ABSTRACT
Cotton flower petals expand even when all leaves on the plant are wilted because of water stress. We examined the water relations of the expanding petals to determine whether this was accomplished by osmoregulation. Flower petals from 3 day preanthesis to day of anthesis were sampled and their water potential, osmotic potential, turgor potential, and relative water content assayed. The water status of the cotton flower petal is independent of the water status of the rest of the plant. It always maintained a higher water potential than subtending bract or leaves regardless of irrigation treatment or age. Its relative water content was constant across all irrigation treatments. The mechanism by which this tissue is able to maintain a higher water potential than other tissues should be investigated further.
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