Effects of shade on the development and sugar metabolism of coffee (Coffea arabica L.) fruits

Abstract

Coffee fruits grown in shade are characterized by larger bean size than those grown under full-sun conditions. The present study assessed the effects of shade on bean characteristics and sugar metabolism by analyzing tissue development, sugar contents, activities of sucrose metabolizing enzymes and expression of sucrose synthase-encoding genes in fruits of coffee (Coffea arabica L.) plants submitted to full-sun (FS) and shade (SH) conditions. Evolution of tissue fresh weights measured in fruits collected regularly from flowering to maturation indicated that this increase is due to greater development of the perisperm tissue in the shade. The effects of light regime on sucrose and reducing sugar (glucose and fructose) contents were studied in fresh and dry coffee beans. Shade led to a significant reduction in sucrose content and to an increase in reducing sugars. In pericarp and perisperm tissues, higher activities of sucrose synthase (EC 2.4.1.13) and sucrose-phosphate synthase (SPS: EC 2.4.1.14) were detected at maturation in the shade compared with full sun. These two enzymes also had higher peaks of activities in developing endosperm under shade than in full sun. It was also noted that shade modified the expression of SUS-encoding genes in coffee beans; CaSUS2 gene transcripts levels were higher in SH than in FS. As no sucrose increase accompanied these changes, this suggests that sucrose metabolism was redirected to other metabolic pathways that need to be identified.

Climatic Vulnerability in Robusta Coffee Mitigation and Adaptation

“…Notably, also the quality of the produced bean under supra-optimal temperatures (or lower altitudes) could be affected, similarly to what was reported to C. arabica fruits, related to a faster (but incomplete) fruit maturation and to the presence of chemical detrimental compounds (as CGAs), with negative impact on the beverage quality (Vaast et al, 2006;Geromel et al, 2008;Bertrand et al, 2012;Barbosa et al, 2012). Furthermore, it is known that these environmental limitations of high temperature and chronic low water availability reported for this region will impact the plant at the physiological level, namely in what concerns the maintenance of balance between respiration and photosynthesis.…”

Ambiente e variedades influenciam a qualidade de cafés das matas de minas

“…Fatores do ambiente, como temperaturas anuais mais baixas recorrentes em maiores altitudes, associados a eventos fisiológicos, como períodos mais longos de enchimento dos grãos, são relatados na literatura e fornecem indícios para explicar as diferenças encontradas na composição química do grão, responsáveis pela qualidade final da bebida (FAGAN et al, 2011;GEROMEL et al, 2008;VAAST et al, 2006).…”

Effect of Dominant Shade Trees on Coffee Production in Manasibu District, West Oromia, Ethiopia

“…There was similar report from Jima zone of Ethiopia (Bote and Struik, 2011). Finding of Geromel et al (2008) indicated that coffee weight was significantly higher in shade zone. Earlier study of Muleta et al (2011) from southwest Ethiopia also confirm higher coffee yield from shade grown.…”