Pollen tube growth in high mountain plants

The reproductive phase is one of the most critical phases in the life cycle of a plant. Processes occurring during flowering are especially vulnerable to changes of environmental conditions including temperature. Functions as stigma receptivity, ovule longevity, pollen germination and pollen tube growth are bound to a certain temperature range beyond which they increasingly fail, and, as a consequence, fertilization and seed production are reduced or absent. Plants at higher elevations are exposed to strong variations of temperature. On clear summer days, flowers may warm up to 30C, but may cool down to freezing temperatures during the night or during a cold spell even in summer. Therefore the question arises, what the optimal temperature range and the limits for reproductive functions during the progamic phase in high mountain plants are. This is investigated in representative plant species from the alpine and nival zone in the Austrian Alps in situ and in laboratory experiments at controlled temperatures. Male and female performance is decisive for the reproductive success and thus has long-term consequences for the colonization potential of a species. In order to understand how plants growing at the upper limits of plant distribution respond to changing environmental conditions, we need information about the plasticity of these vital functions. Beyond this, the reproductive performance under extreme climatic conditions may be an important clue for breeding research.

The reproductive phase is one of the most critical phases in the life cycle of a plant. Processes occurring during flowering are especially vulnerable to changes of environmental conditions including temperature. Functions as stigma receptivity, ovule longevity, pollen germination and pollen tube growth are bound to a certain temperature range beyond which they increasingly fail, and, as a consequence, fertilization and seed production are reduced or absent. Plants at higher elevations are exposed to strong variations of temperature. On clear summer days, flowers may warm up to 30C, but may cool down to freezing temperatures during the night or during a cold spell even in summer. Therefore the question arises, what the optimal temperature range and the limits for reproductive functions during the progamic phase in high mountain plants are. This is investigated in representative plant species from the alpine and nival zone in the Austrian Alps in situ and in laboratory experiments at controlled temperatures. Male and female performance is decisive for the reproductive success and thus has long-term consequences for the colonization potential of a species. In order to understand how plants growing at the upper limits of plant distribution respond to changing environmental conditions, we need information about the plasticity of these vital functions. Beyond this, the reproductive performance under extreme climatic conditions may be an important clue for breeding research.