FOREST LITTER DECOMPOSITION AS AFFECTED BY EUCALYPTUS STAND AGE AND TOPOGRAPHY IN SOUTH-EASTERN BRAZIL1

Forest litter decomposition is a major process in returning nutrients to soils and thus promoting wood productivity in the humid tropic. This study aimed to assess decomposition of eucalypt litter in the Rio Doce region, Brazil. Leaf litter was sampled under clonal eucalypt stands aged 2, 4 and 6 years on hillslopes and footslopes. Soil and soil+litter samples were incubated at two levels of soil moisture, temperature and fertilization. C-CO2 emissions from soil measured during 106 days were higher at 32 °C than at 23°C, mainly for the 2-yr-old stand on footslope. When leaf litter was added on soils, C-CO2 emissions were eight times higher, mainly on footslopes, with no effect of stand age. Leaf decomposition in situ, assessed with a litterbag experiment showed a mean weight loss of at least 50% during 365 days, reaching 74% for 2 yr-old stands on footslopes. In comparison with data from the native forest and the literature, no apparent restrictions were found in eucalypt litter decomposition. Differences between in vitro and in situ results, and between eucalypt and native forest, were most likely related to the response of diverse decomposer communities and to substrate quality.

Production and quality of Anacardium othonianum Rizz. seedlings grown in different substrates

This study aimed to evaluate the effect of substrate on growth, emergence, nutrition, and quality of Anacardium othonianum Rizz. (cerrado cashew tree) seedlings. The experiment was conducted in a greenhouse at the Plant Tissue Culture Laboratory on the Rio Verde campus. The following substrates were used: 1) Bioplant®, 2) Mecplant® (MP) + carbonized rice husk (CRH) (7:3), 3) fine-grained vermiculite (FGV), 4) FGV+CRH (3:1), 5) FGV+CRH (1:1), 6) FGV+CRH (1:3), and 7) sugarcane bagasse (SB) + sugarcane mill filter cake (FC) (3:2). Emerged seedlings were counted at 2-day intervals for 38 days following emergence of the first seedling. At 39, 64, and 89 days after seeding (DAS), the following variables were measured: stem length (SL), stem diameter (SD), and number of leaves (NL). Accumulated dry weight, quality indices, and leaf macro- and micronutrient levels were determined at 89 DAS. Plants grown in the FGV and FGV+CFH (1:3) substrates had shorter stem lengths than the plants grown in other substrates. Increases in seedling growth were smaller between 64 and 89 DAS compared to the initial period of the experiment. The highest leaf N concentrations were found in the SB+FC substrate treatment group; P and K concentrations were higher for the MP+CRH (7:3), SB+FC, and Bioplant® treatments; and Ca levels were higher for the SB+FC and MP+CRH (7:3) substrate treatments. The MP+CRH (7:3) substrate treatment group had the highest leaf B and Mn micronutrient concentrations, and plants from the Bioplant® substrate group had the highest leaf B micronutrient content. Mg, S, Cu, Zn, and Fe concentrations did not differ among the different substrates. The plant traits that differed most among the treatments included stem length for the FGV and FGV+CRH (1:3) substrate groups and leaf nutrient concentrations, which were higher for the SB+FC group followed by the MP+CRH and Bioplant® treatments.

Sanitary quality of broiler litter reused

ABSTRACT Considering the importance of the substrate to bedding in the poultry industry in Brazil, and the enormous pressure on environmental management as to the correct use and management of the waste generated by the production sector, this study aimed to analyze the effect of reuses of two types of litter on sanitary qualities and productive performance of broilers. The study was conducted with litter from 32 different broiler houses, two types of substrates and four cycles of reuses. The litter sanitary quality was verified by the identification of the presence of Escherichia coli and Salmonellaspp. and the incidence of footpad dermatitis. It was observed that the coffee hulls litter presented a reduction of 28.61 percentage points in the probability of occurrence of Salmonella spp when compared to the wood shavings litter, nevertheless, no statistical difference was observed on bacterial occurrence with Salmonella spp. for litter of different types or numbers of reutilization. The presence of Escherichia coli was detected in litter of all cycles, for both types of substrate. The occurrence of footpad lesions was detected for both types of litter, and was influenced by the number of reutilization cycles of the litter. The degree of incidence was detected only for the litter with coffee hull in which there was an increase of 30% between the first and second reuse from which tended to stabilize.

Aspects of energetic substrate metabolism of in vitro and in vivo bovine embryos

Although the metabolism of early bovine embryos has not been fully elucidated, several publications have addressed this important issue to improve culture conditions for cattle reproductive biotechnologies, with the ultimate goal of producing in vitro embryos similar in quality to those developing in vivo. Here, we review general aspects of bovine embryo metabolism in vitro and in vivo, and discuss the use of metabolic analysis of embryos produced in vitro to assess viability and predict a viable pregnancy after transference to the female tract.

Influence of leaf retention on cutting propagation of Lavandula dentata L.

