Androniki C. Bibi, Derrick M. Oosterhuis, and Evangelos D. Gonias. University of Arkansas, 1366 W. Altheimer Dr., Fayetteville, AR 72704
Past experience and recent research has indicated that high temperature is the major factor adversely affecting cotton yields. The ideal temperature range in cotton has been reported to be 30/20oC, although cotton physiological growth is not significantly affected up to 35oC. The influence of temperature on the number of ovules per flower has not been determined directly, although there is an indication that extreme high temperatures can result in a lower number of ovules per locule. Plant growth substances play a controlling role in the process of reproduction. Polyamines (PAs) are substances which are naturally present in plants and act as promoters of growth. The aliphatic triamine spermidine (Spd), the tetramine spermine (Spm) and their procersor putrescine (Put) are the most common polyamines, with widespread occurrence in plants. They play an important role at the time of flowering, pollination and early fruit development. In addition, polyamines have been associated with plant response to abiotic stress. Information is lacking on the effect of exogenous PAs on polyamines content of cotton ovaries. Also no information exists on how PAs affect seed set of cotton under conditions of high temperature. Therefore the objective of this study was to investigate the effect of exogenous putrsecine application on seed set of cotton under two temperature regimes.
