Physiological mechanisms preventing plant wilting under heat stress: a case study on a wheat (Triticum durum Desf.) bound water-mutant

Wilting is the main symptom of plants suffering the dehydration stresses, but the mechanisms governing thisphenomenon are yet to be completely understood. In this work, a holistic analysis of physiological traitspotentially involved in leaf wilting was performed, comparing a wheat wild type (WT), Trinakria and its water-mutant (WM) with a "high affinity for bound water (BW)". In addition to the tendency to wilt, significant dif-ferences between genotypes were observed for leaf temperature achieved under heat stress, leaf turgor loss withdecreasing water potential, cuticular transpiration, and Q10 of leaf water uptake velocity. We hypothesize thatmutant plants prevent the increase in leaf temperature thanks to the rapid and low energetic cost of waterdiffusion from the vessels to the outside, driven by the BW. Under strong thermal-induced dehydration stress, BWdelays leaf wilting through its positive effects on cell wall elasticity and passive osmoregulation