Total Seedling Dry Weight Research Articles

The Effects of Organic Fertilization on The Quality of Eggplant Seedlings

This study investigated the effects of chemical fertilizer (20-20-20) and two different organic fertilizers (compost and wood ash) applications on eggplant seedling quality. Peat was used as the growing medium. Some seedling quality parameters such as stem diameter, seedling height, number of leaves, leaf chlorophyll content, leaf area, root length and total seedling dry weight were investigated. In general, although applying chemical fertilizer is the best value in the seedling quality parameters, it was determined that statistically (P

Growth Response of Platycladus Orientalis (l.) Franco Seedling to Foliar Application of Ga3 And Chelated Nano N.p.k Fertilizer

As part of the ongoing efforts to optimize the application of Nanotechnology in forestry nurseries, the current study came to determine the efficiency of Nano N.P.K-fertilizer and Gibberellic acid in enhancing the growth of the slow-growing species Platycladus orientalis (L.) Franco seedlings. One–year old of P. orientalis seedlings grown in a  greenhouse were been subjected from September 2021 to the  end of Jun 2022 to two and four foliar sprays, four different levels of Nano-fertilizer N.P.K (20:20:20) (control, 1 g. L-1, 2 g. L-1 and 3 g. L-1) and three GA3 levels (control, 300 mg. L-1 and 600 mg.L-1). The experiment was designed according to the RCBD with 1008 seedlings arranged in three replicates with 14 seedlings in each of the 72 experimental units. Duncan's multiple-range test was used for comparing all means. for each factor individually revealed that increasing Nano N.P.K up to 3 g. L-1 and GA3 up to 300 and 600 mg.L-1 increased significantly the values of most of the studied parameters (seedling high, diameter, number of branches, total seedling dry weight, leaf chlorophyll, Protein (%), and percentage of leaf nutrients content as Nitrogen, Phosphorus and Potassium. Increasing the sprays number from two to four increased the values of the studied parameters except for the Diameter, Nitrogen, Chlorophyll, and Protein parameters. The interaction effect between four sprays,  Nano N.P.K 3 g. L-1 and GA3 at rate 600 mg.L-1  significantly increased the values of all studied parameters except Potassium (%), where two sprays,  of 3 g. L-1 Nano N.P.K with 600mg.L-1  of GA3 recorded the highest values. In general, the study revealed the positive role of the foliar application of Nano N.P.K fertilizer separately and in combination with GA3 in accelerating most growth parameters of the slow-growing P. orientalis ornamental shrub

Genome-Wide Association Study for Root Morphology and Phosphorus Acquisition Efficiency in Diverse Maize Panels.

Maximizing soil exploration through modifications of the root system is a strategy for plants to overcome phosphorus (P) deficiency. Genome-wide association with 561 tropical maize inbred lines from Embrapa and DTMA panels was undertaken for root morphology and P acquisition traits under low- and high-P concentrations, with 353,540 SNPs. P supply modified root morphology traits, biomass and P content in the global maize panel, but root length and root surface area changed differentially in Embrapa and DTMA panels. This suggests that different root plasticity mechanisms exist for maize adaptation to low-P conditions. A total of 87 SNPs were associated to phenotypic traits in both P conditions at -log10(p-value) ≥ 5, whereas only seven SNPs reached the Bonferroni significance. Among these SNPs, S9_137746077, which is located upstream of the gene GRMZM2G378852 that encodes a MAPKKK protein kinase, was significantly associated with total seedling dry weight, with the same allele increasing root length and root surface area under P deficiency. The C allele of S8_88600375, mapped within GRMZM2G044531 that encodes an AGC kinase, significantly enhanced root length under low P, positively affecting root surface area and seedling weight. The broad genetic diversity evaluated in this panel suggests that candidate genes and favorable alleles could be exploited to improve P efficiency in maize breeding programs of Africa and Latin America.

