Cold Acclimation Ability and Photosynthesis among Species of the Tropical Coffea Genus

Abstract

Three Coffea species (C. arabica cv. Icatu, C. canephora cv. Apoat and C. dewevrei) were tested in order to identify and study the mechanisms of tolerance to low, non-freezing temperatures. Several photosynthesis-related parameters were monitored during a 20-day period of gradual temperature decrease, from 25/20 8C (day/night) down to 15/10 8C, during chilling treatments (15/4 8C), and upon rewarming (25/20 8C). Differences were found among species, both during low temperature exposure and during rewarming. In general, Coffea species showed cold-induced photoinhibition of photosynthesis, which was attributable to biochemical (in vivo ribulose-1,5-bisphosphate carboxylase/oxygenase activity and carbohydrate synthesis) and biophysical (antennae functioning, photosystem II efficiency and linear electron transport) inactivation, rather than to stomatal constraints. The moderately low temperature of 15/10 8C was enough to cause a negative impact on net photosynthesis (A), mostly due to low (initial) rubisco activity in all species. However, C. arabica cv. Icatu showed a higher tolerance to chilling and recovered quickly and completely upon rewarming, as assessed from the impacts on the photosynthetic machinery (e.g. A max , F o , F v /F m , F v ¢/F m ¢, q P , f e , rubisco activity) and on carbohydrate metabolism. Such lesser effects are likely to be related to the strong increases and higher contents of zeaxanthin, lutein and b-carotene that presumably increased the ability to dissipate excitation energy and contributed to protect the photosynthetic apparatus. During cold exposure, a significant reduction of the a/b carotene ratio, which is considered an acclimation feature, was observed solely in C. arabica cv. Icatu. However, C. canephora cv. Apoat and, especially, C. dewevrei showed to be highly cold-sensitive. In these latter species, the photoinhibitory impairments to photosynthesis were stronger, probably due to the lower contents of protecting pigments during chilling conditions that lead to a higher vulnerability to excess excitation energy. Moreover, the mesophyll impairments (e.g. A max , F v /F m , f e ) became significant even at moderately low temperatures of 15/10 8C, and a lower ability to recover after chilling exposure was observed. The limitation of in vivo rubisco activity and A max may have been due to substrate limitation, but disturbances in sugar metabolism could also play an important role in the expression of chilling sensitivity in C. canephora cv. Apoat and C. dewevrei.

Impacts of drought and temperature stress on coffee physiology and production: a review

“…Such cold-induced tolerance includes increases in enzyme activities (e.g., from the Calvin cycle and sugar metabolism), reinforcement of energy dissipation mechanisms and antioxidative molecules, qualitative and quantitative changes in lipid (e.g., level of FA saturation) and protein membrane composition, all protecting cell structures and keeping metabolic pathway regulation mechanisms, as reported for coffee (DaMatta et al, 1997b;Campos et al, 2003;Ramalho et al, 2003;Quartin et al, 2004). In addition, the maintenance of respiratory metabolism is also of great importance, since it allows the production of energy, reducing power and metabolic intermediates, necessary for repair processes that are increasingly important under chilling conditions.…”

“…Apoatã and C. dewevrei more sensitive and Icatu more tolerant, as already mentioned. Icatu showed a lower increase in membrane selectivity loss and in peroxidative degradation, that could be related to the maintenance of (or increase in) the global FA saturation level of membrane lipids and the reinforcement of the antioxidative system (observed also in Catuaí), responsible for maintaining an organized and functional membrane structure less sensitive to ROS attack on the double bonds of unsaturated FA (Quartin et al, 2000;Campos et al, 2003;Ramalho et al, 2003;Ramalho et al, unpublished results). In contrast, Apoatã and Piatã submitted to chilling showed a strong increase (31 % and 21 %, respectively) in FA unsaturation, which could help to maintain membrane fluidity, but turn it more sensitive to ROS, resulting in higher membrane leakage (Campos et al, 2003).…”

“…A recent set of studies with potted plants of several coffee genotypes, which were submitted to low positive temperatures (Quartin et al, 2000;Campos et al, 2003;Ramalho et al, 2003;Ramalho et al, unpublished results) showed that Icatu (a hybrid of C. arabica x C. canephora, but backcrossed so many times with C. arabica that some researchers consider it as an arabica cultivar) exhibited better cold acclimation ability than the other genotypes studied (see also "Low positive temperature stress" section), namely due to the small membrane selectivity loss and peroxidative degradation. This would be related to the maintenance (or increase) in the FA saturation of membrane lipids and the reinforcement of the antioxidative system (observed also in cv.…”

Seasonal Vegetative Growth in Genotypes of Coffea canephora, as Related to Climatic Factors

“…In coffee, low temperatures (below the range of 13-17 ºC, depending on the authors and genotypes) and pronounced water deficit (-3 MPa) affect various components of the photosynthetic process, as it reduces the stomatal conductance, net photosynthesis, photochemical efficiency of photosystem II, thylakoid electron transport, enzyme activity and carbon metabolism as a whole. Low temperatures also affect the composition and structure of photosynthetic pigment complexes and of the lipid matrix of cell membranes, particularly in the chloroplast, although to different extent among genotype and species Ramalho et al, 2003;Silva et al, 2004, Praxedes et al, 2006Partelli et al, 2009Partelli et al, , 2011Batista-Santos et al, 2011). Such changes may reflect impairments or damages, but in some cases are responses towards plant cold acclimation.…”

Crescimento vegetativo de Coffea arabica L. influenciado por irrigação e fatores climáticos no Cerrado Goiano

“…Ademais, esses fatores acarretam redução da condutância estomática, da fotossíntese líquida, da eficiência fotoquímica do fotossistema II, do transporte tilacoidal de elétrons, da atividade enzimática, bem como o metabolismo do carbono, alterando ainda a composição e a estrutura dos complexos de pigmentos fotossintéticos, classes lipídicas e ácidos graxos com intensidades distintas entre genótipos e espécies (RAMALHO et al, 2003, SILVA et al, 2004, PARTELLI et al, 2009, PARTELLI et al, 2010a.…”