Vegetative propagation of lavender offers several advantages over sexual propagation, among them crop homogeneity and yield of higher quality essential oil. However, Lavandula species have been propagated mostly by seeds and are said to be recalcitrant to rooting when propagated by cuttings. During cutting propagation, one of the important variables that influence the rooting capacity of cuttings is the leaf retention. The objective of this work was to evaluate the influence of leaf retention on rooting of L. dentata cuttings. Apical cuttings of L. dentata of 10 cm in length, keeping approximately 1/3, 1/2 or 2/3 of their leaves were planted in commercial substrate Plantmax HT® under intermittent mist. After two months, averages of root number, length of the longest root, root fresh and dry weights, and the survival percentage were evaluated. Root length and fresh weight were statistically greater with 2/3 of leaf retention and when fewer leaves were kept on the cuttings, lower means of root dry weight was observed. Under the conditions applied in this study, greater leaf retention was better for rooting of L. dentata cuttings.

Postharvest quality of cocona (Solanum sessiliflorum Dunal) stored under ambient condition

Cocona (Solanum sessiliflorum Dunal) is an important genetic resource that has been traditionally used for a variety of purposes, including food, medical and cosmetics applications. The objective of this study was evaluated the quality and the period of postharvest shelf life of cocona 'Mosquet", through the physical, chemical and physiological characterization of fruits stored under the ambient conditions. Physiologically mature fruits were harvested from an orchard, washed with tap water and soaked in a solution of the fungicide Prochloraz (49.5 g/100 L of water) for 5 minutes. After air drying, the fruits were packed in plastic containers and stored at 24 ± 2 ºC and relative humidity 60 ± 5% for 15 days. The fruits developed a respiratory climacteric respiratory patern and remained fit for consumption up to day 6 of storage, that is, without visual symptoms of loss of water and firmness. At this stage, the fruits showed firmness of 117,42 kPa, soluble solids of 6.62º Brix and citric acid of 1.22 %.

Influence of the N/K ratio on the production and quality of cucumber in hydroponic system

The objective of this work was to evaluate the quality of fruits and the nutritional status of cucumber CV. Aodai cultivated in nutrient solutions with different N:K ratios. The hydroponic cultivation was initially performed, during the vegetative growth, in nutrient solution with 1:2.0 mmol L-1 N:K, and, later, during fruit setting, in four different nutrient solutions with N:K (w/w) at the ratios 1:1.4, 1:1.7, 1:2.0 and 1:2.5. An additional treatment with a nutrient solution containing the ratio 1:2.2 (w/w) N:K during the vegetative growth and N:K 1:1.4 (w/w) during fruit setting, both with 10% ammonium (NH4+) was included. The treatments were arranged in a randomized design with six replicates. Irrigation was carried out with deionized water until seed germination, and then with nutrient solution until 30 days after germination, when plants were transplanted. Plants in the hydroponic growing beds were irrigated with the solutions for vegetative growth, and, after 21 days, the solutions were replaced by solutions for fruit setting. At 45 and 60 days after transplanting, the fresh weight, length, diameter, volume and firmness of the fruit were evaluated, and, at 45 days after transplanting, the macronutrient concentrations in the leaves were determined. The use of different N:K ratios during fruit setting influenced the cucumber production. The ratio of 1.0:1.7 N: K (w/w), with 10% of N in the form of ammonia, is recommended for the whole cycle.

Production of basic potato seed minitubers in substrate and different nitrogen rates

The optimal dose of nitrogen (N) in potato crop depends on the production system. The objective of this study was to determine the optimal dose of N for the production of basic potato seed minitubers and evaluate the effect of N rates on physiological and nitrogen indices in the youngest fully developed leaf (fourth leaf) and in the oldest leaf of the plants at 60 days after planting. The experiment was conducted in a greenhouse at the Departamento de Fitotecnia da Universidade Federal de Viçosa. The treatments consisted of five N rates (0, 45, 90, 180 and 360 mg dm-3), with 10% of each dose applied at planting and the remainder through irrigation water, daily, for 30 days. The nitrogen rates positively influenced the physiological indices (length, width, leaf area, number of leaves, fresh mass and dry mass) and nitrogen (level and content of N and N-NO³ in the dry mass and SPAD) both in the fourth leaf and in the oldest leaf. Likewise, the N rates positively influenced the number and mass of harvested tubers. The largest number (5.44 tubers/plant) and the maximum mass of tubers (243.5 g/plant) were obtained with 360.0 and 332.9 mg N dm-3, respectively. Therefore, the mass and number of tubers were not optimized by the same N rate. The critical SPAD index was 38.8 in the fourth leaf, which was more sensitive to the effect of N rates than the oldest leaf.

