DROUGHT IMPACTS THE TIGHTLY INTERRELATED SYSTEMS OF CARBON AND WATER, YIELDING A COMPLEXPROBLEM FOR PLANTS. DURING WATER STRESS, PLANTS CLOSE THEIR STOMATA TO PREVENT WATER LOSS FROMLEAVES, BUT THIS COMES AT THE COST OF REDUCED CARBON CAPTURE. PLANTS ULTIMATELY SUCCUMB TO WATER STRESS BY CARBON STARVATION THROUGH IMBALANCES BETWEEN CARBOHYDRATE SUPPLY AND DEMAND ("SUFFERING FROM HUNGER") ANDHYDRAULIC FAILURE THROUGH LOSS OF FUNCTION OF THE WATER TRANSPORT SYSTEM ("SUFFERING FROM THIRST"). HOWEVER, THE PHYSIOLOGICAL MECHANISMSUNDERLYING THE DIFFERENT WAYS IN WHICH PLANTS RESPOND TO WATER STRESS REMAIN POORLY UNDERSTOOD.THIS KNOWLEDGE GAP HINDERS OUR ABILITY TO PREDICT HOW PLANTS WILL RESPOND OVER THE SECOND HALF OFTHE 21ST CENTURY AS THE INTENSITY AND SEVERITY OF DROUGHTS ARE PROJECTED TO INCREASE.THIS WORK WILL FOCUS ON THE CHALLENGE OF WATER STRESS FOR AGRICULTURAL CROPS DUE TO THEBIOLOGICAL, SOCIAL, AND ECONOMIC CONSEQUENCES. THE OVERARCHING GOAL IS TO 1) ADVANCE OURUNDERSTANDING OFCARBON AND WATER DYNAMICS IN CROPS UNDER WATER STRESS, 2) IMPROVE OUR ABILITY TOPREDICT WHICH CROPS ARE MOST AT RISK OF DAMAGE UNDER GLOBAL CHANGE, AND 3) INFORM MANAGEMENTSTRATEGIES FOR IRRIGATION AND CROP SELECTION TO OPTIMIZE AGRICULTURAL PRODUCTION. TO ACCOMPLISH THISGOAL, TOOLS FROM PLANT PHYSIOLOGY WILL BE COMBINED WITH CUTTING-EDGEIN VIVOMICROCT IMAGINGAND MACHINE LEARNING TECHNOLOGY TO STUDY THE PHYSIOLOGICAL RESPONSES OF FOUR ECONOMICALLYIMPORTANT PERENNIAL CROPS TO EXPERIMENTAL DROUGHT. THIS WORK WILL ADVANCE OUR UNDERSTANDING OFCROP PLANT STRESS PHYSIOLOGY, AND HAS BROADER IMPLICATIONS FOR ENSURING THE HEALTH AND PRODUCTIONOF AGRICULTURAL CROPS IN A CHANGING WORLD.