Growth of the tambaqui Colossoma macropomum (Cuvier) (Characiformes: Characidae): which is the best model?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Iterated deferred correction for linear two-point boundary value problems

An analysis of iterated deferred correction based on various classes of implicit Runge-Kutta formulae is given. Out of different possibilities considered, it is shown that those based purely on Lobatto formulae have the best stability. The enhanced stability of Lobatto schemes is very important for the efficient integration of excessively stiff boundary value problems and this is demonstrated by means of some numerical results.

Biomass production and chemical composition of Lippia alba (Mill.) NEBr. ex Britt & Wilson in leaves on different plant parts in different seasons

Lippia alba, family Verbenaceae, is widely spread in Central and South American. It's a shurb with a quadrangular branch reaching 1,7m tall. The leaves are membranaceous, petiolate, pubescent with a strong flavor. It's limbs have variable forms with pointed apex, cuneiform or decumbent base, and serrated or crenated hordes. It was determined the best harvest season to biomass production, essential oil content and chemical composition, on different plant parts (apical, medium, basal). It has been observed that, both apical and medium parts represented around 80 % of the fresh leaf mass. The foliar biomass yields are about 5 ton/ha in four harvests during an year. The average yield of essential oil considering the three plant parts were 0.15%, 0.47%, 0.46%, 0.55% and 0.61% for summer/98, autumn/98, winter/98, spring/98 and summer/99, respectively. Essential oils showed similar chemical composition either in relation to seasonality, neral, geranial and t-cariofilene were the majority compounds.

Effect of growing media and fertilizers on the early growth of Aechmea fasciata Bak

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of fruit maturation stage and light on seed germination of Aiphanes aculeata

Despite their spiny nature, Aiphanes palms are popular as ornamentals. They can be grown in various soil conditions, but achieve fast, luxuriant growth in sheltered positions with plenty of water. Shaded conditions are the best when plants are young. The objective of this study was to evaluate the effect of fruit maturation stage and light on the germination of seeds of A. aculeata. Fruits were collected at three different maturation stages: (1) yellow, (2) red, (3) collected on the ground without the fleshy mesocarp (removed by birds and insects). The fleshy mesocarp was also removed in treatments (1) and (2). All fruits were then treated with thiram and 25 seeds per plot were seeded in trays full of sand. The treatments (2) and (3) were subdivided in two other treatments: (a) 12 h photoperiod, (b) continuous darkness. The temperature was maintained at 30 degrees C. Seed germination began 34 days after sowing. After 160 days, the final germination percentage was (1) 54,67%, (2a) 61,33%, (2b) 65,33%, (3a) 38,00% and (3b) 45,33%. The best treatment was (2) independently of the light conditions.

Effect of substrata on the development of stem cuttings of Lippia alba (Mill.) NEBR. - Limonene-carvone chemotype

Studies were conducted to show the effect of different substrata on the development of stem cuttings of Lippia alba made of limonene-carvone chemotype. The experiment was done in the College of Agronomical Sciences, UNESP, Botucatu, SP, Brazil in 2000. The cuttings were planted in polystyrene trays consisting of 72 cells. The cuttings had about 0.20 m of length and were put in the following substrata:Fine sand (T1), commercial substratum (T2), carbonised rice peel and local soil (T3), local soil, cow manure and carbonised rice peel (T4), vermiculite (T5), and carbonised rice peel (T6). After 40 days the development of stem cuttings were evaluated. High rate of rooting of stem cuttings was verified, with average of 95 10 and no significant difference between the treatments. In relation to dry mass of aerial parts and dry mass of roots, significant differences were found. For dry mass production of aerial parts the commercial substratum (T2) and the local soil, cow manure, carbonised rice peel (T4) were optimal. For mass of roots the local soil, cow manure, carbonised rice peel (T4) proved to be the best.

Performance of Cultivars for Production of Green Corn in Different Planting Dates in Passos Region, MG

The aim of this work was evaluating the performance of several cultivars of green corn for consumption 'in natura' in different planting dates. The first planting date was on May 26th, and the others, every 40 days. The hybrids (treatments) were: AG-1051, Agroeste 1567, BM-3061, Prezoto-32D10, PL-6880, BX-1382 and GNZ-2004. The following characteristics were evaluated: production, commercial ears weight without husk, commercial ears number, commercial ears diameter and length, male flowering, plant height and height of ear corn insertion. The cultivars AG1051, Agroeste 1567 and BM 3061 presented the best results compared to the others and they should be used in green corn production for ` in natura' consumption in Passos County, MG.

Big fish are the best: Seed dispersal of Bactris glaucescens by the pacu fish (Piaractus mesopotamicus) in the Pantanal, Brazil

We studied the potential role as seed disperser of the pacu fish (Piaracrus mesopotamicus, Characidae) in the Pantanal of Brazil. The most important food item in the diet of the pacu in the wet season was fruits of the palm Bactris glaucescens found in the guts of 73 percent of all fishes collected (N = 70). We found a positive relationship between fish length, weight, and gape size and the number of intact seeds in their gut. Therefore, large pacus are especially important in dispersing B. glaucescens seeds within the studied system. Since the best seed dispersers are the largest fishes, which are preferred by commercial fisheries, we predict that the ongoing over fishing in freshwater ecosystems will have major impacts on the dispersal system of fish-dependent plants. We suggest that it is paramount to change the attitudes in fisheries management of fruit-eating fishes and urgent to evaluate the impact of fishing on forest regeneration.

