Plant hormones and growth regulators are chemicals that affect flowering, aging, root growth, killing of leaves, promotion of stem elongation, color enhancement of fruit, prevention of leafing, and many other conditions. Very small concentrations of these substances produce major growth changes. All plants produce hormones naturally, and growth regulators can be applied by people to are applied to plants by people. Plant growth regulators may be synthetic compounds that mimic naturally occurring plant hormones, or they may be natural hormones that were extracted from plant tissue. In our plant growth experiment growth stimulants and growth inhibitors were used. Ideally the plants that received the growth stimulants should have grown larger than the others.
Methods & Materials:
The 3 plants used in the experiment were corn, peas, and beans. B-Nine, IAA, Gibberlic Acid, and a control substance were the growth regulators used. Gibberellic acid stimulates cell division and elongation, breaks seed dormancy, and speeds germination. Indoleacetic acid (IAA) stimulates internodal elongation, rooting, and leaf abscission. B-nine reduces internodal elongation. The control substance is the independent variable in the experiment.
Four planting pots, which were divided into three parts, were used for planting the seeds. Two seeds from each type of plant were put in the soil of one compartment of the four planting pots. Each of the containers was labeled with the corresponding hormone, and each division of each container was labeled for the corresponding plant. The plants were then watered and stored. Next week the lengths of the plants were recorded, the hormones were put on the plants. One of the four types of hormones was added to each plant in its corresponding labeled container. The next week the plants were measured and lengths were recorded. The process of adding the hormones was repeated for four weeks in the same way as the week before, and also I measured my plant lengths in millimeters. The whole experiment took five weeks to complete.
The experiment was not flawless due to many errors that occurred. As you can see from my results the beans did not grow at all therefore no data was recorded. The corn and peas that received the Gibberlic acid both grew more than the corn and peas that received the control substance. It looks as though the B-nine, which is supposed to reduce internodal elongation, may have actually stimulated internodal elongation. The IAA results in the corn were accurate, but the lengths of the peas that received IAA were less than that of the control. One error that may have occurred could have been the amount of water each plant received. Some plants may have been over watered, or not watered enough. This could have possibly affected the growths of each. Another factor may have been the light each plant was exposed to. I conclude that errors in the experiment may have affected the desired outcome of each plant.