Localization and movement of mineral oil in plants by fluorescence and confocal microscopy

Abstract

Fluorescence and confocal laser scanning microscopy were explored to investigate the movement and localization of mineral oils in citrus. In a laboratory experiment, fluorescence microscopy observation indicated that when a 'narrow' distillation fraction of an nC23 horticultural mineral oil was applied to adaxial and opposing abaxial leaf surfaces of potted orange [Citrus x aurantium L. (Sapindales: Rutaceae)] trees, oil penetrated steadily into treated leaves and, subsequently, moved to untreated petioles of the leaves and adjacent untreated stems. In another experiment, confocal laser scanning microscopy was used to visualize the penetration into, and the subsequent cellular distribution of, an nC24 agricultural mineral oil in C. trifoliata L. seedlings. Oil droplets penetrated or diffused into plants via both stomata and the cuticle of leaves and stems, and then moved within intercellular spaces and into various cells including phloem and xylem. Oil accumulated in droplets in intercellular spaces and within cells near the cell membrane. Oil entered cells without visibly damaging membranes or causing cell death. In a field experiment with mature orange trees, droplets of an nC23 horticultural mineral oil were observed, by fluorescence microscopy, in phloem sieve elements in spring flush growth produced 4-5 months and 16-17 months after the trees were sprayed with oil. These results suggest that movement of mineral oil in plants is both apoplastic via intercellular spaces and symplastic via plasmodesmata. The putative pattern of the translocation of mineral oil in plants and its relevance to oil-induced chronic phytotoxicity are discussed.

Efeito do solo contaminado com óleo diesel na estrutura da raiz e da folha de plântulas de Sebastiania commersoniana (Euphorbiaceae) e Schinus terebinthifolius (Anacardiaceae)

“…No entanto, esses autores não relataram rompimento dessas células, o que foi evidenciado em S. commersoniana. Esses rompimentos podem facilitar a penetração do óleo nos tecidos internos, todavia, se faz necessário análises mais específi cas, como cromatografi a gasosa e espectrometria com fl uorescência (Alkio et al 2005), para detectar a presença do contaminante no interior do órgão (Alkio et al 2005;Tan et al 2005).…”

“…O contaminante pode ser absorvido pelas plantas (Bossert & Bartha 1985;Alkio et al 2005;Tan et al 2005), além de alterar as propriedades do solo (Racine 1994;Li et al 1997;Martinez & López 2001;Roy et al 2003;Chupakhina & Maslennikov 2004;Peña-Castro et al 2006). Solos com hidrocarbonetos têm tendência a reter menor quantidade de água (Roy et al 2003;Peña-Castro et al 2006), a apresentar menor disponibilidade de oxigênio (Pezeshki et al 2000;Merkl et al 2005) e de nutrientes (De Jong 1980).…”

Uso de semioquímicos en el control de plagas. Estudios básicos y de aplicación

“…Sin embargo, está ampliamente demostrado que estos diaspinos han sido capaces de desarrollar resistencias contra numerosos insecticidas utilizados para su control, tales como organofosforados y carbamatos (Yust et al, 1943a;Yust et al, 1943b;Collins et al, 1994;Grafton-Cardwell y Vehrs, 1995;Grafton-Cardwell et al, 1998). Debido a este fenómeno, el uso de aceites minerales como estrategia de control está ampliamente expandido, a pesar de ser potencialmente fitotóxicos (Grout y Richards, 1991a;Grafton-Cardwell y Reagan, 1995;Tan et al, 2005;Urbaneja et al, 2008). La presencia de compuestos acidificantes en los aceites de forma natural, o los productos de oxidación de moléculas insaturadas pueden causar efectos agudos de fitotoxicidad, tales como: quemaduras, necrosis o caída de hojas y frutos (Tan et al, 2005).…”

“…Debido a este fenómeno, el uso de aceites minerales como estrategia de control está ampliamente expandido, a pesar de ser potencialmente fitotóxicos (Grout y Richards, 1991a;Grafton-Cardwell y Reagan, 1995;Tan et al, 2005;Urbaneja et al, 2008). La presencia de compuestos acidificantes en los aceites de forma natural, o los productos de oxidación de moléculas insaturadas pueden causar efectos agudos de fitotoxicidad, tales como: quemaduras, necrosis o caída de hojas y frutos (Tan et al, 2005). Pero los problemas derivados del empleo de aceites también pueden ser originados por una aplicación de forma incorrecta o unas condiciones no adecuadas de temperatura, humedad o dosis.…”

“…However, since the development of resistances to many insecticides was documented for CRS (Grafton-Cardwell and Vehrs, 1995), other control techniques have been introduced. The use of oil sprays has been expanded although these can be potentially phytotoxic (Grout and Richards, 1991a;Grafton-Cardwell and Reagan, 1995;Tan et al, 2005). Thus, satisfactory management of oil applications is essential in order to prevent these effects and to ensure the efficacy of the treatment.…”