Increase In Growth Parameters Research Articles

Ameliorative effects of calcium nitrate and humic acid on the growth, yield component and biochemical attribute of pepper ( Capsicum annuum ) plants grown under salt stress

The present work was carried out in order to determine the effects of calcium nitrate and humic acid applications either separately or in combination on the growth and fruit yield quality of pepper plants under salt stress condition. Two different concentrations of calcium nitrate (Ca1; 60 mg/kg soil and Ca2; 120 mg/kg soil) were applied to the soil before sowing whereas humic acid applications (HA1; 750 mg/kg soil and HA2; 1500 mg/kg soil) were performed during plant growth (at the third true leaves stage). Plants were irrigated with saline water in a concentration of 100 mM NaCl. Data showed that applications of both concentrations of humic acid and lower concentration of calcium nitrate (Ca1) individually caused significant increases in growth parameters, RWC, photosynthetic pigments, minerals content, non-enzymatic antioxidants contents of the plants under normal and salt stress conditions. Moreover, fruit antioxidant compounds and quality of fruits (capsaicin, lycopene, β-carotene, total phenol, total flavonoids and antioxidant activity) were improved by using theses treatments. The combined treatment of Ca1 and HA2 was the most effective one on the previous criteria under salt stress conditions. Therefore, the usage of humic acid and calcium could be suggested to improve the soil properties, growth and antioxidant capacity of pepper plants and to mitigate the damage caused by salt stress.

An Open-label Randomized Controlled Trial to Compare Weight Gain of Very Low Birth Weight Babies with or without Addition of Coconut Oil to Breast Milk.

Nutritional guidelines involving the feeding of very low birth weight babies (VLBW) recommend addition of Human Milk Fortifiers to breast milk. Owing to financial constraints, it is a practice in low- and middle-income countries (LMIC) to add coconut oil to aid better weight gain. There are inadequate data on improvement of growth parameters with oral coconut oil supplementation of breast milk. In this randomized controlled trial, we measured growth parameters and body composition of 60 babies who received either breast milk with coconut oil or breast milk alone. Randomization was stratified according to intrauterine growth appropriate for gestational age (n = 30) and small for gestational age (n = 30). There was no difference in weight gain between the two groups. The weight gain velocity was 15 ± 3.6 and 14.4 ± 3.4 g/kg/day (p value = 0.49) in the breast milk alone and in the breast milk with coconut oil group, respectively. There was no difference in increase in head circumference and length. Triceps skinfold thickness (n = 56) was similar in both groups, but subscapular skinfold thickness was significantly more in the coconut oil group. Total body fat percentage did not differ between the groups (25.2 ± 4.3 vs. 25.5 ± 4.3%, p = 0.79). Oral supplementation of coconut oil along with breast milk did not increase growth parameters or result in change in body composition in very low birth weight (VLBW) babies.

Growth response of litchi to arbuscular mycorrhizal co-inoculation with Trichoderma viride, Azotobacter chroococcum and Bacillus megatarium

To examine the microbial cooperation in the rhizosphere as reflected in terms of growth response of young trees (< 5 years) of litchi (Litchi chinensis), field experiments were conducted during 2012–2015 at ICAR-National Research Centre on Litchi, Muzaffarpur. The microbial inoculants consisting of arbuscular mycorrhizal fungi (AMF), Trichoderma viride (TR), Azotobacter chroococcum (AZ) and Bacillus megatarium (BM) along with their combinations were compared with application of recommended dose of fertilizers (RDF). The data revealed that AMF in combination with other microbial inoculants resulted in significantly higher increase in growth parameters viz., tree height, tree girth, tree spread, leaf area and leaf chlorophyll content. Growth response produced by combination of AMF + AZ + TR were the best or statistically at par (p = 0.05) with AZ + TR for most of the parameters. Similarly, significant higher root biomass, volume and density were observed with application of microbial inoculants. While AMF positively influenced the increase in population of T. viride and A. chroococcum, it negatively influenced the increase of population of B. megatarium which corroborated with the observed growth response of litchi trees. Thus, the studies not only confirmed the positive response of AMF and A. chroococcum reported in different crop species but also demonstrated a synergistic response of AMF with A. chroococcum and T. viride in litchi under field conditions.

