The_Source_of_Gibberellins_and_Effect_of_Abscisic_Acid

Investigating the source of gibberllins (GAs) and the effect ABA has on them by measuring glucose levels in embryonic and no-embryonic portions of wheat seeds. The part of the seed responsible for production of gibberellins (GAs) and the effect abscisic acid (ABA) has on their function for promoting germination was questioned and the hypothesis for this experiment was that an increase in glucose released in the half where GA was released, as well as a lower release of glucose when ABA is added. Higher levels of glucose release in the embryo half would mean that GA was secreted in the embryo and is important because in the absence of the embryo, α-amylase activity as well as many other germinating processes would not take place. In order to determine which part of the seed was responsible for secretion of GA, an experiment was conducted using wheat seeds cut into two halves: the embryonic and non-embryonic halves. Glucose release in the different halves was tested in the presence of GA, ABA, cycloheximide (CHX), GA + CHX as well as a combination of GA and ABA together, and compared to a control group to determine where GA was produced and the effect of ABA on GA activity. According to the results, in the control there was a higher level of glucose increased in the embryonic half which means that GA is secreted in the embryonic halves and in the treatments with ABA added, glucose release was lower, even in the presence of GA (figure 1). The treatments with GA added had much higher glucose released than the control and treatments without GA, indicating that GA yielded positive for glucose release and α-amylase activity while ABA had inhibitive actions on glucose release. Although glucose release was lower with ABA present, the treatments with CHX added showed much lower glucose release indicating a stronger inhibitive effect of GA function. The results supported the idea that increased glucose release from the seed was expected in the region containing GAs which is responsible for germination, and the treatments containing ABA all saw reduced levels of glucose release. Figure 1. amount of glucose released (µg) in embryonic and non-embryonic halves of wheat seeds in the presence and/or absence of gibberellins, abscisic acid, and cycloheximide.