Effects of processing on physical characteristics of diets with distinct levels of carbohydrates and lipids: the outcomes on the growth of pacu (Piaractus mesopotamicus)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of soil water deficit and nitrogen nutrition on water relations and photosynthesis of pot-grown Coffea canephora Pierre

Coffea canephora plants (clone INCAPER-99) were submitted to low N (LN) or high N (HN) applications and two watering regimes (daily irrigation and irrigation every 5 days for a month). Although water potential was not altered significantly by N, HN plants showed higher relative water content than did LN plants under water deficit. Only HN plants exhibited some ability for osmotic adjustment. Plants from both N treatments increased their cell wall rigidity under drought, with a more pronounced augmentation in HN plants. In well-watered plants, carbon assimilation rate increased with increasing N while stomatal conductance did not respond to N supply. Under drought conditions, carbon assimilation decreased by 68-80% compared to well-watered plants, whereas stomatal conductance and transpiration rate declined by 35% irrespective of the N applications. Stable carbon isotope analysis, combined with leaf gas exchange measurements, indicated that regardless of the watering treatments, N increased the long-term water use efficiency through changes in carbon assimilation with little or no effect on stomatal behaviour.

Drought tolerance of two field-grown clones of Coffea canephora

We compared tolerance to soil drought of two field-grown clones of Coffea canephora (clone 46, drought-sensitive; and clone 120, drought-tolerant). Under irrigation, there were no marked differences between the clones in water relation parameters, gas exchange and total leaf area. Under rainfed conditions, clone 46 showed osmotic adjustment and increased tissue rigidity. These adjustments, however, were incapable of preventing substantial decreases in xylem pressure potential. By contrast, clone 120 did not exhibit osmotic adjustment, but was able to increase tissue elasticity and to maintain xylem pressure potentials to a greater extent than clone 46 (despite having twice the total leaf area of this clone). Stomatal conductance was lowered by drought in clone 120 but not in clone 46. Carbon assimilation per unit leaf area in both clones remained unaffected under stress. Long-term water use efficiency (WUE), as estimated through carbon isotope discrimination, was consistently greater in clone 120 than in clone 46. Because of these traits, clone 120 was better able to postpone dehydration and to maintain whole-tree photosynthesis. It is proposed that these features should decisively contribute to buffer its productivity in drought-prone areas. © 2002 Elsevier Science Ireland Ltd. All rights reserved.

Produção de variedades de alface sob diferentes potenciais de água no solo em ambiente protegido

The knowledge of meteorological elements in protected environment is very important for commercial plants, because of possibility to produce for all the year according to the study conduced in Botucatu - SP, in order to evaluate the effects of different irrigation treatments on three lettuce cultivars. (Lisa, Crespa and American). The study was developed in a polyethilene tunnel with orientation northeast/southwest (NE/SW) and the fertigation through drip irrigation. Leaf number, head diameter, fresh weigh, dry weigh, meteorological elements and evaporation from minievaporimeters were determined. Four treatments of minimum soil water potential were applied: 20, 28, 35 and 45 kPa and the results showed the treatment -35 kPa showed the highest lettuce production and maximurn water efficiency use. The highest productions occurred in May/June, July/September and September/November, while the worst one was in February/April. There was not significant difference of dry mass production among the treatments, independently of the year period with exception of the Crespa cultivar which was superior in September/November. The south face showed the highest evaporation.

Efeitos de níveis de cobertura do solo sobre a produtividade e crescimento do feijoeiro irrigado, em sistema de plantio direto

The objective of this research was to study the effects of five different treatments of grass (Brachiaria decumbens) straw mulch on common beans (Phaseolus vulgaris L.): 0% (0 t.ha-1), 25% (2,25 t.ha-1), 50% (4,5 t.ha-1), 75% (6,75 t. ha-1) and 100% (9,0 t/ha) designed by randomized blocks, with four replicates. The irrigation was applied when minimum soil water potential were reached about - 30kPa. The water management based on tensiometers and soil water characteristic curve. A microsprinkler irrigation system was used. The experiment was set up at the Experimental Station of Embrapa Rice and Bean (Empresa Brasileira de Pesquisa Agropecuária Arroz e Feijão) at Santo Antonio de Goiás, Brazil, in a Dark - Red Latosol soil. The results showed: the bean yield and his components were not affected by treatments, except grain number/pod,. The mulch increased the water use efficiency and, consequently, decreased the number of irrigations when the mulch reached more than 50% straw mulch. The treatment with 100% of mulching presented the largest leaf area index and dry matter accumulation was not affected by mulching.

