Jan-Niklas NuppenauDoktorand

Om mig

About me

I am a PhD student in the plant systematics group at Stockholm University. I use a combined experimental and phylogenetic approach to study evolution of cold tolerance in grasses (Poaceae).

My thesis is supervised by Aelys Humphreys, Catarina Rydin and Johan Ehrlen

Research

Climate is thought to be one of the main factors determining plant distribution patterns, yet our understanding of the extent to which the relationship between climate and distribution is causal remains poor. Low temperatures are one of the most important environmental constraints limiting distributions on Earth. The survival of cold temperatures in winter is very complex and involves many adaptations on different levels. Plants originated under tropical conditions and therefore had to evolve these adaptations to be able to conquer the colder parts of Earth.

Grasses are of special interest in this context because their global distribution spans from tropical to the coldest areas on Earth, but the role of cold tolerance evolution in generating this distribution is understudied. Two lineages have transitioned independently from their tropical origins and diversified as temperate groups: Danthonioideae, mostly on the southern Hemisphere, and Pooideae, mostly on the northern Hemisphere. These two clades are distantly related and have been shown to use different molecular mechanisms to tolerate freezing temperatures. However, in general the mechanisms and levels of cold tolerance among grasses are poorly understood . From a practical perspective grasses are mostly fast growing, herbaceous plants, making experimentation relatively straightforward. They are also molecularly well investigated as intensive research has been conducted on cereals and forage grasses.

My PhD project aims to further disentangle the evolutionary history of cold tolerance in grasses, the adaptations involved and their role in determining global distribution patterns. This will be done by combining common garden experimentation, modelling in a phylogenetic framework, and genetic analyses. The findings of these projects are expected to 1) increase the mechanistic understanding of distribution patterns 2) bring much needed experimentation to the rapidly growing field of species distribution modelling and 3) provide new insights into the evolution of abiotic stress tolerance in plants in general and cold tolerance in grasses in particular.