Application of Ga 3 and kinetin to improve corn and soybean seedling emergence at low temperature

Abstract

Plant growth regulators (PGRs) affect the emergence rate and percent emergence of crop seedlings. Our previous studies demonstrated that gibberellic acid (GA) and kinetin stimulate corn ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] seed germination under low temperature conditions and that at a root zone temperature (RZT) of 10°C soybean seedlings grow very slowly, even through the air temperature was 25°C. Because the presence of added PGRs in the rhizosphere and seedling tissues will continue to affect early development after germination, and because some PGRs are synthesized in the roots and so would be affected by low RZT, two controlled environment experiments were conducted to examine the effect of GA 3 and kinetin on seedling emergence and early seedling development at a 10°C RZT. At 10°C, GA 3 and kinetin stimulated corn and soybean seedling emergence and improved corn and soybean seedling development; GA 3 was more effective than kinetin at promoting seedling emergence and development of corn and soybean; of the concentrations tested, 0.1 mM was the most effective.