Role of Indigenous Mycorrhizal Species in Enhancing Physiological and Biochemical Status, Nutrient Acquisition and Yield Pattern of Groundnut (Arachis Hypogaea L.)

Arbuscular Mycorrhizal fungi (AMF) play an important and increasingly well-recognized role in agro ecosystems. Beneficial soil microorganisms like arbuscular mycorrhizal fungi and soil health are key factors for producing safe plants. Arbuscular mycorrhizal fungi form a symbiotic association with roots of plants and facilitate plant growth through enhancing uptake of several macro- and micro-nutrients of low mobility in soil, like phosphorus, zinc, copper, etc. In the present study, we investigated the effect of 10 different isolated mycorrhizal species viz. Glomus mosseae, Glomus clarum, Glomus fasciculatum, Glomus intraradices, Glomus ambisporum, Gigaspora gigantea, Acaulospora denticulata, Glomus globiferum, Gigaspora albida, and Glomus pansiholus on growth, yield, and essential nutrient content of groundnut (Arachis hypogeae L.). Plants inoculated with arbuscular mycorrhizal fungi showed significant increments in growth, yield, and nutrient uptake as compared to control (uninoculated) plants. Amongst all, plants inoculated with Glomus mosseae were more efficient in increasing growth parameters, enzymatic activities of nitrate reductase, and alkaline phosphatase as well as total yield as compared to other mycorrhizal inoculated plants. Overall, the study showed an additive effect of all mycorrhizal species on plant physiology. Thus, this study provides an important insight that arbuscular mycorrhizal fungi are most suitable for sustainable agriculture which will improve and help in increasing the growth as well as yield of groundnut.

Effects of drought stress on the seedling growth, development, and metabolic activity in different cultivars of canola

ABSTRACTThe comparative effects of drought stress on seed performance, growth parameters, free proline content, lipid peroxidation, and several antioxidative enzymes activities were studied in both cultivars of Brassica napus L. Drought stress increased mean germination rate and mean of day germination in both cultivars, and its effect was more pronounced in RGS003. The length and dry weight of root increased significantly in both cultivars under drought. RGS003 was more tolerant and obtained more biomass under drought than that of Sarigol. Proline content and pyrroline-5-carboxylate synthetase expression increased in Sarigol under drought. Measurement of malondialdehyde content in seedlings showed that lipid peroxidation was lower in RGS003 than in Sarigol. Antioxidant enzyme activities showed different trends in the two cultivars under drought stress but were higher in RGS003 than in Sarigol. These results suggest that RGS003 is better protected against drought-induced oxidative damage. Lipoxygenase activity only induced under water deficit condition in RGS003. Changes of respiratory enzymes activities of RGS003 subjected to drought stress showed a pattern different with Sarigol. Drought stress induced aconitase activity in RGS003, but it reduced fumarase and succinate dehydrogenase activity in Sarigol. This study showed that RGS003 exhibits a better protection mechanism against oxidative damage and RGS003 is more drought-tolerant than Sarigol possibly by maintaining and/or increasing growth parameters, antioxidant enzyme activities, and respiratory enzymes activities.

Growth of potato genotypes under different silicon concentrations

The aim of this work was to verify the beneficial potential of Silicon on the growth of potato genotypes in order to select potato genotypes that best respond to Si application. Four potato genotypes were used: SMIJ319-7, Dakota Rose, SMIF212-3 and SMINIA793101, grown in hydroponic system. The plants were transferred to nutrient solutions with four Si concentrations: 0; 0.5; 2.5; and 5.0 mM as NaSiO3. After seven days of exposure to treatments, leaf area, leaf number, shoot length, and fresh and dry weight of roots, stem and leaves were determined. The application of 0.5 mM Si promoted an increase in growth parameters of plants used in this work, mainly in leaf area, leaf number, and leaf and stem dry weight. However, the application of higher concentrations of Si (2.5 mM) promoted reduction in the growth parameters, mainly in leaf area. It was also possible to observe a genotypic variation with respect to Si, SMIJ319-7 and SMIF212-3 genotypes being the most responsive to Si. Therefore, the concentration of 0.5 mM Si is considered optimal for potentiating the growth of potato plants, and SMIJ319-7 and SMIF212-3 genotypes are the most responsive to Si.

