Efeitos da irrigação na sobrevivência, transpiração e no teor relative de água na folha em mudas de Eucalyptus grandis em diferentes substratos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito alelopático de extratos de parte aérea de barbatimão [Stryphnodendron adstringens (Mart.) Coville] na germinação e desenvolvimento da plântula de pepino

Stryphnodendron adstringens (Mart.) Coville (barbatimão), belonging to Mimosaceae family; it is used as ornamental and the wood is used in civil buildings, edification in wet places, lathe and joinery jobs, being very used also in home-made medicine against hemorrhage, diarrhea, hemorrhoids, conjunctivitis, injury cleaning, uterus hemorrhage, ulcerous hurt and excessive oily skin. The objective of this research was to determine the allelopathic potential of an aqueous extract, boiled or not of S. adstringens (Mart.) Coville, in the Cucumis sativus germination and initial development. Thus, the aqueous vegetable extract was extracted from the shoot, which was triturated in 1L of distilled water to 100g of leaf, being the extract filtrated and separated in boiled and not boiled. The treatments used were distilled water (0%) and boiled and not boiled extracts, in the concentrations of 50 and 100%. The cucumber seeds were put to germinate in Gerbox, having filter paper as substrate, which was wet with 25mL from different treatments, in constant temperature of 25°C. The reading germination was accomplished in breaks of 24 hours, for a period of five consequently days after the beginning of the experiment, considering germinated the seeds that showed 2mm of root, approximately. To dry matter determination, the seedlings with five days after the germination were separated in shoot and root, dried during three days to a constant weight in a 60°C forced draft oven. Through results, it can be concluded that the extract of S. adstringens affected more the Cucumis sativus seedling development than the germination, and it didn't show difference if boiled or not.

Identification and frequency of transposable elements in Eucalyptus

Transposable elements (TE) are major components of eukaryotic genomes and involved in cell regulation and organism evolution. We have analyzed 123,889 expressed sequence tags of the Eucalyptus Genome Project database and found 124 sequences representing 76 TE in 9 groups, of which copia, MuDR and FAR1 groups were the most abundant. The low amount of sequences of TE may reflect the high efficiency of repression of these elements, a process that is called TE silencing. Frequency of groups of TE in Eucalyptus libraries which were prepared with different tissues or physiologic conditions from seedlings or adult plants indicated that developing plants experience the expression of a much wider spectrum of TE groups than that seen in adult plants. These are preliminary results that identify the most relevant TE groups involved with Eucalyptus development, which is important for industrial wood production. Copyright by the Brazilian Society of Genetics.

Maturidade fisiológica das sementes do ipê amarelo, Tabebuia chrysotricha (Mart. Ex DC.) Standl

Ipê amarelo Tabebuia chrysotricha (Mart. Ex DC.) Standl. is a native forest species that presents heavy and durable wood: it is common to be used for urban arborization. The species is latte secondary and heliophyta. Occurs from Espirito Santo State until Santa Catarina in the Pluvial Atlantic Forest (Mata Atlântica). The seedling production is hard because their seeds have short longevity after dispersion, and so due to the difficulty to harvest winged seeds that are quickly dispersed by the wind. The present study was carried out to evaluate the physiological maturity of Ipê Amarelo seeds, to establish the best moment to harvest them. The study was to accompany the maturation of 100 fruits in just beginning development, from eleven different trees. Morphological characteristic measures were made weekly, with fruits still on trees, starting from the second week development when fruits presented the following averages: 6.3 cm length, 0.71 cm thickness, and 0.82 cm width. From the sixth week of fruit development we harvest them to proceed the germination test, water content rate, and electric conductivity test. The germination has begun by the seventh week development with 28% of germinated seedlings. The highest germination rate happened by the eighth week development, with 74.5% of germinated seedlings and on the ninth week the rate decrease to 65.5%, when the seeds were already in dispersion. Through the electric conductivity test the highest value obtained was 378.06 μS.g -1.cm -1 on the seventh week development and the lowest one was 183.28 μpS.g -1.cm -1 on eighth week. These results support those obtained in the germination test, because as higher is the electric conductivity of seeds, as higher is their deterioration level. Finally, the study allows concluding that the physiological maturation of ipê amarelo seeds has occurred before dispersion close to the eighth week development when fruits presented the following averages: 22.2 cm length, 1.37 cm width, and 1.05 cm thickness; water content rate was 61.8% and electric conductivity was 183.28 μS.g -1.cm -1. In that moment, the fruits presented greened brown coloration and started to show fissures.