Enhancement in soil fertility, early plant growth and nutrition and mycorrhizal colonization by vermicompost application varies with native and exotic tree species

PurposeThe impact of vermicompost on tree-soil systems is not yet fully understood. This study aimed to comparatively investigate the effects of chemical fertilizer, compost and vermicompost on soil enzymatic activities, seedling mycorrhizal colonization, growth and nutrition of one exotic tree species (radiata pine, Pinus radiata D. Don) and two native tree species (mānuka, Leptospermum scoparium and tōtara, Podocarpus totara).MethodsA 12-month-long pot trial was set up in the glasshouse with a factorial design of three tree species (radiata pine, tōtara and manuka) by six treatments, including T1-control, T2-chemical fertilizer, T3-HS compost, T4-HS vermicompost, T5-LS vermicompost and T6-CM vermicompost. We assessed the main effects and interactions of treatment and species on soil chemical and biological properties, plant growth and nutritional responses.ResultsCompared to the untreated control (T1), application of vermicomposts (T4-T6) and compost (T3) significantly improved soil chemical properties and enzymatic activities, and increased total seedling dry weight by 160–260%, shoot concentrations of nitrogen (N) by 54–97% and phosphorus (P) by 61–91%. Vermicomposts were comparable to diammonium phosphate (DAP) applied at 133 kg N ha−1 (T2) in stimulating the growth of native species (mānuka and tōtara) without negative impact on mycorrhizal colonization, with T5 being better than DAP (T2) in promoting mānuka growth. However, application of vermicompost alone was less effective than DAP in stimulating the exotic radiata pine growth. Overall, soil activities of dehydrogenase, urease, acid phosphatase and invertase were significantly and positively correlated to total C and N and exchangeable Ca and Mg.ConclusionThe increased growth of three tree species after application of vermicomposts was mainly related to improved N and P nutrition associated with enhanced root growth and soil enzymatic activities. Our findings imply that the vermicomposting products from septic tank waste could be a promising alternative to inorganic fertilizers in land application or greenhouse potting media of native tree species.

Effect of Pre-sowing Treatment and Sowing Time on Germination and Early Performance of Melia composita

The pre-sowing treatments (soaking drupes in gibberellic acid 50 ppm for 24 hours, soaking drupes in gibberellic acid 100 ppm for 24 hours, soaking drupes in concentrated H S0 for 10 minutes, soaking drupes in concentrated H S0 for 15 minutes, mechanical scarification-2 4 2 4 cracking of drupes, soaking drupes in cow dung slurry for 30 days and control-no treatment) were tested to enhance the germination of Melia composita at two sowing time (20 April and 04 May). Germination and most of the growth parameters were recorded highest in mechanical th th scarification. The sowing of 20 April had significantly higher collar diameter, number of leaves, fresh shoot weight, dry shoot weight, length of th primary root, number of secondary roots, fresh root weight, dry root weight, total seedling fresh weight, total seedling dry weight and seedling quality index than the sowing date of 04 May. The interaction of mechanical scarification x sowing-20 April also had significantly higher th th values for the most studied growth parameters than the remaining interactions. The study implies that mechanical scarification of drupes of Melia composita and sowing in the month of April is appropriate for obtaining good quality planting stock.

Priming improves germination and seed reserve utilization, growth, antioxidant responses and membrane stability at early seedling stage of Saudi sorghum varieties under drought stress

