Growth responses of Typha orientalis presl to controlled temperatures and photoperiods

Experiments are described in which seedlings of Typha orientalis Presls were grown for up to 6 months under precise conditions of temperature and photoperiod; photosynthesis was by natural daylight and did not vary between treatments. Variable treatments were imposed either from the seedling stage or on large plants raised under constant conditions. In general, total dry matter production increased as photoperiod increased from 8 to 16 h and also as day or night temperature increased, maximum production occurring when there was a warm day (30 or 27°C) and a small temperature drop (to 22°C) at night. The distribution of dry matter was also markedly affected by the imposed variables, leaf growth being favoured by high temperatures (to 30°C) and long photoperiods, and production of roots and rhizomes by low temperatures (to 10°C) and short photoperiods. None of the treatments resulted in floral initiation. The results are considered in relation to growth in the natural habitat.