Aspectos da historia de vida de folhas do palmiteiro (Euterpe edulis Mart., Arecaceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

Leaves of young plants in a population of Euterpe edulis Mart. were studied in a semideciduous forest at Santa Genebra Reserve, Campinas, SP (22°49 45" S, 47°06 33" W, 575 a 585m a.s.l.). Young plants of Euterpe edulis were classified into seedlings, infants and juveniles, according to morphological changes and leaf features. Mean number of pinnae and mean leaf area were proportionaI to the ontogenetic stage of the plant. There was an overlap in leaf area values between infants and the other stages. Leaf populational structure was analysed. High Gini coefficient were determined for number of pinnae, length and width of pinnae and leaf area, indicating a great size hierarchy. The greater heterogeneity occured in juvenile stage, thus suggesting a size hierarchy construction along the ontogenetic stages. Leaves are produced one at time, each leaf beginning its expansion only after the complete expansion of the preceding one. The lamina grows linearly while closed, but the petiole grows logarithmically only after the lamina opens. Damage by herbivory was present in 40 % of all leaves. Seedlings had the highest mortality rate due to herbivores and unknown causes. Infants suffered the largest damage by herbivores. The rates of leaf production, growth and survival were directly related to the size stage of the individual plant. A leaf is expensive to produce and its maintenance is important for plant survival. Different methods for estimating leaf area were compared with the LI-COR estimated leaf area. According the intention to preserve the leaves and to reduce the field work time, the better method was the estimative of the leaf area from the leaf length. Leaf density increased from the apex to the basis of the pinnae and was not influenced by the region of the leaf where the disks were taken. Leaf density increased with plant age. Leaf density positive correlatted with leaf growth rate, and with mean leaf area. The variation in teaf density found within a pinna of Euterpe edulis can be related to the diminishing in thickness and number of veins from the basis towards the apex of the pinna. The largest coefficient of variation among seedlings than among other stages support the hypothesis that surviving plants are selected according to the sclerophilly degree

ASSUNTO(S)

plantas - população palmeira ecologia vegetal palmito

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