Comparação entre trȩs métodos para estimar lâminas de irrigação

An experiment with four treatments was carried out on the experimental area of ADEI to compare three methods of water use requirement: ETc (T1) - irrigation based on crop evapotranspiration (ETc); Tensiometers (T2 and T3) - irrigations were made through reading of tensiometers installed at 40 cm deep and, Control (T4) - only one irrigation to promote the seedlings emergence. Both Class A pan and soil water depletion methods presented good results when the crop was developed without restraint of water. The Katerji method can be utilized in conditions of water restriction. Irrigation frequency was more important than amount of applied water for higher yield.

Efeitos da luminosidade no crescimento de mudas de Caesalpinia ferrea Mart. ex Tul. (Leguminosae, Caesalpinoideae)

Caesalpinia ferrea is a species used a lot as a medicinal plant, for urban arborization and landscape design in the state of Amapa. Yet there is not much ecophysiological information available on it. Light is an important environment factor that controls processes associates with the accumulation of dry matter, contributing thus for plant growth. The object of this research was to study the effect of different luminosity levels on the growth of seedlings of this species. The seedlings were transplanted to plastics bags containing a mixture of soil and sand (2:1), which were maintained in the full sun, under artificial shade with reduction of 50% and 70% of the luminosity and under natural shade of a closed canopy of forest. The experimental design was completely randomized with five replicates. Seedlings submitted to natural shade showed strong growth inhibition. In the full sun, the seedlings presented higher net assimilatory rate (NAR), lower shoot/root ratio (SRR) and lower leaf area ratio (LAR). The results showed little difference in the growth and biomass allocation between seedlings kept in 50 and 70% shade; the seedlings submitted to this treatment presented higher values of SRR and LAR. This indicates plasticity which influences a possible increase in light capture and is important, therefore, to keep the seedling growth and survival under low light levels. The results as a whole showed morphological and physiological adjustment to different light levels in Caesalpinia ferrea.

Efeito de níveis de fósforo no crescimento inicial, biomassa e atividade in vivo da fosfatase ácida em Lychnophora ericoides Mart

The effect of phosphorus levels on seedling growth, dry and fresh matter production, and in vivo acid phosphatase activity was studied in Lychnophora ericoides cultivated during 130 days after transplanting in a greenhouse. Experimental design was completely randomized, with four P 2O 5 levels (0; 40; 80; 160 mg dm -3 as triple superphosphate) and five replicates of four plants each. The used soil was dystrophic acid dark red latosol. Lychnophora ericoides is responsive to phosphate fertilization with modification in daily relative growth rate, dry matter production and distribution among the plant parts. Acid phosphatase activity had significant and negative correlation with total, leaf and stem dry matter production, as well as with P levels accumulated in the leaf tissue. On the other hand, acid phosphatase activity had significant and positive correlation with root/shoot ratio.

Carotenóides totais em Pothomorphe umbellata (L.) Miq. cultivadas in vitro

The aim of the present work was to compare the content of carotenoids between callus and regenerated plants of Pothomorphe umbellate. Germinated seeds (40 days old) were inoculated in different concentrations and combinations of BAP (benzylaminopurine) and NAA (naphthalene acetic acid) in order to stimulate the callus' production. After 60 days of culture, the callus containing some shoots were transferred to organogenesis medium (GA 3 0.1 mg L -1, BAP 0.5 mg L -1) for 40 days. Next, they were subcultivated in a medium for seedling growth (without regulators) for 40 days. Callus (collected after 60 days) and seedlings (collected after 140 days) were frozen in liquid nitrogen and kept under -80°C for future carotenoids' analysis. The highest concentration of carotenoids was found in plants cultivated in medium without regulators. The callus did not showed difference concerning the culture medium; however, they presented lower content of carotenoids in relation to plants.

Testes de vigor para avaliação da qualidade fisiológica de sementesde Sebastiania commersoniana (Baill.) Smith & Downs.

The objective of this work was to evaluate the efficiency of different vigor tests to assess S. commersoniana seeds physiological quality during storage. Therefore, seeds were stored in cloth bags, plastic bags and glass containers for 531 days, both at room temperature and in a cold chamber. Periodically samples were taken and the following tests were conducted: standard germination, germination speed index, first count after germination, seedlings fresh and dry matter, electrical conductivity (imbibitions for 2 and 24 hours) and accelerated aging, in order to monitoring the seeds physiologic quality. Data were submitted to polynomial regression analysis, for each of the combination of packaging/storage condition. The results obtained led to the following considerations: a) the speed germination index and the accelerated aging test permitted a good evaluation of the seed-lots quality; b) the first count of germination did not allow any prediction about seed lots vigor; c) seedling fresh and dry matter did not discriminate among seed lots; d) electrical conductivity test after 2 h imbibitions was not adequate to evaluate the seed lots vigor and e) the electric conductivity test with 24 h imbibitions was more adequate to differentiate among seed lots, but with little efficiency to discriminate among seed lots with intermediate vigor or with low quality differences.

