Respostas fisiológicas e estruturais em plantas submetidas a estresse hídrico recorrente em diferentes condições de luz
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Data
2018-02-28
Autores
Rodrigues, Angélica Lino
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As plantas estão expostas à seca extrema e cada vez mais frequente devido aos cenários das mudanças climáticas. A superação dos períodos de estresse hídrico e a rápida recuperação com o retorno da estação chuvosa são características de ajuste importantes para o estabelecimento e distribuição dos vegetais. Para amenizar os danos causados pela seca e intensa radiação, o metabolismo vegetal dispõe de mecanismos bioquímicos, anatômicos e epigenéticos que auxiliam na eliminação de radicais livres, no transporte e reserva de água e garantem respostas mais rápidas à reidratação assim que a água estiver novamente disponível no ambiente. Neste contexto, estudos baseados na deficiência hídrica se limitam em expor plantas a apenas um ciclo de défice, o que não acontece normalmente no ambiente. Os vegetais armazenam informações de estresses precedentes que não se resumem a padrões de sinalização isolados, mas funcionam como marcas deixadas anteriormente que auxiliam nas respostas a adversidades futuras. Deste modo, as consequências da seca de forma recorrente relacionando o estresse e a reidratação pós-estresse ainda não são bem compreendidos. A espécie utilizada para este estudo foi a Copaifera langsdorffii Desf. que possui folhas com mecanismos anatômicos e fisiológicos para superação das alterações ambientais. É conhecida pelas propriedades medicinais por meio do óleo amplamente consumido pela população em geral. Copaifera langsdorffii que ocorre em ambientes de diferentes regimes hídricos e luminosos é uma espécie chave para compreender a influência das variações ambientais extremas devido ao seu potencial adaptativo de ajuste ao ambiente de acordo com a exposição aos estresses hídricos de forma recorrente. Para isso temos os objetivos; a) avaliar quais os mecanismos fisiológicos, estruturais e bioquímicos que foram diferenciados em plantas submetidas ao estresse hídrico recorrente ao longo da reidratação, comparado a plantas que foram submetidas a evento único de estresse; b) testar se a diferença na intensidade luminosa favorece ou inibe as estratégias de aclimatação da espécie.
Plants are exposed to extreme drought increasingly frequent due to climate change scenarios. Overcoming periods of water stress and fast recovery with the rainy season return are characteristics of important adjustment for the establishment and wide vegetables distribution. To mitigate the damages caused by drought and intense radiation, plant metabolism features biochemical, anatomical and epigenetic mechanisms that assist in scavenging free radicals, increase the transport and water supply and ensure faster response to rehydration as soon as water is available in the environment again. In this context, studies based on water deficiency are limited to exposing plants only in one deficit cycle, which does not normally happen in the environment. Vegetables store information from previous stresses that are not limited to isolated signaling patterns, but function as previously left imprint that assist in responses to future adversities. Thus, the consequences of recurrent drought form related to stress and post-stress rehydration are not well understood yet. The species used for this study was Copaifera langsdorffii Desf. which has leaves with anatomical and physiological mechanisms to overcome environmental changes. The species has medicinal properties through the oil widely consumed by Brazilian population. It is present in several vegetation types in Brazil and South America that have different water and light pattern. These factors, among others, make this one of the most important tree species, from the floristic point of view, in Cerrado. Therefore, C. langsdorffii is a key species to understand the influence of extreme environmental variations due to its adaptive potential to adjust to the environment according to exposure to water stress recurrently. For this we have the objectives; a) to evaluate the physiological, morphological, anatomical and biochemical mechanisms that were differentiated in plants submitted to recurrent water stress during rehydration, compared to plants that were submitted to a single stress event; b) also test 11 whether the difference in light intensity favors or inhibits the acclimatization strategies of the species.
Plants are exposed to extreme drought increasingly frequent due to climate change scenarios. Overcoming periods of water stress and fast recovery with the rainy season return are characteristics of important adjustment for the establishment and wide vegetables distribution. To mitigate the damages caused by drought and intense radiation, plant metabolism features biochemical, anatomical and epigenetic mechanisms that assist in scavenging free radicals, increase the transport and water supply and ensure faster response to rehydration as soon as water is available in the environment again. In this context, studies based on water deficiency are limited to exposing plants only in one deficit cycle, which does not normally happen in the environment. Vegetables store information from previous stresses that are not limited to isolated signaling patterns, but function as previously left imprint that assist in responses to future adversities. Thus, the consequences of recurrent drought form related to stress and post-stress rehydration are not well understood yet. The species used for this study was Copaifera langsdorffii Desf. which has leaves with anatomical and physiological mechanisms to overcome environmental changes. The species has medicinal properties through the oil widely consumed by Brazilian population. It is present in several vegetation types in Brazil and South America that have different water and light pattern. These factors, among others, make this one of the most important tree species, from the floristic point of view, in Cerrado. Therefore, C. langsdorffii is a key species to understand the influence of extreme environmental variations due to its adaptive potential to adjust to the environment according to exposure to water stress recurrently. For this we have the objectives; a) to evaluate the physiological, morphological, anatomical and biochemical mechanisms that were differentiated in plants submitted to recurrent water stress during rehydration, compared to plants that were submitted to a single stress event; b) also test 11 whether the difference in light intensity favors or inhibits the acclimatization strategies of the species.
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Palavras-chave
aclimatação, Copaifera langsdorffii, luminosidade, marca de estresse, seca, acclimation, Copaifera langsdorffii, drought, luminosity, stress imprint