Aclimatização de mudas micropropagadas de bananeira 'Grand Naine' com aplicação de biofertilizantes em duas estações do ano

A utilização de mudas de bananeira micropropagadas de qualidade é o primeiro passo na implantação de um bom pomar e, para isso, sua aclimatização deve ser realizada de forma adequada. em vista disso, objetivou-se, neste trabalho, avaliar o desempenho dos biofertilizantes HUMITEC® e RUTER AA® no desenvolvimento de mudas de bananeira micropropagadas, sendo instalado um experimento em viveiro comercial de produção de mudas. Foram utilizadas mudas de bananeira cv. Grand Naine, obtidas por micropropagação, sendo, posteriormente, transplantadas em sacos de polietileno preto (1,5 L), contendo, como substrato, terra de subsolo (Latossolo Amarelo), casca de arroz carbonizada e composto orgânico Organifol® (1:1:1). O delineamento experimental foi em blocos ao acaso, fatorial 2 x 4 (produtos e doses), com quatro repetições e quatro plantas úteis por parcela. Os tratamentos foram compostos pelos seguintes biofertilizantes e doses: HUMITEC® (0,0; 4,0; 8,0; 16,0 mL planta-1) e RUTER AA® (0,0; 2,0; 4,0; 8,0 mL planta-1). As doses dos produtos foram divididas em duas aplicações (28 e 56 dias após o transplantio das mudas), aplicadas via fertirrigação. Noventa e oito dias após o transplantio avaliaram-se as seguintes variáveis: altura das plantas (cm), diâmetro do colo rente superfície do solo (mm), área foliar total e por folha, biomassas fresca e seca da parte aérea e das raízes (g). Os dados foram submetidos análise da variância e quando o teste F foi significativo, realizou-se análise de regressão. Pode-se concluir que aplicações de HUMITEC® e RUTER AA® favoreceram o desenvolvimento das mudas e que, no verão, as plantas apresentaram maior desenvolvimento durante a aclimatização.

Efeito de substratos na aclimatização de mudas micropropagadas de abacaxizeiro cv. Pérola

Objetivou-se com este trabalho verificar o efeito da matéria orgânica como componente de substratos para mudas micropropagadas de abacaxizeiro cv. Pérola em fase de aclimatização. Mudas micropropagadas de abacaxizeiro cv. Pérola, selecionadas de acordo com o peso (aproximadamente 2 g), foram plantadas em bandejas de isopor de 72 células de 120 cm³ contendo proporções de substratos com terra, esterco bovino, Plantmax e matéria orgânica. O delineamento estatístico utilizado foi o inteiramente casualizado com 4 repetições e 3 plantas por parcela. As avaliações foram feitas 90 dias após o plantio, quando se avaliou: altura da planta, comprimento de raiz, peso de matéria fresca de raiz e parte aérea, peso de matéria seca de raiz e parte aérea e número de folhas. Com os resultados obtidos, conclui-se que a matéria orgânica tem efeito significativo no desenvolvimento das mudas. Com o substrato contendo terra, esterco e Plantmax foi obtido o melhor desenvolvimento das raízes e parte aérea.

Desenvolvimento de mudas de bromélia (Neoregelia cruenta (R. Graham) L. B. Smith) cultivadas em diferentes substartos e adubação foliar

As bromélias apresentam formas exóticas com uma grande diversidade de cores e de flores, constituindo importantes espécies para uso em paisagismo e floricultura. em conseqüência disto, são muito comercializadas. Porém, parte das plantas que se encontram no mercado, ainda são provenientes do extrativismo. Esta situação é também reflexo do pequeno número de informações sobre técnicas de propagação e cultivo. Uma das limitações é o desconhecimento do tipo de substrato e adubação adequados ao cultivo destas espécies. Assim, o objetivo deste trabalho foi avaliar o crescimento de bromélias do Neoregelia cruenta, cultivadas em diferentes substratos e adubações foliares através da altura, do número de folhas, da matéria fresca e seca, da parte aérea e das raízes. As mudas utilizadas foram provenientes de cultura de tecidos. Após um período de pré-aclimatização, foram transplantadas para estufa sem nebulização. Os substratos foram constituídos da mistura de diferentes proporções de solo, areia, casca de arroz carbonizada e por um substrato comercial à base de vermiculita. Aos substratos foi aplicada adubação foliar, combinando uréia e sacarose, em intervalos de quinze dias. Os resultados obtidos mostraram que as interações entre os substratos, dose de sacarose e de uréia, não afetaram a altura das mudas e o número de folhas. O uso de sacarose também não influenciou o desenvolvimento das mudas. O substrato comercial à base de vermiculita, independente da aplicação de adubação foliar, proporcionou maior altura das mudas e número de folhas. A aplicação de uréia apresentou efeito linear crescente durante o período avaliado.

