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Title: Environmental effects on photorespiration of C sub 3 -C sub 4 species. I. Influence of CO sub 2 and O sub 2 during growth on photorespiratory characteristics and leaf anatomy. [Flaveria pringlei; Flaveria flroidana; Flaveria trinervia; Panicum milloides; Panicum laxum]

Journal Article · · Plant Physiology; (USA)
DOI:https://doi.org/10.1104/pp.90.3.1022· OSTI ID:6967439
;  [1]
  1. Univ. of Georgia, Athens (USA)

The possibility of altering CO{sub 2} exchange of C{sub 3}-C{sub 4} species by growing them under various CO{sub 2} and O{sub 2} concentrations was examined. Growth under CO{sub 2} concentrations of 100, 350, and 750 micromoles per mole had no significant effect on CO{sub 2} exchange characteristics or leaf anatomy of Flaveria pringlei (C{sub 3}), Flaveria floridana (C{sub 3}-C{sub 4}), or Flaveria trinervia (C{sub 4}). Carboxylation efficiency and CO{sub 2} compensation concentrations in leaves of F. floridana developed under the different CO{sub 2} concentrations were intermediate to F. pringlei and F. trinervia. When grown for 12 days at an O{sub 2} concentration of 20 millimoles per mole, apparent photosynthesis was strongly inhibited in Panicum milioides (C{sub 3}-C{sub 4}) and to a lesser degree in Panicum laxum (C{sub 3}). In P. milioides, acute starch buildup was observed microscopically in both mesophyll and bundle sheath cells. Even after only 4 days exposure to 20 millimoles per mole O{sub 2}, the presence of starch was more pronounced in leaf cross-sections of P. milioides compared to those at 100 and 210 millimoles per mole. Even though this observation suggests that P. milioides has a different response to low O{sub 2} with respect to translocation of photosynthate or sink activity than C{sub 3} species, the concentration of total available carbohydrate increased in shoots of all species by 33% or more when grown at low O{sub 2}. This accumulation occurred even though relative growth rates of Festuca arundinacea (C{sub 3}) and P. milioides grown for 4 days at 210 millimoles per mole O{sub 2}, were inhibited 83 and 37%, respectively, when compared to plants grown at 20 millimoles per mole O{sub 2}.

OSTI ID:
6967439
Journal Information:
Plant Physiology; (USA), Vol. 90:3; ISSN 0032-0889
Country of Publication:
United States
Language:
English