tailieunhanh - Báo cáo lâm nghiệp: "2 CO response curves can be a measured with field-portable closed-loop photosynthesis system"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: 2 CO response curves can be a measured with field-portable closed-loop photosynthesis system. | 416s Ann. Sci. For. 1989 46 suppl. 416S-420S Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA co2 response curves can be measured with a field-portable closed-loop photosynthesis system . McDermitt1 . Norman2 . Davis3 . Ball4 . Arkebauer2 . Welles1 and . Roemer1 1 LI-COR Inc. Lincoln NE 68504 . 2 Department of Agronomy University of Nebraska Lincoln NE 68583 3 Department of Forestry Fisheries and Wildlife University of Nebraska Lincoln NE 68583 and 4 Carnegie Institution of Washington Stanford CA 94305 . Introduction Assimilation rate versus internal co2 response curves provide an important tool for assessing the efficiency and capacity of the photosynthetic system. Until recently measurement of co2 response curves was limited to laboratory studies where elaborate gas exchange systems were available or to mobile field laboratories. Here we report the use of a portable photosynthesis system LI-6200 LI-COR Inc J for measurement of response curves. The LI-6200 uses a closed-loop design in which varying co2 concentrations are provided as the leaf removes co2 from the system. A typical measurement requires 10-25 min depending upon chamber volume leaf area and assimilation rate. Response curves measured on well-watered soybean and cotton with the LI-6200 are compared to those measured with a fully controlled steady state system. The effects of system leaks and control of leaf temperature are discussed. Materials and Methods Data of Fig. 1 were obtained on well-watered soybeans Glycine max L Merrill cv Hobbit grown in soil and 12 in pots in a temperature-controlled 27 3 C greenhouse in Lincoln NE. Measurements were made on upper cano py fully exposed leaves when the plants were in the early pod-filling stage. PAR was supplied by one Metalarc 400 w lamp and one Lucolux 400 w lamp in a single water-cooled luminaire Sun-brella Environmental Growth Chambers Chagrin Falls OH . The 1 I chamber of the LI-6200 was mounted on a tripod and placed