A model describing photosynthesis in terms of gas diffusion and enzyme kinetics

A model predicting net photosynthesis of individual plant leaves for a variety of environmental conditions has been developed. It is based on an electrical analogue describing gas diffusion from the free atmosphere to the sites of CO 2 fixation and a Michaelis-Menten equation describing CO 2 fixation. The model is presented in two versions, a simplified form without respiration and a more complex form including respiration. Both versions include terms for light and temperature dependence of CO 2 fixation and light control of stomatal resistance. The second version also includes terms for temperature, light, and oxygen dependence of respiration and O 2 dependence of CO 2 fixation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47495/1/425_2004_Article_BF00387066.pd

Floristic and Ecologic Studies of Bryophytes of Selected Habitats at Prudhoe Bay, Alaska

Preliminary floristic and ecologic studies of bryophytes were initiated in the vicinity of Prudhoe Bay, Alaska. Comparisons among different habitats indicated bryofloristic differences with respect to an apparent moisture gradient. A provisional check list consisting of 81 taxa is provided

Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 {times}1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems {ge}2 cm dbh in 10 {times} 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs