Increased Seedling Vigour Research Articles

Seed pelleting technique for mechanized sowing in green gram [Vigna radiata (L.) R. Wilczek

Background: Now-a-days, use of machines is becoming important due to shortage of labour for field operations. One such case is seed drill sowing which warranted enough seed size for easy sowing. Pelleting of seed is one of the techniques through which the size of the seed can be increased thereby it can be sown easily by seed drill. Green gram is one of the important pulses which needs pelleting technique for mechanized sowing. Methods: The experiments on standardization of seed pelleting technique and evaluating under field conditions were conducted in the Department of Seed Science and Technology, Seed Centre, Tamil Nadu Agricultural University, Coimbatore, India during 2019-2022. The green gram var. CO 8 seeds were primed and pelleted with TNAU pelleting mixture. Then, the pelleted seeds were sown by pneumatic seed drill and evaluated for its field performance. Result: The results showed that the green gram seeds primed with MnSO4 @ 0.5% and pelleted with 7 layers of TNAU pelleting mixture along with imidacloprid 70 WS @ 7 g/kg have recorded increased seedling vigour without affecting the seed germination. Also, the seeds sown by seed drill have recorded with better plant growth traits and higher yield. Also, single seed placement was achieved by seed drill sowing and about 25% seeds can be saved.

Seed phytic acid concentration affects rice seedling vigor irrespective of soil phosphorus bioavailability.

Rice with a black-colored pericarp (hereafter, black rice) is well-known as an antioxidant-rich food, but a high grain phytic acid (PA) concentration affects its nutritional quality. However, phytic acid helps improve seedling vigor, which is crucial for enhancing subsequent plant growth. This study investigated the effect of seed phytic acid concentration in black rice on seedling vigor compared to the effects on white rice. In the first experiment, three phytic acid concentrations in the seeds of black rice, low (LPA, 15.5 mg g-1 per seed), medium (MPA, 24.7 mg g-1 per seed), and high (HPA, 35.4 mg g-1 per seed) were tested for seedling vigor in phosphorus-deficient soils. The HPA seedlings showed substantially increased seedling vigor and shoot P uptake due to early root development and enhanced physiological processes. LPA grown seedlings showed increased ethylene production in response to P stress, which is the main physiological mechanism modulating seedling growth under P stress conditions. In the second experiment, the three phytic acid concentrations in black and white rice seeds were tested under low and high soil P conditions. Again, LPA seedlings showed significantly reduced seedling vigor in both rice varieties in P-deficient soils. Interestingly, seed phytic acid and external P application had an additive effect on seedling vigor, suggesting that the combined effect further improved seedling growth. Our results reveal that black rice seeds with a HPA concentration can be used as a seed source for planting in P-deficient ecosystems for rice plants as they can increase seedling vigor and subsequent growth, thus reducing dependence on finite P resources.

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

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

Plant Growth and Yield Response to Salinity Stress of Rice Grown under the Application of Different Nitrogen Levels and Bacillus pumilus Strain TUAT-1

Rice is an important food crop, and its production is significantly affected by salt stress under the changing climate. Soil-inhabiting microbial inoculants as well as efficient nitrogen (N) nutrition may have ameliorative effects on rice growth and yield under salt stress. However, the effects of the interaction between N application and microbial inoculants on the growth and grain yield of rice under salt stress is not yet fully understood. This study aimed to clarify whether the use of the Bacillus pumilus strain TUAT-1 biofertilizer, along with the right amount of N fertilizer, would alleviate salt stress in lowland rice production. We applied the Bacillus pumilus strain TUAT-1 as a biofertilizer in combination with different rates of N fertilizer: control (0% N), 2.64 g (NH4)2SO4 per nursery tray (100% N: the farmer-recommended amount), and 3.96 g (NH4)2SO4 per nursery tray (150% N). Salinity (100 mM of NaCl) was applied at the heading stage of rice plants in pot culture in the greenhouse, and the growth and yield components were accessed at harvest. In the nursery phase, the application of the biofertilizer TUAT-1 significantly increased seedling vigor and the root development of 21-day-old seedlings. Salinity stress at the heading stage significantly reduced chlorophyll content, panicle number, straw biomass, and grain yield; however, either the application of N alone or in combination with TUAT-1 ameliorated the salinity-related reduction in grain yield and yield component parameters. Plants receiving a high amount of N fertilizer (150% N) showed similar straw biomass and grain yield with or without TUAT-1 inoculation, regardless of saline or non-saline conditions. In both saline and control conditions, straw biomass and grain yield were higher in the plants inoculated with TUAT-1 than in those without TUAT-1. Specifically, the combined application of TUAT-1 and the farmer-recommended N level (100% N) led to an increase of 8% in straw biomass and 15% in grain yield under saline stress when compared with their respective plants without TUAT-1. Straw biomass and grain yield were similar in the (un-inoculated) plants grown under normal conditions and TUAT-1 + 100% N under salinity treatments, because TUAT-1 enhanced root development, which may promote soil nutrient uptake. Our results indicated that combined nursery application of TUAT-1 biofertilizer and 100% N fertilizer rate has the potential to boost the capacity of this bacteria to increase seedling vigor, which subsequently ameliorated the salt-induced reduction in the grain and straw yield.

