Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Increased sink strength offsets the inhibitory effect of sucrose on sugarcane photosynthesis
AU - Ribeiro, Rafael V.
AU - Machado, Eduardo C.
AU - Magalhaes Filho, Jose Rodrigues
AU - Moreira Lobo, Ana Karla
AU - Martins, Marcio Oliveira
AU - Silveira, Joaquim Albenisio Gomes
AU - Yin, Xinyou
AU - Struik, Paul C.
PY - 2017/1/31
Y1 - 2017/1/31
N2 - Spraying sucrose inhibits photosynthesis by impairing Rubisco activity and stomatal conductance (gs), whereas increasing sink demand by partially darkening the plant stimulates sugarcane photosynthesis. We hypothesized that the stimulatory effect of darkness can offset the inhibitory effect of exogenous sucrose on photosynthesis. Source-sink relationship was perturbed in two sugarcane cultivars by imposing partial darkness, spraying a sucrose solution (50 mM) and their combination. Five days after the onset of the treatments, the maximum Rubisco carboxylation rate (Vcmax) and the initial slope of A-Ci curve (k) were estimated by measuring leaf gas exchange and chlorophyll fluorescence. Photosynthesis was inhibited by sucrose spraying in both genotypes, through decreases in Vcmax, k, gs and ATP production driven by electron transport (Jatp). Photosynthesis of plants subjected to the combination of partial darkness and sucrose spraying was similar to photosynthesis of reference plants for both genotypes. Significant increases in Vcmax, gs and Jatp and marginal increases in k were noticed when combining partial darkness and sucrose spraying compared with sucrose spraying alone. Our data also revealed that increases in sink strength due to partial darkness offset the inhibition of sugarcane photosynthesis caused by sucrose spraying, enhancing the knowledge on endogenous regulation of sugarcane photosynthesis through the source-sink relationship.
AB - Spraying sucrose inhibits photosynthesis by impairing Rubisco activity and stomatal conductance (gs), whereas increasing sink demand by partially darkening the plant stimulates sugarcane photosynthesis. We hypothesized that the stimulatory effect of darkness can offset the inhibitory effect of exogenous sucrose on photosynthesis. Source-sink relationship was perturbed in two sugarcane cultivars by imposing partial darkness, spraying a sucrose solution (50 mM) and their combination. Five days after the onset of the treatments, the maximum Rubisco carboxylation rate (Vcmax) and the initial slope of A-Ci curve (k) were estimated by measuring leaf gas exchange and chlorophyll fluorescence. Photosynthesis was inhibited by sucrose spraying in both genotypes, through decreases in Vcmax, k, gs and ATP production driven by electron transport (Jatp). Photosynthesis of plants subjected to the combination of partial darkness and sucrose spraying was similar to photosynthesis of reference plants for both genotypes. Significant increases in Vcmax, gs and Jatp and marginal increases in k were noticed when combining partial darkness and sucrose spraying compared with sucrose spraying alone. Our data also revealed that increases in sink strength due to partial darkness offset the inhibition of sugarcane photosynthesis caused by sucrose spraying, enhancing the knowledge on endogenous regulation of sugarcane photosynthesis through the source-sink relationship.
KW - Photosynthesis
KW - Saccharum
KW - Source-sink
KW - Sugarcane
KW - Sucrose
U2 - 10.1016/j.jplph.2016.11.005
DO - 10.1016/j.jplph.2016.11.005
M3 - Journal article
VL - 208
SP - 61
EP - 69
JO - Journal of Plant Physiology
JF - Journal of Plant Physiology
SN - 0176-1617
ER -