Abscisic acid is produced in the roots in response to decreased soil water potential and other situations in which the plant may be under stress. s-ABA then translocates to the leaves, where it rapidly alters the osmotic potential of stomatal guard cells, causing them to shrink and stomata to close. Strawberries have a lot of stomata, so the effect is marked in this plant species :)

Thanks for your nice explanation.

Andrew gave the precise answer.