Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: November 2, 2003
Publication Date: November 6, 2003
Citation: Mahan, J.R. 2003. Antioxidant metabolism in cotton seedlings exposed to chilling stress in the field[abstract]. ASA-CSSA-SSSA. Technical Abstract: Cotton planted in late April and late May of 2003 was subjected to a period of relatively high air temperatures (40°) followed by exposure to low temperatures (18°) over a 24 h period. Antioxidant metabolism and oxidative damage were assessed. Early season temperature variation is common on the Southern High Plains of Texas. Minimum and maximum temperatures can vary by 15°C over 24 hour periods due to changes in weather. High and low temperature stress can result in the production of reactive oxygen species that can damage the plant. Cotton has a variety of antioxidant mechanisms to prevent damage from oxidative stress. In this study antioxidant metabolism was monitored in cotton seedlings grown in the field and exposed to normal thermal variation. April and May plantings allowed comparison of the response of plants of different ages to temperature variation. On day of year 139 the temperature fell by 15°C over a 24 hour period. The foliar level of malondialdehyde, an indicator of oxidative damage, was elevated on DOY 142 and 143 and declined in the following days suggesting low temperature damage to the seedlings. Antioxidant metabolism measured in terms of abscorbate and glutathione content as well as the activities of the enzymes ascorbate peroxidase and glutathione reductase did not respond to the stress. These data suggest that early season low temperatures may contribute of oxidative damage in the field.