Influência do substrato e do tipo de fertilizante na aclimatação de mudas de bananeira 'Prata-Anã'

Objetivando-se avaliar a influência do substrato e tipo de fertilizante na aclimatação de mudas de bananeira 'Prata-Anã', provenientes de micropropagação, foi instalado um experimento em blocos casualizados, no esquema fatorial 5 x 3, com quatro repetições. Os substratos utilizados foram: S1 - Terra de subsolo + casca de arroz carbonizada + substrato comercial Rendimax Floreira®; S2 - Terra de subsolo + casca de arroz carbonizada + composto orgânico Organifol®; S3 - Terra de subsolo + casca de arroz carbonizada + composto orgânico Organifol® 9% SiO; S4 - substrato comercial Technes Vivatto®; S5 - Areia grossa + casca de arroz carbonizada + Rendimax Floreira®, todos na proporção 1:1:1 (v/v/v). Os fertilizantes utilizados foram: SF - sem fertilizante; FLL - fertilizante de liberação lenta, 14-14-14 (5,0 kg m-3) misturado ao substrato; e FLN - fertilizante de liberação normal, 14-14-14 (5,0 kg m-3) aplicado em cobertura, 30 dias após o plantio. As mudas foram plantadas em sacos de polietileno quando apresentavam quatro a cinco folhas, sendo mantidas em viveiro com 50% de sombreamento. Foram feitas medidas de altura, diâmetro do colo e número de folhas, e determinada a massa seca das mudas. As diferenças químicas das misturas utilizadas como substrato, juntamente com o tipo de fertilizante utilizado, proporcionaram crescimento diferenciado das mudas. O substrato S4 pode ser utilizado sem fertilização. Os substratos S2 e S3 devem ser utilizados com fertilizante de liberação normal ou lenta de nutrientes, e S1 e S5, sendo pobres em nutrientes, com fertilizante de liberação lenta.

Effect of thermal stress on physiological parameters, feed intake and plasma thyroid hormones concentration in Alentejana, Mertolenga, Frisian and Limousine cattle breeds

The aim of the present study was to assess the heat tolerance of animals of two Portuguese (Alentejana and Mertolenga) and two exotic (Frisian and Limousine) cattle breeds, through the monitoring of physiological acclimatization reactions in different thermal situations characterized by alternate periods of thermoneutrality and heat stress simulated in climatic chambers. In the experiment, six heifers of the Alentejana, Frisian and Mertolenga breeds and four heifers of the Limousine breed were used. The increase in chamber temperatures had different consequences on the animals of each breed. When submitted to heat stress, the Frisian animals developed high thermal polypnea (more than 105 breath movements per minute), which did not prevent an increase in the rectal temperature (from 38.7 degrees C to 40.0 degrees C). However, only a slight depression in food intake and in blood thyroid hormone concentrations was observed under thermal stressful conditions. Under the thermal stressful conditions, Limousine animals decreased food intake by 11.4% and blood triiodothyronine (T3) hormone concentration decreased to 76% of the level observed in thermoneutral conditions. Alentejana animals had similar reactions. The Mertolenga cattle exhibited the highest capacity for maintaining homeothermy: under heat stressful conditions, the mean thermal polypnea increased twofold, but mean rectal temperature did not increase. Mean food intake decreased by only 2% and mean T3 blood concentration was lowered to 85,6% of the concentration observed under thermoneutral conditions. These results lead to the conclusion that the Frisian animals had more difficulty in tolerating high temperatures, the Limousine and Alentejana ones had an intermediate difficulty, and the Mertolenga animals were by far the most heat tolerant.