Management of root knot nematode, Meloidogyne incognita in Okra through bio-agents and neem oilcake

A pot culture study was carried out in net house condition during kharif 2016 to study the efficacy of Trichoderma viride, Pseudomonas fluorescens and neem cake alone and in combinations for management of Meloidogyne incognita in okra. Among all the treatments, soil application of neem cake @ 1 ton/ha at 15 days prior to sowing followed by soil application of Trichoderma viride @ 2.5 kg/ha at 15 days after sowing recorded maximum increase in growth parameters of okra plant (71.4, 72.7, 76.9, 63.9, 67.1 and 76.15 in plant height, fresh shoot weight, fresh root weight, dry shoot weight, dry root weight and root volume, respectively) with lowest reproduction factor (0.34) and highest reduction (79.0%) in root knot nematode population followed by plants treated with soil application of neem cake @ 0.5 ton/ha + T. viride @ 1.25 kg/ha which were at par. Soil application of T. viride in combination with neem cake at different doses were found more effective against M. incognita with increase in plant growth parameters and decreasing root knot nematode population in soil than other treatments.

Element content, growth and metabolic changes in Cu- and Cd- stressed Phaseolus vulgaris plants

A large-scale pot experiment was accomplished for investigation of the varied effects of different concentrations of Cu and Cd on certain growth and metabolic attributes of roots and shoots of Phaseolus vulgaris plants, over a period of three weeks. Plants supplemented with Cu and Cd at the concentrations of 10-6 and 10-3 M, showed increased levels of Cu and Cd in both shoots and roots, above those levels in controls. However, Cu or Cd accumulation was lower in shoots than in roots. As compared with control levels, the low (10-6 M) concentration of Cu induced either a significant or an insignificant increase in growth parameters, photosynthetic pigments, PS II activity, glucose, proline and glycine contents in both roots and shoots. Otherwise, insignificant decreases in fructose, sucrose, polysaccharides, total saccharides, total soluble-N, protein –N, DNA and RNA contents, in the same test plant parts, were obtained. A reverse situation was however observed with the high concentration (10-3 M) of Cu as well as with the low and high concentrations (10-3 and 10-6 M) of Cd. In general, the observed adverse effects were more pronounced with Cd at (10-6 M) as compared with those maintained with Cu at the same concentration. Furthermore, the most detrimental adverse effects were apparent upon administration of the high (10-3 M) concentration of Cd. The prominence of the above mentioned changes in growth and metabolism to stress tolerance in common bean is discussed.

The Potential Role of Cupper and Combined Action with IAA on Tolerance Strategy of Two Broad Bean Cultivars

The present work was conducting to study the strategy response of two broad bean cultivars Assiut 84 and Assiut 125 to different Cu2+ concentrations 100 ppm, 200 ppm, 300 ppm and 350 ppm in addition to control and interactions with IAA treatments. The dry matter exhibited the biphasic effect of Cu2+ on the growth criteria of the two broad bean cultivars. While the lower and moderate doses of Cu2+ (100 ppm and 200 ppm) stimulated the growth of the two cultivars, the higher doses revealed the opposite event where the growth dropped in both cultivars. This effect was more pronounced in cv. Assiut 84 than in cv. Assiut 125 and also at the higher Cu2+ concentration the growth dropped slightly in cv. Assiut 84 and highly significantly in cv. Assiut 125. The percent of increase in dry matter at 200 ppm in stem and leaf of cv. Assiut 84 was 120.45% and 155.31%, otherwise this percent of increase in these organs of cv. Assiut 125 was 114.29% and 131.41%. However the percent of reduction at 350 ppm Cu2+ in root and stem of cv. Assiut 84 was 74.13%, 79.23% and in root, stem and leaf of cv. Assiut 125 was 59.27%, 70.91%, 70.76% compared with control plants. Soluble carbohydrate in cv. Assiut 84 and cv. Assiut 125 was markedly increased while soluble protein was decreased in root, stem and in leaves at lower Cu2+ concentration. Also while Cu2+-stressed cv. Assiut 84 maintained potassium and magnesium levels around the control values and some promotion occurred especially in roots and stems, these cations dropped markedly in cv. Assiut 125 as a result of Cu2+ treatments. While Cu2+ had a marked stimulatory effect in the absorption and accumulation of calcium in the different organs of cv. Assiut 84, it, on the other hand, significantly inhibited the accumulation of this cation in the different organs of cv. Assiut 125. Treatments broad bean cultivars with Cu2+ plus IAA induced an increase in growth parameters, soluble suga, soluble protein, K+, Ca++ and Mg++ in different parts of two tested cultivars. The uptake, translocation and distribution of mineral ions are affected by various growth regulators among others by IAA. This strategy might be important in heavy metals tolerance mechanisms of crop plants.

