Hermínia Emília Prieto Martinez

Tolerância de genótipos de cafeeiro ao alumínio em solução nutritiva. I. Crescimento e desenvolvimento da parte aérea e sistema radicular

An experiment was carried out in January of 1994, in the greenhouse of the Crop Science Department of the Universidade Federal de Vicosa, located in the Zona da Mata, State of Minas Gerais, Brazil (651 meter mean altitude) to evaluate the effect of aluminum on growth and development of nine coffee genotypes. Coffee plants with two pairs of fully expanded leaves were submitted to 0 and 0.296 mmol L-1 of aluminum in nutrient solution with pH 4.0 for 115 days. After this period, the plants were harvested and separated in higher and lower leaves, first pair of fully expanded leaves, stems, and roots. These plant parts were dried and evaluated for dry matter production. In addition, the following variables were evaluated: plant height, main root length, lateral root number, and leaf area of the first pair of fully expanded leaves. The aluminum inhibited shoot and root growth, with the latter showing typical symptoms of aluminum toxicity. Root dry matter reduction in presence of aluminum in the nutrient solution was the characteristic which best differentiated the genotypes. There was a reduction in the length of the main root, plant height and leaf area, and increase of lateral root number in response to increase of aluminum concentration. The evaluated characteristics allowed the differentiation of the genotypes into four groups or classes: tolerant (UFV 1359, UFV 2149), moderately tolerant (UFV 2145, UFV 2877 e UFV 2163), moderately sensitive (UFV 3880) and sensitive (UFV 2147, UFV 2198, UFV 2237).

Dinâmica de cálcio e magnésio em folhas e frutos de Coffea arabica

Knowledge on mineral nutrient dynamics in coffee trees is important to identify the period of greatest nutritional requirement by the plant, allowing the improvement of fertilization techniques. The aim of our research was to study Ca and Mg dynamics in coffee fruits from anthesis to maturation and compare it with the dynamics of the same elements in leaves of productive branch leaves. The experiment was carried out with three Arabic coffee varieties (Catuai Vermelho IAC-99, Rubi MG-1192 and Acaia IAC-474-19) in three independent trials (low, sufficient and high fertilizer levels), arranged in randomized blocks with two replications using a split-plot scheme in time. The varieties presented the highest Ca and Mg fruit concentrations in the initial growth stage and decreasing concentrations in the stages of fast fruit expansion. In the stages of ceasing fruit growth and fruit formation-maturation little or no variation was observed in the Ca and Mg fruit concentrations. In the 3rd and 4th pair of leaves of the productive branches Ca and Mg concentrations decreased in the beginning of the reproductive period and recovered afterwards. In general, the fertilization levels influenced the Ca and Mg concentration in fruits and leaves of the varieties of Arabic coffee plant throughout the reproductive period. However, Ca and Mg concentrations in leaves and fruits were not only influenced by the fertilizer levels, but by other factors as well that determine the distribution rate of the mineral elements in the coffee plants, such as fruit load.

Remoção de carga orgânica e produtividade da aveia forrageira em cultivo hidropônico com águas residuárias da suinocultura

A study to quantify the productivity of forage oat and the efficiency in the removal of the organic load of swine wastewater, used in different proportions for composition of the nutritive solution for the hydroponic cultivation, was accomplished inside a shed, containing individualized systems of cultivation, in tanks of 3.20 x 0.80 m, equipped with aeration systems. The proportions of 70, 50, 30 and 10% of swine wastewater were used in the preparation of the nutritive solution, represented by values of initial electrical conductivity of 4.2, 2.8, 1.8 e 0.97 dS m-1. The oat was sown on a plastic screen inside the cultivation tanks. The concentration of dissolved oxygen, the electrical conductivity and the temperature of both the nutritive solutions and the air inside the shed were monitored daily, while samples of the solutions were collected weekly for determination of the concentration of COD and BOD. A treatment was used with a conventional nutritive solution as the control. The forage oat cultivated in a hydroponic system, with the use of swine wastewater in the preparation of the nutritive solution, provided productivities of up to 31.5 t ha-1 y-1 and significant decrease of the organic load of the nutritive solution.

