TY - JOUR

T1 - Roots are important sources of carbohydrates during flowering and fruiting in ‘Valencia’ sweet orange trees with varying fruit load

AU - Dovis, Veronica Lorena

AU - Machado, Eduardo Caruso

AU - Ribeiro, Rafael Vasconcelos

AU - Magalhaes Filho, Jose Rodrigues

AU - Marchiori, Paulo Eduardo Ribeiro

AU - Sales, Cristina R. G.

PY - 2014/7/22

Y1 - 2014/7/22

N2 - The influence of fruit loading on flowering and fruiting, CO2 assimilation, and non-structural carbohydrates (NSC) in citrus trees was evaluated in four-year-old ‘Valencia’ sweet orange grafted onto ‘Rangpur’ lime. One group of trees was completely de-fruited (DFT) on May 14 (autumn), whereas fruit were left on the remaining trees (FT). The seasonal variation in photosynthesis and stomatal conductance was unaffected by fruit loading, with the minimum diurnal-integrated CO2 assimilation (PNI) occurring in July (98.3 mmol m−2 day−1) and the maximum PNI occurring in November (199.5 mmol m−2 day−1). Fruit loading inhibited sprouting and flowering in the citrus trees, but this effect was not correlated with NSC in the leaves, branches, or roots. The DFT trees exhibited nearly four times as many reproductive structures as the FT trees, with a high remobilization of reserves. Our data showed that flowers are stronger sinks than fruit and that flowering is the most expensive phenological stage. In the DFT trees, approximately 80% of NSC were consumed prior to the end of fruit drop, primarily until flowering. NSC reserves from leaves, branches, and roots were remobilized. Between the stages of de-fruiting and the end of physiological fruit drop, the plants remobilized approximately 312 g NSC, with the roots contributing more than 230 g NSC per plant.

AB - The influence of fruit loading on flowering and fruiting, CO2 assimilation, and non-structural carbohydrates (NSC) in citrus trees was evaluated in four-year-old ‘Valencia’ sweet orange grafted onto ‘Rangpur’ lime. One group of trees was completely de-fruited (DFT) on May 14 (autumn), whereas fruit were left on the remaining trees (FT). The seasonal variation in photosynthesis and stomatal conductance was unaffected by fruit loading, with the minimum diurnal-integrated CO2 assimilation (PNI) occurring in July (98.3 mmol m−2 day−1) and the maximum PNI occurring in November (199.5 mmol m−2 day−1). Fruit loading inhibited sprouting and flowering in the citrus trees, but this effect was not correlated with NSC in the leaves, branches, or roots. The DFT trees exhibited nearly four times as many reproductive structures as the FT trees, with a high remobilization of reserves. Our data showed that flowers are stronger sinks than fruit and that flowering is the most expensive phenological stage. In the DFT trees, approximately 80% of NSC were consumed prior to the end of fruit drop, primarily until flowering. NSC reserves from leaves, branches, and roots were remobilized. Between the stages of de-fruiting and the end of physiological fruit drop, the plants remobilized approximately 312 g NSC, with the roots contributing more than 230 g NSC per plant.

KW - Fruit load

KW - Photosynthesis

KW - Alternate bearing

KW - Root reserves

KW - Remobilization

KW - Citrus

U2 - 10.1016/j.scienta.2014.05.011

DO - 10.1016/j.scienta.2014.05.011

M3 - Journal article

VL - 174

SP - 87

EP - 95

JO - Scientia Horticulturae

JF - Scientia Horticulturae

SN - 0304-4238

ER -