Abstract Detail

Biotic and abiotic stress

Willick, Ian R. [1], Fowler, Brian [1], Tanino, Karen [1].

Where did the water go? Mapping ice migration and regions of damage in winter cereal crowns during freezing stress.

The most critical region for winter wheat (Triticum aestivum L.) survival during freezing is the crown. Ice formation in the crown can cause severe disruption in tissue structure as ice crystals in the apoplast (cell wall & middle lamella) grow at the expense of intracellular water. While roots of winter cereals are most susceptible to freezing, they can regenerate if crown meristematic regions in the vascular transition zone remain uninjured and there is sufficient energy to support regrowth. On a tissue level, acclimated crowns are more resistant to freezing due to less free water (bound to apoplastic constituents), reducing the formation of ice and subsequent amount of physical damage. Remarkably, little work has been done to investigate the tissue-specific mechanism of crown injury as well as the route of ice propagation into crown tissues. A difference in the location of damage during freezing indicates the possibility for barriers preventing ice growth. Since the apoplast is the primary physical barrier of ice propagation into cells and may also regulate water flow, we believe that cellular components in the primary cell wall play an important role in limiting frost damage. To better understand what is happening in the crown during low temperature stress, we examined changes in tissue structures during acclimation using micro-NMR and synchrotron micro-CT and determined the formation and localization of ice within wheat and hardy rye (Secale cereale L.) non-acclimated and acclimated crown tissues using infrared thermography. Results from these studies are were used to quantify shifts in water flow and activity as well as identify apoplastic fluid carbohydrate composition and freezing potential in acclimated and non-acclimated crown tissues. Advancements in our understanding of mechanisms of low temperature hardiness in winter cereals will be particularly useful to breeders’ intent on improving winter hardiness in winter wheat.

1 - University of Saskatchewan, Plant Sciences , College of Agriculture and Bioresources, 51 Campus Drive Room 4D36 Agriculture Building, Saskatoon, SK, S7N 5A8, Canada

Keywords:
freezing
Acclimation
winter wheat
crown.

Presentation Type: Oral Paper:Papers for Topics
Session: 7
Location: Salon 13/14/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 11:30 AM
Number: 7014
Abstract ID:528
Candidate for Awards:2015 Graduate Student Best Oral Presentation Award,CSPB President's Award for Best Student Presentation