Abstract Detail

Ecology

Rominger, Kody [1].

Dormancy Induction in Astragalus holmgreniorum (Fabaceae) Seedlings.

Astragalus holmgreniorum is a federally listed endangered plant that has a range restricted to within 10 miles of the city of St. George, Utah. This short lived perennial plant grows exclusively on the Virgin limestone member of the Moenkopi formation on the gravely slopes and aprons of mesas. A. holmgreniorum emerges in the late winter, flowers early to mid spring, and goes dormant in early summer. The survival of seedlings from the first year to second is only 17.4%, so their ability to go dormant (a period of slowed to no growth) is critical to their overall survival. Other geophytes and desert ephemerals that are dormant during all or part of summer generally go dormant in response to high temperature conditions or lack of precipitation. The purpose of this experiment is to understand what causes dormancy induction in seedlings. This was determined by exposing A. holmgreniorum seeds to different environmental conditions in a growth chamber (temperature, photoperiod, amount of available water). Four blocks of 20 seedlings were grown in growth chambers under ideal conditions for seven weeks. At the seven week mark, three of the four blocks of seedlings was separated and exposed to different environmental conditions for three additional weeks. The fourth block remained under ideal conditions for control. The first block had a regular water regime, 12/12 hours of light/dark, but the temperature was increased from ideal to 30.7° C during daytime hours, and 22.1° C during nighttime hours. The second block had a regular water regime, and remained under ideal temperature conditions, but was exposed to 16/8 hours of light/dark. The third block was under ideal temperature conditions, 12/12 hours of light/dark, but had a very restricted watering regime, ½ as much as ideal. In order to distinguish which plants had gone dormant, and which had died, the plants were taken out of dormancy after ten weeks. Half of each of the blocks were put back into ideal conditions, and half of each of the blocks was placed into winter conditions of 5° C temperature, 10/14 hours light/dark, and a consistent water regime. Understanding the process of breaking dormancy for this species is very important for the protection of this endangered species.

1 - Utah Valley University, Biology, 800 S University Pkwy, Orem, UT, 84058, USA

Keywords:
endangered species
Mojave Desert
astragalus
dormancy.

Presentation Type: Poster
Session: P, Ecology Section Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC038
Abstract ID:931
Candidate for Awards:Ecological Section Best Undergraduate Presentation Award