The effects of pre-planting refrigeration on bulbs over the development and yield of garlic 'Chines', 'Contestado' and 'Quiteria'

The objective of this research uas to evaluate the effect of five pre-planting refrigeration periods previously to the cloves planting (0,10,20, 30 and 40 days at a temperature of 4.0 ± 1° C and three garlic cultivars ('Chines', 'Contestado' and 'Quiteria') uere used. According to the obtained results it was observed that the best preplanting refrigeration period was dependent upon the cultivar behavior. For the 'Chines' well adapted to the region, there was no effect of the pre-planting refrigeration period up to 30 days after treatment on the plant height, bulb weight, and total bulb production. 'Contestado' the best pre-planting refrigeration period was 40 days however, there was no statistical difference among 30 and 40, days for the 'Quiteria'. For both cultivars pre-planting refrigeration periods under 20 days, there was no clove's formation.

Effects of rooting media, indolbutyric acid and fertilization on the rooting of rose (Rosa sp. 'Dalas') leafy cuttings

The objectives of this study were to evaluate the effects of rooting media (vermiculite, carbonized rice bark, fenolic spume and sand), presence of IBA (indole-3-butyric acid) and presence of fertilization during the rooting of rose (Rosa sp.) leafy cuttings, Dalas cultivar. This investigation was carried out in Jaboticabal (Sao Paulo State - Brazil) during the period of March to April 1997. The experimental design was a randomized block in a factorial arrangement. It consisted of 16 treatments (the 4 rooting media combined with IBA concentrated solutions - 0 and 1.000 ppm and fertilizer - 0 and commercial product with macro and micronutrients, applied weekly) with 3 replicates. The evaluations were 30 days after cuttings showed that the best rooting percentage occurs in sand (98%), followed by vermiculite (90%) and fenolic spume (87%) and cuttings treated with IBA (95%), while the fertilization showed no promoting effects. The number of cuttings roots wasn't affected with rooting media or DBA treatment, while the fertilization showed effective.

Methodology for kariological study of Brazilian Palms

In the laboratory of cytogenetics of the DBAA-UNESP we are studying the karyotipe of some Brazilian Palms. To determine the best protocol, methods of seed germination, inhibition of mitosis, time to pick up the roots and staining were analyzed. The results shown that the seed germination in sphagnum is effective to achieve good roots. The best time to collect the root tips is between 11 to 12 AM., when there are more cell metaphases. The inhibition of mitosis cycle at metaphases may be effective both with 8-hydroxiquinoleine (0,03% -5 hours) or with cold water (0°C - 18-20 hours). The staining with Giemsa 2% showed the best chromosome figures in the metaphases. Now, to get good metaphases slides the method in use in the lab is: 1) seed germination in sphagnum at room temperature and high humidity; 2) The major roots are cut maintaining at least 5 cm, because this technic allows new emergence of roots, increasing the number of roots collected per germinated seed, that is very important in some species with poor germination rates; 3) To get the mitosis inhibition we are using cold water (0°C) treatment for 18-20 hours, following the standard protocols for conservation and hydrolysis; or enzyme digestion with pectinasecellulase 4) the staining procedures are made using Giemsa 2%. The Brazilian palms species studied and their respective chromosome number were: Aiphanes acanthophylla (2n=30), A. caryotaefolia (2n=30), Syagrus quinquifaria (2n=32), S. coronata (2n=32), S. romanzoffiana (2n=32), Euterpe edulis (2n=36), E. oleracea (2n=36), Copernicia prunifera (2n=36), Scheelea lauromuelleriana (2n=32) and Bactris gasipaes (2n=30).

Aspects of the sexual reproduction of the Brazilian arnica (Solidago chilensis Meyen var. megapotamica (D.C.) Cabrera - Asteraceae)

The species is a very popularly used plant as woundwort. Leaves, top flowers and rhizomes are used. The objective of this work is a contribution to the germination study, photoblastism and more adequate temperature for reproduction of the species. The best temperature for the germination was found to be 20°C and no seeds germinated under continuous darkness, within 14 days; therefore, the seeds are positive photoblastics. The seed germination percentage was low, in relation to the mass of the achene produced, varying from 8,2 to 20,0%. The alternated temperatures of 20° and 30°C did not influence the seed germination and the average of the weight of 100 seeds was 0,026 1 g.

Early rooting in Rosemary's (Rosmarinus officinalis L.) cuttings under the influence of chemical treatments and collecting time

The present work aimed to verify the early rooting development and the root production in rosemary's (Rosmarinus officinalis L.) cuttings under the influence of treatments with sythetics auxins, boric acid and collecting time. The branches were collected at the end of the season and the stakes were prepared and placed into solutions containing NAA or IBA (25, 50, 75 and 100 pppm) without and with boric acid and then removed to a chamber of nebulization (all experimental work). In all the experimentes, the branches were collected after 30 days, the mean number of rooted cuttings was calculated, along with the mean number of roots per stakes and the dry weight of roots. The end of winter outstood as the best season for all analysed parameters.