Eficiência de uso de boro no crescimento de clones de eucalipto em vasos

This paper evaluated the critical level, responsivity and boron use effciency on growth and the biomass production in six Eucalyptus grandis x Eucalyptus urophylla clones (Ca, Cb, Cc, Cd, Ce and Cf). An experiment was carried out in pots containing ground silicon, under greenhouse conditions using four boron rates per solution (0; 0.135; 0.27; 0.54 mg L -1 of B). The treatments were combined in a randomized block experimental design in a 4 × 6 factorial scheme with three replications. Plant height, stem diameter, dry matter production in the shoots of the plant and boron use effciency in the leaves, stem and total dry matter at the 8th month of age were evaluated. Due to boron fertilization, growth and shoot biomass were observed in the Eucalyptus plants after 240 days of being planted in pots. The increases in growth and biomass were 35 to 54% and 21 to 64%, respectively. The boron rates that promoted major growth of the plants were 0.33 to 0.44 mg L -1 of B and in this range the most effcient clone for dry matter production of leaves was Cf and the least effcient one to stem biomass production and the shoot biomass was Cd, no signifcant differences among other clones were observed. The critical level of boron in solution was 0.09 to 0.24 mg L -1 of B in the growth of the plants.

Efeito de métodos de determinação de parâmetros para o controle da irrigação na eficência do uso da água do feijoeiro, sob três diferentes lâminas de água no solo

The objective of this research was to study three methods of parameter determination for irrigation control under different tensions in common bean (Phaseolus vulgaris L.). The treatments were a combination of three methods of parameter determination for irrigation control (tensiometer, water retention curve, USWB Class A pan) with three soil water tensions (1:-30 kPa; 2:-60, kPa both for the whole plant cycle; 3:-60 kPa for the vegetative phase and -30 kPa for the reproductive phase). The experimental design was randomized blocks, factorial 32 with three replicates. Although no significant effect on water use efficiency was found, a tendency for increasing water use efficiency in treatments with tensions of -60 kPa at the vegetative phase and -30 kPa at the reproductive phase was observed in all methods of parameter determination for irrigation control. Water was saved as less irrigation was applied during the vegetative phase and more irrigation at the reproductive phase. No precipitation was observed from June to September 1995, leading to a high yield and therefore to a higher water use efficiency.

Estimativa da exigência hídrica do amendoim usando um modelo agrometeorológico

In the experimental area of the Department of Environmental Sciences (21.85° S; 48.43° W; 786 m), in the School of Agronomical Sciences, UNESP, Botucatu, SP, an experiment was carried out using peanut (Arachis hypogaea L), cv. IAC-TATU-ST, to quantify the crop daily water requirements. During the peanut crop cycle, the environmental variables, such as rainfall, air temperature, air relative humidity, soil matric potential, soil heat flux and radiation balance, have been registered continually. These measurements were used to calculate the daily crop evapotranspiration, by the Bowen ratio method. The water replacement required by the peanut crop was done the dripping irrigation system, oriented by a dynamic agrometeorological model that computes the entrance and exit of water in the soil. During the peanut crop cycle, 9.0 mm of water was used from sowing to emergence; 67.0 mm of water, in the growth stage; 166.0 mm, in the flowering stage; 124.0 mm in the final stage and 46.0 mm from physiological maturity to harvest. Oot of 412.0 mm of the total consumption, 246.0 mm of water was supplied by irrigation and 166.0 mm by the rain. The grain yield was 3.15 t ha-1 for 15% of humidity, and the water use efficiency was 0.764 kg m-3.

Efeito do uso de água cinza sobre a vazão de um microaspersor dinâmico

The work was realized at the Laboratório de Ensaio de Equipamentos de Irrigação do Departamento de Engenharia Rural da Universidade Estadual Paulista FCA- UNESP de Botucatu - SP, it aims evaluated in bench, the flow of a microsprinkler flow with dynamic nominal 43L h-1, before and after the use of gray water. In the first phase were 25 new emitters were separated and performed tests with clean water, at pressures from 50 to 300 kPa. In a second phase the emitters have been submitted 1000h operating with gray water. At the end of this time, the emitters were submitted again into conditions of initial essay, to evaluate the new costume water effect on medium flow from microsprinkler. At the end we can see that the average flow of the emitters, after use, has declined compared to the emitters discharge before use in 6,6%, the coefficient of variation after use was 5,1%, increased in proportion the coefficient of initial production was 4,3%, the R 2 fell from 0.9946 to 0.9898 and the microsprinkler continued with a high rating, according to the ABNT and ASAE.

Effect of plant density on Stevia rebaudiana Bertoni water consumption

Stevia rebaudiana is a traditional crop of Latin America, now rising to international interest thanks to its specific glycosides that are very sweet and still poor of calories making its potential interesting for dietary recommendations. Its short growing cycle makes this species possible as an annual crop also in non tropical areas, including the Mediterranean Basin and parts of Italy, where rainfall or irrigation is available during late spring and summer. One of the main concerns is the quantity of water necessary for the crop and the ideal number of plants per hectare in order to maximize water use efficiency. The present research was carried out in central Italy to compare yields and water consumption in plots with three plant densities (50, 25, 16 plants per square metre). The results show that the most dense plots can give the best results in the area of the trial.

