Gibberellins: Help For Your Garden, From Mother Nature

3 Pages 740 Words

Japanese plant pathologists studying the "bakanae" disease ("foolish seedling") of rice discovered Gibberellins (Internet Source #4.) In this disease the seedlings elongated so rapidly that the plant collapsed and died prematurely (Internet Source #6.) In 1898 Shotaro Hori concluded that a fungus, which is now known as Gibberella fujikuroi, caused the disease (Internet Source #3.) Then in 1926 Eiichi Kurosawa reported that a chemical produced by the fungus caused the symptoms and that the substance was heat-resistant, and didn’t lose its activity after 4 hours at 100°C (212°F) (Internet Source #7.) Then in 1935 Teijiro Yabuta first isolated a non-crystalline solid and named it Gibberellin (Internet Source #3.) In the year 1938, Yabuta and Yusuke Sumiki first isolated a crystalline compound from the cultured fungus (Internet Source #8.) Since this time seventy-nine different Gibberellins have been in the seeds of a wide variety of species. Gibberellic acid-3 (GA-3) is the most widely used and is produced commercially by growing the fungus in huge vats and then extracting and purifying the GA-3 (Internet Source #5.)
Gibberellic acid (GA) is a very potent hormone whose natural occurrence in plants controls their development (Internet Source #9.) Since GA regulates growth, applications of very low concentrations can have a profound effect (Internet Source #1.) Timing is critical: too much GA may have an opposite effect from that desired; too little may require the plant to be repeatedly treated to sustain desired levels of GA (Internet Source #4.)
Many different Gibberellins are present in common plants. Rice contains fourteen GAs, and rice anthers contain up to 3.4 micrograms of GA-4 per gram fresh weight (Internet Source #2.) Maize (corn) seed contains twelve GAs, maize pollen 9 GAs, wheat and barley contain 5, and 4-day-old wheat seedlings contain 11 (Internet Source #2.) GAs are produced in the roots of oni...