Sucrose feeding
Immediately after emerging, the fifth leaf of well-watered plants and plants subjected to mild and severe drought stress were fed with 0.3 M sucrose solution contained in a glass vial through the cut leaf tip as in Spoehr (1942). The treatment was initiated early in the beginning of the night (22:00h). After the treatment and at the end of the night (6:00 h, EN), 10 samples of 1 cm were collected along the base of the leaf for soluble sugar concentration determination. Leaf length was measured as described below for LER determination.