Development in the red alga,Griffithsia pacifica: Control by internal and external factors

✍ Scribed by Susan Drury Waaland; Robert Cleland

• Publisher: Springer-Verlag
• Year: 1972
• Tongue: English
• Weight: 562 KB
• Volume: 105
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00385391

✦ Synopsis

Development in the red alga Gri/]ithsia paci]ica is affected by both external and internal factors. Under 16:8 photoperiods, both cell division and cell elongation show a diurnal rhythm. The rhythm of division persists for at least 7 cycles in continuous light, and can be reset; this indicates that the timing of cell division is controlled by an endogenous rhythm. Both cell division and elongation require light, but the rate of division of apical cells and the rate of cell elongation are both relatively insensitive to either light intensity or photoperiod. In contrast, division in nodal cells, which leads to branch formation, is strongly promoted by high light intensity or long photoperiods. By manipulating the conditions of illumination, one can obtain Gri/]ithsia plants varying from unbranched to highly branched.