Caracterização morfoanatômica de plântulas de Gomphrena elegans Mart. (Amaranthaceae)

Aiming to describe seedlings' morphology and cotyledons and eophylls anatomy of Gomphrena elegans Mart., 100 seeds were put into plastic bags, with sand and fertilized soil (1:3), kept in the greenhouse under room conditions, with 50% shady and watered daily. Cotyledonous petiole and limb and seedlings eophylls were sectioned in median and border. They were then analyzed in transversal and paradermic sections. Seedlings initial morphology is epigeal-foliar, the root is axial, and hypocotyls and epicotyl are reddish. Venation is of pinnate type, camptodrome and brochidrodome in cotyledons and eophylls. Petiole and leaf show uniseriated epidermis with cells of varied sizes and anomocytic stomata. Druses of calcium oxalate occurred in leaves and petiole. Dorsiventral mesophyll shows one palisade parenchyma layer and several lacunary ones.

Peroxidase activity as an indicator of water stress in sweet pepper plants

The purpose of the study was to evaluate the physiological and biochemical behavior of sweet pepper (Capsicum annuum L.) plants under different soil water availability conditions and the efficiency of the peroxidase (EC. 1.11. 1.7) activity as an indicator of water stress in plants. The experiment was carried out at the Faculdade de Ciências Agronômicas UNESP, Botucatu, SP. Sweet pepper plants were grown for 230 days after transplanting of seedlings and arranged in a completely randomized experimental design with 4 treatments, two irrigation managements (50 and 1500 kPa) and two soil surface managements (presence or absence of black polyethylene covering), and six replications. Physiological activities, such as stomatal transpiration and resistance to water vapor diffusion, were evaluated as well as biochemical activities, such as peroxidase activity and total soluble protein in foliar tissues. It was observed that soil water availability may lead to physiological and biochemical alterations in plants. Successive water stress cycles may promote the development of characteristics responsible for improving plant tolerance to periods of low water availability. The peroxidase enzyme activity showed to be an efficient indicator of water stress in sweet pepper plants.

Substrato e solução nutritiva desenvolvidos a partir de efluente de biodigestor para cultivo do meloeiro

Looking for the sustainability of a small farming enterprise, the present study focused the benefit of the biodigestor effluent resulting from the anaerobic fermentation of the bovine manure in a soilless melon plant experiment. The research was conducted in Jaboticabal, in the State of Sao Paulo, Brazil, at latitude of 21° 15' 22'' S and a longitude of 48° 18' 58'' W. The melon plant (Cucumis melo L. cv Bonus n° 2) was grown with substrate, seedling obtained in 10/2003. An experimental design was adapted in a randomized block with 16 treatments and 5 replications in a factorial 4 x 4 (4 substrates and 4 nutrient solutions). The 4 substrates were made up of different proportions in volume of the blend composition taking into consideration both the solid part of the biodigestor effluent and the washed raw sand. The 4 nutrient solutions were made up of the liquid part of the biodigestor effluent (biofertilizer) in substitution to the mineral water soluble fertilizers. The addition of the effluent in the sand led to a more rapid vegetative growth, a more precoceous crop with heavier fruits and a much better yield of melon crop. The mineral water soluble fertilizers used in the cultivation of plants in substrates can be partially replaced by the biofertilizer studied.

Morfologia de plântulas e estádios juvenis de espécies invasoras

The morphology of 20 species of weeds that occur in the most common crops in Maringá, Paraná State, Brazil and adjacent regions were described at early developmental stages, in order to identify the species in the field and provide information for taxonomic and ecological works. Sixteen species featured epigeal-foliaceous seedlings. The seedling in Cardiospenuum halicacabum is epigeal-fleshy; in Cenchrus echinatus and Digitaria horizontalis it is hypogeal and in Commelina virginica is epigeal-cryptocotyledonar. The differentiation of the first eophyll occurred within ten (Digitaria horizontalis) to 35 days (Bidens pilosa) and the first metaphyll appeared within 22 (Commelina virginica) to 49 days (Acanthospenuum australe). The number of eophylls varied from one to four, and the phyllotaxis varied from alternate to opposite.

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.