Crescimento de mudas micropropagadas da bananeira cv. Nanicão, em diferentes substratos e fontes de fertilizante

With the objective of evaluating the effect of different substrates combined with fertilizers in the growth of micropropagated seedlings of Cavendish banana (Musa spp. AAA), ail experiment was conducted in a randomized block design, in a 5 x 3 factorial scheme, with four repetitions. The substrates used were: S1 - subsoil land + carbonized rice hull + Rendmax Floreira (R); S2 - subsoil land + carbonized rice hull + Organifol (R); S3 - subsoil land + carbonized rice hull + Organifol (R) 9% SiO; S4 - Technes Vivatto (R); S5 - thick sand + carbonized rice hull + Rendmax Floreira (R). The fertilizer sources were: SA - without fertilizer; LL - slow-release fertilizer - Osmocote (R) 3M 14-14-14 (5.0 kg m(-3)) inixed in the substrate; and LN - normal-release fertilizer, 14-14-14 (7.5 g seedling(-1)) applied in covering. The height, collar diameter, leaf number, leaf area and dry matter were determined. Based on the differences of growth, substrates S 1, S2, S3 and S4 can be used with fertilizer 14-14-14, with slow (5.0 kg m(-3)) or normal (7.5 g seedling(-1)) release of nutrients.

Effect of ambient temperature and thyroid hormones on food intake by pigs

Food intake and plasma thyroid hormone levels (T4 and T3) were higher in pigs acclimated to cold (12°) than hot (32°) environments. The exposure of cold pigs to hot ambient temperature decreased food intake and plasma T4 and T3, whereas for hot acclimated animals the change in ambient temperature (from 32 to 12° C) increased food intake and plasma thyroid hormone levels, but the new steady state level of food intake was reached only after 96 hr of temperature transfer despite the rapid change in plasma levels of thyroid hormones. Cold-acclimated pigs, when transferred to a hot environment after thyroidectomy, also reduced food intake, but hot pigs shifted to cold ambient temperature after thyroidectomy did not significantly increase food ingestion. The results of this experiment suggest that food intake adjustment depends on the previous living temperature and that thyroid hormones seem to play an important role in increasing the metabolically active mass that probably sustains the new steady state level of food intake, particularly in a cold environment.

Effects of acute cold exposure on rectal temperature, blood glucose and plasma free fatty acids in alloxan-diabetic rats

These experiments were carried out to study the effects of acute cold exposure (0-2°C/4 hr) on rectal temperature, blood glucose and plasma free fatty acids (FFA) in alloxan-diabetic rats. Male Wistar rats weighing 170-190 g were used and diabetes was induced by i.v. alloxan injection (40 mg/kg body wt). Cold exposure produced severe hypothermia in diabetic rats. After 4 hr of cold, blood glucose of diabetic rats was reduced from 296±16 to 86t±12 mg/dl (P<0.01), and FFA increased slightly, but was not statistically different (P>0.05) from the initial value. As expected, interscapular brown adipose tissue (IBAT) and retroperitoneal and epididymal white adipose tissues were significantly lower in diabetic than in control rats. Cold exposure reduced total IBAT lipids in control but not in diabetic animals. The results of this experiment suggest that diabetic rats were unable to maintain body temperature in the cold, probably because of a failure to generate an adequate amount of heat by nonshivering thermogenesis in brown adipose tissue.

Cold-acclimation improves cold-tolerance of diabetic rats

1. 1. The aim of these experiments was to study the extent to which previous cold-acclimation improves the cold-tolerance of diabetic rats. 2. 2. Alloxan diabetic rats (fasting blood glucose higher than 200mg/dl) were used in the experiments. 3. 3. In Expt. 1, non-cold-acclimated control and diabetic rats were exposed to cold environment (7-9°C), and the percentage of survival calculated during a 12-day experimental period. In Expt. 2, the rats were previously cold-acelimated before alloxan or saline injection (diabetic and control cold-acclimated rats) and the survival rate was also assessed during a 12-day period in the cold. 4. 4. The percentage of survival of the non-cold-acclimated diabetic rats (Expt.l) was 19% compared with 79% of the diabetic cold-acclimated animals (Expt. 2). There were no deaths in the control groups. 5. 5. Cold-acclimated diabetic rats maintained a near-normal thermogenic response after noradrenaline injection. This response was impaired in non-cold-acclimated diabetic rats. 6. 6. The results of these experiments suggest that the enhanced cold-tolerance of diabetic cold-acclimated rats could be related to the increased sympathetic activity and enhanced insulin sensitivity in thermogenic tissues, such as brown fat. © 1987.

