AbstractThe kinetics of decline in net photosynthesis and transpiration after cutting was followed in a batch ofLolium multiflorumleaves at light saturation in an assimilation chamber where air temperature, leaf temperature, carbon dioxide concentration and water vapour concentration were controlled. After leaf excision the rates of photosynthesis and transpiration increased or remained the same for 1–2 min and then decreased sharply following a curve with two breaks of slope at 15 min and 30 min. To investigate stomatal behaviour, fragments of leaf tissue were removed, fixed by freezing in liquid nitrogen, then examined by scanning electron microscopy. The stomata were optically closed by 15 min after excision. The practical implications for field drying of Italian ryegrass are discusse