Abstract Detail

Conservation Biology

Tyler, Stephanie [1], Abbo, Tito [2], Parker, V. T. [3], Litt, Amy [4].

Factors affecting seed germination in manzanitas.

Arctostaphylos, commonly known as manzanitas, are diverse woody shrubs of the Ericaceae family that are native to California and western North America. Most manzanitas live in chaparral conditions of drought and fire, and seeds germinate in response to fire. About one third of manzanitas are facultative seeders, which allows them to regenerate populations through seed germination and also by individuals resprouting through a burl after a fire. A burl is an enlarged woody structure at the root crown that contains dormant buds and that survives through a fire. This then allows for the plant to resprout even after the above ground canopy is burned. The rest of manzanitas are obligate seeders; they do not form a burl, thus when there is a fire the entire adult population dies and does not resprout. Obligate seeders use the soil seed bank to regenerate after a fire to create a new generation. Therefore the lifespan of obligate seeders is the length of time between fires, estimated on average to be about 30 years in California, whereas for facultative seeders it may be hundreds of years.
Arctostaphylos glandulosa, Eastwood manzanitas, are abundant and widespread facultative seeders. They commonly resprout after fires but seedlings are rarely observed. This raises concern about the rate at which new individuals are being produced and whether in some areas, the current plants are the last generation, perhaps because a changing climate is eliminating some of the required germination cues. There are some reports of attempts to germinate seeds. Some were not successful and those that were successful had very low germination rates. This raises the possibility that the seeds may not be viable. We dissected seeds and tested viability. Our results with dissection show that some seeds are viable but many appear to lack embryos. We wanted to see if we can achieve higher rates of germination and identify why rates in the field are so low. Our experimental design involves combinations of multiple germination cues, including liquid smoke, acid treatment, gibberellic acid, scarification, and cold stratification. Our first attempt to germinate seeds using only liquid smoke was unsuccessful. The current experiment involves a heat treatment followed by liquid smoke and cold stratification; results are forthcoming. Using these other treatments in different combinations we hope to gain a better understanding of the factors required for germination.

1 - University of California, Riverside, 900 University Avenue, Department of Botany and Plant Sciences, Riverside, CA, 92521, United States
2 - University of California, Riverside, 900 University Ave, Riverside, CA, 92521, United States
3 - San Diego state university
4 - University Of California Riverside, Botany Dept, 900 University Ave, Riverside, CA, 92521, United States

Keywords:
Arctostaphylos
manzanita
Seed germination
fire.

Presentation Type: Poster
Number:
Abstract ID:630
Candidate for Awards:None