Growth cessation

When protonemal cells cultured under continuous red light are transferred to darkness, the growth rate is reduced and ultimately cell growth stops (Kadota and Furuya, 1977). Simultaneously, the nucleus moves a short distance towards the cell base and after a period of time cell division occurs (Figure 1.5) (Wada et al., 1980). The timing of cell division is controlled by phytochrome (Wada and Furuya, 1972), as will be discussed in Section 1.5. The timing of growth retardation and the length of cell growth during the dark period before cell division occurs are also controlled reversibly by red/far-red light irradiation just before transferring to the dark (Kadota and Furuya, 1977). Protonemal cell growth may be controlled in conjunction with the timing of cell division by the same phytochrome system. It is curious, however, that the timing of cell division is delayed by far-red light whereas growth retardation is advanced and, consequently, growth is reduced. This result indicates that cell cycle advancement and cell growth retardation (i.e., cell growth) are not really parallel. Protonemal cell growth is also controlled by blue light; this will be discussed in Section 1.5.

Figure 1.5 Light micrographs of a longitudinal section of Adiantum capillus-veneris protonemata during cell cycle in the dark. Nuclear migration towards the base of the cell and structural changes of organelle patterns are shown. (After Wada et al., 1980.)

Was this article helpful?

0 0
10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook

Post a comment