Could alcohol make vines more drought-resistant?

n Toulouse, the young researcher Neila Ait Kaci has just demonstrated that adding small quantities of alcohol to vines can improve their response to water stress. She sprayed potted cuttings of Gamay just over a month old with differing physiological quantities of ethanol. Kaci then measured the plants’ transpiration based on the weight of the pots and the vines’ leaf surface.

For three weeks, Kaci calculated the fraction of transpirable soil water (FTSW) on a daily basis. Starting at 1, the FTSW for all the well-watered pots remained above 0.7 for the 24 days measured. As expected, for the pots subjected to water stress it gradually dropped from 1 to under 0.1 over an average of 15 days. The FTSW dropped at a reduced rate, remaining above 0.1 through to the 24th day.

The technique has already been successfully trialled on wheat and rice and must now be tested in real conditions. “The impact of the ethanol still needs to be assessed on several variables such as photosynthesis and leaf temperature to avoid scorching”, explains the researcher. Yields will also need to be monitored. “In a previous study, spraying with ethanol led to a 10% increase in berry weight, but the vine had not been subjected to water stress”, concludes Kaci.