Is anoxia tolerance related to flooding tolerance?

Three barley cultivars, Hordeum vulgare L. cv. Kustaa, Hankkija-673 and Pokko were tested for their anoxia and. flooding tolerance to observe whether anoxia tolerance is related to flooding tolerance and whether the cultivars differ in their anoxia and flooding tolerance. Three-day-old seedlings were incubated under anoxia at +5 degrees C for 10-20 days. In addition a tetrazolium chloride test was carried out to identify the site of anoxic or post-anoxic damage. Flooding tolerance of the barley cultivars was investigated by growing plants to maturity (flowering and seed production) under permanently flooded conditions. The flooding tolerance of the cultivars correlated positively with anoxia tolerance, Kustaa being the most and Pokko the least tolerant and productive of the three tested cultivars. Thus at an intraspecific level anoxia tolerance can be related to flooding tolerance. The TTC-test showed that root tissue, and especially root tips, were more susceptible to anoxia than shoot tissue. The roots of the cultivar Kustaa showed longer tolerance of anoxia than the other two cultivars, with the proximal region of the roots surviving the anoxic treatment. In some cases surviving shoots of the variety Kustaa produced new roots at the base of the stem.