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Title: CO{sub 2} exchange, environmental productivity indices, and productivity of Agaves and Cacti under current and elevated atmospheric CO{sub 2} concentrations. Terminal report

Technical Report ·
DOI:https://doi.org/10.2172/82381· OSTI ID:82381

The research described in the proposal investigated net CO{sub 2} uptake and biomass accumulation for an extremely productive CAM plant, the prickly pear cactus Opuntia ficus-indica, under conditions of elevated CO{sub 2} concentrations for relatively long periods. The influences of soil water status, air temperature, and the photosynthetic photon flux (PPF) on net CO{sub 2} uptake over 24-h periods were evaluated to enable predictions to be made based on an Environmental Productivity Index (EPI). Specifically, EPI predicts the fraction of maximal daily net CO{sub 2} uptake based on prevailing environmental conditions. It is the product of indices for temperature, soil water, and intercepted PPF, each of which range from 0.00 when that index factor completely inhibits net CO{sub 2} uptake to 1.00 when no limitation occurs. For instance, the Water Index is 1.00 under wet conditions and decreases to 0.00 during prolonged drought. Although the major emphasis of the research was on net CO{sub 2} uptake and the resulting biomass production for O. ficus-indica, effects of elevated CO{sub 2} concentrations on root: shoot ratios and on the activities of the two carboxylating enzymes were also investigated. Moreover, experiments were also done on other CAM plants, including Agave deserti, Agave salmiana, and Hylocereus undatus, and Stenocereus queretaroensis.

Research Organization:
Univ. of California, Los Angeles, CA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-91ER61252
OSTI ID:
82381
Report Number(s):
DOE/ER/61252-T2; ON: DE95013304; TRN: 95:005173
Resource Relation:
Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English