Lignification of the plant and seed quality of RR soybeans sprayed with herbicide glyphosate

Differences in levels of lignin in the plant between conventional and transgenic cultivars RR has been reported by several authors, however, there are few studies evaluating the influence of spraying of glyphosate on the lignin in the plant and RR soybean seeds. The aim of this study was to evaluate the physiological quality of RR transgenic soybean seeds and the lignin contents of plants sprayed with the herbicide glyphosate. The assays were conducted both in greenhouse and field in the municipality of Lavras, MG, in the agricultural year 2007/08. The experiment was arranged in a splitplot design with four replicates, considering the treatments hand weeding and herbicide glyphosate as plots, and five RR soybean cultivars (BRS 245 RR, BRS 247 RR, Valiosa RR, Silvânia RR and Baliza RR) as splitplots. In the greenhouse, the cultivars tested were BRS 245 RR and Valiosa RR in a randomized block design with four replicates. The sprayings were carried out at stages V3, V7 and early R5 (3L/ha). The 1000 seed weight, mechanical injury, germination and germination velocity index, emergence velocity index, accelerated aging, electrical conductivity and water soaking seed test, lignin content in the seed coat, in the stem and legumes were determined. The spraying of glyphosate herbicide, in greenhouse and field, did not alter the physiological quality of seeds and the lignin contents in the plant.

Zinc supplementation, production and quality of coffee beans

Besides its importance in the coffee tree nutrition, there is almost no information relating zinc nutrition and bean quality. This work evaluated the effect of zinc on the coffee yield and bean quality. The experiment was conducted with Coffea arabica L. in "Zona da Mata" region, Minas Gerais, Brazil. Twelve plots were established at random with 4 competitive plants each. Treatments included plants supplemented with zinc (eight plots) and control without zinc supplementation (four plots). Plants were subjected to two treatments: zinc supplementation and control. Yield, number of defective beans, beans attacked by berry borers, bean size, cup quality, beans zinc concentration, potassium leaching, electrical conductivity, color index, total tritable acidity, pH, chlorogenic acids contents and ferric-reducing antioxidant activity of beans were evaluated. Zinc positively affected quality of coffee beans, which presented lower percentage of medium and small beans, lower berry borer incidence, lower potassium leaching and electrical conductivity, higher contents of zinc and chlorogenic acids and higher antioxidant activity in comparison with control beans.

Chemical treatment of papaya seeds aiming at long-term storage and control of damping off

Damping off is a nursery disease of great economic importance in papaya and seed treatment may be an effective measure to control. The aim of this work was to evaluate the quality of papaya seeds treated with fungicides and stored under two environmental and packaging conditions. Additionally, the efficiency of fungicide treatments in the control of damping-off caused by Rhizoctonia solani was evaluated. Papaya seeds were treated with the fungicides Captan, Tolylfluanid and the mixture Tolylfluanid + Captan (all commercial wettable powder formulations). Seeds of the control group were not treated. The seeds were stored for nine months in two conditions: packed in aluminum coated paper and kept at 7 ± 1ºC and in permeable kraft paper and kept in non-controlled environment. At the beginning of the storage and every three months the seed quality (germination and vigor tests), emergence rate index, height, dry mass and damping of plants in pre and post-emergence (in contaminated substrate and mycelia-free substrate) were analyzed. Both storage conditions as well as the fungicide treatments preserved the germination and seed vigor. In the infested substrate, seedling emergence was favored by fungicides, but in post-emergence, fungicides alone did not control the damping off caused by R. solani. Symptoms of damping off were not observed in the clean substrate. The results showed that the fungicide treatments may be used to pretreat papaya seed for long-term storage and commercialization.

Growth and nutrient accumulation in mycorrhized papaya seedlings cultivated in a phosphorus-fertilized substrate

ABSTRACT The indiscriminate use of mineral fertilizers in papaya orchards has increased production costs, and the use of arbuscular mycorrhizal fungi is a promising alternative to reduce such expenses. Therefore, the present research aimed at studying the efficiency of arbuscular mycorrhizal fungi (AMF) on dry matter and nutrient accumulation in Sunrise Solo papaya seedlings, by applying doses of P2O5 (triple superphosphate) that are harmful to the symbiosis. The experiment was carried out in a protected environment and was set up in a randomized block design with four replications, and consisted of four P2O5 doses (0, 672, 1386 and 2100 mg dm-3), three mycorrhizal fungi species (Gigaspora margarita, Entrophospora colombiana and Scutellospora heterogama) and the control treatment (mycorrhiza-free). Shoot and root dry matter as well as nitrogen, phosphorus and potassium contents in leaf and root tissues were assessed. Mycorrhizal inoculation promoted a 30% increase in shoot dry matter in relation to the control treatment. Mycorrhizal fungi promoted increases in leaf and root nitrogen content up to 672 mg dm-3 P2O5. Inoculation of E. colombiana favored the highest gains in root and shoot dry matter. P2O5 fertilization increased foliar and root phosphorus content.

Student stress and quality of education

Today, managers are increasingly interested in knowing how the work in organizations aftects employees' health. Less common is the interest in stress erupting in the academic community - among students, faculty and administrators. The authors present a reflection paper focused on student stress. In this paper, they first examine McLean 's model of context, vulnerability and stressors. This model provides the framework for the student surveys and for the entire paper. Based on the students surveys, an assessment is made of how asma" group of students are coping with stress. The paper fina"y suggests what can be done by students, faculty, and administrators to insta" and/or improve social support systems that might reduce the harmful eftects of stress on students and thus impact the quality of education.