Effects of Selenium Application on Heat Tolerance in Peanut Seedlings
Peanut production faces many challenges in the world today, and one such issue is heat stress. One of the implications of heat stress on the plants is oxidative stress, which is detrimental to plant health and physiological function. A method to combat oxidative stress could be through the use of antioxidants such as Selenium (Se), which is thought to increase growth and development of plant material. This experiment evaluated tolerance to heat stress in four-week-old seedlings from a set of diverse peanut genotypes. Additionally, the antioxidant activity of Selenium was examined to determine if a) it allowed for increased heat tolerance, and b) if it was associated with specific genotypes. At the conclusion of the treatments, SPAD chlorophyll measurements and fresh-weights were taken, with dry-weights being calculated after seedlings were oven-dried at 80˚C for 48 hours. The experiment concluded that Se did not produce a significant change in tolerance to heat stress. Genotype had a significant effect on SPAD chlorophyll readings and dry-weight. Additionally, temperature did not have a significant effect on dry-weight, but did on SPAD chlorophyll readings and fresh-weight. The effect of temperature on SPAD readings is of interest as the above optimal temperature of 39˚C produced higher relative chlorophyll contents than the 26˚C normal temperature. Due to this result, seedling total leaf area (LA) was further measured to determine if a potential trend could exist. Even though not statistically significant, LA was slightly smaller for seedlings at 39˚C treatment compared to the 26˚C treatment. In summary, the experiment did not discover genotypes that allowed for a significant improvement in tolerance to above-optimal temperatures or validate Se as an additive for increased tolerance to heat stress and improved seedling growth. However, it did demonstrate the ability of peanut seedlings to withstand an increase in temperature at an early stage without significant detrimental impacts.