Situation of tension and difficulty faced by plants in the face of lack of water especially in the summer. The water level of the plants results from the balance between the one they absorb by the roots and the one they give off in the traspiration by leaves, stomata and lenticelas. In the face of scarcity they seek solutions : limit evaporation and deepen the root. The old vine, for example, thus gives the grapes and wine new nuances and aromas, in the words of the connoisseurs.
