**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** WEEDS CHALLENGE THE SUSTAINABILITY AND PROFITABILITY OF CROP PRODUCTION SYSTEMS IN THE U.S. IF LEFT UNCHECKED, THE ANNUAL CROP YIELD LOSS DUE TO WEEDS IS ESTIMATED TO BE &GT;40 BILLION DOLLARS, AND DESPITE THE CURRENT AGGRESSIVE MANAGEMENT PRACTICES, WEEDS CAUSE A 12% OVERALL REDUCTION IN CROP YIELD. COMPOUNDING THIS PROBLEM IS THE PHYSIOLOGICAL ADAPTATION IN WEEDS THAT WOULD ALLOW THEM TO CIRCUMVENT THE CURRENT MANAGEMENT PRACTICES AND THRIVE UNDER OTHERWISE LETHAL ENVIRONMENTS. PARTLY, THE ABILITY OF WEEDS TO CIRCUMVENT THESE CHALLENGES COULD ORIGINATE FROM THEIR ABILITY TO PRODUCE AND UTILIZE A RICH ARRAY OF PHYTOCHEMICALS. THESE PHYTOCHEMICALS COULD FACILITATE THE WEEDY NATURE IN MULTIPLE WAYS: I) THE PHYTOCHEMISTRY COULD NEUTRALIZE THE HARMFUL RADICALS THAT ARE PRODUCED DURING THE STRESS, II) THE PHYTOCHEMICALS, DUE TO ITS GROWTH-STIMULATING EFFECT, COULD FACILITATE AN OVER-COMPENSATORY RECOVERY OF WEEDS FROM A MILD STRESS (HORMESIS), III) SOME OF THESE PHYTOCHEMICALS THAT ARE PRODUCED IN RESPONSE TO STRESS COULD LINGER EVEN AFTER THE INITIAL STRESS HAS PASSED, AND THUS COULD PROTECT THE WEEDS FROM FUTURE STRESS (STRESS PRIMING), IV) WHEN THE PHYSIOLOGICAL DAMAGE CAUSED BY TWO DIFFERENT STRESSORS ARE SIMILAR, THE EXPOSURE OF WEEDS TO ONE STRESSOR COULD ALSO PROTECT THE WEEDS FROM THE OTHER, EVEN WITHOUT THE WEED EXPERIENCING THE SECOND STRESSOR DIRECTLY (CROSS-PRIMING). EVEN THOUGH IT IS WELL DOCUMENTED THAT WEEDS ARE ABUNDANT IN PHYTOCHEMICALS, AND PHYTOCHEMICAL INCREASES IN RESPONSE TO STRESS, THE PRECISE MECHANISMS THROUGH WHICH THESE COMPOUNDS FACILITATE STRESS RESILIENCE IS LESS KNOWN.THE KEY OBJECTIVE OF THIS RESEARCH IS TOTO INVESTIGATE THE ROLE OF PHYTOCHEMICALS IN FACILITATING HORMETIC OUTCOMES IN WEEDS WHEN EXPOSED TO MILD ENVIRONMENTAL STRESSORS.TO INVESTIGATE THE MECHANISMS THROUGH WHICH THE INITIAL STRESS RESPONSE EQUIPS THE WEEDS TO OVERCOME FUTURE STRESS THAT MIGHT BE RELATED OR UNRELATED TO THE INITIAL STRESS.WE WILL USE PALMER AMARANTH (AMARANTHUS PALMERI), AN ANNUAL WEED, AS A STUDY SPECIES.AMARANTHUS PALMERIIS THE MOST ECONOMICALLY DAMAGING GLYPHOSATE-RESISTANT WEED, MAINLY IN CORN, COTTON AND SOYBEAN PRODUCTION SYSTEMS IN THE U.S., CAUSING YIELD LOSSES RANGING FROM 50 TO 95%. THE KNOWLEDGE FROM THIS STUDY WOULD ENABLE US TO UNDERSTAND STRESS MITIGATION STRATEGIES IN WEEDS AND HELP US DEVISE NOVEL PRACTICES THAT WOULD PREDISPOSE THE WEEDS TO MANAGEMENT PRACTICES BY DISRUPTING THE PHYTOCHEMICAL PRODUCTION IN WEEDS.