Homobaric and heterobaric leaves in tomato (Solanum lycopersicum L.): morphological, anatomical and physiological implications in different environmental conditions

• Ano de defesa: 2017
• Autor(a) principal: Barbosa, Maria Antonia Machado
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Tomate; Solanum lycopersicum; Folhas - Anatomia; Análise foliar; Folhas - Aspectos ambientais; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/27553

Homobaric and heterobaric leaves are characterized, respectively, by the absence and presence of bundle sheath extensions (BSEs), a structure formed by parenchymatic cells which connects the leaf epidermis to the vascular bundles. Species that have heterobaric leaves present less resistance to water transport, however, homobaric leaves are less hydraulically integrated and have greater resistance to water movement. The objective of this work was to evaluate the influence of BSE on tomato plants under different environmental conditions. This dissertation was divided into two chapters: 1- an evaluation of the structure and physiology of homobaric and heterobaric plants grown in different irradiance conditions and 2- response to soil water deficit. We have shown that the presence of BSE altered the coordination between lamina thickness and structural and biochemical parameters in response to different levels of irradiance. Heterobaric leaves showed phenotypic plasticity, mainly in relation to vein density and SPI, showing that BSE acts by coordinating the flow of water from the vascular bundle to the epidermis, when the levels of irradiance are low. The homobaric mutant, whose BSE is absent, showed a response pattern, whereby the plastic response is transferred to a different set of characteristics that were not affected in heterobaric plants. Also, the plants that harbor the obv mutation exhibited a reduced leaf rolling, higher values of TRA and leaf water potential in comparison with heterobaric leaves, in the condition of water deficit, suggesting that the absence of BSE positively influenced the response of these plants in dry condition. Lastly, we present our conclusions in a final section, where we discuss how this work could contribute to increased understanding of the relationship between form and function in angiosperm leaves.