The Effects of Gibberellins on stem elongation in dwarf and normal Pea seedlings
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 Monceau's 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 Monceau's 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. 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 differentiation, 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. al, 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 (Alaska)
Gibberellins solution 0,1 mg/L
Gibberellins solution 10 mg/L
Gibberellins solution 100 mg/L
1. Measure length in centimeters the shoot system of the plant from stem to leaves which enclosed the apical bud and average these for each of the four rows (6 seedlings per row). 2. Apply 1st row with 2 drops of water (for each plant) to the apical bud of the plant. This row will be a controller. 3. Apply the same amount of the different concentrations of Gibberellins to the other plants. Start 2nd row with the lowest concentration (0,1 mg/L), 3rd row with 10mg/L, and last one with...
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