LIFE ON THE EDGE: STRESS SURVIVAL ADAPTATIONS IN SOUTHERN LIMIT MACROCYSTIS PYRIFERA POPULATIONS

In spite of subtropical temperatures often occurring at the Macrocystis pyrifera distributional southern limit in the Northern Hemisphere in Baja California, Mexico, the population has been successful at surviving and recovering from disturbance. To explore the physiological characteristics of south...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Journal of phycology 2000-12, Vol.36 (s3), p.40-41
1. Verfasser: Ladah, L.B.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:In spite of subtropical temperatures often occurring at the Macrocystis pyrifera distributional southern limit in the Northern Hemisphere in Baja California, Mexico, the population has been successful at surviving and recovering from disturbance. To explore the physiological characteristics of southern limit M. pyrifera, microscopic and macroscopic phases of southern limit plants were tested for stress tolerance and compared to northern plant responses in three experiments. In spore development experiments, under constant temperature and nitrate stress treatments, spores from the southern‐limit population survived higher temperatures, had greater survivorship, and were able to complete their life cycle at higher temperatures and lower nitrate concentrations than northern population spores. During stress‐recovery treatments, where all microscopic stages were tested for recovery after stress shock exposure (temperature, nitrate and light stress), 96% of all haploid treatments showed some regrowth during recovery; haploid survival was not significantly affected by spore population origin, light, or nitrate. However, only 26% of diploid treatments showed regrowth and diploid survival was significantly affected by spore population origin; only the southern limit spores recovered after stress treatment exposure. In juvenile transplant experiments, under all conditions, juvenile plants originating from the southern‐limit had higher tissue nitrogen content, greater frond addition rates, and higher photosynthetic efficiency than northern plants, particularly at higher temperatures. The physiological differences observed for the southern limit plants versus those from the north contributes to our understanding of how the southern limit plants can survive in an environment that might otherwise be considered extreme for the species.
ISSN:0022-3646
1529-8817
DOI:10.1046/j.1529-8817.1999.00001-120.x