Seeds of three sorghum (Sorghum bicolor (L.) Moench.) varieties from Southwest Saudi Arabia were used to investigate the potential of osmopriming with polyethylene glycol (PEG 8000) to improve germination performance, seed reserve utilization and early seedling growth and drought stress tolerance. The primed (PS) and unprimed (UPS) seeds of the three sorghum varieties were germinated for 8 days under increasing PEG-induced osmotic stress. The treatments were arranged in a completely randomized design, in a factorial arrangement, with three sorghum cultivars (‘Zaydia’, ‘Shahbi’ and ‘Ahmar’) and four osmotic potentials (0.0; -0.4; -0.8 and -1.2 MPa) with four replicates of 50 seeds each. The results showed that drought stress affected seed germination and seedling emergence and establishment, but increased the activity of the antioxidant enzyme catalase (CAT). The strongest inhibition of germination and growth occurred at the highest PEG concentration and a significant difference was noticeable between the studied varieties. We confirmed also that seed osmopriming improved seed germination performance, seedling growth and enhanced the CAT activities while reduced malonyldialdehyde (MDA) accumulation and electrolyte leakage (EL) in the drought-stressed seedlings. Seed priming have enhanced also the α-amylase and total proteases activities in all varieties. The largest increase of these hydrolysing enzymes was shown in ‘Ahmar’. Furthermore, the PEG priming lead to improvement of the weight of utilized (mobilized) seed reserve (WUSR), seed reserve depletion percentage (SRDP) and total seedling dry weight (SLDW) of sorghum seedlings under water stress conditions. Still, the highest values or all three parameters were found in the ‘Ahmar’ variety. Under increasing drought stress conditions, ‘Ahmar’ showed the highest yield stability index (YSI) and the least EL and MDA contents in comparison to the other two varieties during the seedling establishment stage. Therefore, the former variety can tolerate better a rigorous water stress condition. ‘Zaydia’ appears to be the most vulnerable to drought stress. Thus, the use of species or varieties with eminent seed metabolic quality is an advantageous trait in drought-prone regions.

Correlation and Path Coefficient Analysis in Rice (Oryza sativa L.) Genotypes under Normal and Cold Condition

An experiment was conducted with the objective of determining the magnitude of association between seedling vigour index and its component characters. Fifty rice genotypes were evaluated in completely randomized design with three replications. Correlation coefficient analysis of vigour index showed positive and significant association with total seedling length, root length, total seedling dry weight, root dry weight, shoot length, germination percentage and first leaf area under normal condition. Germination percentage, total seedling length, root length, shoot length and first leaf area showed strong and significant positive association with seedling vigour index under cold condition. Thus, these traits could play pivotal role in developing cold tolerant rice. Separation of correlation coefficients into direct and indirect effects of component traits for vigour index revealed that the traits total seedling length and root dry weight exerted maximum positive direct and indirect effect respectively on vigour under normal condition. Under cold stress the traits shoot length and root length exerted maximum positive direct and indirect effects respectively for vigour index. These characters, therefore, are required to be considered during selection for vigour improvement in rice under normal and cold condition in rice.

Effects of ascorbic acid on the germination and vigour of cowpea seeds under water stress

Water is one of the most compromising factors in the germination and initial growth of seedlings, where its restriction causes a reduction in the water potential of cells in addition to causing oxidative stress. Ascorbic acid (AsA) is known to protect organelles and cells against the accumulation of ROS. The aim of this work was to study the effects of ascorbic acid on the conditioning of cowpea seeds subjected to water stress. The seeds of the BRS Marataoa and Setentao genotypes were conditioned at a concentration of 0.0 (control), 0.25, 0.50, 0.75 and 1.00 mM AsA, and sown on paper rolls (Germitest®) moistened with mannitol solution at a potential of 0.0 (control), -0.3, -0.6, -0.9 and -1.2 MPa, and stored in a germination chamber (BOD) at 25 oC. The experiment was conducted in a completely randomised design, in a 2×5×5 factorial scheme, with four replications of 50 seeds per treatment. The variables under analysis were percentage germination, first germination count, germination speed index, shoot and root length, total seedling dry weight and electrolyte leakage in the leaves and roots. Conditioning the seeds with ascorbic acid at a concentration of 0.50 mM for the BRS Marataoa genotype and 0.75 mM for the Setentao genotype, enabled the development of more vigorous seedlings and a reduction in the damage caused to the membranes by oxidative stress, both in the absence of a water deficit and at the osmotic potentials under test, including at the lowest potential.

