Environmental stresses, such as repeated injury by herbivory, stunt plant growth and reduce crop yield. A spectacular example of this effect is exemplified in ornamental bonsai plants. Wounding induces the synthesis of a plant hormone, jasmonates (JAs), which in turn activate non-specific defence against pests and pathogens. On the other hand, a most dramatic effect of the application of jasmonates to plant however is the inhibition of growth, and this raised the question of whether another function of endogenous jasmonates is to inhibit growth. The results presented in this thesis first demonstrated that a previous wounding primes plants to give an enhanced response to following wounds. Following this discovery, I have investigated the genetic and physiological basis of "bonsai effect" by repeatedly wounding leaves of the model plant Arabidopsis. Repeated wounding reduced the size of wild type plants by 50% and increased the endogenous content of jasmonate (JA) by seven-fold, but unexpectedly had no significant effect on the mutants unable to synthesise JA, or unable to respond to JA. This second discovery suggests another function of endogenous JA is to inhibit growth under stress.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:502215 |
| Date | January 2009 |
| Creators | Zhang, Yi |
| Publisher | University of East Anglia |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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