The data plotted in Fig. 1 illustrates the type of response that can be found following the accumulation and disappearance of water soluble carbohydrates in wheat stems. In 1999 the temperature in the field during collection of the samples was in excess of 32°C so that grains filled rapidly and photosynthesis was adversely affected. Dependence on stored carbohydrates was great and this demonstrates the ability of wheat stored carbohydrates to supplement current photoassimilates so that gradients in the kernel do not fluctuate greatly. Stem storage then has two important functions, first as a supplement to source supply and second as a modulator of the signal molecules sucrose and glucose. Remobilization of stored stem reserves, as a source for carbon, could be beneficiad for greater productivity (25) but this would clearly reduce the flexibility of wheat and barley to respond to reductions in source supply during graiin fill. Progress in assessing the contributions of fructan to grain yield remains elusive, however Gebbing et al. (28) could use data collected using the stable isotope 13C to assess remobilization of stem carbon assimilated by the leaves before storage in the stem. Research on the induction of synthesis and hydrolysis is not far into the future with continued isolation of the genes of fructan metabolism. It would not be surprising to find that sucrose, glucose and fructose are signal molecules with in the regulation of fructain metabolism. Future research is also needed to investigate the regulatory aspects of sugar movement to the site of storage.
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WHAT IT IS A three-phase plan that has been likened to the low-carbohydrate Atkins program because during the first two weeks, South Beach eliminates most carbs, including bread, pasta, potatoes, fruit and most dairy products. In PHASE 2, healthy carbs, including most fruits, whole grains and dairy products are gradually reintroduced, but processed carbs such as bagels, cookies, cornflakes, regular pasta and rice cakes remain on the list of foods to avoid or eat rarely.