Estresse hídrico induzido por manitol em cultivares de algodão

The main goat of this work was to evaluate the effects induced by mannitol- water stress in the initial growing of cotton plants. The experiment was conducted as a completely randomized design, in factorial design 4 x 5, with 3 replications. Treatments were generated by the combination of four cotton cultivars (LD CV Frego; LD CV 02; FMT 701 and IAC 25) and five levels of water stress (0; -0.3; -0.6, -0.9 and -1.2MPa), obtained with mannitol solutions. Water potentials of -0.9 MPa reduced significantly the rate of cotton plants growth. The decrease of the water potential reduced the production of dry mass of the aerial part of all cultivars and increased the production of root dry mass on -0.6MPa potential. LD CV 02 cultivar exhibited a superior performance under water stress.

Efeito dos reguladores de crescimento vegetal nas características agronômicas do algodoeiro e no controle de insetos

The experiment was carried out in 1993/94, in Jaboticabal, São Paulo State, Brazil, to verify the efficiency of plant growth regulators on agronomic characteristics of cotton and as pest control technique. The experimental design was a complete randomized block with four replications and seven treatments: 1) control; 2) ethephon + cyclanilide (720 + 90 g/ha a.i.); 3) ethephon + cyclanilide (960 + 120 g/ha a.i.); 4) ethephon + cyclanilide (1200 + 150 g/ha a.i.); 5) ethephon (960 g/ha a.i.); 6) ethephon (1200 g/ha a.i.) and 7) cyclanilide 150 g/ha a.i.). Results suggest that plant growth regulators can reduce harvest time in 15 days, contributing significantly to decreased late-season squares and immature bolls that serve as feeding and oviposition sites to boll weevils and pink bollworm.

Efeito de aldicarb em populações de pulgão em artrópodes benéficos e na fisiologia do algodoeiro

In order to study the efficiency of aldicarb against aphids, beneficial arthropods, and on cotton physiology, a trial was made at Jaboticabal, SP, Brazil, in 1992/93. The experimental design was a complete randomized block with seven replications and three treatments: 1) aldicarb 750 g of a.i./ha; 2) aldicarb 1050 g of a.i./ha; and 3) control. The results showed that aldicarb was effective in the control of aphids. Aldicarb applied in the furrow significantly increased boll number per plant, yield, and precociousness. The beneficial arthropods were not affected.

Utilização do cloreto de clorocolina no controle do bicudo-do-algodoeiro

The objective of the present work was to evaluate the effect of the growth regulator chlorocholine chloride (CCC) in the control of the boll weevil (Anthonomus grandis Boheman) on cotton ( Gossypium hirsutum L. ). The experiment was conducted at the Experimental Farm of the Faculdade de Ciências Agrárias e Veterinárias (UNESP), Jaboticabal Campus, State of São Paulo, Brazil, during the 1988/1989 growing season. The experimental design used was the latin square. The chlorocholine chloride was sprayed on the cv IAC-19 cotton plants 70 days after emergence in the doses of 0, 25, 50, and 100 g/ha in a single application as well as 25 g/ha + 25 g/ha in two applications. The second application was 15 days after the first. There was no significant differences on cotton yield. Although the split application as well as the single application of 25 g/ha increased yield in 11.6% and 11.5%, respectively.These same treatments also increased earliness. After the last hand harvest the number of immature cotton bolls left in the field was 64.5% lower in the plots treated with chlorocholine chloride. Despite the higher earliness and the reduction of the number of immature cotton bolls, the chlorocholine chloride treatments were not sufficient to induce an effective aid in the boll weevil control but indicates a possibility of using growth regulators in the cotton crop as an auxilary strategy in integrate pest management programs.

