426 resultados para plant growth-promoting rhizobacteria


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Mikania glomerata Sprengel leaf extracts have been used in cough syrup formulations due to the presence of active coumarin derivatives. Yields of such natural compounds in cultivated plants can be affected by several nutritional factors. To determine the effect of fertilization on biomass productivity, organ proportion and coumarin content, Mikania glomerata plants were submitted during one year to treatments with organic (humus or manure) and inorganic (different levels of nitrogen) fertilizers. Coumarin concentration was raised by organic fertilization, inorganic nutrients induced increased phytomass (stem and leaf) yield, however no fertilized plants showed enhanced leaf production.

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The present work was conducted with the objective to study the effects of mineral nutrition on Eucalyptus grandis and Brachiaria decumbens (#BRADC) growth, when submitted to inter- and intra-specific competition. The treatments consisted of two plants of Eucalypts/pot, two plants of BRADC/pot, and one plant of each species/pot. The plants were nourished with the Hoagland e Arnon (1950) complete solution; with no K, P or N; or only with either N, P or K. Sixty days after growing side by side, no effect of the inter- and intra-specific competition on eucalypts plant high, branch number and leaf dry mass was observed. When mineral nutrition did not limit plant growth (complete solution or solution with no K), intra-specific competition reduced on average, 23% of eucalypts root length, leaf area, and stem and root dry mass, and inter-specific competition reduced, on average, 75% of BRADC dry mass. When mineral nutrition became a limiting factor, no plant competition effect on the parameters studied was detected.

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This work was carried out with Psychotria ipecacuanha, a Brazilian medicinal plant the roots of which contain emetine. The main objective was to develop a protocol for the micro-propagation of these species, by testing different culture techniques, the temporary immersion system, and the semi-solid and liquid media systems. In the semi-solid system, experiments were developed in flasks of two different sizes containing MS, B5, and WP media to which were added different growth regulators. Innoculum density was also evaluated. The liquid medium system consisted of MS medium supplemented with different growth regulators. For the temporary immersion system, the MS medium received an addition of 1.5mg/L BAP and 0.5mg/L GA3, and a reverse digital apparatus and vacuum pump were used. The liquid medium system with MS medium supplemented with 1.5mg/L BAP and 0.5mg/L GA3 presented the best results for shoot proliferation in a period of 30 days in culture (2.37 ± 0.32 shoots/explant). Cultures carried out for 90 days in the semi-solid system, using 8.5 × 5.5cm flasks and 3 explants per flask, developed 1.80 ± 0.20 shoots/explant, achieving 3.06 ± 0.51 cm of height adn presented superior survival ratio (96%). Explants cultured in temporary immersion system for 90 days showed 2.30 ± 1.10 shoots/explant achieving a growth of 2.08 ± 0.12 cm and 52% survival.

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Growth effects of cultivation on soil, sand and commercial substrate, on summer and winter time, of 'Bonus #2', 'Don Carlo's and 'Hy Mark' were assessed. The experiments were conducted in a greenhouse of FCAV-UNESP, in Jaboticabal- SP, Brazil, 21° 15' 22 S, 48° 18'58 W, and an altitude of 595 m, comprising the period from November '99 to April 2000 (Summer), and from July to November 2000 (Winter). On soil cultivation, chemical nutrients were used, and the plants received drip irrigation. On sand, fertigation with recirculation of the nutrient solution were used, and slabs and fertigation with non circulating nutrient solution was used with commercial substrate. 'Bonus #2', grown on sand and in the summer season had improved plant height, internodes length, stem diameter, leaf area and dry matter of shoots and roots. 'Hy Mark', when cultivated on commercial substrate had lower growth. During winter season, the growth was slower.

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Two field trial were conducted in Eucalyptus grandis W. Hill ex Maiden x Eucalyptus urophylla S.T. Blake crops at Três Lagoas, Mato Grosso do Sul State and Brotas, São Paulo State, Brazil, to evaluate the effects of weed control in strip of different width on the Eucalyptus plant growth. The experiments consisted of two groups treatments: group 1 - with constant width control strips being kept during the first 12 months, i.e., at 0, 25, 50, 100, 125 and 150cm on each side of the Eucalyptus row and, group 2: with increasing width control strips being adopted along the experimental period, i.e., at 25 to 150, 25-50-150, 50 to 150, 50-125-150, 100-125-150, 100 tot 150 and 125 to 150 cm on each side of the Eucalyptus row during the first 12 months. At 49 moths after planting it was verified that the Eucalyptus plants that had grown both in the constant and increasing width control strips, equal to or higher than 100 and 50 cm, respectively, showed higher steam diameter, plant height, volume and annual increment average of wood. These results led to the conclusion that the minimum control strip width should be 100 cm on each side of the Eucalyptus row in order to keep the crop free of weed interference.

