Relationship between flower intensity, oxidative damage and protection in citrus under water stress conditions

Manzi, Matias; Borsani, Omar; Díaz, Pedro; Rivas Sánchez, Fernando

Relationship between flower intensity, oxidative damage and protection in citrus under water stress conditions

2015

Manzi, Matias | Borsani, Omar | Díaz, Pedro | Rivas Sánchez, Fernando

Stress conditions are known to promote reproductive sprouting and flowering in Citrus. However, signalling involved in stress perception and flowering induction remains obscure. To gain insight into the mechanism involved in stress signalling, the aim of this work was to study the physiological and biochemical changes triggered by water stress and their relationship with budbreak in ‘Valencia’ orange (C. sinensis (L.) Osb.) and ‘Ellendale’ tangor (C. reticulate Bl.). Water stress was promoted by subjecting plants to 70-days of water deficit (water potential: Ψw <-4.0 MPa) thereby increasing photoinhibition (decreasing Fv/Fm and increasing Fo). An increase in oxidative damage was achieved. Water stress raised proline content in both cultivars and was slightly higher in ‘Ellendale’. After rewatering, plants of both cultivars increased sprouting and flowering. Under these conditions, ‘Valencia’ trees produced 55% more flowers (160 flowers/100 nodes) than ‘Ellendale’. This was explained by an increase in multiflowered shoots. These results suggest that Citrus flowering in response to stress conditions is variety dependent and that the active compounds that increased in response to stress such as proline, are positively correlated with flowering intensity. Overall, the intensity of oxidative damage in Citrus leaves during stress could act as an indicator of flowering intensity in each variety.

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