Biologia de Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae) em algodoeiro

Leaf discs obtained from the first or second non-cotyledonal leaf of cotton (Gossypium hirsutum L.) seedlings were used for the study of the biology of Polyphagotarsonemus latus on cotton IAC-20 cultivar. Seedlings were grown in pots and placed on a layer of cotton moistened with distilled water. The assays were carried out at 28.5 ± 0.3°C, relative humidity of 71.0 ± 2.6% and a 14 h photophase. The duration of immature phases was 4.1 ± 0.1 days for females and 4.1 ± 0.3 days for males, with a survival of 91.2%. After a pre-oviposition period of 1.1 ± 0.2 days, the females deposited 4.5 ± 0.9 eggs per day during 6.8 ± 1.3 days, i.e., 29.6 ± 7.3 eggs per female. The longevity was 10.0 ± 1.5 days for females and 8.8 ± 1.1 days for males. The intrinsic rate of increase (rm) was 0.323; finite rate of increase (λ) 1.38 individual per female per day; mean generation time (T) 9.54 days and net reproductive rate (Ro) 21.73.

The significance of root growth on cotton nutrition in an acidic low-P soil

Toxic levels of Al and low availability of Ca have been shown to decrease root growth, which can also be affected by P availability. In the current experiment, initial plant growth and nutrition of cotton (Gossypium hirsutum var. Latifolia) were studied as related to its root growth in response to phosphorus and lime application. The experiment was conducted in Botucatu, Sao Paulo, Brazil, in pots containing a Dark Red Latosol (Acrortox, 20% clay, 72% sand). Lime was applied at 0.56, 1.12 and 1.68 g kg -1 and phosphorus was applied at 50, 100 and 150 mg kg -1. Two cotton (cv. IAC 22) plants were grown per pot for up to 42 days after plant emergence. There was no effect of liming on shoot dry weight, root dry matter yield, root surface and length, but root diameter was decreased with the increase in soil Ca. Shoot dry weight, as well as root length, surface and dry weight were increased with soil P levels up to 83 mg kg -1. Phosphorus concentration in the shoots was increased from 1.6 to 3.0 g kg -1 when soil P was increased from 14 to 34 mg kg -1. No further increases in P concentration were observed with higher P rates. The shoot/root ratio was also increased with P application as well as the amount of nutrients absorbed per unit of root surface. In low soil P soils the transport of the nutrient to the cotton root surface limits P uptake. In this case an increase in root growth rate due to P fertilisation does not compensate for the low P diffusion in the soil.

Tipos de resistência a Alabama Argillacea (Huebner, 1818) (Lepidoptera: Noctuidae) envolvidos em genótipos de algodoeiro: II. Antibiose

Cotton genotypes resistance to Alabama argillacea (Huebner, 1818) due to antibiosis has been evaluated in laboratory trials (at 27 ± 2°C, 70 ± 10% relative humidity and 14 hours photoperiod). Six different genetic materials (T 1122-13-1, STO 285 N, JPM 157, T 953-13-4-2, CNPA 9211-21, and CNPA 9211-31) have been tested in a completely randomized experimental design, with ten replications, each one with ten larvae/genotype. Larvae have been supplied with leaves daily. The following variables have been scored: time length of several insect stages (from larvae to adult), average mass of larvae and pupae as well as average larval, pre-pupal and pupal mortality rates. All genotypes have revealed longer overall average time length of stage duration from larvae to adult, as compared to STO 285 N; however, CNPA 9211-31 and CNPA 9211-21 have shown the smallest average mass of pupae along with high frequencies of pre-pupae and larvae to adult mortalities. The results strongly suggest that antibiosis is one of the resistance mechanisms to A. argillacea in that two cotton genotypes.

Cotton growth and boron distribution in the plant as affected by a temporary deficiency of boron

The knowledge of nutrient mobility is an important tool to define the best fertilizer management and diagnosis techniques. Patterns of boron (B) mobility in plants have been reviewed, but there is very little information on B distribution and mobility in cotton. An experiment was conducted to study plant growth and B distribution in cotton when the nutrient was applied in the nutrient solution or to the leaves, and when a temporary deficiency was imposed. Cotton (Gossypium hirsutum, Latifolia, cv. IAC 22) was grown in nutrient solutions where B was omitted or not for 15 days. Boron was applied to young or mature cotton leaves in some of the minus B treatments. Root growth decreased when the plants were transferred to B solutions, but there was a full recovery when B was replaced in the nutrient medium. Boron deficiency, even when temporary, reduced cotton shoot dry matter yields, plant height and flower and fruit set, and these could not be prevented by foliar application of B. Because of decreased dry matter production, leaves of deficient cotton plants actually showed higher B concentrations than non deficient leaves. This would be misleading when a mature leaf is sampled for diagnosis. If there is any B mobility in cotton phloem, it is very low.

