Diferenças entre as dimensões das fibras nos anéis de crescimento determinados no D. A. P. e em níveis diferentes do fuste de árvores adultas de Eucaliptus saligna Smith

This paper deals with the variation of fiber dimentions in growth rings taken at the breast height (B.H.) and at three aditional level of trunk height (10%, 20% and 30% of total height) of two plants of Eucalyptus saligna Smith. Statistical analyses of variance for fiber length, fiber diameter and fiber thikness in diferent growth rings at B.H., 10%, 20% and 30% of trunk height is prsented. Analysis of variance allowed the following conclusion: 1° - Significant diferences were observed for fiber dimentions mean, taken at B.H. and those taken at the levels of 10%, 20% and 30% of trink height; 2° - In any growth rings along the trunk, the fiber length means increased consistently from B.H. to the levels of 10%, 20% and 30% of trink height, however the means for fiber diameter and thikness of the wall decreace from the B.H. point to the leves of 10%, 20% and 30% of trink height; 3° - The results obtained in the present study confirm those obtained by BISSET & DASDWELL (1949) in that the maximum fiber lenght is reached at aproxmately one third of the total height of the trink and also confirm the afirmation made by RUDMAN et al (1969) that the samples taken at the B.H. level are inadequate for qualitative wood studies, specially in raltion with forest genetics investigation.Neste trabalho apresentamos os resultados dos estudos das diferenças entre as dimensões (comprimento, diâmetro e espessura) das fibras lenhosas nos anéis de crescimento (da periferia ao centro do fuste), determinadas ao nível do D. A. P. (distância a altura do peito) e em diferentes níveis (10%, 20% e 30% da altura do fuste) de árvores adultas de Eucalyptus saligna Smith, tendo como objetivo verificar se em nossas condições, as amostras tomadas apenas no D. A. P. representam o fuste da árvore

A idade adulta do Eucalyptus saligna Smith em, Rio Claro Estado de São Paulo, determinada pelas dimensões das fibras

The objetive of this study was to get some information about fiber length variation in the growth rings of Eucalyptus saligna, with 21 year old, which data could give the mature age of this plant at São Paulo States. Two disc from two plants were colected at the level of D. B. H. at Forest Experiment Station "Navarro de Andrade" at Rio Claro, in which there were stands of this species, which age was known. From each disc was take one sector of south side of the trunk and the surface was polished with the finality to identify the growth rings by macroscopic and microscopic observation. Since each sector had 21 growth rings and the age of the plants was 21 years old, it was possible to correlated the number of growth rings with the age of the plants. After that, each growth rings from 3 sectors of one plant was macerated in individual vials and 6 or 8 slides was prepared in which 5 fibers and 5 veessels was measured. The statistical analysis showed the following results: 1.º) The analysis of variance of mean fiber length in the 3 sectors point out that the value of residual error was praticaly the same. (See Table I). This make possible to analyse the data of both sectors together, and the analysis of variance for fiber length mean in the growth rings was significant at 1% leve of probability. (See Table II). By using the regression equation it was possible to determine the maximum of the fiber length among the 21 growth rings and also in which the mean value of "Runkel coefficent" reache the assintotic value. The maximum value or fiber length was reached at the 10th growth ring and Runkel coefficent reache between 14th and 15th growth rings in one plant and between 9th and 10th in other. (See Figure 1 and 2). These results led us to conclude that in São Paulo States the mature age in Eucalyptus saligna was reached at the 9th or 10th growth rings, that correspond to 9 or 10 years old.O presente trabalho, faz parte de um plano de estudo em desenvolvimento, sôbre fibras lenhosas de Eucalyptus saligna, Smith no Departamento de Botânica (Disciplina Anatomia de Madeira) desde 1966. Nêle apresentamos os resultados da determinação da idade adulta do E. saligna em função da variação do comprimento e da espessura da parede das fibras nos diferentes anéis de crescimento do lenho, de duas árvores com mais de 20 anos de idade. Os resultados das mensurações microscópicas das fibras analisadas num setor apenas e em dois discos tomados ao nível do D.A.P., nos permite afirmar que nas condições do Hôrto de Rio Claro, as duas árvores atingiram a idade adulta entre o 9.º e 10.º anel de crescimento os quais corresponde respectivamente a idade de 9 e 10 anos. Os resultados apresentados nêste trabalho nos forneceu informações importantes para a continuação do plano em desenvolvimento, qual seja o estudo de outros fatôres (longa e curta duração) que afetam a estrutura e as características dos elementos constituintes do lenho que apresentam valor industrial

Observações preliminares sôbre a longevidade dos "Seedlings" de feijoeiro - Phaseolus vulgaris : em função das reservas cotiledonares

According previous studies about longevity in maize by ACCORSI e ADÂMOLI DE BARROS, (1961) the authors presents in this paper the results of work on longevity of seedlings of beans. Seeds were separated in three groups according their weight, as followings: small 80-120 mg; medium 130-140 mg and big 150-200 mg. The sowing of the seeds was made in pure sand and the seedlings were distributed in distil. water and in complete solution of Arnon and Hoagland. Each treatment was made in two replications with eight seedlings by treatment. At present time the following conclusions can be related: 1.°) - Eight days after germination, the cotiledones of all the seedlings started to fell down, fourteen days after, all cotiledones had fell down. 2.°) - Fifteen days after germination, the seedlings in nutritive solution showed better development than those in distil. water. Table I e II gives results. 3.°) - All seedlings in distil. water showed symptoms of N, Ca, Fe deficiencies. 4.°) - Twenty nine days after germination the seedlings in distil. water manifested exhaust trace, by falling of the leaves and death of some plants although the aplicai buds keep green. 5.°) - After thirty-one days the plants in nutritives solution was in better condition than those in distil. water, although some alteration aboved mentioned was observed. The causes of this alteration are being studied. 6.°) - In many plants in complet solution the seminal leaves showed clorosis initial and some with necrosis, although apical buds keeps in ativity. 7.°) - Symptoms of clorosis and necrosis in diferents stages were observed in all leaflet; these symptoms were more strong in the groups of little seed and medium seeds