The Effect of Gibberellic Acid on Wild Type and Rosette Brassica rapa Plants
This experiment was performed to test two hypotheses concerning the plant hormone gibberellic acid and a mutant rosette shaped phenotype of the plant Brassica rapa. This experiment was done in order to test the effects o gibberellic acid on plants and its effect on rosette shaped complexes. The two hypotheses in this experiment are as follows: Hypothesis number one states that Gibberellic acid allows for stem elongation in plants. Hypothesis number two. The rosette complex in the rosette phenotype plant contains less gibberellic acid naturally and therefore grows shorter.
Plant hormones are certain chemicals present in plants that control plant growth and development by affecting the division, differentiation, and elongation of cells. (Campbell, 2008) Each hormone has multiple effects depending on its site of action, its concentrations, and the developing stage of the plant. (Campbell, 2008) Auxin is a plant hormone that is synthesized within the apical meristems and young leaves of a growing plant. Auxin stimulates stem elongation when it is present is low concentrations. It promotes the formations of lateral and adventitious roots, regulates development of fruit, enhances apical dominance, functions in gravitropism and phototropism, promotes vascular differentiation, and retards leaf abscission. Gibberellic acid is one of several plant hormones that govern a plant’s growth. Gibberellins allow for stem elongation in plants. Plants without enough of this hormone tend to grow short or stunted. This chemical is high in the element potassium, which is one the main components of plant fertilizer and very important for plant growth on its own. There are many plant hormones that affect the plant during its growth. Among these are auxins, gibberellic acids, cytokinins, brassinosteroids, Abscisic acid, and ethylene. These not only affect the plant in their specific ways, they also have different effects when they are present in certain ratios with the other chemicals. Plant hormones maintain a delicate balance, and this experiment serves to observe that balance (Campbell and Reese, 2008).
There were two types of plants used. Both were of the same species, Brassica rapa but two of the plants contained rosette shaped complexes that were deficient in producing gibberellic acid compared to the wild-type plants. Therefore, they grew smaller and shorter as a phenotype....