MICROMORFOMETRIA FOLIAR DE Schinus molle L. (ANARCADIACEAE) EM DIFERENTES ALTURAS NA COPA

Abstract

MICROMORFOMETRIA FOLIAR DE Schinus molle L. (ANARCADIACEAE) EM DIFERENTES ALTURAS NA COPARESUMO: A caracterização foliar em árvores é essencial para a sua identificação e utilização, bem como para se compreender as suas relações com o ambiente. Neste trabalho, objetivou-se o estudo da anatomia dos folíolos e das características biométricas das folhas de S. molle em diferentes alturas na copa, em função das modificações ambientais e fisiológicas promovidas. As folhas foram coletadas em três diferentes alturas na copa: base, meio e alto da copa em uma população cultivada de S. molle. Para as analises anatômicas, as folhas foram fixadas em FAA e armazenadas em etanol sendo, posteriormente, submetidas a secções paradérmicas e transversais. As lâminas foram fotomicrografadas e as imagens analisadas no software UTHSCSA-Imagetool. Para as análises biométricas foram avaliadas a área, comprimento, largura, massa seca foliares, bem como a área foliar específica. Os folíolos possuem epiderme unisseriada, estômatos anomocíticos e ciclocíticos, mesofilo isobilateral e camada subepidérmica em ambas as faces da epiderme. Canais secretores e colênquima foram observados na nervura central e bordo dos folíolos. Ocorreram modificações nas espessuras da cutícula e do mesofilo, no sistema vascular, espessura do floema e na densidade estomática de acordo com a altura em que os folíolos se encontram na copa das árvores. As folhas foram menores e demonstram reduzida área foliar para as partes mais altas da copa. A anatomia foliar de S. molle é diferente de outras espécies do gênero Schinus e demonstra modificações sob as diferentes condições ambientais e fisiológicas promovidas pelas diferentes alturas na copa. LEAF MICROMORPHOMETRY OF Schinus molle L. (ANARCADIACEAE) IN DIFFERENT CANOPY HEIGHTS.ABSTRACT: Leaf characterization of trees is essential for its identification and use, as well as to understand its relationships with environment. The objective of this work is to study the leaflet anatomy and leaf biometrical characteristics at different canopy heights of Schinus molle plants as a function of its environmental and physiological modifications. Leaves were collected at three different canopy heights: base, middle and upper canopy in a plantation of S. molle. Leaves were used for anatomical and biometrical analysis. For the anatomical analysis, leaves were fixed in FAA and stored in ethanol 70% and further submitted to transversal and paradermical sections. Slides were photomicrographed and image analysis was performed in UTHSCSA-Imagetool. For biometrical analysis leaf area, length, width, dry mass and specific leaf area were evaluated. The leaflets exhibited single layer epidermis, anomocytic and ciclocytic stomata, isobilateral mesophyll, subepidermal parenchyma layer in both adaxial and abaxial faces of epidermis, secretory vessels and lamellar collenchyma in midrib and leaf border. Leaf anatomy modifications occurred in cuticle and mesophyll thickness, vascular system, phloem thickness, and stomatal density in accordance wit...

Morphological characterization of leaves at different crown positions of tangerine genotypes

“…In contrast, the Fremont tangerine leaves had thinner spongy parenchyma in the lower crown (Figure 1 F), similar to the palisade parenchyma (as shown in Table 2). This shows that the upper crown of this plant variety receives more solar radiation, forming thicker leaves, which is very common in most plants and shows the greater photosynthetic potential of leaves in the upper and middle crown (Pires et al, 2015). However, the Thomas variety showed a different pattern, that is, its lower crown leaves had a thicker spongy parenchyma than the other study varieties ( Table 2 Figure 1 I).…”

“…Furthermore, height differences in canopy position affect leaf anatomy and may change leaf physiology because leaves respond differently to variations in light intensity, water availability, air temperature, vapor pressure, and wind speed as a function of plant height (Yoshimura 2011;Gebauer et al 2015). Upper crown leaves are subjected to greater light availability and lower hydraulic conductivity and nutrient availability and therefore, these leaves will be thicker, with a higher mesophyll ratio and epicuticular wax deposition, among other specificities (Pires et al, 2015).…”

MORPHOLOGICAL AND PHYSIOLOGICAL PLASTICITY OF SAPLINGS OF Cabralea canjerana (Vell.) MART. IN DIFFERENT LIGHT CONDITIONS

“…Because they are in the upper part of the crown, the apical leaflets have xeromorphic characteristics similar to the sun leaves, since there is a greater interception of solar radiation in this portion of the crown than in the other portions. Similarly, Pires et al (2015), analyzing the anatomical characteristics of leaflets of S. molle found greater thickness of the mesophyll in the leaves positioned in the higher parts of the canopies.…”

“…This may be one of the photoprotective mechanisms required to prevent photoinhibition under high light conditions. Pires et al (2015), divided the crown of Schinus molle in three strata and verified that the leaves placed in the upper stratum of the crown are smaller in relation to the leaves of the other positions and also consider these results a strategy to decrease the transpiration rate.…”

Leaf Morpho-Anatomical and Physiological Plasticity of Two Vriesea Species (Bromeliaceae) in Atlantic Coast Restingas (Brazil) / Plasticidade Morfoanatômica E Fisiológica Foliar De Duas Espécies De Vriesea (Bromeliaceae) Em Restingas Da Costa Atlântica (Brasil)

“…Larger leaves allow the plant to capture more light because they increase the contact area of the leaf with irradiance in individuals under shading. On the other hand, leaves with reduced area, such as those found among individuals in the Open Clusia formation, decrease the transpiration surface, which is important for survival in sunny environments (Oliveira et al 2009, Pires et al 2015. The leaves of Dry Forest individuals from both species also presented more succulence.…”