Parental effects and provisioning under drought and low phosphorus stress in common bean

AbstractLow soil fertility and drought are primary constraints for crop production and food security in many developing nations. Since smallholder farmers often collect seed for the next year's crop from plants grown with abiotic stress, it is important to understand how progeny from a stressed parental environment perform when they are grown under similar stresses. This study investigates the impact of a low phosphorus (P) or drought parental environment on progeny seed and root traits in common bean (Phaseolus vulgaris), with the intention of distinguishing impacts of reduced parental provisioning from adaptive responses. Greenhouse, field, and seedling experiments were used to evaluate seed, seedling, and mature root phenotypes in progeny from stressed and nonstressed parental conditions. In addition, progeny from different positions within the pod and pod developmental times were evaluated since they are expected to vary in parental provisioning. Seeds from the peduncular position in the pod had less individual seed weight, fewer basal roots, reduced root dry weight, and smaller taproot diameter than those from the stylar position. Progeny of some genotypes from drought‐stressed parents had smaller individual seed weight, fewer basal roots, less total seedling dry weight, shorter seedling basal roots, and smaller basal root diameters. Progeny of some genotypes from a low P parental environment had smaller individual seed P concentration, fewer shoot‐borne roots, and greater basal root whorl number. Progeny from drought‐stressed parents, progeny from a low P parental environment, and seeds from the peduncular position had root phenotypes that were likely to be related to less parental provisioning. Possible adaptive parental effects were found in both parental drought and parental low P studies. Adequate seed provision under stress merits consideration as a selection target in crop breeding for stressful environments.

Ascorbic acid of cowpea seeds under saline stress

Abstract: Salinity adversely affects plant growth and metabolism by triggering increased production of reactive oxygen species (ROS). Ascorbic acid (AsA) is known to protect organelles and cells against ROS by preventing accumulation. The objective of this study was to study the effects of AsA on cowpea beans under saline stress. Cowpea seeds of the cultivars (BRS Marataoã and Setentão) were conditioned at concentrations of 0.0 (control); 0.25; 0.50; 0.75 and 1.00 mM AsA and seeded on paper towels, moistened at saline levels of 0.0 (control); 1.5; 3.0; 4.5; 6.0 and 7.5 dS.m-1, packed in a bench germinator at 25 °C. The statistical design adopted was a completely randomized 2 × 5 × 6 factorial design (cultivar x ascorbic acid x saline levels) with four replicates of 50 seeds per treatment. The analyzed variables were percentage of germination, first germination count, germination speed index, shoot and root length, total seedling dry weight, and leaf and root electrolyte leakage. Ascorbic acid at concentrations of 0.50 mM for BRS Marataoã and 0.75 mM for the Setentão, enabled the development of more vigorous seedlings and the reduction of membrane damage caused by oxidative stress both in the absence of salt and at the saline levels tested, including the highest one.

GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

Differential Responses of Hordeum vulgare L. to Allelochemicals of Some Olea europaea L.Cultivars

The present investigation was carried out to study the bioactivity of four Olea europaea cultivars (Chemlali; CHM, Manzanilla; MAZ, Picaul; PIC and Tofahi; TOF) leaves aqueous extract (OELAE) as well as crude powder (OELCP) on germination efficiency, physiological, biochemical and molecular parameters of Hordeum vulgare. The allelopathic effect varied according to treatment and cultivar. An increase in total seedling dry weight (TSDW) was achieved with all tested concentrations (0.25, 0.5, 0.75, 1, 1.25 and 1.5%) of the four cultivars except TOF cultivar. Leaves of the donor species attained values of oleuropein varied from 35 to 67 mg g-1 dry weight depending upon the cultivar which was highly correlated with the level of antioxidants activity of germinated H. vulgare. Chlorophyll a (Chl a) recorded a marked increase with the increase in OELCP except for TOF. Noticeably, chlorophyll b (Chl b) and carotenoids (Carot) has shown a disturbance in their concentrations with both treatments and cultivars. The CHM (low oleuropein content) cultivar elicits high percentage of genomic template stability (GTS %) in H. vulgare for the two-affecting concentration measuring about 86% and 82% respectively. To go through with this, TOF cultivar (high oleuropein content) achieved the lowest percentage of genomic template stability (GTS %) in the two-affecting concentrations of about 36% and 32%. Finally, we can conclude that if the growing barley is planting for herbal medicine purposes as antioxidant it prefers to be cultivated under CHM and MAZ olive trees and avoided cultivation under the two other cultivars; PIC and TOF.

