Photosynthetic responses to understory shade and elevated carbon dioxide concentration in four northern hardwood tree species.
MetadataShow full item record
Seedling responses to elevated atmospheric CO(2) concentration ([CO(2)]) and solar irradiance were measured over two growing seasons in shade-tolerant Acer saccharum Marsh. and Fagus grandifolia J.F. Ehrh. and shade-intolerant Prunus serotina, a J.F. Ehrh. and Betula papyrifera Marsh. Seedlings were exposed to a factorial combination of [CO2] (ambient and elevated (658 micromol mol-1)) and understory shade (deep and moderate) in open-top chambers placed in a forest understory. The elevated [CO(2)] treatment increased mean light-saturated net photosynthetic rate by 63% in the shade-tolerant species and 67% in the shade-intolerant species. However, when measured at the elevated [CO(2)], long-term enhancement of photosynthesis was 10% lower than the instantaneous enhancement seen in ambient-[CO(2)]-grown plants (P < 0.021). Overall, growth light environment affected long-term photosynthetic enhancement by elevated [CO(2)]: as the growth irradiance increased, proportional enhancement due to elevated [CO(2)] decreased from 97% for plants grown in deep shade to 47% for plants grown in moderate shade. Results suggest that in N-limited northern temperate forests, trees grown in deep shade may display greater photosynthetic gains from a CO(2)-enriched atmosphere than trees growing in more moderate shade, because of greater downregulation in the latter environment. If photosynthetic gains by deep-shade-grown plants in response to elevated [CO(2)] translate into improved growth and survival of shade-intolerant species, it could alter the future composition and dynamics of successional forest communities.
Showing items related by title, author, creator and subject.
Korczynskyj, Dylan (2002)Australian grasstrees are a long-lived group of arborescent, monocotyledonous plants that persist in fire-prone landscapes. Renowned for their capacity to survive fire, and flower soon after, these species have long ...
Developing completion criteria for rehabilitation areas on arid and semi-arid mine sites in Western AustraliaBrearley, Darren (2003)Continued expansion of the gold and nickel mining industry in Western Australia during recent years has led to disturbance of larger areas and the generation of increasing volumes of waste rock. Mine operators are obligated ...
Gaol, Mangadas Lumban (2002)The ecology of plant species at Sandford Rocks Nature Reserve (SRNR) was studied. The study site is an important nature reserve that contains relatively undisturbed natural vegetation. It has a mosaic of exposed granite ...