<b>Wettability and morphology of the leaf surface in cashew tree from the Amazon, Northern Brazil

Abstract

ABSTRACT. Leaves surfaces, which represent an interface with plants and the environment, have several structures with specific functions. Some foliar properties, including wettability and mechanical containment, are inferred in terms of cellular adaptation and the presence or absence of cuticular wax. Various morphological parameters, ranging from macro-to nano scales, are analyzed and contribute to the study of taxonomy, pharmacognosy, and ecology of plants. The aim of this paper was to analyze the effect and influence of epicuticular wax granules on the hydrophobicity of Anacardium occidentale L. leaf surfaces. Leaf specimens were directly examined with an environmental scanning electron microscope without metal coating. Images revealed epidermis ornament, stomata type, was, and trichomes. Static contact angle between water and the surface was also measured on both sides. On the adaxial side, an angle of 104.09° ± 0.95° was found, suggesting that adaxial surface is hydrophobic. On the abaxial side, the angle was 62.20° ± 1.60°, which indicates a hydrophilic nature, probably because of the greater amount of epicuticular wax on the adaxial leaf surface. The present investigation provided an important contribution to morphological and ultrastructural characterization of leaves of cashew tree, which is a plant of great medicinal and economic importance.Keywords: hydrophobic, hydrophilic, Anacardium occidentale L., wax.Molhabilidade e morfologia da superfície da folha em cajueiro da Amazônia na Região Norte do Brasil RESUMO. Superfícies de folhas têm diversas estruturas com funções específicas e contribuem para a relação delas com o meio ambiente. Algumas propriedades foliares, incluindo molhabilidade e contenção mecânica, são inferidas em termos de adaptação celular e da presença ou ausência de cera cuticular. Diversos parâmetros morfológicos, variando da macroescala até a nanoescala, são analisados e contribuem para o estudo de taxonomia, farmacognosia e ecologia de plantas. O objetivo deste trabalho foi analisar o efeito e a influência de grãos de cera epicuticular na hidrofobicidade da superfície de folhas de Anacardium occidentale L. Amostras de folha foram examinadas com um microscópio eletrônico de varredura ambiental sem recobrimento metálico. As imagens evidenciaram algumas características (epiderme, tipo de estômato, cera e tricomas). O ângulo de contato estático entre a água e a superfície também foi medido em ambos os lados. No lado adaxial, foi encontrado um ângulo de 104,09° ± 0,95°, sugerindo que esta é hidrofóbica. No lado abaxial, o ângulo foi de 62,20° ± 1,60°, que indica uma natureza hidrofílica, provavelmente devido à grande quantidade de cera epicuticular na superfície abaxial da folha. A presente investigação forneceu uma contribuição importante para a caracterização morfológica e ultra-estrutural de folhas de cajueiro, que é uma planta de grande importância econômica.Palavras-chave: hidrofóbico, hidrofílico, Anacardium occidentale L., cera.

Influence of Multiple Factors on the Wettability and Surface Free Energy of Leaf Surface

“…This camera has 2.8 million pixels and ultra-high sensitivity, the maximum camera shooting speed is 1603 fps at full resolution (1920 × 1440 pixels) and 3822 fps at 1008 × 1000 pixels, the shortest shutter time is 1.5 μs. Figure 2 shows the static contact angel (θ) of droplet on solid surface, which is an important index to quantitatively evaluate the wettability of solid surface [33]. The clean WSP and wax were directly placed on the sample platform, while the leaves were cut into pieces (avoiding veins and lesions) and fixed on the glass slide.…”

“…According to the SEM sample preparation method, the SEM samples of rice and rape leaves were prepared respectively. The following procedure was applied: (a) the samples were fixed with 2.5% glutaraldehyde overnight at 4 °C; (b) the samples were rinsed with phosphoric buffer (0.1 M, pH 7.0) three times, 15 min each time; (c) the samples were fixed with 1% osmic acid in the ventilated Figure 2 shows the static contact angel (θ) of droplet on solid surface, which is an important index to quantitatively evaluate the wettability of solid surface [33]. The clean WSP and wax were directly placed on the sample platform, while the leaves were cut into pieces (avoiding veins and lesions) and fixed on the glass slide.…”

Synthesis and Surface Properties of Piperidinium-Based Herbicidal Ionic Liquids as a Potential Tool for Weed Control

“…Theoretically, the two sides of a leaf are morphologically different. 60,61 That is, the sides of a leaf have different degrees of hydrophilicity and hydrophobicity. The exact CA values on the adaxial and abaxial leaf surfaces are summarized in the Supporting Information (Table S15).…”

“…Generally, the variation in the CA values of the HILs was due to differences in the plant morphologies, which are determined by the plant chemical compositions. , Common wheat belongs to the Poaceae family, cornflower belongs to the Asteraceae family, whereas white mustard and winter rapeseed are part of the Brassicaceae family. − It should be emphasized that the CA for a given substance is related to the morphological structure of the plant, that is, the adaxial and abaxial surfaces of the leaf. Theoretically, the two sides of a leaf are morphologically different. , That is, the sides of a leaf have different degrees of hydrophilicity and hydrophobicity. The exact CA values on the adaxial and abaxial leaf surfaces are summarized in the Supporting Information (Table S15).…”

Identifikasi Sifat Fisiologis Dan Produksi Tanaman Jambu Mete Pada Ketinggian Tempat Berbeda Di Kota Baubau, Sulawesi Tenggara

“…Lebar bukaan stomata erat kaitannya dengan penyerapan CO 2 dari udara melalui daun sebagai bahan baku proses fotosintesis. Menurut Ramos et al (2016) pengaturan pembukaan stomata juga berkaitan dengan laju kehilangan air oleh transpirasi, sehingga tanaman dapat tetap bertahan walaupun dalam kondisi kurang air. Berdasarkan Tabel 2 menunjukkan bahwa lebar bukaan stomata tidak berpengaruh nyata terhadap perbedaan ketiggian tempat.…”