Effect of Inoculum Density of &amp;lt;i&amp;gt;Stromatinia cepivora&amp;lt;/i&amp;gt; on the Ability of Sclerotial Mycoparasites to Suppress White Rot in Garlic

White rot, an garlic disease caused by the soil-borne fungus <i>S. cepivora</i>, is a serious problem of garlic productions in Egypt. This study examines the potential of controlling the disease biologically by using three sclerotial mycoparasites <i>i.e</i>., <i>Chaetomium globosum</i> (Chg6), <i>Clonostachys rosea</i> (Cr12) and <i>Penicillium oxalicum</i> (Po9) employed either alone or in combinations. In <i>in vitro</i> assays, these sclerotial mycoparasites showed high antagonistic effect against <i>S. cepivora</i> isolate (Sc8). In greenhouse experiments, the chemical treatment of tebuconazole was the most effective, with the lowest incidence of white rot in garlic compared to the control. Sclerotial mycoparasites either alone or in combinations significantly reduced the incidence of white rot in garlic. In general, dual and triple combinations of the sclerotial mycoparasites were more effective than these isolates used individually. In field experiments, under low (40 sclerotia/kg of soil) and high (600 sclerotia/kg of soil) inoculum levels, the standard fungicide programme gave statistically significant white rot control, decreasing disease incidence by 67.7 & 32.4% in 2016/2017 season and 72.6 & 31.1 % in 2017/2018 season, respectively. Under low inoculum levels, significant control, equal to the fungicide treatment, was achieved with the triple combination of three sclerotial mycoparasites. However, no sclerotial mycoparasites employed alone give significant control of garlic white rot under high inoculum levels. The triple combination of three sclerotial mycoparasites decreasing disease incidence by 70.8 & 25.9 % in 2016/2017 season and 73.7 &27.6 % in 2017/2018 season, under low and high inoculum levels, respectively. The activities of defense enzymes, i.e. peroxidase, polyphenoloxidase and chitinase due to application of sclerotial mycoparasites were enhanced in garlic plants either grown under low or high inoculum levels. Reduction of white rot disease incidence was accompanied by increasing growth parameters and bulbs yield of garlic plants grown under field conditions. These results concluded that the performance of sclerotial mycoparasites may be influenced as much by the absolute disease pressure. At the low disease pressure site, the low level of S. cepivora inoculum enabled sclerotial mycoparasites to bring about disease control.

Improving Growth of Lebbeck and Chinaberry Transplants for Drought by Using Organic Amendments

Field experiment was carried out at the Experimental Farm of the Salinity and Alkalinity laboratory, Sabaheia- Alexandria, to quantify growth, biomass and chemical composition on responses of lebbeck and chinaberry to three levels of drought stress and three organic amendments after two successive seasons of 2015 and 2016. The results indicated that well-watered treatment had the higher values of height growth, stem diameter, leaves number, shoots dry weight, shoots: roots (S: R) ratio, total chlorophyll and total carotenoides. On the other hand, severe treatment (50% field capacity) resulted in the highest values of roots dry weight, proline and total phenols contents for both tree species. Compost was better to enhance the growth parameters of lebbeck while, humate was the better to increase growth parameters of chinaberry. Total chlorophyll and total carotenoides of the two species were enhanced by adding humate. The interaction results indicated that the highest values of growth parameters of lebbeck resulted from compost combined with moderate or well-watered treatments. While humic acid combined with well-watered or moderate treatments were the best for growth of chinaberry seedlings.

