Abstract Detail



Physiology & Ecophysiology

Melcher, Peter [1], Preston, Jill [2].

Understanding freezing and drought resistance mechanisms in Pooidae.

Pooids constitute approximately 3,800 species of grasses, containing many of the world's most important crop, forage, and turf species, including barley, oats, rye, and tall fescue. Despite their ancestry in the tropics, pooids have diversified extensively throughout the temperate zones. This is probably due in part to their novel adaptation to an extended period of freezing/desiccation stress. The goal of this study was to determine the range of responses to freezing and drought of several grass species in this group. To achieve this, several different species of pooids were either subjected to drought treatments or cold acclimated and then subjected to freezing treatments. For the freezing experiments, leaf tissue samples were collected from cold-adapted plants and were then exposed to a suite of temperatures ranging from +5 to –30 oC using a controlled cooling environmental chamber. The temperature at which intercellular ice crystal formation occurred was measured by determining ice-nucleation temperature responses of tissue using fine-wire thermocouples interfaced to a datalogger. Cellular and tissue damage was also determined from ion-leakage and from chlorophyll fluorescence imaging of photosystem of samples exposed to the same cold temperature treatments. Plant responses to drought stress were assessed from pressure volume curve analysis of leaf samples and by determining the water stress that caused stomatal closure of plants exposed to varying drought conditions. Both soil and leaf water status were measured during drought treatments and stomatal closure was monitored using both a gas exchange system and determined from anatomical assessment from stomatal peels.


1 - Ithaca College, Biology, 953 Danby Road, Ithaca, NY, 14850, United States
2 - University Of Vermont, Plant Biology, 63 Carrigan Drive, 111 Jeffords Hall, Burlington, VT, 05405, United States

Keywords:
Freezing
drought
fluorescence
stomata.

Presentation Type: Poster
Session: P, Physiology & Ecophysiology
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM
Number: PPE003
Abstract ID:390
Candidate for Awards:None


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