyme activity and malondialdehyde (MDA) content, chlorophyll fluorescence parameters, and photosynthetic physiological parameters of maize (Zea mays L.) seedling roots. Different genotypes of maize types SD609 (Stay-green Maize type) and SD902 (senescent type) were used as test materials in the test and the test set three root zone temperatures (24, 30, and 36°С). The results showed that properly increasing the root zone temperature could significantly promote the growth of maize seedlings, increase the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and actual photochemical efficiency (ΦPS) electron transfer rate (ETR), photochemical quenching coefficient (qP), increase leaf photosynthesis and transpiration rate. However, when the root zone temperature was too high, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in the roots of maize seedlings would be significantly reduced, and the content of malondialdehyde (MDA) would be increased. This lead to excessive accumulation of reactive oxygen, which affects the functions of root system absorption, synthesis, transportation, etc., leading to reduced leaf enzyme activity, damaged to the PSII reaction center, and reduced photosynthetic rate. Among them, the Stay-green Maize type SD609 had a significantly smaller change than the aging type SD902. Under high temperature stress in the root zone, the relatively high antioxidant enzyme activity, better stability of the PSII reaction center, and photoprotection mechanisms of SD609 were the physiological basis for maintaining a stable photosynthetic rate and resisting high temperature in the root zone. PSII reaction center damage and relatively low non-photochemical quenching coefficient may be an important factor for non-stomatal limitation of SD902.

Role of soil bacterial consortia on glyphosate degradation and growth of maize seedlings

Pre-growing weed control by glyphosate herbicides is effective for increasing yield, but glyphosate residues in the soil might reduce soil quality and can accumulate in agricultural products. Naturally, microbes are able to breakdown glyphosate into nontoxic substances orthophosphate and glycine. Glyphosate degradation in soil by single soil microbes are reported elsewhere, but the information about glyphosate removal by soil bacterial consortia was limited. The objective of this research was to determine the effect of carbon (C), nitrogen (N), and phosphorus (P) composition in liquid media to increase glyphosate degradation and its degradation product by soil bacterial consortia and 2) verify the effect of bacterial consortia on maize seedlings growth, their N and P uptake, as well as total and soluble P in soil. Glyphosate degradation test was set up by incubating bacterial consortia in a different composition of C-N-P liquid basal media. Greenhouse experiment has been performed in a randomized block design to treat maize grown in Inceptisols with bacterial and glyphosate application. The results showed that C-N-P composition of liquid media affected the concentration of glyphosate, as well as orthophosphate and glycine as by-products. In-planta experiment verified that inoculation of glyphosate-degrading bacterial to maize seedling grown in glyphosate-contaminated soil enabled to enhance shoot dry weight of maize seedling and N and P uptake at 4 weeks after inoculation.

EKSPLORASI DAN UJI VIRULENSI BAKTERI Bacillus sp. ENDOFIT JAGUNG TERHADAP PENYAKIT BUSUK PELEPAH JAGUNG

[EXPLORATION AND VIRULENT TEST OF MAIZE ENDOPHYTE Bacillus sp. AGAINST MAIZE SHEATH BLIGHT]. Capability of endophytic bacterial, effectivity, and its effect on R. solani. and on maize seedlings growth were investigated from April 2018 to January 2019. Exploration of endophytes bacteria in maize was taken from Banyumas Regency (Sumbang, Kembaran, Baturraden) and Purbalingga Regency (Padamara, Bojongsari, Pratin). Taking plant samples using Purposive Random Sampling and Diagonal Sampling methods. Completely randomized design was used in in vitro test with 16 treatments repeated twice. Completely randomized block design was used in in planta experiment with 5 treatments repeated 5 times. The treatment consisted of control, fungiside (mankozeb), and 2 isolates of endophytes bacteria performing the best in vitro result. Variables observed included characteristics of endophytic bacteria and pathogenic fungi, inhibition diameter, incubation period, disease intensity, incidence of disease, AUDPC, plant height, leaf number, root length, plant fresh weight, canopy fresh weight, and root fresh weight. Resultshowed that the exploration obtained 15 endophytic Bacillus sp. isolates. The PD A.4 and BK A.1 isolates werw able to inhibit the growth of pathogenic fungi in-vitro by 56.93 and 51.5%, respectively. The soaking treatment using BK A1 was able to reduce disease intensity by 59.377%, and AUDPC value 34.19%. Endophytic bacteria influence plant height, plant fresh weight, canopy fresh weight, and fresh weight of roots respectively as 89.17 cm, 126.06 g, 106.67 g and 19.4 g.