Resposta produtiva do feijoeiro comum a diferentes manejos de irrigação

The objective of this work was to analyze the most appropriate management to achieve higher productivity for carioca beans (phaseolus vulgaris) and pearll cultivar. The research was developed in the Demonstrative and Experimental Area of Irrigation (ADEI) of FCAV/UNESP, Campus of Jaboticabal, SP. Four treatments were used: T1- irrigation with base in ETo estimated by the method of Class A pan; T2- irrigations based on the readings of tensiometers installed at 0,20 m and 0,40 m of depth; T3- irrigations carried out with base in ETo estimated by the method of Penman-Monteith and T4- witness. The results were submitted to analysis of variance. To compare the averages the test Turkey was used at 5% of probability. The treatment T3 had smaller applied water depth than the treatments T1 and T2, and also smaller productivity. The conclusion is that the treatments irrigated with larger frequency showed higher production of grains.

Produção e Qualidade Física dos Frutos do Abacaxi sob Diferentes Lâminas e Frequências de Irrigação

The objective of this study was to evaluate the performance of pineapple cultivar Smooth Cayenne as the physical production and the quality of the fruit when subjected to different frequencies of water dpeth and soil water in Triângulo Mineiro - Uberaba-MG. The experimental area soil is Oxisol, clay loam sandy and soft undulating local relief. A randomized block design in a factorial 4 x 2 with four levels of soil water depth (50%, 75%, 100% and 125%) of crop evapotranspiration (ETc) and two irrigation frequencies (1 day and 3 days = F1 = F2) and four replications was utilized. The crop productivity, number of seedlings, mean weight, diameter, and hardness of the fruit, plus water use efficiency were evaluated. Productivity was not significantly affected by the water depth and by the frequency of water applied; however the fruit shell resistance, the efficiency of water use, and ratoon seedlings were significantly influenced by irrigation, the water depth of 50% of the crop evapotranspiration (ETC) provided greater efficiency of water use for the production of pineapple fruit.

Growth and carbon isotopes of Mediterranean trees reveal contrasting responses to increased carbon dioxide and drought

Forest dynamics will depend upon the physiological performance of individual tree species under more stressful conditions caused by climate change. In order to compare the idiosyncratic responses of Mediterranean tree species (Quercus faginea, Pinus nigra, Juniperus thurifera) coexisting in forests of central Spain, we evaluated the temporal changes in secondary growth (basal area increment; BAI) and intrinsic water-use efficiency (iWUE) during the last four decades, determined how coexisting species are responding to increases in atmospheric CO2 concentrations (Ca) and drought stress, and assessed the relationship among iWUE and growth during climatically contrasting years. All species increased their iWUE (ca. +15 to +21 %) between the 1970s and the 2000s. This increase was positively related to Ca for J. thurifera and to higher Ca and drought for Q. faginea and P. nigra. During climatically favourable years the study species either increased or maintained their growth at rising iWUE, suggesting a higher CO2 uptake. However, during unfavourable climatic years Q. faginea and especially P. nigra showed sharp declines in growth at enhanced iWUE, likely caused by a reduced stomatal conductance to save water under stressful dry conditions. In contrast, J. thurifera showed enhanced growth also during unfavourable years at increased iWUE, denoting a beneficial effect of Ca even under climatically harsh conditions. Our results reveal significant inter-specific differences in growth driven by alternative physiological responses to increasing drought stress. Thus, forest composition in the Mediterranean region might be altered due to contrasting capacities of coexisting tree species to withstand increasingly stressful conditions. © 2013 Springer-Verlag Berlin Heidelberg.

Instantaneously measured traits may detect non-plastic ecophysiological performances in response to drought, explaining distributions of Styrax species in the Cerrado

We analyzed the differences between irrigated and non-irrigated plants of three congeneric Styrax species that present distinct distribution patterns in the physiognomies of the Cerrado vegetation in Brazil. Styrax ferrugineus showed a stomatal conductance (gs) unresponsive to soil water deficit in potted plants. This may explain the high gas exchange and photochemical efficiency found in this species, which is well adapted to the Cerrado sensu stricto (s. str.), a savanna-type vegetation. S. camporum, which is widely distributed in the Cerrado sensu lato (s. l.) areas, was the only species that exhibited increased intrinsic water use efficiency on the days of maximum water deficit. This result distinguishes S. camporum from S. pohlii, which is a forest species, since the gs of both species decreased during the days of maximum water stress. In contrast to other studies, we propose that instantaneously measured traits, such as leaf gas exchange rates and chlorophyll fluorescence, may be used to detect non-plastic performances in response to environmental stress, helping explain distinct geographical distributions of congeneric species in the Cerrado vegetation. © 2013 Springer-Verlag Berlin Heidelberg.

Silagem ácida de resíduos da filetagem de tilápias em dietas de alevinos de piauçu Leporinus macrocephalus

Pós-graduação em Aquicultura - FCAV