Effect of Gibberellins free essay sample

The Effects of Gibberellins on stem elongation in dwarf and normal Pea seedlings Abstract The effect of Gibberellins on dwarf and normal peas was studied under laboratory conditions in order to gain a better understanding of plant hormones. Problem: determine how the plant hormone Gibberellins affects on steam elongation and to measure the effect of this hormone on growth. Introduction Plant Hormones are small chemical messengers that act as internal signals within a plant. (Campbell et. at. , 2011) Plant hormones are also known as Phytochromes. Plants, unlike  animals, lack  glands  that produce and  secrete  hormones. Instead, each cell is capable of producing hormones (2). For over two millennia, people have observed that one part of the plant may influence that of another. Duhamel du Monceaus experiments in 1758 suggested that sap movement controlled the growth of plants. Julius von Sachs who is acknowledged as the father of plant physiology revised du Monceaus theory by presenting evidence that organ-forming substances were made by the plant and moved to different parts of the plant where they controlled growth and development. We will write a custom essay sample on Effect of Gibberellins or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Charles Darwin, is considered to be the scientist responsible for beginning the modern research in plant growth substances with his experiments on phototropism described in his book The Power of Movement in Plants. It was in 1926 that this compound was first isolated from plants by a graduate student in Holland named Fritz Went and was later termed auxin (Greek auxein, to increase) by  Kogl and Haagen-Smit in 1931. Shortly after this time other lines of investigation led to other plant hormones:  gibberellins  were discovered in plant pathogenesis studies; efforts to culture tissues led to  Cytokinins; efforts of controlling abscission and dormancy aimed to  Abscisic acid; and the effects of illuminating gas and smoke brought us to  ethylene (3). Also there is another plant hormone, which is has been discovered and known as a Brassinosteriod. The main function of plant hormones include regulating plant growth, as well as affecting the processes of cell division, cell elongation, cell ifferentiation, polarity of growth, pattern of branching, seed germination, flowering, and senescence (Campbell et. al, 2011). Plant hormones also play a role in determining where the stems, leaves, flowers and fruits will form on the plant. The Gibberellins found in meristems of apical buds and roots, and young leaves, and developing seeds are the primary sires of production. Major function of Gibberellins: stimulate stem elongation, pollen development, pollen tube growth, fruit growth, and seed development and germination; regulate sex determination and the transition from juvenile to adult phases (Campbell et. l, 2011). The purpose of this experiment was to test the effects of the high/low concentrations of plant hormones Gibberellins on dwarf and normal pea plants. The plant organism studied in this experiment was the Pisum sativum L. The group hypothesized the Gibberellins hormone would cause the plants to grow tremendously: the higher concentrations of Gibberellins hormone would cause the plant to grow at a faster rate than the lower concentrations of this hormone. Materials and Methods 1 box of dwarf pea seedlings (Little Marvel) 1 box of normal pea seedlings. After all of our measurements on 21 days the average internodes length of dwarf and normal pea seedlings has been calculated and shown in Figure 5, Figure 6 and Figure 7. The Figure 5 depicts the relationship between the plant heights 21 days the average internodes lengths at the week 14 days of dwarf and normal pea seedlings. The Figure 6 displays the average values of the internodes lengths of Control plants and Gibberellins affected plants during the experiment. Figure 6 The Figure 7 present a graph of results entire whole experiment based on Control Dwarf Peas, Gibberellins-Treated Dwarf Peas and Control Normal Peas. Figure 7 According to our results, at 21 days after after 1st measurements, the control dwarf peas only showed an average height of 25. 8 cm, while the Gibberellins acid-treated group of dwarf peas had an average height of 43. 2 cm. The Control tall peas had an average height of 58 cm. According on these values showed in Figure 7, there is a significant difference between the Control dwarf and the Gibberellins acid-treated dwarf peas and between the control dwarf and the control tall peas. Also between the Control tall and the Gibberellins acid-treated dwarf showed there is not a significant difference between these two groups. Since the Gibberellins acid-treated peas grew to a height similar to that of the tall peas, and significantly more than the dwarf peas, the results suggest that Gibberellins hormone may replace the substance genetically missing from the dwarf peas, or may enhance the growth of these peas. Variations in the amount of Gibberellins hormone applied to the seedlings may account for variations in the heights of the treated dwarf peas. Errors of 0. 5 to 3 cm may also occur in the measuring, especially when the peas start to grow tall and twist. Temperature and light intensity under the fluorescent lights was not measured. It is possible that changes in light intensity from one plant position to the next might influence growth rates. The experimental results obtained in the previous section supported hypothesis. Gibberellins made the plant grow tall, and throughout the week it was noticed that experimented plants seemed to have shrunk. These sources of error could be due to the fact that measurements were a little wrong or that the plants were breaking off from day to day. As for the plants with the high concentrations of each hormone, the results supported the overall hypothesis determined by the class as well. In the future it would be very useful to use the string method, throughout the entire measurement process, and to prevent the deterioration of the plants in general by placing them in more isolated areas if possible.  In conclusion, data results support the group hypothesis: the Gibberellins hormone of higher concentrations would cause the plant to grow at a faster rate than the lower concentrations of this hormone. The Gibberellins hormone increases the growth rate of genetically dwarf peas.