Tolerância de genótipos de cafeeiro ao alumínio em solução nutritiva. II. Teores de P, Ca e Al e eficiência ao P e Ca

An experiment was carried out in January of 1994 in the greenhouse at the Crop Science Department of the Universidade Federal de Vicosa, State of Minas Gerais, Brazil. The objective of this experiment was to evaluate the effecets of aluminum on P, Ca and Al concentrations in the plants and on the P and Ca efficiencies of utilization by nine coffee genotypes. Plants were grown with 0 and 0.296 mmol L-1 of aluminum in nutrient solution, in pH 4.0, for 115 days. After this period, plants were separated in higher leaves, lower leaves, first pair of completely expanded leaves, stem and roots to evaluate dry matter yield and phosphorus, calcium and aluminum concentrations in plant parts. Aluminum tolerance was associated with lower root phosphorus accumulation, lower reduction of phosphorus translocation to shoot, lower reduction of calcium uptake and higher phosphorus and calcium use efficiency. A large accumulation of aluminum in the roots was observed, reducing the Al transport to shoot, for all coffee genotypes.

Acumulação de matéria seca pelo cafeeiro conilon

Dry matter accumulation by Conilon coffee The objective of this study was to characterize the dry matter accumulation of Conilon (Coffea canephora Pierre) coffee plants. The experiment was conducted in Marilândia/ES, Brazil, in an orchard with the clone 02, from the clonal variety EMCAPA 8111, established in October 1995. The experiment was arranged in a randomized block design, with twenty-four treatments (date of sampling) and three repetitions. It was found that up to six years of cultivation, plants of Conilon coffee show a sigmoid growth pattern, with a continuous increase in dry matter accumulation. There was a decline in the absolute growth rate after 48 months of cultivation, whereas for the relative growth rate, the reductions were observed after only one month of cultivation.

Crescimento da planta e coloração das raízes com hematoxilina como critérios de avaliação de genótipos de café quanto à tolerância à toxidez de alumínio

A selecao de plantas tolerantes ao Al e uma alternativa para solos que apresentam Al em niveis toxicos. Neste contexto, vinte e cinco genotipos de cafe foram estudados quanto a tolerância ao Al avaliada pela inibicao no crescimento da parte aerea e das raizes e pelo teste de coloracao das raizes com hematoxilina. Avaliou-se, tambem, a alocacao do Al nas pontas das raizes. Apos 35 e 75 dias de cultivo em solucao nutritiva, na ausencia ou presenca de Al, foram avaliados o comprimento da raiz principal e, aos 80 dias, a producao de biomassa seca da parte aerea e das raizes. Os resultados expressos em percentagem de inibicao causada pelo Al foram analisados pela tecnica multivariada, e os genotipos foram separados em classes: tolerante, intermediaria e sensivel. O teste de coloracao com hematoxilina foi realizado apos 80 dias de cultivo em solucao nutritiva, e os genotipos foram avaliados de acordo com a intensidade de coloracao da ponta da raiz. Apenas tres genotipos foram tolerantes ao Al e seis foram sensiveis, enquanto a maioria deles pertenceu a classe de tolerância intermediaria. O teste de coloracao com hematoxilina nao permitiu a adequada diferenciacao dos genotipos quanto a tolerância ao aluminio. Em cortes transversais das pontas das raizes do genotipo mais tolerante, observou-se a localizacao do aluminio apenas nas celulas epidermicas, enquanto, no genotipo de tolerância intermediaria, o Al localizou-se nas celulas epidermicas e em varias camadas de celulas do cortex.