Effect of nitrogen and phosphorus application on growth and flowering in golden rod (Solidago canadensis L.) cv. Local

An experiment was conducted to study the effect of nitrogen and phosphorus on growth, quality and flower production of golden rod (Solidago canadensis L.) cv. Local. Using sixteen treatment combinations consisting of four levels of nitrogen (0, 150, 175 and 200 kg N/ha) and four levels of phosphorus (0, 50, 75 and 100 kg P/ha), the experiment was laid out in Randomized Block Design (RBD) with three replications. The results revealed that the application of nitrogen @ 200 kg/ha and phosphorus 100 kg/ha significantly increased growth parameters viz., plant height, plant spread, fresh weight of plant, dry weight of plant, suckers per plant, fresh weight of panicle, dry weight of panicle, length of panicle, vase life and panicles per plant.

EFFECT OF PRIMING ON GERMINATION AND INITIAL GROWTH OF MELON PLANTS UNDER SALT STRESS

The objective of this work was to evaluate the effect of different osmotic agents and priming durations on the germination and initial growth of melon in salinity. The osmotic agents were NaCl and CaCl 2 and durations 2 and 4 days. First a response curve of germination to salinity was made. After priming the seeds were placed to germinate in a saline medium (14 dS m -1 ). The germination percentage was determined. The two treatments with the best results (NaCl and CaCl 2 2 days in both salts) were selected to evaluate the initial growth of the plants in salinity. It was sown in pots, irrigated with nutrient solution and 60 mM NaCl. The germination was reduced to 50% with 14 dS m -1 and inhibited with 22 dS m -1 . The best germination was achieved with NaCl and CaCl 2 2 days with 99 and 94% respectively. Both treatments showed an increase in growth parameters and chlorophyll content.

Effect of Potassium Humate and Potassium Silicate on Growth and Productivity of Wheat Plants Grown under Saline Conditions.

A lysimeter experiment was carried out at Sakha Agricultural Research Station, Kafr El-Sheikh governorate, during the growth season of 2013-2014 to investigate the effect of potassium humate, potassium silicate and/or their interaction on improving growth parameters and yield components of wheat plants grown under salinity stress. Irrigation of wheat plants with diluted sea water i.e. EC 6, 9 and 12 dS/m reduced growth parameters and yield components, these reductions were gradually increased with increasing the concentrations of diluted sea water. Addition of potassium humate at (4 & 8 kg/fed.) to soil and foliar application of potassium silicate at (500 & 1000 ppm) alone or together increased growth parameters and yield components of wheat plants grown under salinity stress, the duality treatments of potassium humate and potassium silicate were the most effective treatments especially at low concentration in amelioration the depressive effect of salinity on growth and yield of wheat plants.

Abiotic stress of ZnO‐PEG, ZnO‐PVP, CuO‐PEG and CuO‐PVP nanoparticles enhance growth, sweetener compounds and antioxidant activities in shoots of Stevia rebaudiana Bertoni

Nanoparticles are known to play remarkable role as abiotic stress elicitors in plants. This study reports the comparative analysis of effects produced by capped [zinc oxide (ZnO)-polyethylene glycol (PEG), ZnO-polyvinyl pyrrolidone (PVP), copper oxide (CuO)-PEG, CuO-PVP] and uncapped (ZnO and CuO) nanoparticles on the medicinal plant, Stevia rebaudiana raised in vitro for the production of commercially important sweetener compounds. In context of shoot organogenesis, ZnO-PEG, ZnO-PVP, CuO-PEG, CuO-PVP were employed to the growth medium that resulted in increased growth parameters, and larger content of steviol glycosides as compared to the shoots raised in medium containing ZnO and CuO, revealed by high-performance liquid chromatography. In the meanwhile, non-enzymatic antioxidant activities including total phenolic content, total flavonoid content, total antioxidant capacity, total reducing power and 2,2-diphenyl-1-picryl hydrazyl-free radical scavenging activity were calculated and showed comparatively greater amounts in shoots grown in medium containing capped ZnO or CuO nanoparticles. Furthermore, the ZnO and its derivatives revealed to be more reactive at 1 mg/l of concentration. Whereas, the CuO and its derivatives produced greater response on Stevia at 10 mg/l concentration of nanoparticles. This study paves the way for more such studies encompassing capped and uncapped nanoparticles and their ultimate effect on in-vitro grown plant tissues for the production of active metabolites on industrial scale.