Effects of Waterlogging On Maize Seedling Growth during Seed Germination

In order to understand the resistance of maize seed germination characteristics, to varying degrees of early germination of maize seeds flooding stress, explore the seed germination of maize seedling vigor and growth period of flooding stress, help to understand inverse resistant mechanism of corn seed germination period, to help agricultural production results show that the seeds of waterflooded development, continue to develop at a young age, compared with control, corn seedling variety of enzyme activity and soluble sugar and soluble protein in different degree of change Compared with the control group, the chlorophyll content of Lu yu 36 maize seedlings decreased, while the chlorophyll content of Zheng Dang 958 showed a trend of first decreasing and then increasing. Peroxidase (POD), malondialdehyde (MDA) and soluble sugar all showed an increasing trend. These results provided a basis for better understanding of the waterlogging stress tolerance of maize seeds during germination.

Combining humic acid with phosphate fertilizer affects humic acid structure and its stimulating efficacy on the growth and nutrient uptake of maize seedlings

This paper analyzed the compositional and structural changes of humic acid (HA) after combined with phosphate fertilizer (PHA), and investigated its effects on the growth of maize seedlings with four humic acid concentrations. The results showed that the atomic ratios of O/C and (O + N)/N of PHA were significantly lower than those of HA, which indicated that PHA had poor hydrophilicity compared with HA. The spectra of FTIR and NMR results suggested that the relative content of carboxyl group in PHA was higher than that in HA. X-ray photoelectron spectroscopy technology showed that the relative amount of C–C in PHA was lower than that in HA, while C–H was the opposite. The above changes were attributed to the crack of HA structure during the preparation of humic acid enhanced phosphate fertilizer, which was verified by the results from the determination of gel permeation chromatography that there were more low molecular weight components in PHA than that in HA. However, compared with HA, PHA showed a worse effect in promoting growth and the uptake of nitrogen, phosphorus and potassium by maize seedlings. This worse effect might be attributed to the poor hydrophilicity and unsuitable addition amount of PHA.

Biological function of Klebsiella variicola and its effect on the rhizosphere soil of maize seedlings.

BackgroundDeterioration of the ecological environment in recent years has led to increasing soil salinization, which severely affects the cultivation of agricultural crops. While research has focused on improving soil environment through the application of pollution-free microbial fertilizers, there are relatively few plant growth-promoting bacteria suitable for saline-alkali environments. Although Klebsiella variicola can adapt to saline-alkali environments to successfully colonize rhizosphere microenvironments, only a few studies have investigated its role in promoting crop growth. Its effect on the crop rhizosphere soil microenvironment is especially unclear.MethodsIn this study, the biological function of K. variicola and its colonization in maize seedling rhizosphere soil were studied in detail through selective media and ultraviolet spectrophotometry. The effects of K. variicola on the rhizosphere soil microenvironment and the growth of maize seedlings in saline-alkali and neutral soils were systematically analysed using the colorimetric method, the potassium dichromate volumetric method, and the diffusion absorption method.ResultsOur results showed that K. variicola played a role in indole acetic acid, acetoin, ammonia, phosphorus, and potassium production, as well as in nitrogen fixation. A high level of colonization was observed in the rhizosphere soil of maize seedlings. Following the application of K. variicola in neutral and saline-alkali soils, the nutrient composition of rhizosphere soil of maize seedlings increased in varying degrees, more notably in saline-alkali soil. The content of organic matter, alkali-hydrolysable nitrogen, available phosphorus, available potassium, alkaline phosphatase, sucrase, urease, and catalase increased by 64.22%, 117.39%, 175.64%, 28.63%, 146.08%, 76.77%, 86.60%, and 45.29%, respectively, insaline-alkalisoil.ConclusionK.variicola, therefore, performed a variety of biological functions to promote the growth of maize seedlings and effectively improve the level of soil nutrients and enzymes in the rhizosphere of maize seedlings, undersaline-alkali stress conditions. It played an important role in enhancing the rhizosphere microenvironment of maize seedlings under saline-alkali stress.

