Effects of nitrogen supply on the physiological and morphological responses to elevated [CO2] in yellow birch (Betula alleghaniensis Britt.)
Abstract
Ongoing climate changes can substantially impact soil nitrogen availability through its
effects on other environmental conditions such as temperature, precipitation, and the frequency
and intensity of extreme whether events, eventually altering the primary productivity of plants
and ecosystems. Effects of environmental changes on soil nitrogen cycling and availability vary
with among season and ecosystem. Nitrogen is a critical factor regulating the photosynthetic
responses of plants to elevated [CO2] as it is a main component in photosynthetic enzymes and
apparatus. Thus, changes in soil nitrogen availability will likely affect the ecophysiological
responses to climate change, particularly elevated [CO2] and the effects can change with species.
A good understanding of how nitrogen supply affects the physiological and morphological
responses of plants to elevated [CO2] is critical for predicting plant performance under future
climate conditions. This study examined the interactive effects of elevated [CO2] and nitrogen
(N) supply on the physiological and morphological responses in yellow birch (Betula
alleghaniensis britt.). Seedlings were exposed to two levels of [CO2] (ambient 400 µmol mol-1
versus elevated 1000 µmol mol-1
), and five levels of N supply (25, 50, 100, 150, and 200 mg N
L
-1
) for 4 months. Seedling height, root collar diameter, specific leaf area, biomass, biomass
allocation, and foliar gas exchange parameters were assessed. [...]