Effect of Storage Conditions and Containers on Storability of Pole Type Frenchbean cv. Arka Sukomal

Background: Maintenance of seed quality in storage is important without losing its living entity against biotic and abiotic stress. Arka Sukomal seeds are protein rich and include other nutrient composition which is required for seed germination and seedling establishment. There is a need to minimise the deterioration of cellular structure and biochemical compounds by adopting suitable storage conditions and containers. Methods: The laboratory experiment was carried out to identify the suitable storage conditions and containers on seed quality parameters. The seeds were stored in four different containers viz., cloth bag, polythene bag, super grain bag and poly-lined aluminium pouch at ambient and at controlled condition (15oC). The observations were recorded bimonthly up to fourteen months. Result: The results showed that seeds in poly-lined aluminium pouch at controlled conditions had shown better quality parameters like lower moisture content (7.70%), higher seed germination (93.58%), more increased seedling vigour index II (5316) and low electrical conductivity of seed leachate (0.437 dS m-1) whereas it was lower in cloth bag at ambient condition (10.40%, 80.67%, 3611 and 0.649 dS m-1, respectively) at the end of storage period. Hence, the viability and vigour of seeds could be maintained better by storing in moisture impervious containers (poly-lined aluminium pouch and polythene bag) at the controlled condition, which is cost-effective and easily adaptable.

Nanotechnology and biological advances, novel tools for plant genetics and physiological role of newly crops and limited factors affecting growth

Nano-pesticides are essential for the successful and sustainable management of different pests, and they can decrease the use of agrochemicals, thereby mitigating current environmental dangers. Nevertheless, advancements in nano-particles or micro-particles, as well as distribution models for biolistic gene delivery in various plants, are still needed to enhance grain growth and crop and plant protection. , seed priming is being used effectively to expedite and synchronize germination, increase seedling vigor, and make plants extra resilient to various biotic and abiotic stresses, resulting in increased efficiency and quality of food. Nano fertilizers have distinct properties like mega absorption, increase in production, enhanced activity of photosynthesis, and a substantial improvement in leaf surface area. Growth of plants is changed to a particular environment conditions at different phases of development; and hence, a proper choice of planting date increases photosynthesis efficacy. In this perspective, providing carbon nano-tubes in to the chloroplasts has resulted in a progress for plants' enhanced capacity to collect more energy from the sun. Lower rates of photosynthetic activity in the crop plants under the cold stress limited metabolic pathways for Carbon assimilation.

Seed priming with vermicompost leachate, Ecklonia maxima extract-Kelpak® and smoke-water induce heat stress amelioration and growth in Vigna unguiculata L. seedlings