Uso da adubação foliar nitrogenada e potássica no algodoeiro

The present work was conducted in Selvíria county (MS-Brazil), in the agricultural year of 1998/99, for evaluating nitrogen and potassium foliar application to supplement sowing fertilization on cotton (IAC 22) crop. A randomized complete block design with 13 treatments and four replications was used. The treatments were constituted by a control (without foliar application) and nitrogen and/or potassium foliar applications two, four, six or eight weeks after beginning of flowering. The urea was used as source of N and potassium chloride as source of K. Urea in the concentration of 10% and potassium chloride at 4% were applied at a rate of 250 L.ha-1. Height of plants, nodule number, number of reproductive branches, boll per plant, 30 boll mass, yield and fiber percentage were evaluated. It is concluded that the N doses increased the yield and decreased the fiber percentage. There was no evaluated response to the application of K or NK.

Comparação de sistemas de avaliação de dietas para bovinos no modelo de produção intensiva de carne. Confinamento de tourinhos jovens

Thirty 3/4 Canchim + 1/4 Nelore young bulls with 417 kg of body weight and 15 months of age, were confined during 84 days. The animals were fed with diets composed with corn silage, corn grain, cottonseed meal, soybean meal, whole soybean and mineral mix, adjusted in agreement with the recommendations of the Metabolizable Protein System (MP), Cornell Net Carbohydrate and Protein System (CNCPS) and Intestine Digestible Protein System (PDI), for predicted body weight gain of 1.3 kg/head/day. The daily body weight gain did not differ among treatments CNCPS, MP and PDI, with 1.51; 1.48; and 1.13 kg/head, respectively. The economic analysis revealed net profit of R$116.25; R$148.30; and R$108.51/head for CNCPS, MP and PDI systems, respectively. The diets adjusted by CNCPS and MP systems provided superior animal performance than that expected, while the diet adjusted by PDI system did not allow the predicted body weight gain.

Comportamento do cafeeiro apoatã em consórcio com culturas anuais

This study was conducted in Adamantina, region of Alta Paulista, São Paulo State, Brazil, from 1989 to 1993. Yield of Apoatã coffee (Coffea canephora Pierre ex Froehner) was evaluated during four years of intercropping with five plant species: IAC 20 - cotton (Gossypium hirsutum L.); cv. Tatu - peanut (Arachis hypogaea L.); IAC 165 - rice (Oryza sativa L.); cv. Guarani - castor bean (Ricinus communis L.) and IAC 100-B - corn (Zea mays L.). The crops were seeded 50 cm apart from coffee canopy. The treatments were arranged in randomized complete block design with five replications. Yield was significantly decreased when coffee was intercropped with castor bean, corn, cotton and peanut, but height and diameter of orthotropic branches were not affected. Linear correlation analysis showed that coffee yield was inversely correlated with the dry biomass of the intercrops.

Métodos de coleta de fezes e determinação dos coeficientes de digestibilidade da fração protéica e da energia de alimentos para o pacu, Piaractus mesopotamicus (Holmberg, 1887)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fatores que afetam a oviposição de Bemisia tabaci (Genn.) biótipo B (Hemiptera: Aleyrodidae) na cultura algodoeira

The objective of this work was to evaluate the oviposition behavior of the whitefly Bemisia tabaci (Genn.) biotype B in relation to leaf position, plant age, and adult density on cotton plants. The genotype IAC 22 was used to do the tests. In free-choice tests, 20, 30 and 40 day-old plants were used to evaluate age efects and 40 day-old plants to study egg distribution in the plant and on the leaf surface. In a no-choice test, 20 day-old plants were used to evaluate densities of 50, 100 and 150 adults per plant. The lobe areas on the leaf surface and apical leaves were preferred for whitefly egg laying and therefore more suitable for egg sampling in cotton plants. The 20 day-old plants were preferred for oviposition, and the densities of 100 and 150 adults per plant ensured the number of eggs enough to discriminate cotton genotypes with different whitefly resistance degrees.