Sulfur Protects Pakchoi (Brassica chinensis L.) Seedlings against Cadmium Stress by Regulating Ascorbate-Glutathione Metabolism.

Cadmium (Cd) pollution in food chains pose a potential health risk for humans. Sulfur (S) is a significant macronutrient that plays a significant role in the regulation of plant responses to diverse biotic and abiotic stresses. However, no information is currently available about the impact of S application on ascorbate-glutathione metabolism (ASA-GSH cycle) of Pakchoi plants under Cd stress. The two previously identified genotypes, namely, Aikangqing (a Cd-tolerant cultivar) and Qibaoqing (a Cd-sensitive cultivar), were utilized to investigate the role of S to mitigate Cd toxicity in Pakchoi plants under different Cd regimes. Results showed that Cd stress inhibited plant growth and induced oxidative stress. Exogenous application of S significantly increased the tolerance of Pakchoi seedlings suffering from Cd stress. This effect was demonstrated by increased growth parameters; stimulated activities of the antioxidant enzymes and upregulated genes involved in the ASA-GSH cycle and S assimilation; and by the enhanced ASA, GSH, phytochelatins, and nonprotein thiol production. This study shows that applying S nutrition can mitigate Cd toxicity in Pakchoi plants which has the potential in assisting the development of breeding strategies aimed at limiting Cd phytoaccumulation and decreasing Cd hazards in the food chain.

Multifaceted Rhizobacteria-Mediated Growth Augmentation in Chickpea

Sixty-nine rhizobacteria isolated from chickpea rhizosphere were screened for their antagonistic potential against Fusarium oxysporum f. sp. ciceris under in vitro condition. Of these, 30 isolates inhibited growth of the pathogen and 13 potent antagonists were assessed for their functionality traits. Among the antagonistic traits exhibited by antagonists, production of diffusible antimetabolites insured its inhibitory effect on growth of test fungus as well as spore germination on solid media. Inhibition of fungus biomass in broth-based dual culture was revealed by 11 antagonists, while metabolic extracts of 5 isolates reduced the radial proliferation on solid media. Implication of biocidal volatiles in antagonism was demonstrated by 11 isolates; 3 produced cyanogenic volatiles, while all were ammonia producers. Investigation for hydrolytic activity demonstrated production of chitinase by 4 isolates and β-1,4-glucanase by 11, while all were protease and amylase producers. Revealing the dual potential of bioantagonists, all the isolates tested positive for IAA and salicylic acid production, 7 for siderophore production while 10 were P-solubilizers and 8 Zn-solubilizers. Under glass house condition, bacterization of chickpea seeds with potential isolate Ps14c alone and in consortium with Mesorhizobium ciceris reduced wilt incidence in pots (soil amended with F. oxysporum) to 48 and 28%, respectively, as compared to uninoculated control (74%) and also recorded appreciable increase in growth parameters. Present investigation clearly reveals the potential of rhizobacteria for use as bioinoculants.

Caracterización y efecto de Azotobacter, Azospirillum y Pseudomonas asociadas a Ipomoea Batatas del Caribe Colombiano

El uso de Rizobacterias promotoras de crecimiento vegetal (PGPR, por sus siglas en ingles) constituye una alternativa al uso de fertilizantes químicos favoreciendo el rendimiento de los cultivos. La presente investigación tuvo como objetivo la búsqueda, selección y caracterización de PGPR de los géneros Azotobacter, Azospirillum y Pseudomonas nativas de la rizósfera de cultivos de Ipomoea batatas de zonas productoras representativas del Caribe Colombiano. Los aislados seleccionados se caracterizaron molecularmente y realizaron pruebas de solubilización de fósforo, producción de índoles y reducción de acetileno. Las cepas fueron probadas a nivel de invernadero en plántulas de Ipomoea batatas producidas in vitro en las que se evaluó la altura, longitud radicular, masa seca de la parte aérea y radicular. Asociada a la rizósfera de Ipomoea batatas se obtuvieron cepas de Azotobacter vinelandii, Azotobacter chroococcum, Azospirillum lipoferum, Azospirillum brasilense y Pseudomonas denitrificans, las cepas fueron capaces de solubilizar fósforo, producir índoles y reducir acetileno. Se obtuvo incrementos en parámetros de crecimiento como longitud radicular, altura, peso seco aéreo y radicular en plántulas de Ipomoea batatas en invernadero con la inoculación de las bacterias seleccionadas frente a plántulas sin inocular. Los resultados catalogan a los aislados obtenidos como posibles microorga-nismos con potencial como biofertilizantes en batata.