With the human population increase, food production will be required to double. However, there is a direct correlation between prevalent abiotic stresses and yield reduction in crops. Cowpea (Vigna unguiculata) makes a staple meal in most diets worldwide, but its growth remains susceptible to stress. Biostimulants; vermicompost leachate (VCL), seaweed extract Kelpak® (KEL) and smoke-water (SW) are suggested as economical solutions with the potential to improve yield under abiotic stresses. Therefore, the aim of the present study was to investigate the effects of seed priming (SP) and non-priming (NP) with VCL, KEL and SW on germination and growth of cowpea (local cv. IT18) cultivated under 30, 35 and 40 °C. VCL 1:20 (v/v), KEL (0.6%) and SW 1:1000 (v/v) were more potent as priming germination cues under the three examined temperatures. Seed priming using the three biostimulants significantly (P ≤ 0.05) increased seedling vigour index, root length and fresh weight of 7-day-old seedlings under 30, 35 and 40 °C compared to non-primed controls. They also elicited significant increases in shoot length, leaf number, seedling area and reduced average germination time at 40 °C. KEL and SW-priming markedly increased stem diameter, seedling area, shoot length, leaf number, fresh and dry biomass after 28 d under 30 and 40 °C compared to control. However, SP inhibited root stimulation in cuttings. These results are encouraging and showcase the potential of the three stimulants for maintaining crop yields under heat stress and are relevant for other neglected staple crops in South Africa and globally.

Evaluating the optimization of irradiation components of mung bean seeds with ultrasound for increased seedling vigor, using artificial neural network

Evaluating the optimization of irradiation components of mung bean seeds with ultrasound for increased seedling vigor, using artificial neural network

Scarification and Seed Biomatriconditioning Effect Using Endophytic-Rhizobacteria in Areca Nut (Areca catechu L.) Seedling Vigor.

<b>Background and Objective:</b> Intensive and commercial development of areca nut requires the provision of high-vigour areca nut. This study aimed to evaluate the effect of scarification and seeds biomatriconditioning using endophytic-rhizobacteria in increasing seedlings vigor of areca nut. <b>Materials and Methods:</b> The research was carried out at the Agronomy Unit of Agrotechnology Laboratory, Agriculture Faculty, Halu Oleo University, from November, 2020-March, 2021. The research design was split-plot in a Completely Randomized Design (CRD). The main plot, seed scarification, consisted of 2 treatments, without scarification and scarification. Sub-plots, seeds biomatriconditioning using endophytic-rhizobacteria, consisted of 6 treatments, control, L1-R, M5-R, LA6-R, LA2-E and RJ6-R. <b>Results:</b> The results showed that the scarification treatment did not affect the seedlings vigor of the areca nut. Seed biomatriconditioning using endophytic-rhizobacteria was able to increase seedling vigor both without scarification and with scarification. There were 3 isolates of endophytic-rhizobacteria which were more able to increase the vigor of areca nut without scarification, namely L1-R, LA6-R and LA2-E, with an increase of 137, 104 and 102%, respectively compared to the control, while in scarified seeds, L1-R isolate was able to increase the seedlings vigor of areca nut by 194% compared to the control. <b>Conclusion:</b> Scarification treatment did not affect the vigor of the areca nut. Seed biomatriconditioning with endophytic-rhizobacteria was able to increase the vigor of areca nut seeds either without scarification or with scarification.

Evaluation of antifungal plant extracts against cereal and legume seed-borne pathogens for effective management

Sri Lanka as an agricultural country needs to manage the seed-borne fungal pathogens that have caused infections and diseases that result in significant crop losses and a decline in yield and productivity. Therefore, it is imperative to apply pathogen management strategies that are environmentally friendly, and economically feasible such as plant extractions, to reduce seed-borne fungi and increase the quality of the seed. This study was aimed at identifying the antifungal efficacy of <italic>Allium sativum</italic>, <italic>Aloe vera</italic>, <italic>Azadirachta indica</italic>, and <italic>Zingiber officinale</italic> extracts and their effective concentrations to control the seed-borne fungal pathogens; <italic>Aspergillus flavus</italic>, <italic>A. niger</italic>, <italic>Orbilia foliicola</italic>, <italic>Rhizopus oryzae</italic>, and <italic>Talaromyces oumae-annae</italic> isolated from <italic>Arachis hypogea</italic>, <italic>Oryza sativa, Vigna radiata,</italic> and <italic>V. sinensis</italic> respectively. Antifungal efficacy was determined by the agar well diffusion method and poisoned food technique. Plant extracts’ effectiveness for seed germination and seed quality was evaluated by pot experiments. <italic>Zingiber officinale</italic> crude extract exhibited the highest antifungal activity against the tested pathogens which was as effective as Captan 50% (WP), a positive control. Further analysis of the results from the pot experiment revealed that <italic>O. sativa</italic>, and <italic>V. radiata</italic> seeds treated with<italic> A. indica</italic>, and<italic> Z. officinale</italic> aqueous extracts showed 100% germination percentage. <italic>Azadirachta indica</italic>, and<italic> Z. officinale</italic> aqueous extracts are the most effective in promoting seed germination and seedling vigor while <italic>A. vera</italic> extract is the least effective extract. Comparing the two different extracts, aqueous extracts significantly promote seed germination and increase seedling vigor.