Alterations in chlorophyll a fluorescence, pigment concentrations and lipid peroxidation to chilling temperature in coffee seedlings

Coffea arabica L. is considered to be sensitive to low temperatures throughout its life cycle. In some Brazilian regions, seedling production occurs under shade conditions and during the winter, with average temperatures of around 10 °C. The formation and functioning of the photosynthetic apparatus are strongly controlled by temperature. This study aimed to assess the changes that occurred in pigment contents, lipid peroxidation and variables of chlorophyll a fluorescence during the greening process of coffee seedlings submitted to chilling. Results indicate that saturation of the photosynthetic activity of coffee seedlings occurred before saturation of the accumulation of chloroplastid pigments. Pigment accumulation during the greening process is far beyond the metabolic needs for the maintenance of photosynthetic activity, more specifically of photosystem II. Coffee seedlings attained a quantum yield equivalent to that of the control with approximately half the chlorophyll a and b contents and around 40% of the carotenoid. Low temperature decreases the metabolism of seedlings, consequently reducing free radical production and lipid peroxidation. The chilling temperature (10 °C) used inhibited the accumulation of chloroplast pigments, in turn altering the capacity of the photosynthetic tissue of etiolated coffee seedlings to capture and transfer photon energy to the photosystem II reaction centre. These alterations were better demonstrated by O-J-I-P chlorophyll a fluorescence transients, rather than F v/F m and F v/F 0 ratios. © 2009 Elsevier B.V. All rights reserved.

Umedecimento e substratos para germinação de sementes de repolho

The availability of water for seeds is closely related to their germination, since hydration is a limiting factor for their metabolic processes. Therefore, in tests carried out in laboratory, substrate must be sufficiently moistened, in order to assure both the embryo growth and seedling formation. This research was carried out to evaluate the influence of different quantities of water, in different substrates, for cabbage (Brassica oleracea var. capitata) seeds germination. The seeds, processed with Thiran 0.1%, were obtained in shops located in Jaboticabal, São Paulo State, Brazil. Germination tests were made in germitest rolled paper towel substrates, between and on draft paper, moistened with quantities of water equivalent to 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; and 4.0 times the dry substrate weight. For each treatment, four repetitions of 50 seeds were used. The seeds were kept in a germinator, at an alternate temperature of 20-30°C, without further addition of water to the substrate. The evaluations were made on the fifth and tenth days after the experiment preparation. The results obtained revealed that the quantities of water ranging from 1.5 to 2.5 times the paper weight were favorable for seeds germination, mainly in the substrate on and between the paper, while water levels above 3.0 times the substrate weight were harmful for cabbage seeds germination in the rolled paper towel substrates and between the paper.

Avaliação do vigor de sementes de rúcula pelo teste de lixiviação de potássio

The objective of this study was to evaluate methodologies for the potassium leaching test and to verify its sensitivity for identifying different levels of vigor of arugula seed lots. Five seed lots each of Rucula Cultivada and Rucula Gigante were used. Standard germination, first count of germination, seedling emergence and variations of the potassium leaching test (50 or 100 seeds imbibed in 50 mL or 75 mL in water; at 25 °C and 30 °C; for 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3, 4 and 5 hours) were done. It was observed that the period seeds need to be soaked can be reduced to 2 hours and the water volume can be reduced to 50 mL. The utilization of 50 seeds showed a smaller variation coefficient and the best temperature was 30 °C. It can be concluded that the potassium leaching test for arugula seeds can be run using 50 seeds in 50 mL of water for 2 hours at 30 °C.

Custo de produção e indicadores de rentabilidade da cultura do milho safrinha

The objective of this study was to evaluate the production cost and profitability of the second season corn crop in the Medio Paranapanema region, São Paulo State Brazil, under two technological levels (middle and high technology), crop 2008/2009, and compare the results with the 2006/2007 agricultural year. Effective and total operational cost as well as five profitability indicators were used. It was concluded that the high technology production cost for corn crop (direct seedling, sowing during the recommended period, use of simple hybrid seed, application of side-dressing fertilization, and treatment of seeds with different insecticides) was superior to the middle technology production cost (direct seedling, sowing after the recommended time, use of double hybrid seed, and no side-dressing fertilization). However, the average cost was inferior (US$ 8.5), due to a higher yield (4 t). The high technology corn crop was profitable (gross income and profitability index of 14% and 12%, respectively). For the middle technology crop, profitability indexes pointed out that the cropping system needs to be reevaluated by technicians and research institutions, regarding the adequate technical recommendations. Profitability indexes decreased considerably in both cropping systems. It was verified that, in relation to the 2006/2007 harvest period, the total operational cost increased for both technologies, mainly because of the increase of supplies prices.