Deletion of the Trichoderma virens NRPS, Tex7, induces accumulation of the anti-cancer compound heptelidic acid

The anticancer antibiotic heptelidic acid is a sesquiterpene lactone produced by the beneficial plant fungus Trichoderma virens. This species has been separated into two strains, referred to as P and Q, based on its biosynthesis of secondary metabolites; notably, only P-strains were reported to produce heptelidic acid. While characterizing a Q-strain of T. virens containing a directed mutation in the non-ribosomal peptide synthetase encoding gene Tex7, the appearance of an unknown compound in anomalously large quantities was visualized by TLC. Using a combination of HPLC, LC-MS/MS, and NMR spectroscopy, this compound was identified as heptelidic acid. This discovery alters the strain classification structure of T. virens. Additionally, the Tex7 mutants inhibited growth of maize seedlings, while retaining the ability to induce systemic resistance against the foliar fungal pathogen, Cochliobolus heterostrophus.

Phytotoxic Effects of Aqueous Extracts of Olax subscorpioidea Oliv. on Seed Germination and Growth Parameters of Maize (Zea mays L.)

Phytotoxicity of wild plants is sometimes utilized in the control of weeds. Their effects on crops are however not extensively documented. Effects of aqueous extracts of Olax subscorpioidea Oliv. were thus examined on seeds and seedlings of maize. Two experiments were laid out in complete randomized designs (CRD) and replicated five times. Ten seeds of maize were initially placed in separate petri-dishes and moistened daily with two (2) ml water extracts of different parts of Olax sp. while 2 ml of distilled water served as control. Secondly, maize seedlings growing on top soil in experimental pots were treated with 100 ml of extracts at seven days intervals for eight weeks. Data were collected on number of germinated seeds daily, and lengths of five randomly selected plumules and radicles at 7 days after sowing (DAS). Number of leaves, plant height, root dry weight and shoot dry weight of seedling were measured using standard methods. Analysis of variance and Duncan’s Multiple Range Test were conducted to statistically determine significant means at P=0.05. Mean germination of (0.71±0.00) was observed at 2 DAS and 2.81±0.10 at 7 DAS. Leaf extracts significantly reduced germinability, but significantly increased number of leaves, plant height (26±1.28), root dry weight (10.30±3.24) and shoot dry weight (14.99±2.13). The results showed that Olax subscorpioidea has alloallelopathic (phytotoxic) effects on maize seeds, but stimulated growth of maize seedlings. Its use as a bio-herbicide or growth stimulant in should be well-timed.

