Influência do pulso de inundação na fenologia foliar e conteúdo de clorofila em duas espécies da floresta de Igapó da Amazônia Central, Brasil

Abstract

RESUMO -Com o objetivo de verificar a influência da dinâmica do pulso de inundação na fenologia foliar e conteúdo de clorofilas a, b e total, 15 indivíduos adultos de duas espécies típicas das cotas mais baixas da floresta de igapó, Eschweilera tenuifolia e Hevea spruceana, foram estudados no baixo curso do rio Tarumã-Mirim, Amazonas, Brasil. A fenologia foliar foi acompanhada em observações semanais de campo de julho de 1993 a dezembro de 1994 e o conteúdo de clorofilas foi medido em laboratório, mensalmente. Mudanças no conteúdo de clorofilas relacionaram-se à idade da folha. As concentrações médias de clorofila total em folhas maduras e velhas de E. tenuifolia foram de 473,5 e 288,6 mg m -2 , e em H. spruceana de 418,5 e 199,0 mg m -2 . Na fase aquática deu-se o pico de abscisão e brotamento foliar. Palavras-chave:Igapó, fenologia, clorofila, Eschweilera tenuifolia, Hevea spruceana. Influence of the Flood-Pulse on Leaf Phenology and Chlorophyll Content in Two Species of the Igapó Forest in Central Amazonia, BrazilABSTRACT -In order to verify the influence of flood-pulse dynamics on leaf phenology and concentrations of chlorophyll a, b and total, 15 individuals of two species typical of the blackwater igapó forest, Eschweilera tenuifolia and Hevea spruceana, were studied in the lower course of the river Tarumã-Mirim, Amazonas, Brazil. Leaf phenology was followed weekly from July 1993 to Dezember 1994 and the chlorophyll content was measured in the laboratory every month. Variations in the chlorophyll contents were related to leaf age. Mean concentrations of total chlorophyll in mature and old leaves of E. tenuifolia were 473.5 and 288.6 mg m -2 , and 418.5 and 199.0 mg m -2 in H. spruceana. The peak shedding and flush occurred during the aquatic phase.

TEMPORAL VARIATION AND SPATIAL DISTRIBUTION OF RELATIVE INDICES OF LEAF CHLOROPHYLL IN GRAPEVINE cv. CHARDONNAY

“…In line with this finding, Filimon et al (2016) stated that the fruit maturation phase may be considered the starting point of leaf senescence in grapevines. Other authors (Maia & Piedade, 2002;Zhang et al, 2008;Paula et al, 2015) also obtained results indicating chlorophyll content variation according to the phenological stages in other plant species, in a pattern similar to that reported in that study. Specifically in wine grape cultivars, chlorophyll content variation in leaves of Pinot Noir with leaf age and position in the plant has been described by Bertamini & Nedunchezhian (2002).…”

Phytochemical screening of Cordia glabrata (MART.) A.DC. extracts and its potential antioxidant, photoprotective, antimicrobial and antiviral activities

“…With the senescence of the leaves, chlorophyll and other metabolites, such as carotenoids, are reabsorbed so that biological recycling can happen, directing these metabolites to other plant tissues. (Maia and Piedade, 2002;Sousa et al, 2015).…”

“…During the different phenophases of the leaves, there was significant variation in the EC 50 values provided by the DPPH radical scavenging method. The greater potential antioxidant activity found in the extract of adult leaves can be explained by the accumulation of metabolites produced during the growth process of this organ, with a subsequent decrease in senescent leaves, where the accumulated metabolites are reabsorbed by the plant to be reused (Maia and Piedade, 2002). From the DPPH and ABTS + data, it was possible to verify a tendency between the results of the methods, that is, even if different mechanisms of analysis were presented, the values obtained showed the same profile of potential antioxidant activity for the analyzed extracts (Gaber et al, 2021).…”