CPSC Lecture with Ole Pedersen – Københavns Universitet

CPSC Lecture with Ole Pedersen

Flood tolerance of terrestrial plant

Flooding is a compound stress that invokes a series of responses in plants. In many cases, waterlogging is the first step in a submergence event and most species respond by increasing the gas‑filled spaces of the roots in order to facilitate gas‑phase diffusion of oxygen which is needed to sustain aerobic respiration of the growing root tip.

However, the steep gradient in oxygen concentration between root tissue and the waterlogged, anoxic soil drives a substantial diffusive flux of oxygen from tissues to soil referred to as radial oxygen loss (ROL). As a countermeasure, some species form a barrier to ROL, a constitutive or inducible root trait present in many wetland plants, to restrict the radial oxygen loss.

I propose, however, that the ROL barrier also serves to protect against soil phytotoxins such as reduced metals, organic acids and sulphides, which are produced by anaerobic bacteria in waterlogged, anoxic soils. During more severe flood events, the entire shoot can also become submerged, which invokes additional stress due to the slow diffusion of both oxygen and carbon dioxide in water as well as low light availability in murky floodwaters.

This presentation shows examples of laboratory and in situ measurements of internal aeration in wheat and rice as well as in natural wetland plants facing waterlogging, partial or complete submergence. I also report on a newly discovered gene, LGF1, that confers flood tolerance in rice by greatly enhancing underwater photosynthesis during complete submergence. Taken together, the many beneficial traits available calls for a promising future with “climate-smart” crops if we manage to combine QTLs via pyramidization in e.g., rice and wheat.