Accepted: 24 May 1984.
CRITICAL IRRADIANCE LEVELS AND THE INTERACTIVE EFFECTS OF QUANTUM IRRADIANCE AND DOSE ON GAMETOGENESIS IN THE GIANT KELP, MACROCYSTIS PYRIFERA1
Article first published online: 16 NOV 2004
Journal of Phycology
Volume 20, Issue 4, pages 520–524, December 1984
How to Cite
Deysher, L. E. and Dean, T. A. (1984), CRITICAL IRRADIANCE LEVELS AND THE INTERACTIVE EFFECTS OF QUANTUM IRRADIANCE AND DOSE ON GAMETOGENESIS IN THE GIANT KELP, MACROCYSTIS PYRIFERA. Journal of Phycology, 20: 520–524. doi: 10.1111/j.0022-3646.1984.00520.x
We thank C. Criger who assisted with the culturing and enumerating of the gametophytes, and EcoSystems Management, Inc. for providing the quantum irradiance data for the San Onofre Kelp Bed. This research was funded by the Marine Review Committee (MRC), Encinitas, California. The MRC does not necessarily accept the results, findings, or conclusions stated herein.
- Issue published online: 16 NOV 2004
- Article first published online: 16 NOV 2004
- quantum dose;
Gametophytes of Macrocystis pyrifera (L.) C. Ag. were cultured under a series of quantum irradiances in three photoperiod regimes. The quantum irradiances in each photoperiod were adjusted to provide equal daily irradiation dosages between photoperiods which allowed a critical examination of the interactions between quantum irradiance and quantum dose in determining gametophyte fertility. The lowest quantum irradiance which stimulated gametogenesis in more than 50% of the female gametophytes was 5 μE·m−2·s−1. The saturating irradiance was ca. 10 μE·m−2·s−1 at photoperiods of 12 h or greater. In terms of daily quantum dose, the lowest dose at which greater than 50% gametogenesis occurred was 0.2 E·m−2·d−1. However, this critical quantum dose was higher (0.4 E·m−2·d−1) when instantaneous irradiances were less than 5 μE·m−2·s−1. The saturation quantum dose was also affected by the rate at which the quantum dose was received and varied from 0.4 to 0.8 E·m−2·d−1. Gametophytes in all three photoperiods reached 100% fertility at quantum irradiances above 5 μE·m−2·s−1. Photoperiod effects were small and could be accounted for by quantum dosage effects.