Juvenile Coffee Leaves Acclimated to Low Light Are Unable to Cope with a Moderate Light Increase

Frontiers in Plant Science

Sandrine Roques¹  Denis Fabre¹  Hervé Etienne²  Benoit Bertrand²  Lucile Toniutti²  Jean-Christophe Breitler²  Luc P. R. Bidel³  Yves Lizzi⁴  Jawad Aarrouf⁴  Laurent Urban⁴  Sylvie Doulbeau⁵  Claudine Campa⁶  Céline Letrez⁶  Philippe La Fisca⁷  Laurence Mondolot⁷ 

[1]CIRAD, Unité Mixte de Recherche-Amélioration Génétique et Adaptation des Plantes Méditérranéennes et TropicalesMontpellier, France

[2]CIRAD, Unité Mixte de Recherche-Interactions Plantes Microorganismes Environnement, IRD, CIRAD, Université de MontpellierMontpellier, France

[3]Institut National de la Recherche Agronomique (INRA), Unité Mixte de Recherche-Amélioration Génétique et Adaptation des Plantes Méditerranéennes et TropicalesMontpellier, France

[4]Institut National de la Recherche Agronomique (INRA)-Centre d’Avignon, UR 1115 Plantes et Systèmes de Culture HorticolesAvignon, France

[5]Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche-Diversité Adaptation et Développement des Plantes, IRD, Université de MontpellierMontpellier, France

[6]Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche-Interactions Plantes Microorganismes Environnement, IRD, CIRAD, Université de MontpellierMontpellier, France

[7]Laboratoire de Botanique, Phytochimie et Mycologie, Faculté de Pharmacie, Unité Mixte de Recherche 5175 Centre d’Ecologie Fonctionnelle et Evolutive, Centre National de la Recherche Scientifique (CNRS)Montpellier, France

关键词: antioxidant activity;    Arabica;    coffee culture;    phenolics;    photoprotection;    plasticity;   

DOI  :  10.3389/fpls.2017.01126

来源: DOAJ

【 摘 要 】

The understorey origin of coffee trees and the strong plasticity of Coffea arabica leaves in relation to contrasting light environments have been largely shown. The adaptability of coffee leaves to changes in light was tested under controlled conditions by increasing the illumination rate on C. arabica var. Naryelis seedlings acclimated to low light conditions and observing leaf responses at three different developmental stages (juvenile, growing and mature). Only mature leaves proved capable of adapting to new light conditions. In these leaves, different major mechanisms were found to contribute to maintaining a good photosynthetic level. With increased illumination, a high photosynthetic response was conserved thanks to fast nitrogen remobilization, as indicated by SPAD values and the photorespiration rate. Efficient photoprotection was accompanied by a great ability to export sucrose, which prevented excessive inhibition of the Calvin cycle by hexose accumulation. In contrast, in younger leaves, increased illumination caused photodamage, observable even after 9 days of treatment. One major finding was that young coffee leaves rely on the accumulation of chlorogenic acids, powerful antioxidant phenolic compounds, to deal with the accumulation of reactive oxygen species rather than on antioxidant enzymes. Due to a lack of efficient photoprotection, a poor ability to export sucrose and inadequate antioxidant protection, younger leaves seemed to be unable to cope with increased illumination. In these leaves, an absence of induced antioxidant enzyme activity was accompanied, in growing leaves, by an absence of antioxidant synthesis or, in juvenile leaves, inefficient synthesis of flavonoids because located in some epidermis cells. These observations showed that coffee leaves, at the beginning of their development, are not equipped to withstand quick switches to higher light levels. Our results confirm that coffee trees, even selected for full sunlight conditions, remain shade plants possessing leaves able to adapt to higher light levels only when mature.

【 授权许可】

Unknown