The Role of Salicylic Acid and Pseudomonas fluorescens in Systemic Resistance Against Rhizoctonia solani kühn in Guar (Cyamopsis tetragonoloba (l.) Taub.)

Rhizoctonia solani was found to be associated with root rot symptoms of guar plants collected from different fields in New Valley governorate, Egypt. All the obtained isolates were able to attack guar plants (cv. Local) causing damping-off and root rot diseases. R. solani isolates No. 8 (RG8) was the more virulent ones in the pathogenicity tests. Salicylic acid (SA) and Pseudomonas fluorescens (PF) individually or in combination were examined for their potential in suppression damping-off and root rot and growth promotion of guar plants in vitro and in vivo. Both SA and P. fluorescens either individually or in combination inhibited the growth of the tested pathogenic fungi.SA combined with P. fluorescens recorded the highest inhibited growth followed by P. fluorescens alone. Under greenhouse and field conditions, all treatments significantly reduced damping-off and root rot severity. The combination of SA and P. fluorescens was more effective than using them individually. Under field conditions, all these treatments significantly increased growth parameters (plant height and No. of branches plant-1) and yield components (No. of pods plant-1, weight of 100 seeds and total yield fed.-1 and Guaran content (gm plant-1) in both locations (El-Kharga and Mallawy Agric. Res. Stations) during growing season 2014.The combination of SA and P. fluorescens were recorded the highest growth parameters and yield components. Generally, the combination of SA and P. fluorescens recorded the best results for controlling damping-off and root rot diseases in greenhouse and field with addition improved plant growth and increased yield components in the field. In physiological studies, activity of defense-related enzymes, including peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), pathogenesis related (PR) protein (chitinase and β 1,3 gluconase), were increased in inoculated and non-inoculated plants treated with the SA and P. fluorescens either individually or in combination, during the experimental period. The combination of SA and P. fluorescens recorded the highest increase in activity of all enzymes. In general, the activity of these enzymes begins to accumulate after two days of treatment and reached maximum levels at 6 to 10 days, then the activities of these enzymes were decreased progressively. On the other hand, total phenols and lignin increased in guar plants inoculated with R. solani and treated with SA and P. fluorescens individually or in combination. The highest accumulation of phenols was recorded 8th days from application, while lignin recorded the highest level at 10th days from application. In the end, these results suggested that SA and P. fluorescens either individually or in combination may play an important role in controlling the guar damping-off and root rot diseases, though they have induction of systemic resistance in guar plants.

Rubrivivax gelatinosusbiomass as an immunostimulant for pacuPiaractus mesopotamicus

Rubrivivax gelatinosus is a bacterium present in the environment successfully used for treatment of fish industry effluent. Besides cleaning the effluent, this bacterium provides a biomass rich in proteins and carotenoid as a metabolic product. This study describes for the first time the use of this biomass as an immunostimulant feed. Haematological, immunological, biochemical and growth parameters in pacu Piaractus mesopotamicus fed control diet or diets supplemented with 0.5 or 1.5 g kg−1 of the R. gelatinosus biomass during 60 days were assessed. Fish were sampled at 0, 30 and 60 days. The inclusion of increasing levels of biomass in feed increased thrombocytes and neutrophils (P < 0.05) and decreased lymphocytes (P < 0.05) as well as activated the complement system (P < 0.05). Glucose levels, hepatosomatic index and weight were positively affected by the inclusion of R. gelatinosus biomass (P < 0.05). The use of R. gelatinosus biomass in feed improved the immune response of fish through the enhancement of some phagocytic cells, reduced time to activation of the complement system and increased growth parameters. This study reveals a promising use for a by-product resulted in the wastewater treating in aquaculture.