H2O2 signaling regulates seed germination in ZnO nanoprimed wheat (Triticum aestivum L.) seeds for improving plant performance under drought stress

Nanopriming has proved to be an effective technique to protect plants from various stresses. The aim of the present work is to investigate the underlying mechanism of zinc oxide (ZnO) nanopriming in imparting drought stress tolerance in wheat. The changes in primed and unprimed wheat plants associated during drought stress were studied by monitoring their physiological and biochemical performance. Results showed that zinc oxide nanoparticles (ZnO NPs) pre-treatment prevented chlorophyll degradation under drought condition thereby improving overall photosynthetic performance and overall plant growth. Study of Chl a fluorescence induction kinetics showed a drastic increase in various photosynthetic parameters in primed drought stressed plants. Nanopriming seems to have protected the photosynthetic apparatus of plant by improving the efficiency of primary photochemistry of PSII under drought stress conditions. Furthermore, the activity of antioxidant enzymes such as catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) as well as malondialdehyde (MDA) content were decreased significantly in nanoprimed drought stressed (NP + DS) plants as compared to unprimed drought stressed (UP + DS) plants. Generation of more reactive oxygen species (ROS) mainly hydrogen peroxide (H2O2) was observed in nanoprimed germinating seeds. We propose role of H2O2 to act as signaling molecule in improving seed germination and vigor by enhancing activity of α-amylase. Lower levels of reactive oxygen species (ROS) production in NP + DS plants was observed which indicates better tolerance to drought stress in nanoprimed plants. It is concluded that nanopriming facilitates improved seed germination and increased seedling vigor through H2O2 signaling networks.

Chitosan-silicon nanofertilizer to enhance plant growth and yield in maize (Zea mays L.)

We report a novel chitosan-silicon nanofertilizer (CS–Si NF) wherein chitosan-tripolyphosphate (TPP) nano-matrix has been used to encapsulate silicon (Si) for its slow release. It was synthesied by ionic gelation method and characterized by dynamic light scattering (DLS), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic absorption spectrophotometry (AAS). The developed CS-Si NF exhibited slow release of Si and promoted gowth and yield in maize crop. Seeds primed with different concentrations of CS-Si NF (0.04–0.12%, w/v) exhibited up to 3.7 fold increased seedling vigour index (SVI) as compared with SiO2. Its foliar spray significantly induced antioxidant-defence enzymes’ activities and equilibrated cellular redox homeostasis by balancing O2−1 and H2O2 content in leaf as compared with SiO2. Application of nanofertilizer (0.01–0.16%, w/v) stirred total chlorophyll content (21.01–25.11 mg/g) and leaf area (159.34–166.96 cm2) to expedite photosynthesis as compared with SiO2. In field experiment, 0.08% CS-Si NF resulted in 43.4% higher yield/plot and 0.04% concentration gave 45% higher test weight as compared with SiO2. Fecund and myriad effects of developed nanofertilizer over SiO2 could be attributed to slow/protective release of Si from nanofertilizer. Overall, results decipher the enormous potential of CS-Si NF for its use as a next generation nanofertilizer for sustainable agriculture.

58 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value

Abstract Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at day 0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.

57 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value

Abstract Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at d0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.

Assembly and characterisation of a unique onion diversity set identifies resistance to Fusarium basal rot and improved seedling vigour

