Effects of High Night Temperatures At Flowering

High night temperatures are considered to be one of the main environmental factors contributing to lowered yields in cotton and this has been attributed to a negative effect on respiration and carbohydrate accumulation, but the evidence for this is lacking. The objectives of this study were to eavaluate the effects of high night temperatures on the metabolism of cotton flower.Growth chamber studies were conducted in 2011 at Altheimer Laboratory at University of Arkansas. Cotton cultivar ST5288B2F was planted in 2L pots and normal day/night temperatures of 32/24C were applied until flowering. At flowering the plants were separated in two groups with the first group remaining under normal conditions (32/24C) while high night temperatures (32/30C) were imposed on the second group for two weeks. Measurements of respiration and photosynthesis were taken at the end of each week, while white flowers and their subtending leaves were sampled for carbohydrates, antioxidant and ATP content. Results are still being analyzed.