Sudden openings and gradual closures in canopy cover modulate acclimation,survival,and growth of a shade-tolerant rainforest tree species  

作　　者：Ana Paula Moretti Flavia Yesica Olguin Juan Marcelo Gauna Corina Graciano 

机构地区：[1]INFIVE(CONICET-Universidad Nacional de La Plata),Diagonal 113 N°495,1900 La Plata,Provincia de Buenos Aires,Argentina [2]CONICET,Godoy Cruz 2290,C1425FQB Buenos Aires,Argentina [3]Facultad de Ciencias Agrariasy Forestales,Universidad Nacional de La Plata,Calle 60y 118,1900 La Plata,Provincia de Buenos Aires,Argentina [4]Facultad de Ciencias Forestales,Universidad Nacional de Misiones,Bertoni 124 km 3,3380 Eldorado,Provincia de Misiones,Argentina

出　　处：《Journal of Forestry Research》2024年第5期78-90,共13页林业研究（英文版）

基　　金：supported by UCAR,Ministerio de Agricultura,Ganadería y Pesca de la Nación,Argentina(PIA 12010 and 14,031);ANPCyT-MINCyT,Argentina(PUE INFIVE:10520180101142CO).

摘　　要：Forest disturbances at gap levels are one of the most important events for the regeneration and establishment of intermediate tree species.Abrupt canopy openings expose plants to high light intensity and high evaporative demands that stress shade-acclimated plants.Later,the slow closure of gaps reduces light availability to plants established when the incident irradiation was higher.This work evaluated the morphological and physiological acclimation of Cabralea canjerana(Vell)Mart.regeneration to sudden and to gradual changes in canopy cover.A pot experiment was carried out with plants exposed to a sudden opening.A few days after the light shock,plants rapidly increased photosynthetic rates and decreased leaf water potential.After two months,plants activated physiological responses at leaf and whole plant levels to high light and water stresses,e.g.,increased stoma-tal conductance,stomatal index and reduction of leaf:fine roots ratio and chlorophyll.After seven months,hydraulic conductivity of petioles and the whole leaf increased,and growth was much higher than plants that remained under the canopy.In a field experiment in gaps in the rainforest,plants acclimated to all canopy covers.Seven years after planting,growth was maximum in open environments within the gaps,even if the canopy closed during the first 20 months after planting.In conclusion,if this species is planted to enrich the rainforest,positions within gaps with lower canopy cover should be chosen and gap closure will not affect growth.To manage C.canjerana natural regeneration,the opening of gaps and removal of understory will increase survival and growth without the risk that the stress caused by these sudden openings could lead to the death of seedlings.Com-bining pot and field experiments helps to understand the autecology of trees with particular ecological interest,and to build sound restoration practices.

关 键 词：Cabralea canjerana Atlantic forest Abiotic stress Regeneration SEEDLING 

分 类 号：S718.5[农业科学—林学]