Interactive Effect of Biochar and Silicon on Improving Morpho-Physiological and Biochemical Attributes of Maize by Reducing Drought Hazards

Maize (Zea mays L.) is one of the most important food and feed cereals of the world, but its production is threatened by sudden climate change especially drought. While, low organic matter in soils increases the drought severity. Therefore, study was planned to investigate the interactive effect of biochar and silicon (Si) nutrition on morpho-physiological and biochemical traits under water-deficit environment. Drought stress was applied subsequent 15 days of seedlings development. Experimental treatments comprised of CK (controlled soil no drought stress nor amended), only drought (40% water holding capacity (WHC)), drought + Si (40% WHC with 100 mg Si kg−1 soil), drought + biochar (40% WHC with 4 t ha−1), and drought + Si + biochar (40% WHC + 100 mg Si kg−1 soil +4 t ha−1). Data were collected after 15 days of treatment application. Drought reduced the growth of maize seedlings by reducing shoot biomass (38%), seedling weight (37%), photosynthetic rate (29%), transpiration rate (28.7%), and relative water contents (23.8%) and increased the activities CAT (30%), SOD (38.5%), and POD (33%). The positive effect of sole application of biochar and silicon was observed in improving physio-biochemical traits. In addition, better results were obtained with combined application of biochar and Si in enhancing maize growth such as shoots (25%), roots (40%), and seedlings (27%) as compared with drought. Combined application of biochar and Si may be a viable option to alleviate adversities of drought stress for maize growth and development.

The leaf extract of crofton weed (Eupatorium adenophorum) inhibits primary root growth by inducing cell death in maize root border cells

The extract of crofton weed (Eupatorium adenophorum) inhibits seed germination and weed growth; however, the physiological mechanisms underlying the effect of crofton weed extract on the modulation of seedling growth and root system development remain largely unclear. In this study, we investigated the effects of the leaf extract of crofton weed (LECW) on primary root (PR) growth in maize seedlings. Treatment with LECW markedly inhibited seed germination and seedling growth in a dose-dependent manner. Physiological analysis indicated that the LECW induced reactive oxygen species (ROS) accumulation in root tips, thereby leading to cell swelling and deformation both in the root cap and elongation zone of root tips, finally leading to cell death in root border cells (RBCs) and PR growth inhibition. The LECW also inhibited pectin methyl esterase (PME) activity, thereby decreasing the RBC number. Taken together, our results indicated that the LECW inhibited PR growth by inducing ROS accumulation and subsequent cell death in RBCs. The present study provides a better understanding of how the LECW modifies root system development and provides insight for evaluating the toxicity of crofton weed extracts in plants.

Evaluation of the Mixed Effects of Some Indigenous Strains of Arbuscular Mycorrhizal Fungi on the Growth of Maize Seedlings Under Greenhouse Conditions

The objective of the study was to evaluate the joint effects of three groups of native arbuscular mycorrhizal fungi (AMF) (Glomeraceae, and Diversisporaceae) on the growth of Maize Seedlings. The mycorrhizal fungi were isolated by the wet sieving method through decreasing sieve (300 µm, 125 µm, 63 µm and 38 µm) followed by centrifugation on a sucrose gradient. The growth tests were evaluated in greenhouse conditions for 40 days. After opening a planting hole, two maize (2000 SYNEE-W) seeds, one coated with AMF and the other not coated (Control) were introduced into the planting hole for each treatment. Data on different parameters were evaluated. The results of this study revealed that the maximum heights, the largest noose diameters and the largest numbers of leaves were obtained with treatment Acaulosporaceae + 50% NPK-Urea having 20.55% and 17.04% respectively and 11.77% for that of the control. The produced biomass and the leaf area of the maize plants were improved by the treatment Glomeraceae+ 50NPK-Urea with a respective increase of 54.97% for fresh above biomass (FAB), 42.94% for fresh underground biomass (FUB) and 55.23% for the leaf area compared with the control. Also, very high frequency of mycorrhiza was recorded with treatment Glomeraceae while the largest numbers of mycorrhiza spores and intensity were recorded with treatment Acaulosporaceae. These results augur the possibility of using these mixed AMF bio-products as organic fertilizers to improve maize productivity in Benin.

Degradation of acetochlor and beneficial effect of phosphate-solubilizing Bacillus sp. ACD-9 on maize seedlings.