Key messageA unique, global onion diversity set was assembled, genotyped and phenotyped for beneficial traits. Accessions with strong basal rot resistance and increased seedling vigour were identified along with associated markers.Conserving biodiversity is critical for safeguarding future crop production. Onion (Allium cepa L.) is a globally important crop with a very large (16 Gb per 1C) genome which has not been sequenced. While onions are self-fertile, they suffer from severe inbreeding depression and as such are highly heterozygous as a result of out-crossing. Bulb formation is driven by daylength, and accessions are adapted to the local photoperiod. Onion seed is often directly sown in the field, and hence seedling establishment is a critical trait for production. Furthermore, onion yield losses regularly occur worldwide due to Fusarium basal rot caused by Fusarium oxysporum f. sp. cepae. A globally relevant onion diversity set, consisting of 10 half-sib families for each of 95 accessions, was assembled and genotyping carried out using 892 SNP markers. A moderate level of heterozygosity (30–35%) was observed, reflecting the outbreeding nature of the crop. Using inferred phylogenies, population structure and principal component analyses, most accessions grouped according to local daylength. A high level of intra-accession diversity was observed, but this was less than inter-accession diversity. Accessions with strong basal rot resistance and increased seedling vigour were identified along with associated markers, confirming the utility of the diversity set for discovering beneficial traits. The onion diversity set and associated trait data therefore provide a valuable resource for future germplasm selection and onion breeding.

The Role of Grain Priming and its Duration on Wheat Germination and Seedling Growth

This study was designed to investigate the effect of different grain priming methods on germination and seedling vigour of wheat cultivar (Gemmiza 9) was performed. Grains were primed for 8, 16 and 24 hours in 13 priming media (water, polyethylene glycol 6000 at 2.5, 5, 7.5 %; CaCl2 at 250, 500, 1000 ppm; ascorbic acid (AsA) at 25, 50, 100 ppm; salicylic acid (SA) at 50, 100, 150 ppm) beside dry grain as a control. In general, it was observed that a priming duration of 24 hr gave the highest values of all duration studied. In addition, results indicated that all grain priming in any priming materials significantly increased seedling vigour index (SVI) represented by germination %, length of seedling and fresh and dry weights of seedling. In most cases, SA at 100 ppm was the most effective in this regard. The greatest germination % was obtained due to 7.5 % PEG; 500 ppm CaCl2; 100 ppm AsA and 100 ppm SA. The highest seedling length was obtained due to 2.5 % PEG; 250 ppm CaCl2; 50 ppm AsA and 100 ppm SA. In addition, seedling dry weight was highest due to 7.5 % PEG; 1000 ppm CaCl2; 50 ppm AsA and 100 ppm SA. The highest SVI values were obtained due to 2.5 % PEG; 250 ppm CaCl2; 50 ppm AsA and 100 ppm SA. These results indicate that priming of grains had a significant effect to promote the germination and seedlings growth of wheat.

In vitro cultivation of Mouriri elliptica (Mart.) a species with alimentary and medicinal potential using alternative to agar media

Alternative supports can be successfully used in place of agar for 'in vitro' culture to increase seedling vigor. The objective of the present study was to evaluate the efficiency of alternative support materials compared to agar in the 'in vitro' cultivation of 'Mouriri elliptica' (Mart.) in the absence or presence of naphthalene acetic acid (NAA). The alternative support materials used were medium-grain vermiculite, sugarcane ('Saccharum spp.' L.) bagasse and queen palm fiber ['Syagrus romanzoffiana' (Chamisso) Glassman]. For this, young plants with at least two axillary buds under in vivo conditions were transferred to in vitro condition considering four replications with three young plants. After 45 days was evaluated the growth and anatomical explant characteristics. Autoclaving these alternative supports without the media and proceeding the explant desinfestation was an efficient method to contamination control and plant growth in a in vitro condition. No differences were observed between agar, vermiculite and sugarcane bagasse cultures for most growth characteristics evaluated. Greater numbers of adventitious and secondary roots and greater root length were significantly observed in plantlets grown in the presence of vermiculite and the absence of naphthalene acetic acid. In the agar culture, roots had weak points and poorly differentiated tissues, with parenchymal tissue predominating. The addition of 2.0 mg L-1 naphthalene acetic acid used did not stimulate rooting in this specie. So, other auxin source and concentrations should be evaluated in future studies. Both support materials used, vermiculite and sugarcane bagasse, representing promising agar substitutes to obtain seedlings with roots.