Effect of light quality on seed germination and seedling growth of six medicinal plant species in Tarai region, Uttarakhand

The influence of light quality (direct light, red, far-red and dark) on seed germination and seedling growth was examined in six different medicinal plant species viz., Lepidium sativum Linn., Spilanthes acmella Linn., Matricaria chamomilla Linn., Ammi majus Linn., Andrographis paniculata Nees. and Cassia tora Linn. in Tarai region of Uttarakhand with three replicates for 15 days under laboratory conditions. The results revealed that the rate of germination and per cent seed germination differ from species to species and light conditions. The per cent seed germination was maximum inL. sativum (89.67% in far - red) and minimum in M. chamomilla (40.0% in direct). M. chamomilla and S. acmella was failed to germinate under dark condition, whereas L. sativum showed maximum per cent seed germination (62%). The seedling growth in terms of length (cm) and dry weight (mg) of 15 days old was significantly affected by light quality in all the species. All the species exhibited maximum radicle length (cm) under direct light except in S. acmella (6.67 in red light) whereas plumule length (cm) was maximum in C. tora (11.78), L. sativum (8.59), A. paniculata (7.18) and A. majus (5.93) in dark. Interestingly, maximum total seedling dry weight (mg) was under direct light in all the species and it was maximum in C. tora (7.06) and minimum in M. chamomilla (2.80) indicating that direct light is favourable for seedling growth.

Low doses of glyphosate change the responses of soyabean to subsequent glyphosate treatments

SummaryMany herbicides promote plant growth at doses well below the recommended application rate (hormesis). The objectives of this study were to evaluate glyphosate‐induced hormesis in soyabean (Glycine max) and determine whether pre‐treating soyabean seedlings with low doses of glyphosate would affect their response to subsequent glyphosate treatments. Seven doses (1.8–720 g a.e. ha−1) of glyphosate were applied to 3‐week‐old seedlings, and the effects on the electron transport rate (ETR), metabolite (shikimate, benzoate, salicylate, AMPA, phenylalanine, tyrosine and tryptophan) levels and dry weight were determined. The lowest dose stimulated ETR and increased biomass the most. Benzoate levels increased 203% with 3.6 g a.e. ha−1 glyphosate. Salicylate content and tyrosine content were unaffected, whereas phenylalanine and tryptophan levels were increased by 60 and 80%, respectively, at 7.2 g a.e. ha−1. Dose–response curves for these three amino acids were typical for hormesis. In another experiment that was replicated twice, soyabean plants were pre‐treated with low doses of glyphosate (1.8, 3.6 or 7.2 g a.e. ha−1) and treated with a second application of glyphosate (1.8, 3.6, 7.2, 36, 180 or 720 g a.e. ha−1) 14 days later. For total seedling dry weight, a 3.6 and 7.2 g a.e. ha−1 glyphosate dose preconditioned the soyabean seedlings to have greater growth stimulation by a later glyphosate treatment than plants with no preconditioning glyphosate exposure. Optimal hormetic doses were generally higher with pre‐treated plants than plants that had not been exposed to glyphosate. Thus, pre‐exposure to low doses of glyphosate can change the hormetic response to later low‐dose exposures.

Cork Oak Seedling Growth under Different Soil Conditions from Fertilisation, Mycorrhizal Fungi and Amino Acid Application

