Cellular survival strategies in high alpine and polar plants

Plants growing in high mountains or in polar regions have to cope with three harsh conditions during their life in comparison to lowland plants: short vegetation period, cold, which occasionally can stress the plants also during summer, and high irradiation. Only a part of the strategies which form the basis for a survival at high altitudes or in the Arctic are known so far. Investigations from ecology and ecophysiology could describe some survival strategies, mostly addressing the whole plant or a plant organ. Several studies performed during the last years deal with possible metabolic adaptations. If e.g. a leaf metabolism adapts to unfavourable conditions, this includes the cooperation of cell organelles and membrane functions. Until now only the applicant has worked on a detailed desription of ultrastructure of leaves from a number of alpine and polar plants, trying to combine the results with metabolic and ecological data. These studies have shown, that a deeper understanding of survival adaptations in alpine and polar plants on the basis of cellular functions requires the methods of modern cell biology. Via studies made by transmission electron microscopy the applicant could show that under influence of cold and high light chloroplasts of several alpine and polar plants form special structures, called protrusions, which could explain some of the physiological adaptations described in the literature. These structures seem to be formed in a dynamic way; to understand their induction, dynamics and possible physiological role one should use methods of cell biology, comparable as they are introduced for cytoskeleton studies. The formation of protrusions, their stability and their 3-D appearance shall be studied by means of confocal laser scanning microscopy (CLSM), using "green fluorescent protein" (GFP), fluorescence-labelled antibodies or inhibitors of the cytoskeleton. Basic data for the experiments are climate records of the growth site and photosynthesis activity to describe the factors, which induce the formation of plastid protrusions. Previous studies have shown that in high alpine plants a close cooperation of plastids, mitochondria and microbodies can help to explain survival in the field. This dynamic organelle cooperation shall also be studied. All experiments will be made with wild plants from high alpine or polar growth sites and interpretation of results will include ecophysiology.

Plants growing in high mountains or in polar regions have to cope with three harsh conditions during their life in comparison to lowland plants: short vegetation period, cold, which occasionally can stress the plants also during summer, and high irradiation. Only a part of the strategies which form the basis for a survival at high altitudes or in the Arctic are known so far. Investigations from ecology and ecophysiology could describe some survival strategies, mostly addressing the whole plant or a plant organ. Several studies performed during the last years deal with possible metabolic adaptations. If e.g. a leaf metabolism adapts to unfavourable conditions, this includes the cooperation of cell organelles and membrane functions. Until now only the applicant has worked on a detailed desription of ultrastructure of leaves from a number of alpine and polar plants, trying to combine the results with metabolic and ecological data. These studies have shown, that a deeper understanding of survival adaptations in alpine and polar plants on the basis of cellular functions requires the methods of modern cell biology. Via studies made by transmission electron microscopy the applicant could show that under influence of cold and high light chloroplasts of several alpine and polar plants form special structures, called protrusions, which could explain some of the physiological adaptations described in the literature. These structures seem to be formed in a dynamic way; to understand their induction, dynamics and possible physiological role one should use methods of cell biology, comparable as they are introduced for cytoskeleton studies. The formation of protrusions, their stability and their 3-D appearance shall be studied by means of confocal laser scanning microscopy (CLSM), using "green fluorescent protein" (GFP), fluorescence-labelled antibodies or inhibitors of the cytoskeleton. Basic data for the experiments are climate records of the growth site and photosynthesis activity to describe the factors, which induce the formation of plastid protrusions. Previous studies have shown that in high alpine plants a close cooperation of plastids, mitochondria and microbodies can help to explain survival in the field. This dynamic organelle cooperation shall also be studied. All experiments will be made with wild plants from high alpine or polar growth sites and interpretation of results will include ecophysiology.