The biodegradation of acetochlor in solution and soil and improvements in the growth of maize seedlings by a phosphate-solubilizing bacterial strain were investigated in this research. The strain Bacillus sp. ACD-9 optimally degraded acetochlor at pH 6.0 and 42°C in solution. And acetochlor with an initial concentration of 30mg/L was efficiently (> 60%) degraded by the strain after 2days in solution. Acetochlor biodegradation and the resulting beneficial products were also identified by LC-MS, and the probable degradation products of acetochlor and two kinds of plant growth hormones, namely, 2-chloro-N-(2-methyl-6-ethylphenyl) acetamide (CMEPA), indoleacetic acid (IAA), and zeatin, were detected from the fermentation broth of strain ACD-9. The effects of the strain on the growth and acetochlor accumulation of maize seedlings were also analyzed in laboratory-scale pot experiments. Inoculation of the strain in soil could significantly improve growth (> 9.4%) and phosphorus uptake (> 14.8%) and decrease the accumulation (> 70%) and toxic effects of acetochlor on seedlings. Taking the results together, strain ACD-9 may be useful in the degradation of acetochlor in soil and promotion of the growth and phosphorus uptake of maize.

Impact of short-term application of seaweed fertilizer on bacterial diversity and community structure, soil nitrogen contents, and plant growth in maize rhizosphere soil.

The effects of the short-term application of Ascophyllum nodosum-fermented seaweed fertilizer on the bacterial community, soil nitrogen contents, and plant growth in maize rhizosphere soil were evaluated. The changes in the bacterial community composition and nitrogen contents including those of total nitrogen (TN), nitrate nitrogen (NO3--N) and ammonium nitrogen (NH4+-N) in rhizosphere soils in response to treatment with seaweed fertilizer were determined. Furthermore, soil enzymatic activity and crop biomass were analyzed. The relative abundance of the dominant phyla varied regularly with fertilization, and bacterial α-diversity was apparently influenced by seaweed fertilizer amendment. The TN contents of all soil samples decreased gradually, and the NO3--N and NH4+-N contents of the soils treated with seaweed fertilizer were much higher than those of the control soils. Similarly, the enzymatic activities of dehydrogenase, nitrite reductase, urease, and cellulase in the soil were significantly increased on day 3, day 8, and day 13 after the application of seaweed fertilizer to the maize rhizosphere soil. However, there was no difference in the activity of soil sucrase between the treatment group and the control group. In this study, the growth of maize seedlings was confirmed to be greatly promoted by the utilization of seaweed fertilizer. These results deepen our understanding of plant-microbe interactions in agroecosystems and should benefit the wide use of seaweed fertilizer in sustainable agricultural production.

Film mulching optimizes the early root and shoot development of rain‐fed spring maize

AbstractFull ridge‐furrow plastic film‐mulching (FM) is a key agriculture drought mitigation technique in the semiarid Loess Plateau of China. The establishment of high‐yield maize (Zea mays L.) population under FM is built on robust plant development and indispensable soil support that generally started from the seedling stage. However, there is still a lack of information on the root‐shoot development of maize seedling under FM. A 2‐yr field experiment was performed in rainfed plots of Loess Plateau experimental station to study the effects of FM on root‐shoot growth of maize seedlings. Root samples were harvested from different soil layers until max rooting depth at V3 and V6 stages to detail the vertical development. Our results implied that FM significantly improved soil hydrothermal conditions and canopy development at V3 and V6 stages. At the V3 stage, there was no significant difference in root biomass between treatments or growth seasons, but root length under FM treatment was decreased by about 17%; moreover, ridge‐furrow without mulching (CK) treatment intended to distribute 4–9% more root biomass in deeper soil layers, and the root biomass per unit length under FM treatment was increased. At the V6 stage, FM brought about significant advantages in root biomass and length. Nonetheless, maize seedlings under FM treatment had a consistently lower root/shoot ratio, higher root efficiency, and higher water use efficiency during the V3–V6 period. In conclusion, FM helped rainfed maize seedlings run a lightweight but high‐efficiency root to support its productive shoot since the very beginning.

