Abstract
Any visible injury can not be observed when the whole rice seedlings (Akitakomachi) are exposed for a week to chilling conditions at around 10°C. We, however, reported the severe injury in leaves that often led to leaf death, after the chilling only for a few days, only when the roots were not chilled, being preceded by a severe inhibition of photosynthetic electron transport. Based on a hypothesis that an excess water supply from roots is involved in the cause of this high-root-temperature (HRT)-induced chilling injury, we explore the relationship between the chilling injury and the nutrient solution. The results showed that it was not water but nitrate ion to affect the vulnerability to HRT-chilling stress. The current report also suggests that the HRT-chilling destroys some component between photosystem II and I without the aid of light, causing over-reduction of photosystem II in the light, thereby the visible injury is induced.
