Relationships between crown architecture and available irradiance in two cerrado species with different leaf phenologies

AUTOR(ES)

Santos, Karine M., Consolaro, Hélder N., Moreno, Maria Inês C., Prado, Carlos Henrique B.A., Souza, João Paulo

FONTE

Braz. J. Bot.

DATA DE PUBLICAÇÃO

2012

RESUMO

Structural differences between cerrado species with different leaf phenologies are linked to crown architecture, leaf production, and biomass allocation to shoots and leaves. The present study characterized crown structures and the patterns of biomass allocation to leaves and shoots in two woody cerrado species with contrasting leaf phenologies and quantified the irradiance reaching their leaves to determine the best period during the day for photosynthetic activity. The shoots and leaves of five individuals of both Annona coriacea (deciduous) and Hymenaea stigonocarpa (evergreen) were collected along a 50 m transect in a cerrado fragment within the urban perimeter of Catalão - GO, to determine their patterns of biomass allocation in their crowns. The evergreen H. stigonocarpa had significantly higher mean values of shoot inclination (SI), petiole length (PL), leaf area (LA), leaf display index (LDI), and individual leaf area per shoot (ILA), while the deciduous species A. coriacea had significantly higher leaf numbers (LN). The more complex crown of H. stigonocarpa had shoots in more erect positions (orthotropic), with intense self-shading within shoots; A. coriacea, on the other hand, had slanting (plagiotropic) shoots in the crown, allowing similar irradiance levels to all leaf surfaces. The production of plagiotropic shoots by the deciduous species (A. coriacea) is a strategy that enables its use of incident sunlight early in the morning and preventing excessive water loss or excessive irradiance. Hymenaea stigonocarpa (an evergreen), by contrast, had orthotropic shoots and uses intense self-shading as a strategy to avoid excessive irradiance, especially at midday. Differences in crown architectures between evergreen and deciduous species of cerrado sensu stricto can therefore be viewed as adaptations to the environmental light regime.

Documentos Relacionados

• Influence of shoot inclination on irradiance and morphophysiological leaf traits along shoots in cerrado trees with distinct leaf deciduousness
• Dominance Relationships between Two Allelic Genes Controlling Glycosyltransferases with Different Substrate Specificity in Melandrium
• Architectural changes in larval leaf shelters of Noctuana haematospila (Lepidoptera: Hesperiidae) between host plant species with different leaf thicknesses
• Structure and floristic relationships between Cerrado sensu stricto sites on two types of substrate in northern Cerrado, Brazil
• Leaf Respiration of Snow Gum in the Light and Dark. Interactions between Temperature and Irradiance1