<p class="TESE">Regeneration process deals with some constrains related with the livestock management, pasture rotations, and dependence of a sequence of favourable climatic years, among others, which can lead to a continuous delay in the initiation of the regeneration process. The purpose of this study is to promote an increase of cork oak seedling growth in order to decrease the time required for regeneration and also to contribute to avoid the effect of post-transplant stress on cork oak. With this objective, a study was carried out on a greenhouse, where the effect of fertilisation, mycorrhizal fungi inoculation, and amino acid supply were tested. Results showed that cork oak seedling capability to growth, expressed as total seedling dry weight, was positively affected by treatments, except when only fertilisation was applied. We verified that cork oak seedlings inoculated with mycorrhizal fungi presented better results in terms of aerial structures growth. Any of the treatments was suitable to contribute positively for tap root and total belowground dry weight accumulation. Only fine roots structures were sensitive to treatments effects; it was verified that both inoculated and non-inoculated seedlings subjected to fertilisation were capable to invest largely on the production of these structures (33 and 30%, respectively). To reinforce the cork oak seedling growth, the equilibrium between fertilisers and mycorrhizal fungi inoculation would probably be the better option to enhance the cork oak regeneration process. Thus, the balance between shoot and root systems growth would be guaranteed, fertilisation mainly for root system and mycorrhizal fungi inoculation for shoot growth.</p>

Relationships between leaf-litter traits and the emergence and early growth of invasive Pinus radiata seedlings

Baker AC & Murray BR (2010). Relationships between leaf-litter traits and the emergence and early growth of invasive Pinus radiata seedlings. Weed Research 50, 586–596. Summary Pinus radiata is an invasive weed in Australia that spreads from plantations and establishes in surrounding native eucalypt woodlands. To determine factors linked to the invasiveness of P. radiata, we compared emergence and growth traits of P. radiata seedlings at five different depths of leaf litter under pine needles, native eucalypt leaves and an equal mix of the two. Seedling emergence, height, survival and establishment were significantly reduced as leaf-litter depth increased. Seedlings had lower root:shoot ratios and higher specific leaf area (SLA) under deeper litter treatments, shifts linked to the provision of more surface area for light capture and greater light access by seedlings. Total seedling dry weight was highest in treatments with 1 cm of litter cover due to greater moisture retention provided by a small amount of leaf litter outweighing the costs of seedling penetration through leaf litter. Importantly, we found that at any given depth of leaf litter, there were no significant differences in emergence and growth traits between pine, eucalypt or mixed leaf-litter treatments. The ability of P. radiata seedlings to succeed equally well under a range of different leaf-litter types is undoubtedly an important trait linked to its invasiveness. Given ethical concerns of introducing highly invasive species, such as P. radiata into remnant native woodland in field-based studies, glasshouse research is highly desirable and invaluable in elucidating important factors underpinning the invasiveness of weed species such as P. radiata.

Qualidade fisiológica de sementes de arroz submetidas à radiação gama

O objetivo deste trabalho foi avaliar os efeitos da radiação gama (Co60) na qualidade fisiológica de sementes de arroz. O estudo foi realizado em três ensaios. No primeiro ensaio, sementes de arroz foram irradiadas com doses de 0; 1; 2,5 e 5Gy e, para o segundo e o terceiro ensaio, as sementes foram submetidas a envelhecimento acelerado, antes da irradiação. No segundo ensaio, as sementes foram dividas em úmidas e secas após envelhecimento acelerado e, então, foram irradiadas nas doses 0; 1; 2,5 e 5Gy. No terceiro ensaio, as sementes foram secas após o envelhecimento acelerado e irradiadas com doses de 0, 10, 25 e 50Gy. Para avaliação dos efeitos fisiológicos da radiação gama, foram realizados teste de germinação - TG, índice de velocidade de germinação - IVG e crescimento de plantas (comprimento de parte aérea e sistema radicular e massa seca total), em todos os ensaios. Foram determinadas as atividades enzimáticas da fosfatase ácida e alfa amilase nas sementes secas, no segundo ensaio. Os resultados obtidos nos ensaios indicam que as doses de radiação gama estudadas não afetam a qualidade fisiológica das sementes de arroz.

