Partially submerged Rumex crispus
Underwater vdo from a crystal clear gravel pit with submerged terrestrial vegetation
Underwater vdo of leaf gas films on Glyceria fluitans (NOT Catabrosa aquatica)

Flood tolerance of natural wetland plants

I am working with experimental plant eco-physiology of wetland plants with emphasis on traits conferring flood tolerance. Root traits conferring to flood tolerance are mainly related to enhanced internal aeration such as root tissue porosity (to enable gas phase diffusion of oxygen), a barrier to radial oxygen loss (resulting in high internal root pO2 and perhaps also a barrier to phytotoxin intrusion of e.g., H2S and Fe2+). 

Natural wetland plants are well adapted to soil flooding (waterlogging) and some of them also tolerate partial or complete submergence. The adaptive traits in both roots and shoot can be used to improve flood tolerance of wetland (e.g., rice) and dryland crops so that these are better suited for a changing climate with more floods following torrential rains throughout the growth season (see topic below).

 See recent examples of research in flood tolerance of wetland plants and also the list of publications

Flood tolerance of wetland and dryland crops

Vast area of arable land is each year flood resulting in loss of yield. Rice, being a wetland plan, tolerates flooding to some extend whereas wheat shows little tolerance to waterlogged soils. We have recently worked extensively with submergence tolerance of both rice and wheat and we have shown that both species possess superhydrophobic leaf cuticles that enhance gas exchange with the flood water when completely submerged.  See recent examples of research in flood tolerance of dryland crops and also the list of publications

Tropical seagrasses in Western Australia
Take a tour in the stunning environment around Tannon Island in Western Australia

Seagrass eco-physiology
Worldwide, coastal seagrass ecosystems are threatened by eutrophication and anthropogenic activities. I have recently been involved in research revealing severe root stress caused by elevated levels of toxic sulfide in the sediments, a side effect of decades with too many nutrients coming from nearby cities and extensive farming. Moreover, rising temperatures result in heat stress also of tropical seagrasses and we predict that we will still be loosing seagrasses in the years to come even if actions are taken now.   See recent examples of research in seagrass eco-physioly and also the list of publications

Lobelia lakes in Scandinavia
Scandinavia and other countries on the northern hemisphere host some of the most exciting lake ecosystems of the world - the lobelia lakes. These lakes are typically crystal clear as the receive very few nutrients so algal growth is scarce. The aquatic vegetation is primarily composed by isoetids, small plants represented by many different plant families but with similar morphology and a very exciting physiology. Some are CAM plants (a feature which is normally found in cacti) and they all utilize the CO2 in the sediment to compensate for the carbonate-poor water surrounding them.  See the list of publications for articles on this exciting topic!

Lobelia dortmanna flowering under water

Potamogeton in Lake Värsjön, Sweden

Brownification of lobelia lakes
Brownification of lobelia lakes is a growing problem on the Northern Hemisphere, where humic substances formed in the terrestrial catchment is washed into pristine lakes. The colored dissolved organic matter (cDOM) absorbs light and greatly reduces the depth penetration of submerged aquatic plants including the slow-growing and ultra-sensitive isoetids e.g., Lobelia dortmanna, Littorella uniflora, Isoetes lacustris, I. echinospora and the rare Subularia aquatica. The mechanisms behind brownification are not yet fully understood and so management plans cannot be developed based upon scientific recommendations.  See the list of publications for articles on this exciting topic!