Nocturnal transpiration currently corresponds to 15-50% of total water loss compared to diurnal transpiration, depending on the environmental conditions, for grapevines. This phenomenon could be exacerbated in a climate change scenario, which predicts that nocturnal temperatures will increase at a higher rate compared to diurnal temperatures (IPCC 2010). Since nocturnal transpiration is not associated to photosynthesis it contributes to reduce water use efficiency. This research area will be one of the main focuses of the VoF, which will aim to develop irrigation and management techniques to reduce transpiration and to maximise refill or night-time re-hydration.

The hypothesis that nocturnal transpiration will decrease as diurnal plant water stress increases was tested on the Tempranillo and 6 other cultivars in Mallorca – Spain. Recently, a paper describing results and conclusions from this study has been accepted for publication in the Agricultural Water Management Journal.

Escalona J., Fuentes S., Tomas M., Martorell S., Flexas J., Medrano H. 2012. Responses of leaf night respiration and transpiration to water stress in Vitis vinifera L. Agricultural Water Management (Accepted).