Efeito da calagem e sulfato de amônio no algodão. I - Transporte de cátions e ânions no solo

Applying lime on the soil surface in soils managed under no-tillage has caused an excess of basic cations in the most superficial layers of the soil profile. On the other hand, subsoil acidity is considered a constraint to the development of deep plant roots. The objective of this study was to evaluate Ca 2+, Mg 2+, NO 3- and SO 4 2- leaching in the soil profile as affected by liming and top dressing nitrogen fertilization in cotton, grown with straw cover on the soil surface. Cotton plants (Gossypium hirsutum) were grown for 60 days in PVC columns filled with a Distroferric Red Latosol (sand loam Rhodic Oxisol) with liming applied over the straw on the soil surface, incorporated liming 0-20 cm deep, or without liming. Nitrogen was applied at rates of 0, 50, 100 and 150 kg ha -1 as ammonium sulfate. The PVC columns were set up in layers of 0-5, 5-10, 10-20, 20-30 and 30-30 cm, totaling 15.71 dm 3. The ammonium sulfate application caused intense leaching of SO 4 2- in the soil, irrespective of the lime application method. Liming increased the concentration of NO 3 in the 0-20 cm soil layer, whereas the correction of the soil acidity did not affect the NO 3- concentration in the 30-50 cm soil layer. The influence of ammonium sulfate on Ca 2+ leaching below 20 cm was only observed in the soil with incorporated lime. Nitrogen application resulted in extensive Mg 2+ leaching from the soil, regardless of the lime application method. In the soil layer below 30 cm, SO 4 2- presented a higher correlation than NO 3- in the formation of ionic pairs with Ca 2+ and Mg 2+.

Central nifedipine-induced alterations in salivary flow and compounds: Role of nitric oxide

The aim of this study was to examine the role of nifedipine and Nitric Oxide (NO) on salivary flow and compounds (salivary amylase, saliva total proteins, saliva calcium, sodium and potassium). Male Holtzman rats weighting 200-250 g were anesthetized with zoletil 50 mg kg -1 (tiletamine chloridrate 125.0 mg and zolazepan chloridrate 125.0 mg) into quadriceps muscle and stainless steel cannulas were implanted into their lateral ventricle of the brain (LV). Animals in divided group were injected with nifedipine (50 μg μL -1) alone and in combination with 7-nitroindazol (7-NIT) (40 μg μL -1), neuronal NO Sinthase Inhibitor (nNOSI) and Sodium Nitroprussate (SNP) (30 μg μL -1) NO donor agent. As a secretory stimuli, pilocarpine dissolved in isotonic was administered intraperitoneally (ip) at a dosage of 10 mg kg -1 body weight. Saliva was collected for 7 min with four cotton balls weighing approximately 20 mg each, two of which were placed on either side of the oral cavity, with the other two placed under the tongue. Nifedipine treatment induced a reduction in saliva secretion rate and concentration of amylase, total protein and calcium without changes in sodium and potassium concentration in comparison with controls. Co-treatment of animals with nifedipine and SNP retained flow rate and concentration of amylase, total protein and calcium in normal levels. Co-treatment of animals with nifedipine and 7-NIT potentiated the effect of nifedipine on the reduction of saliva secretion and concentrations of amylase, total protein and calcium. Nifedipine (dihydroperidine) calcium-channel blocker widely in use is associated with salivary dysfunction acting in the central nervous system structures. NO might be the mechanism for protective effect against the nifedipine-induce salivary dysfunction, acting in the CNS. © 2006 Asian Network for Scientific Information.