The Biochemical Effects of Heat Stress On Flowering Cotton

Cotton yields in the Mississippi Delta are below optimum and suffer from significant year-to-year variability.  Research has identified the correlation of high temperature stress and reduced cotton yields, however little work identifies potential acclimation effects cotton may have to stressful environmental factors such as temperature.  A field study was conducted in 2011 in Fayetteville, AR to determine possible adaptive effects of cotton.  Growth chamber and field experiments were undertaken in an effort to determine adaptive effects cotton may possess to tolerate high temperature stress.  Three planting periods were setup with four replications of each planting period established with cultivar ST5288B2R.  Measurements from the white flower and the subtending leaf were taken during first flower when temperatures were below 32C, above 38C, and again below 32C.  This was followed up with a growth chamber experiment at flowering that indicated potential adaptive effects for membrane leakages comparing a week of heat stress to another cycle of stress one week following.  Protein concentrations for the leaf and ovary indicated a significance comparing week one to week three for the ovaries but not for leaf tissues.  The antioxidant glutathione reductase showed significance between weeks one and three for the ovaries but not for the leaf tissues.  The antioxidant peroxidase also displayed significance for the ovaries but not for leaf tissues.  According to our results, there appears to be an adaptive response to cotton during heat stress that can be identified across multiple different areas of the cotton plant