Starter Nitrogen Fertilizer Affects Rice Growth and Nitrogen Uptake but Not Grain Yield

Core Ideas Starter N may be beneficial to increase yields of drill‐seeded, delayed‐flood rice. Starter N did not increase plant height or grain yield in both years. Starter N does not appear to be a viable option to increase rice yield in Mississippi. Seedling rice (Oryza sativa L.) growth can be slow on high cation‐exchange‐capacity clay soils, which represent the majority of rice acreage in Mississippi and elsewhere in the Mid‐South US rice‐growing region. Strategies to increase vigor and growth of seedling rice may be beneficial to increase yields of drill‐seeded, delayed‐flood rice. Studies were established during the 2007 and 2008 growing seasons in Stoneville, MS to evaluate the use of starter N fertilizer to improve growth and yield of rice conventional cultivar Cocodrie and the hybrid cultivar XL 723. Ammonium sulfate (AMS) was applied at 20 lb N/ac as starter N fertilizer at the two‐leaf stage. Recovery of starter N was also determined at multiple sampling times using 15N‐labeled ammonium sulfate. Hybrid XL 723 had greater tissue N concentration when measured at V5 (five‐leaf stage) than Cocodrie, but Cocodrie had greater total dry matter (TDM) and total N uptake (TNU) compared with XL 723 likely due to the higher seeding rate for Cocodrie. XL 723 produced 27 and 25% greater grain yield than Cocodrie in 2007 and 2008, respectively. Recovery of 15N was greater in XL723 compared with Cocodrie at the R1 and R3 stages but similar at V5 stage in 2007. Starter N did not increase plant height or grain yield in either variety in both years, but it increased TDM and TNU in 2008. The use of starter fertilizer does not appear to be a viable option to increase seedling vigor or grain yield of rice cultivars Cocodrie and XL 723 in Mississippi.

Nanopriming with zero valent iron (nZVI) enhances germination and growth in aromatic rice cultivar (Oryza sativa cv. Gobindabhog L.)

Engineered nanoparticles are utilized in agriculture for various purposes. They can be used as fertilizer, carrier for macro/micro nutrients or priming agents. Various nanoparticles are reported to have toxicity at very high doses, but at optimum concentration, they can be beneficial for plant growth and development. In the present study, low concentrations of nZVI nanoparticles were evaluated for their growth enhancement potential as seed priming agent in an aromatic rice cultivar, Oryza sativa cv. Gobindabhog. Seeds were primed with different concentrations (10, 20, 40, 80, 160 mg L−1) of nZVI and allowed to grow for 14 days. Seed germination and seedling growth were studied by assessing physiological, biochemical, and structural parameters at different time points. Maximum activities of hydrolytic and antioxidant enzymes, along with root dehydrogenase enzyme were observed in 20 mg L−1 nZVI primed seeds. Priming with low doses of nZVI increased seedling vigour, as expressed by increased root and shoot length, biomass and photosynthetic pigment content. Our study also confirmed that after 14 days growth, the seedling showed absence of membrane damage, reduction in proline level and anti-oxidant enzyme activities. However, seedlings primed with 160 mg L−1 nZVI suffered oxidative stress. SEM micrographs also revealed damage in root tissue at that concentration. AAS study confirmed uptake of nZVI by the rice plants as maximum level of iron was found in the plants treated with highest concentration (i.e. 160 mg L−1 nZVI). Thus, nZVI at low concentrations can be considered as priming agent of rice seeds for increasing plant vigour.

Silicon improves seed germination and alleviates drought stress in lentil crops by regulating osmolytes, hydrolytic enzymes and antioxidant defense system

Silicon (Si) has been widely reported to have beneficial effect on mitigating drought stress in plants. However, the effect of Si on seed germination under drought conditions is still poorly understood. This research was carried out to ascertain the role of Si to abate polyethylene glycol-6000 mediated drought stress on seed germination and seedling growth of lentil. Results showed that drought stress significantly decreased the seed germination traits and increased the concentration of osmolytes (proline, glycine betaine and soluble sugars), reactive oxygen species (hydrogen peroxide and superoxide anion) and lipid peroxides in lentil seedlings. The activities of hydrolytic enzymes and antioxidant enzymes increased significantly under osmotic stress. The application of Si significantly enhanced the plants ability to withstand drought stress conditions through increased Si content, improved antioxidants, hydrolytic enzymes activity, decreased concentration of osmolytes and reactive oxygen species. Multivariate data analysis showed statistically significant correlations among the drought-tolerance traits, whereas cluster analysis categorised the genotypes into distinct groups based on their drought-tolerance levels and improvements in expression of traits due to Si application. Thus, these results showed that Si supplementation of lentil was effective in alleviating the detrimental effects of drought stress on seed germination and increased seedling vigour.