Effect of Various Nursery Media on Onion Seedlings Development

A field experiment was conducted to standardize the nursery raising technique for onion at the Horticulture Research Farm, Department of Horticulture, Allahabad Agricultural Institute-Deemed University, Allahabad, during 2005-2006. The treatments comprised combinations of soil, sand, FYM and vermicompost. Altogether, 14 treatments were applied in a randomized block design with three replications. Hundred percent germination was found with a combination of soil, sand and FYM in proportions of 2:1:2&2:2:1, and, 1:1:1&2:2:1 Soil:Sand:Vermicompost. Among all the treatments, the combination of soil 2 parts, sand 1 part and FYM 2 parts, significantly influenced growth and health of seedlings and produced the maximum seedling height (11.42 cm), stem diameter (0.33 cm), root length (10.86 cm), shoot fresh weight (6.96 g), root fresh weight (3.22 g), total seedling fresh weight (10.18 g), shoot dry weight (3.95 g), root dry weight (1.53 g) and total seedling dry weight (5.48g). Highest benefit:cost ratio of 3.72 was also seen in this treatment combination.

Screening of allelochemicals on barnyardgrass ( Echinochloa crus-galli) and identification of potentially allelopathic compounds from rice ( Oryza sativa) variety hull extracts

Experiments were conducted to screen 23 known allelochemicals, including sinapic acid, and an equimolar mixture of the chemicals for potential allelopathy on barnyardgrass ( Echinochloa crus-galli var. oryzicola), and to identify allelochemical(s) from hull extracts from three rice ( Oryza sativa L.) cultivars. In a bioassay, the inhibitory effect was increased as the concentration of allelochemicals increased from 10 −5 to 10 −3 M. Ferulic, p-hydroxybenzoic, p-coumaric, and m-coumaric acids were the most active compounds and caused the greatest effect on seed germination, germination rate, and total seedling dry weight reduction . p-hydroxybenzoic acid (10 −3 M; pH 4.1) showed the greatest inhibitory effect on the same parameters. HPLC analysis using three rice cultivars, Janganbyeo, Baekambyeo, and Labelle, showed that the concentration and composition of potentially allelopathic compounds depended upon the cultivar. Hull extracts from the allelopathic cultivar Janganbyeo contained higher levels of p-hydroxybenzoic acid than did those of the non-allelopathic cultivars Labelle and Baekambyeo. Nine compounds, including p-hydroxybenzoic acid (4.29 mg/g) in Janganbyeo, seven compounds including m-coumaric (0.43 mg/g) in Labelle, and five compounds including p-hydroxybenzoic acid (0.36 mg/g) in Baekambyeo, were detected. Preliminary identification by HPLC analysis resulted in peaks with retention times near those of standards, including p-hydroxybenzoic acid that was confirmed with EI/MS. It is suggested that these compounds may be, at least, a key factor in rice allelopathy on barnyardgrass, and the information presented may contribute to the development of naturally occurring herbicides.

Effect of manganese on endomycorrhizal sugar maple seedlings

Manganese (Mn) toxicity may play an important role in the poor survival of seedlings in declining sugar maple (Acer saccharum Marsh.) stands in northern Pennsylvania. To determine the effect of Mn on the growth of sugar maple seedlings, 1‐year‐old seedlings inoculated with vesicular‐arbuscular mycorrhizal (VAM) fungi and growing in sand‐vermiculite‐peat moss medium were irrigated for 7 weeks with nutrient solution (pH 5) containing 0.1 (control), 1, 2, 4, 8, or 16 mg L−1 Mn. Total seedling dry weight was negatively correlated with Mn, becoming significantly different than the control at 2 mg L−1 Mn. Stem and root dry weight were reduced by lower Mn levels than leaf dry weight. Manganese had no effect on the root/shoot ratio. The concentration of Mn in roots and leaves increased as the level of Mn in the nutrient solution increased, with the concentration in the leaves 2.2‐ to 3.7‐fold greater than the concentration in the roots. Except for a reduction of P in the roots, Mn had little effect on the concentration of nutrient elements in the roots or leaves. Colonization of the roots by VAM fungi was increased by Mn, with a maximum percentage at 4 mg L−1 Mn. Manganese toxicity symptoms in the leaves, small discrete chlorotic spots, began to appear at 1 mg L−1 Mn. The sensitivity of sugar maple seedlings to Mn found in this study supports the hypothesis that Mn may affect regeneration in declining sugar maple stands. However, evaluation of the effects of Mn on seedlings in native soils under field conditions will be necessary before the role of Mn in sugar maple regeneration can be understood.