Evolutionary and Ecophysiological Responses of Mountain Plants to the Growing Season Environment

Publisher Summary This chapter highlights the evolutionary and ecophysiological responses of mountain plants to the growing season environment. The responses of mountain plants to their environment are due to a complex mixture of genetic and environmental influences. Plants growing on mountains experience reduced temperatures and vapor pressures with altitude, as well as a reduction in the partial pressure of air. There are many morphological, physiological, and biochemical features of plants that change with altitude, such as decrease in stature. Model simulations of canopy energy balance and CO 2 fixation indicate that canopy structure and leaf area index (LAI) strongly influence both photosynthetic rate (A) and the ratio of 13 C to 12 C (δ 13 C) in leaves. δ 13 C measurements on expanded leaves provide a time integral of CO 2 discrimination during the photosynthetic life of the leaf; they also include some unknown δ 13 C contribution from photosynthate exported or remobilized from other leaves and organs. The model simulations, for just the period of peak irradiance during the day, indicate that the energy balance and gas exchange of a leaf are dependent on its aerodynamic coupling with other leaves in the plant canopy, and with the air at some reference height above the canopy.