Capim-colonião e seus efeitos sobre o crescimento inicial de clones de eucalyptus × urograndis

This study aimed to evaluate the guinea grass effect (Panicum maximum) on the initial growth of different Eucalyptus × urograndis clones. Two assays were established with eucalyptus clones and guinea grass seedlings. The plants were grown in plots with cement borders filled with soil. Each plot received a eucalyptus seedling. The first assay had a completely randomized experimental design, with three replications, and treatments in a 5x2 factorial scheme (five eucalyptus clones and the absence or presence of two guinea grass plants at 10 cm distance from eucalyptus seedling). The second assay was similar to the first, however with three eucalyptus clones. The experimental design was completely randomized, with five replications, and a 3x2 factorial scheme (three eucalyptus clones and the absence or presence of two guinea grass plants). The presence of eucalyptus clones did not affect guinea grass development. The eucalyptus clones that coexisted with guinea grass plants did not show differences in their development, making the clones equal when under competition. The most susceptible characteristics of eucalyptus clones to guinea grass were foliar area, shoot and stem dry matter. Clone 3 showed the most sensitivity to guinea grass, and clone 1 was the most tolerant, but all clones studied suffered a negative interference from guinea grass.

Resistance of rose rootstocks to Meloidogyne hapla nematode

Roses are widely used in landscaping. One of the most important fitossanitary problems of this ornamental plant in gardens is the fitonematodes, especially Meloidogyne hapla, which is the most important one in colder climate regions. This work had the objective of study the resistance of nine rose rootstocks (Rosa multiflora 'Paulista', R. multiflora 'Japanese', R. multiflora 'Iowa', R. multiflora 'Kopman's', R. indica × multiflora, R. indica 'Mayor', R. sp. 'Natual Brier', R. manetti and R. canina 'Inermis') to Meloidogyne hapla nematode. Ten replications of each rootstock were used. The roots, collected in a commercial area of cut roses, visually had galls there were isolated and identified. The inoculum of M. hapla was previously produced in rose and tomatoes seedlings under greenhouse conditions. The plants were harvested ninety days after inoculation. The roots were washed and the number of eggs and juveniles recuperated in the root system of each plant was estimated by the Final Population (FP), and the Reproductive Factor (RF) was calculated. The rootstocks with RF<1 values were considered resistant, and the ones with RF>1, susceptible. Rosa manetti and Rosa sp. 'Natual Brier' rootstocks showed the lowest values for RF, indicating that, although they are susceptible, they provide the lowest nematode reproduction. Based on the RF values, it was concluded that all the rose rootstocks evaluated were susceptible to M. hapla nematode.

Morfologia de sementes e de estádios iniciais de plântulas de espécies de Bromeliaceae da Amazônia

Seeds of Aechmea bromeliifolia, A. castelnavii (Bromelioideae); Dyckia duckei, D. racemosa (Pitcairnioideae) and Tillandsia adpressiflora (Tillandsioideae) were collected in the Amazon regions (Mato Grosso) and studied to describe morphological characterization and post-seminal development, which can be taxonomically useful, and to assess percent germination. All the species have epigeous germination and produce cryptocotyledonary plantlets. Seeds have no dormancy and percent germination is high (over 86%), which facilitates the production of seedlings and conservation studies. Exclusive characteristics of the genera include: the seed coat of Aechmea (Bromelioideae) has mucilage that prevents desiccation; whereas that of Dyckia (Pitcairnioideae) has membranaceous wings and that of Tillandsia (Tillandsioideae) has feathery appendages, both of which make dispersal easier and establish the epiphytic habit. Initial post-seminal development of Aechmea (Bromelioideae) and Dyckia (Pitcairnioideae) is marked by the emergence of primary roots, interpreted as a basal character, whereas that of Tillandsia adpressiflora (Tillandsioideae) is marked by the emergence of the cotyledon, interpreted as a derived character. Dyckia and Tillandsia have a small tank only in the seedling phase while the contrary occurs in Aechmea.

Avaliação de substratos na emergência de plântulas de araticum-de-terra-fria (Annona emarginata (Schltdl.) H. Rainer)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualidade fisiológica de sementes de diferentes árvores matrizes de Corymbia citriodora (Hook.) K.D.Hill & L.A.S. Johnson

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Germinação e vigor de sementes de crambe sob estresse hídrico

This study aimed to evaluate crambe seeds germination and vigor under water stress conditions induced by polyethylene glycol solutions. The seeds were germinated on substrate moistened with polyethylene glycol solutions, using the osmotic potentials of 0 (control), -0.2, -0.4, -0.6, -0.8, -1.0, -1.2 and -1.4 MPa. The seeds germination was evaluated by normal seedlings and root emission percentages. Vigor was evaluated by germination average time, relative frequency, velocity and synchronization index. It was observed that more negative osmotic potential caused significant reduction in crambe seed germination and vigor, and no normal seedlings was observed at potentials below -0.6 MPa.