Respuestas morfo-fisiológicas de plantas de Lithraea caustica (Anacardiaceae) sometidas a restricción hídrica controlada

Abstract

SUMMARYLithraea caustica (litre) is an endemic tree species of Chile that grows in a Mediterranean climate, characterized by a summer with low water availability in the soil, high solar radiation and high temperatures. In these conditions, litre should have physiological mechanisms to survive under restricted water conditions. To investigate these mechanisms we performed an experiment under natural summer conditions. The plants were assigned to three different treatments: Permanent irrigation, moderate water restriction and severe water restriction. During the study, we evaluated predawn leaf water potential and predawn leaf water relative content, photosynthesis, gas exchange and chlorophyll fluorescence. Additionally, we evaluated the growth and accumulation of biomass. Under restricted water conditions, litre developed the osmotic adjustment mechanism, presenting a high cellular turgor and a leaf water relative content over 80 %. This strategy allowed litre to tolerate the low soil water contents observed during the phase of maximum water restriction. It also repaired damages caused during the photoinhibition period observed at noon, with values of F v /F m always equal to or higher than 0.8. This study provides valuable information of litre attributes that could be applied in future scenarios of reforestation and climate change in Mediterranean areas.Key words: litre, Mediterranean forest, drought, osmotic adjustment, photoinhibition. RESUMENLithraea caustica (litre) es una especie arbórea endémica de Chile que se desarrolla en un clima de tipo mediterráneo, caracterizado por presentar una estación estival con baja disponibilidad hídrica del suelo, elevada radiación solar y altas temperaturas. Bajo estas condiciones, litre debe desarrollar respuestas ecofisiológicas que le permitan sobrellevar períodos de restricción hídrica. Con el objetivo de conocer dichas respuestas, se estableció un ensayo de restricción hídrica controlada bajo condiciones naturales de verano. Las plantas se sometieron a tres tratamientos: riego permanente, restricción hídrica moderada y restricción hídrica severa. Durante el estudio se evaluaron variables hídricas (potencial hídrico foliar a pre-alba y contenido hídrico relativo foliar a pre-alba), fotosíntesis, intercambio gaseoso y fluorescencia de las clorofilas. Adicionalmente, se evaluó el crecimiento y acumulación de biomasa. Bajo condiciones de restricción hídrica, litre presentó el mecanismo de ajuste osmótico, permitiendo mantener un alto turgor celular y un contenido hídrico foliar sobre 80 %. Esta estrategia permitió a litre tolerar los bajos contenidos hídricos de sustrato observados durante la fase de mayor restricción hídrica. También fue capaz de reparar los daños provocados durante el periodo de fotoinhibición observado a mediodía, con valores de F v /F m siempre igual o superior a 0,8. Se entrega información valiosa sobre los atributos de litre, posible de aplicar en futuros escenarios de reforestación y cambio climático en zonas mediterráneas.Palabras clave: litre, bo...

Shading as a means of mitigating water deficit in seedlings of Campomanesia xanthocarpa (Mart.) O. Berg

“…Many studies on native species searching for information on the production of seedlings for reforestation in areas subject to water deficit and different levels of shading, consider physiological responses 235 such as gas exchanges that these species present (Flexas et al, 2012;Dos Anjos et al, 2015;Junglos et al, 2016;Pena-Rojas et al, 2018). Holmgren et al (2012) noted in their review that in various ecosystems plants are exposed to water and thermal stress, however, shading can improve plant survival and growth as it reduces air and leaf temperature and leaves and transpiration.…”

Endophytic Fungi Isolated from Plants Growing in Central Andean Precordillera of Chile with Antifungal Activity against Botrytis cinerea

“…In this work, three endophytic fungi (Ac1, Lc1 and Ec1) with antifungal activity against B. cinerea obtained from native and endemic plants growing in Central Andean Precordillera of Chile were isolated. This region has a Mediterranean climate [ 9 , 10 , 30 ]. It has been described that the plant colonization by endophytic fungus is dependent on the ecosystem.…”

“…This is the first report of endophytic fungi isolated from plants located in the studied area and it is also the first time that endophytic fungi with antifungal activity against B. cinerea have been isolated from L. caustica, A. caven and E. chiloensis. L. caustica (litre) is an endemic tree of Chile and E. chiloensis is an endemic columnar cactus species widely distributed in north-central Chile that inhabits mainly equatorial-facing slopes in semiarid environments [30,38]. A. caven is a native tree found in several countries in South America [39].…”

Quillaja saponaria Mol. en un escenario de elevada contaminación atmosférica y bajo dos diferentes condiciones de riego

“…Las condiciones de verano generan múltiples condiciones de estrés en las plantas. El estrés hídrico es uno de los factores que más limita el crecimiento, la composición y la distribución de las especies en climas mediterráneos (Donoso et al, 2011) afectando varios aspectos del funcionamiento de las plantas, tales como la baja fijación de CO2, el crecimiento y la fotosíntesis, entre otras (Peña-Rojas et al, 2018).…”