Electromyographic validation of the pectoralis major and deltoideus anterior muscles in inverted fyling exercises with loads

Inverted flying exercise with external loads of 25, 50, 75 and 100% of each individual maximum load in the pectoralis major and deltoideus anterior muscles was electromyographically analyzed in eleven male volunteers, using surface electrodes MEDI-TRACE-200 connected to a biological signals acquisition module coupled to a PC/AT computer. Electromyographic signals were processed and the effective values obtained were standardized through maximum voluntary isometric contraction. When the concentric phase of each muscle with the same load was statistically compared with the eccentric phase, it was observed that for all loads all the muscles presented significant electromyographic difference, and that the concentric phase was always higher. By analyzing the different loads for each muscle, it was noticed that in the concentric phase all the muscles presented significant electromyographic activity, being it higher with maximum load. When the effect of each load on different muscle in the concentric and eccentric phases was analyzed, the muscles presented a distinct activity profile.

Ventilatory frequency of Nile tilapia subjected to different stressors

Ventilatory frequency (VF) was investigated in the fish Nile tilapia, Oreochromis niloticus, subjected to confinement, electroshock or social stressor. Fish were allowed to acclimatize to tank conditions for 10 days (1 fish/aquarium). VF baseline was determined 5 days after adjustment had been started. At the 10th day of isolation, stressor effects on VF were assessed. The stressors were imposed during 60 min: pairing with a larger resident animal (social stressor), or gentle electroshock (AC, 20 V, 15 mA, 100 Hz for 1 min every 4 min), or space restriction (confinement). VF was quantified immediately after the end of the stressor imposition. Baseline of VF was not statistically different among groups. Social stressor clearly induced VF to increase, while an increased or decreased VF can be observed for both confinement and electroshock. However, fish tend to increase their VF in response to confinement and decrease in the case of electroshock. These results suggest that VF is a sensitive behavioural indicator for distinguishing stress responses in the fish Nile tilapia among different stressors. © 2006 Elsevier GmbH. All rights reserved.

Enraizamento in vitro e aclimatização de mudas micropropagadas de Aloe vera L.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Crescimento inicial do eucalipto em função da aclimatação em viveiro

This study aimed to evaluate the acclimatization effects in the Eucalyptus grandis vs. Eucalyptus urophylla seedlings nursery in their initial growth in two soils types, clay and sandy. The seedlings were planted in Plantmax substrate and in rice hulls plus vermiculite, and managed, after 60 days of the mass propagation (DAE), during the rustication. There were five different frequencies of subsurface drip irrigation, restoring the soil field capacity condition: F1, F2, F3 and F4, which were irrigated once, twice, three and four times a day, respectively, and FD, kept in continue irrigation until planting at 90 DAE. In a randomized block design with four replications, plant height (HPA) were evaluated at 6 and 13 months after planting and the diameter at breast height (DAP) at 13 months after planting. Findings show that water management at hardening phase seedlings had no influence on growth in both soils.

Seleção de agentes alternativos ao ágar para propagação de plântulas de Cattleya loddigesii Lindley (Orchidaceae)

The aim of this study was to evaluate the in vitro growth of Cattleya loddigesii in alternative agents to agar with starch and physical matrix with acclimatization of regenerated plants. Protocorms with 90 days after sowing (0.5 cm of length) were subcultured in 1/2 MS culture medium among the treatments consisting of: agar 7 g L-1 (T1, which corresponds the control), agar 3,5 g L-1 with cassava starch 30 g L-1 (T2), cassava starch 60 g L-1 (T3), cotton fiber (T4) and chopped polyurethane foam (T5). Plantlets were retained in these treatments for over 150 days, and at the end of in vitro culture, were analyzed by their biometric data and acclimatized in a greenhouse during 120 days and evaluated the survival and relative growth rate (RGR). The substrate comprising of chopped polyurethane foam (T5) showed greater efficiency for growth in vitro and also increased survival rate, while substrate cassava starch (T3) provided delay for plantlet growth. Therefore, chopped polyurethane foam is recommended because of low cost and suitable characteristics for the propagation of Cattleya loddigesii.

Blood Cues Induce Antipredator Behavior in Nile Tilapia Conspecifics

In this study, we show that the fish Nile tilapia displays an antipredator response to chemical cues present in the blood of conspecifics. This is the first report of alarm response induced by blood-borne chemical cues in fish. There is a body of evidence showing that chemical cues from epidermal 'club' cells elicit an alarm reaction in fish. However, the chemical cues of these 'club' cells are restricted to certain species of fish. Thus, as a parsimonious explanation, we assume that an alarm response to blood cues is a generalized response among animals because it occurs in mammals, birds and protostomian animals. Moreover, our results suggest that researchers must use caution when studying chemically induced alarm reactions because it is difficult to separate club cell cues from traces of blood. © 2013 Barreto et al.