On the quest to waterproofing crops – submergence tolerance of wheat or rice

Hovedområde:Eco-physiology
 
Målgruppe:Biology
 
Niveau:Masters, Bachelor
 
Projektbeskrivelse:

Join our team (professor, PhD-student and postdoc) working on flooding stress in plants

Background

Global climate changes have world-wide caused more heavy rainfall events over the last few decades along with an increased likelihood of devastating floods. Widespread increases in heavy precipitation have occurred, even in places where annual rain fall have decreased because warmer air can hold more moisture. Moreover, shifts in snowfall patterns, the onset of spring and snow melting may all exacerbate some flooding risks. As a consequence, cereals – even those that are currently grown on well-drained soils – may experience flooding throughout the growth season with serious impact on farming practice and eventually also yield. In this project you will help assess the submergence tolerance of wheat (Triticum aestivum) with the potential to develop wheat cultivars capable of surviving future climate-change induced floods.

Questions asked

Terrestrial plant survival during flooding is highly dependent on availability of O2 and sugars for respiration. Hence, the project aims to assess the i) capacity for underwater photosynthesis in wheat (Triticum aestivum) as function of light and CO2 in the flooding environment and ii) importance of leaf gas films for underwater photosynthesis. Wheat forms gas films on its super hydrophobic leaf surfaces during inundation and leaf gas films have been shown to improve the flooding tolerance of rice and many wild wetland plants so questions related to gas film functioning are included in the examination of the capacity for underwater photosynthesis.

However, O2 produced during underwater photosynthesis has to reach O2 consuming tissues, e.g. roots, to ensure plant functioning. In flooding tolerant plants, this is enabled by gas-filled tissues (aerenchyma) connecting plant organs. This allows for faster O2 movement throughout the plant, termed internal aeration. The capability for internal aeration in wheat during complete submergence is however poorly understood. Therefore you will also have the possibility to help assess the capabilities of internal aeration in wheat.

Approach

Leaf segments of 5-6 weeks old wheat are incubated in glass vials under controlled light and CO2 conditions and underwater net photosynthesis is measured using the O2 evolution technique. Leaf gas films can be experimentally manipulated using a dilute detergent enabling comparison of photosynthesis rates with and without leaf gas films. Rates of underwater net photosynthesis can be compared to rates obtained in air. Additional tests on effects of submergence can be tested on various cultivars, including the effect of temperature upon mortality during submergence.

Also, the applications of O2-microelectrodes both in situ and in controlled laboratory experiments will help assess the capacity for internal aeration in wheat. The application of microelectrodes requires a bit of technical interests. Collaboration with the University of Western Australia may also be an option.

 
Anvendte metoder:measuring underwater photosynthesis, field work, plant anatomy, wheat submergence studies, microelectrode applications, respiration measurements
 
Keywords:flooding stress, plant aeration, underwater photosynthesis, submergence tolerance, leaf gas films
 
Projekthjemmeside: www.flooding.dk
 
Vejleder(e): Ole Pedersen
 
E-mail:opedersen@bio.ku.dk