It is important, therefore, that we continue to attempt difficult syntheses and thereby test synthetic procedures to the limit. In this way the practitioner is forced to seek a better understanding of the chemical processes involved, to improve existing methodology, and to invent new ways of building organic molecules. Within this context, the group has successfully completed syntheses of numerous complex natural products and developed a number of useful synthetic procedures. GAs affect numerous aspects of plant growth and development, e.g. germination and flowering, although their most characteristic property is the induction of stem growth. The rind of citrus fruit typically softens at maturity, and is subject to injury by pests which adversely affect the appearance of otherwise marketable fruit.
GAs maintain the rind in better condition.
A variety of ornamental plants can be induced to flower either earlier than usual, or in off-seasons. Studies on GAs, pursued in collaboration with several groups within the plant development program in the Cooperative Research Centre for Plant Science, have led to the discovery of semi-synthetic derivatives that selectively promote flowering, but not growth. Other analogues interfere with the plant's natural production of phytohormones, thereby inhibiting growth. Because they can be expected to be environmentally benign, these materials have considerable commercial potential and are presently being screened in field tests in N. America, Israel and Europe, as well as in Australia. Most kaurenoids, however, are not as easily obtained as the more common gibberellins.