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The objective of this work was to evaluate the effect of different artemisinin concentrations in the flowering induction of A. annua. Two genotypes of A. annua (CPQBA 239x1V and 3MxPOP) were atomized with four different artemisinin concentrations (0, 500, 5000, and 10000 mg L-1). The application of artemisinin didn't induce the flowering of both genotypes tested, in none of the used concentrations.

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The aim of this study was to evaluate the influence of different types of rhizomes utilized as seed and the effects of mulch in the culture of Turmeric. This work was conducted in the experimental cultivation area of the Universidade de Ribeirão Preto - UNAERP, in Ribeirao Preto, state of Sao Paulo, Brazil from September/1997 to July/1998. The experiments were arranged in a randomized complete block with a factorial arrangement 2x3, design with 4 replications (32 plants each). The treatments consisted of the use of types of rhizomes utilized to proliferation (head and finger) and types of mulch (absent, grass and leaves/branches). This study investigated proliferation (61, 88 and 124 days after installation), length, shooting and number of leaves of the mother plant besides the number of leaves of the shoot (112, 146 and 233 days after installation), number of finger rhizomes and head rhizomes, fresh and dry biomass of rhizomes and the yield of essential oil (after harvest - July 1998). Obtained results showed a great influence of the type of rhizome used to proliferation. Head rhizomes produced, in weight, about 30% more, when compared to plants from finger rhizomes. Mulching almost duplicated rhizome productivity from 2338 kg.ha -1 of dry rhizomes to 4499 kg.ha -1, when rhizome used to proliferation was finger and from 3046 kg.ha -1 to 5943 kg.ha -1, when using head rhizomes. The yield of essential oil did not show any alteration, independently of the treatments realized.

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This experiment was developed at Adamantina, west region of the State of São Paulo, Brazil, during May 1995 to June of 2000. The plant growth and productivity of two coffee cultivars Catuaí Amarelo IAC 47 and Obatã IAC 1669-20, were evaluated considering to plant densities of 2.500, 5.000, 7.519 and 10.000 plants ha-1. The density of 2500 also was studied with two plants in the same hole, spaced of 2,0 m in the plant line. The experimental design was the randomized completely blocks with three replications, using the split-plot system. The plots were the densities and the split-plots were the cultivars. Results showed that, with increasing of the planting density, the plant height also increased, while the stem and plant basis diameters were reduced, however the planting density did not affect the height of the first branch. The increase of the planting density also increased the field productivity and reduced the production of individual plant. The cultivation of two plants at the same hole reduced the stem diameter and the plant yield. The cultivar Catuaí Amarelo IAC 47 showed the higher plant height and the higher plant basis diameter while cv. Obatã IAC 1669-20 showed the higher stem diameter. The field productivity and individual plant productivity were not different between those cultivars in the period studied (1997-2000).

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In Brazil zinnias have good prospect for the flowering potted plant market, once consumers demand for new forms of products is stimulated by novelty. 'Persian Carpet' is a highly ornamental plant, with fast growth, minimal labor requirements and low cost seeds. The present study evaluated the effect of growth regulators on development and quality of 'Persian Carpet' grown as a potted plant. Growth regulators are commonly used to control growth and produce short and compact plants. Paclobutrazol (0.5, 0.75 and 1.0 mg a.i./pot) and chlormequat (1.0, 2.0 and 3.0 g. L-1) were applied as a single drench, and daminozide (2.5, 3.75 and 5.0 g. L-1) as a single foliar spray to runoff. Regulators were applied at apical flower bud stage. Daminozide (5.0 g. L-1), paclobutrazol (0.5, 0.75 and 1.0 mg a.i./pot) and chlormequat (1.0 g. L-1) significantly reduced plant height and side branches length compared to the control. Plant height showed a negative linear response to the increasing concentration of daminozide or paclobutrazol. Paclobutrazol (1.0 mg a.i./pot) and chlormequat (1.0 g. L-1) increased foliage and flowers harvest index. Plant spread diameter and canopy shape were improved with paclobutrazol (0.75 mg a.i./pot). Chlormequat (2.0 and 3.0 g. L-1) caused phytotoxicity symptoms, turning plants unsuitable for commercialization. Studied regulators concentrations did not affect flower diameter and production cycle. Although regulators controlled height and side branches growth significantly, plants were not short and compact enough to attend market quality.

