The Germination of Light-Sensitive Seeds of Typha Latifolia L.

Abstract

Germination in Typha lalifolia L. is strongly favored by white light and by low oxygen concentration. Microscopic study shows that the effect is on the aleurone grains, whose colloids are so affected that they attract and hold water more strongly, and the resultant swelling ruptures the seed coat. The swelling of the grains was observed under various sets of conditions. Its progress is described and has a bearing on current theories with respect to these structures. The process of vacuolation in the cells was also studied. On it light has no apparent effect, but it is notably stimulated under conditions of vigorous, aerobic respiration. In some samples of seed, where the tendency to vacuolate is especially strong, atmospheric pressure of oxygen strengthens vacuolation to an extent that will compensate for its depressing effect on swelling of the grains, and satisfactory germination follows. In other samples this is not so. Under very low light intensity, rather wide alternations of temperature promote germination. This was found to be due to promotion of vacuolation. Respiration studies show slow respiration and a low respiratory quotient at the low temperature. It is suggested that this allows a clearing away, during the time at low temperature, of the products of respiration, thus allowing, when the higher temperature is resumed, the vigorous respiratory activity that makes for vigorous vacuolation.

Seed germination of two Everglades species, Cladium jamaicense and Typha domingensis

“…Up to 85% of T. domingensis seeds germinated at 30 • C during an eight-day incubation period, which is comparable to other reported germination percentages for this species (Stewart et al, 1997). Reduced germination of T. domingensis in water at 15 • C, is comparable to the temperature response observed with seeds of T. latifolia (Sifton, 1959). However, low-oxygen concentration and peat substrate increased germination percentage and reduced the incubation period required by T. domingensis seeds, especially at low temperatures.…”

“…The germination is enhanced by diurnal changes in temperature (Lombardi et al, 1997) and low oxygen concentrations with germination ranging between 80% and 100% under optimal conditions (Morinaga, 1926;Sifton, 1959;Bonnewell et al, 1983). A study of seed germination of T. latifolia and T. domingensis as a function of nutrient level indicated that the germination requirements in T. domingensis are similar to those in T. latifolia (Stewart et al, 1997).…”

Seed germination of two cattail (Typha) species as A function of Everglandes nutrient levels

“…Without light, seed germination of T. latifolia was 0%-10%, whereas with light, seed germination increased to 91%-100% (Sifton 1959). High percentages of germination of T. latifolia required long exposure to light, low oxygen concentrations, and high temperatures (Bonnewell et al 1983).…”

THE BIOLOGY OF CANADIAN WEEDS.: 73. Typha latifolia L., Typha angustifolia L. and Typha xglauca Godr.

“…Additional data from the extensive studies of Marsh (1962) (Sifton 1959;Kadlec and Wentz 1974;Sharma and Gopal 1979a), and light quality (Sifton 1959). Oxygen is not req'.rired for germination (Morinaga 1926b;Sifton 1959).…”

“…Additional data from the extensive studies of Marsh (1962) (Sifton 1959;Kadlec and Wentz 1974;Sharma and Gopal 1979a), and light quality (Sifton 1959). Oxygen is not req'.rired for germination (Morinaga 1926b;Sifton 1959). Seeds retain viability for long periods when conditions are not suitable for germination (Crocker 1938;Bedish 1967; van der Valk and Davis 1976) .…”