Reactions of three soybean cultivars to interruptions in phosphorus supply

Three soybean cultivars (Santa Rosa, Doko and UFV1) were submitted to 0, 4, 8 or 12 days of P omission periods in nutrient solution. Following the omission treatments, the plants were returned to a complete solution until they were 36 days old. Dry matter (DM) yield, phosphate content (PC), plant P-concentration (P%), inorganic-P (Pi) and organic-P (Po) concentrations in fresh material were determined. Short P-omission periods affected DM and PC only slightly, and longer ones caused a reduction on these. Roots supported longer P-omission periods without losses in DM than shoots. With longer P-omission periods, DM yield decreases were followed by Pi and P% increases at the basal and intermediate leaves. The variations of root parameters were smaller than those of the shoots, showing that homeostasis is maintained for longer periods of time in roots when compared with shoots. Small differences were found between the genotypes.

Omissão de nutrientes em plantas de pinhão-manso cultivadas em solução nutritiva

O pinhao-manso (Jatropha curcas L.), pertecente a familia Euphorbiaceae, e uma planta oleaginosa que tem recebido expressiva atencao para producao de biocombustivel. O objetivo deste trabalho foi avaliar o efeito da deficiencia de macro e micronutrientes no crescimento e estado nutricional de pinhao-manso, cultivado em solucao nutritiva. O delineamento experimental utilizado foi o inteiramente casualizado, com treze tratamentos e tres repeticoes. Os tratamentos constituiram-se de solucao completa e omissao individual de cada um dos seguintes nutrientes: N, P, K, Ca, Mg, S, B, Cu, Mn, Mo, Zn ou Fe. A ordem decrescente de restricao da producao de massa de materia seca foi N>Mg>S>K>Ca=P>Zn>B=Fe. As omissoes de N e de P foram as que mais afetaram os teores dos macronutrientes da parte aerea das plantas e os sintomas de deficiencias observados foram clorose, reducao do crescimento e folhas deformadas.

YIELD GAINS OF COFFEE PLANTS FROM PHOSPHORUSFERTILIZATION MAY NOT BE GENERALIZED FOR HIGHDENSITY PLANTING

Inconclusive responses of the adult coffee plant to phosphorus fertilization have been reported in the literature, especially when dealing with application of this nutrient in high density planting systems. Thus, this study was carried out for the purpose of assessing the response of adult coffee plants at high planting density in full production (in regard to yield and their biennial cycle/stability) to the addition of different sources and application rates of P in the Zona da Mata region of Minas Gerais, Brazil. The experiment with coffee plants of the Catucai Amarelo 6/30 variety was carried out over four growing seasons. Treatments were arranged in a full factorial design [(4 × 3) + 1] consisting of four P sources (monoammonium phosphate, simple superphosphate, natural reactive rock phosphate from Algeria (Djebel-Onk), and FH 550®), three P rates (100, 200, and 400 kg ha-1 year-1 of P2O5), and an additional treatment without application of the nutrient (0 kg ha-¹ year-¹). A randomized block experimental design was used with three replicates. The four seasons were evaluated as subplots in a split plot experiment. The P contents in soil and leaves increased with increased rates of P application. However, there was no effect from P application on the yield and its biennial cycle/stability regardless of the source used over the four seasons assessed.

Micronutrientes em Pinus caribaea morelet I. Efeitos da omissão sobre o desenvolvimento e sintomas de carência

A pot experiment was conducted in a green house in Piracicaba, Brazil, in order to determine the visual symptoms of deficiency, and the effects of micronutrient omission in P. caribaea var. hondurensis, P. caribaea var. bahamensis and P. caribaea var. caribaea seedling height and dry matter production. The following treatments were employed: complete, without boron, without copper, without iron, without manganese and without zinc. Washed sand was used as a substrate. The plants were watered twice a day with the corresponding nutrient solution. After the deficiency symptoms were established, the plants were cut and separated into needles, branches and roots, washed, dried at 75°C and weighed. Visual symptoms were described. Pinus caribaea var. hondurensis and P.caribaea var. caribaea were more affected than P. caribaea var. bahamensis seedlings by boron omission. P. caribaea var. bahamensis and P. caribaea var. caribaea were more affected than P. caribaea var. hondurensis seedlings by copper omission. Pinus caribaea var. hondurensis was the most affected by iron omission.