CAVITATIONS INDUCED BY WATER STRESS IN PLANTS

AN ULTIMATE GOAL OF GENETIC ENGINEERING IS TO BUILD INTO PLANTS THE GENES THAT PROVIDE RESISTANCE TO A WIDE RANGE OF ENVIRONMENTAL STRESSES SO AS TO PROMOTE BIOMASS PRODUCTION. A NECESSARY PREREQUISITE TO GENETIC ENGINEERING FOR DROUGHT RESISTANCE IS TO UNDERSTAND THE MECHANISMS THAT CONFER DROUGHT RESISTANCE TO PLANTS. IT IS KNOWN THAT AN EXPLOSIVEPHASE CHANGE (TERMED A CAVITATION CAN OCCUR IN THE XYLEM WATER OF PLANTS SUBJECTED TO A RELATIVELY MILD WATER STRESS.A CAVITATION EVENT IMPAIRS WATER CONDUCTION AND RENDERS THE PLANT EVEN MORE SUSCEPTIBLE TO WATER STRESS. LITTLE IS KNOWN ABOUT THE EXTENT TO WHICH CAVITATION EVENTS AFFECT PLANT PRODUCTIVITY OR ABOUT THE MECHANISMS BY WHICH CAVITATIONS ARE AVOIDED BY PLANTS. THIS RESEARCH PROPOSAL OUTLINES A PROGRAM OF WORK TO DEVELOP AND OPTIMIZE AN INSTRUMENT THAT: 1. WILL ALLOW PLANT STRESS PHYSIOLOGISTS TO STUDY CAVITATIONEVENTS IN PLANTS AND THE MECHANISMS BY WHICH CAVITATION EVENTS ARE AVOIDED, AND 2. WILL ACT AS A GENERAL INDICATOR OF WATER STRESS THAT CAN BE USED BY FARMERS TO OPTIMIZE IRRIGATION PRACTICES. THE INSTRUMENT WILL BE BASED UPON THE FACT THAT CAVITATION PRODUCES ULTRASONIC WAVES, WHICH CAN BE DETECTED USING THE TECHNOLOGY OF ACOUSTIC EMISSION PREVISOUSLY DEVELOPED FOR DETECTING FLAWS IN BRIDGES, AIRCRAFT AND NUCLEAR REACTORS.