Morphological and physiological acclimations of coffee seedlings to growth over a range of fixed or changing light supplies

作者：Rodriguez Lopez Nelson F; Martins Samuel C V; Cavatte Paulo C; Silva Paulo E M; Morais Leandro E; Pereira Lucas F; Reis Josimar V; Avila Rodrigo T; Godoy Alice G; Lavinski Alyne O; DaMatta Fabio M^*

来源：Environmental and Experimental Botany, 2014, 102: 1-10.

DOI：10.1016/j.envexpbot.2014.01.008

• Coffea arabica
• Light acclimation
• Phenotypic plasticity
• Photosynthesis
• Photoinhibition
• Sun/shade tolerance

Acclimations to low and high light levels are located in opposite extremes. We examined how the coffee plant (Coffea arabica), which is considered to be shade-demanding although it performs well under full sun exposure, can acclimate to a range of light regimens. We hypothesised that the growth and physiological performance depends on the total amount of light received by the plant per day and on the temporal order of diurnal variations in the light supply. The biomass accumulation and allocation and the key photosynthetic traits of pot-grown coffee seedlings were examined over a range of light treatments as follows: plants grown entirely under 100%, 40% or 10% sunlight; plants grown at either 40% or 10% sunlight from sunrise to midday and then submitted to full sunlight until sunset; and plants grown under full sunlight from sunrise to midday and then submitted to either 40% or 10% sunlight throughout the afternoon. The total biomass increased linearly with the increasing total light supply; however, plants receiving high amounts of light in the morning grew more than those receiving high amounts of light in the afternoon. Extensive morphological changes (e.g., specific leaf areas and leaf area ratios) primarily responsive to total light rather than diurnal light fluctuations or light quality, at a given light supply, were noted. In contrast, changes in the photosynthetic performance per unit leaf area among the treatments were narrower and apparently unrelated to carbohydrate accumulation or photoinhibition. Overall, we found a poor leaf-level physiological plasticity of traits to light. We suggest that adjustments in leaf number and leaf area, coupled with whole-plant physiological adjustments, could largely account for the differences in the biomass amongst treatments. We also suggest that coffee could be classified as a shade-tolerant species as its traits do not match the requirements of either a classic shade-avoiding or a classic shade-demanding species.

• 出版日期2014-6