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Aiming to describe seedlings' morphology and cotyledons and eophylls anatomy of Gomphrena elegans Mart., 100 seeds were put into plastic bags, with sand and fertilized soil (1:3), kept in the greenhouse under room conditions, with 50% shady and watered daily. Cotyledonous petiole and limb and seedlings eophylls were sectioned in median and border. They were then analyzed in transversal and paradermic sections. Seedlings initial morphology is epigeal-foliar, the root is axial, and hypocotyls and epicotyl are reddish. Venation is of pinnate type, camptodrome and brochidrodome in cotyledons and eophylls. Petiole and leaf show uniseriated epidermis with cells of varied sizes and anomocytic stomata. Druses of calcium oxalate occurred in leaves and petiole. Dorsiventral mesophyll shows one palisade parenchyma layer and several lacunary ones.

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The purpose of the present research was to evaluate the effect of plant growth regulators in biomass production and essential oil yield content in lemongrass (Cymbopogon citratus (DC.) Stapf), in different seasons. The experiment was conducted on São Manuel Experimental Farm, Faculdade de Ciências Agronômicas, UNESP - Botucatu. Which plants were randomly assigned into blocks to treatments with three repetitions. The treatments consisted of GA3 (50 and 100 mg L-1); Ethrel (100 and 200 mg L-1); CCC (500 and 1000 mg L-1); Alar 85 (1000 and 2000 mg L-1); Accel (20 and 40 mg 0L-1) and control. Four applications of plant growth regulators were realized every three months. After 40 days of each foliar spray, the plants were cut to determine the fresh weight and essential oil yield. The application of plant growth regulators did not increase the biomass production, showing difference among collect periods when the major production was detected at the fourth collect (summer). The greatest essential oil yield was found at the second collect (winter). In the present study, the used concentrations of plant growth regulators did not increase biomass neither essential oil yield.

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This study aimed to evaluate the effect of different plant growth regulators on essential oil yield in Salvia officinalis L. plants. The experiment was held in a greenhouse and the experimental design was completely randomized, with 5 treatments and three replications. The Treatments consisted in the application of gibberellic acid (GA3), benzylaminopurine (BAP), 2-chloroethyl phosphonic acid (ethephon), and Stimulate at 2%, compared with control plants (water). Applications of plant growth regulators were performed in three consecutive periods, in turn, 15, 25 and 35 days after transplanting of seeding germinating in the light at 25°C. The dry mass yield of the aerial part and the oil essential content were determined 131 days after the transplant. The aerial part of the plants was dried in an oven at 35°C; after dry mass determination, the oil was extracted by hydrodistillation and its volume was determined. Plants treated with GA 3 and Stimulate showed increase in essential oil content, while plants treated with BAP and ethephon showed decrease in essential oil volume when compared with the control plants.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The lateral shoots of the Aloe vera L. Burm have been inoculated in culture medium. The work has been divided in two phases. In the phase I different concentrations of NAA and BAP were added to the MS . In the phase II, plants proceeding of the MS were inoculated in medium containing or not spermidine and/or spermine. In the phase I the best results for mass production and shooting came out with the use of MS + 8,88 m mol L -1 BAP + 5,36 m mol L -1 NAA and these treatments didn't induce the rooting. Plants submitted to treatments with polyamines presented emission of roots during the phase II, suggesting possible inductor effect when used by isolated means during the rooting. No traces of oxidation were noted in the culture medium containing the polyamines. The use of spermidine in the culture-medium promoted a greater mass increasing and the most number of shoots was obtained with the use of the combination of polyamines. © 2008 1999, Editorial Ciencias Médicas.