Trehalose Protects Maize Plants from Salt Stress and Phosphorus Deficiency.

This study is undertaken to elucidate the role of trehalose (Tre) in mitigating oxidative stress under salinity and low P in maize. Eight-day-old maize seedlings of two maize varieties, BARI Hybrid Maize-7 and BARI Hybrid Maize-9, were subjected to salinity (150 mM NaCl), low P (5 µM KH2PO4) and their combined stress with or without 10 mM Tre for 15 d. Salinity and combined stress significantly inhibited the shoot length, root length, and root volume, whereas low P increased the root length and volume in both genotypes. Exogenous Tre in the stress treatments increased all of the growth parameters as well as decreased the salinity, low P, and combined stress-mediated Na+/K+, reactive oxygen species (ROS), malondialdehyde (MDA), lipoxygenase (LOX) activity, and methylglyoxal (MG) in both genotypes. Individually, salinity and low P increased superoxide dismutase (SOD) activity in both genotypes, but combined stress decreased the activity. Peroxidase (POD) activity increased in all stress treatments. Interestingly, Tre application enhanced the SOD activity in all the stress treatments but inhibited the POD activity. Both catalase (CAT) and glutathione peroxidase (GPX) activity were increased by saline and low P stress while the activities inhibited in combined stress. Similar results were found for ascorbate peroxidase (APX), glutathione peroxidase (GR), and dehydroascorbate reductase (DHAR) activities in both genotypes. However, monodehydroascorbate reductase (MDHAR) activity was inhibited in all the stresses. Interestingly, Tre enhanced CAT, APX, GPX, GR, MDHAR, and DHAR activities suggesting the amelioration of ROS scavenging in maize under all the stresses. Conversely, increased glyoxalase activities in saline and low P stress in BHM-9 suggested better MG detoxification system because of the down-regulation of glyoxalase-I (Gly-I) activity in BHM-7 in those stresses. Tre also increased the glyoxalase activities in both genotypes under all the stresses. Tre improved the growth in maize seedlings by decreasing Na+/K+, ROS, MDA, and MG through regulating antioxidant and glyoxalase systems.

Influence of Aqueous Leaf Extract of Senna Alata L, Roxb. on the Germination and Seedling Growth of Beans, Maize and Groundnut

Plants extracts have been known to either promote or inhibit plant growth and germination. The influence of aqueous leaf extract of Senna alata (L.) Roxb on the germination and seedling growth of maize ( Zea mays ), Beans ( Phaseolus vulgaris ) and Groundnut ( Arachis hypogea ) were investigated. The experiment was carried out at Michael Okpara University of Agriculture Umudike, green house situated besides the University apex Library. The leaves of Senna alata were air dried, ground, mixed with water and then used for the treatment. Concentrated extracts and its dilutions 1:1, 1:2.5, 1:5 v/v was used as treatments and water served as control. Each treatment was replicated three times. The experiment was designed using Randomized Completely Block Design (RCBD) and the results obtained were statistically analyzed using ANOVA. The result obtained showed that all treatments significantly (P<0.05) inhibited germination in maize except for 1:2.5, which improved germination. Also, the treatments significantly (P<0.05) inhibited germination in beans except for treatments 1:1 and 1:5, which improved germination. However, all treatments significantly (P<0.05) improved germination in groundnut. There was significant increase (P<0.05) in plant height and dry weight of the plant compared with the control. This indicates that seedling growth of Beans, Maize and Groundnut were positively affected by the aqueous leaf extract of S. alata . High concentration of the extract leads to increased plant height and dry matter of the plant. Further study is needed to ascertain the bio-activity of S. alata . Keywords: Influence, Aqeouos leaf extract, Germination. DOI : 10.7176/JBAH/9-24-04 Publication date: December 31 st 2019