Department of Botany, University of Washington, Seattle, USA.
Planta. 1972 Sep;105(3):196-204. doi: 10.1007/BF00385391.
Development in the red alga Griffithsia pacifica 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 Griffithsia plants varying from unbranched to highly branched.
红藻 Griffithsia pacifica 的发育受内外因素的影响。在 16:8 的光周期下，细胞分裂和细胞伸长都表现出昼夜节律。在连续光照下，分裂的节律至少持续 7 个周期，可以重置；这表明细胞分裂的时间由内源性节律控制。细胞分裂和伸长都需要光照，但顶端细胞的分裂速度和细胞伸长速度对光强或光周期都相对不敏感。相比之下，导致分支形成的节间细胞的分裂强烈地受到高光强或长光周期的促进。通过控制光照条件，可以得到从无分枝到高度分枝的 Griffithsia 植物。
