. The ecology of delta marshes of coastal Louisiana : a community profile. Marsh ecology -- Louisiana; Wetlands -- Louisiana. D. spicata c E o CO O o (A a> 3 z g a cc O CO OQ < cc. NaCI (mM/l) Figure 46. Effects of NaCl concentration in the root medium on the rate of Rb absorption by excised root tissue of S. alterniflora and D. spicata (1 mM Rb; 2 mM Ca; reprinted from Bot. Gazette, 1981, by Parrando, Gosselink, and Hopkinson with permission of The Univer- sity of Chicago). the concentration of other ions such as K (Smart and Barko 1978). Finally, the plant leaves have se
. The ecology of delta marshes of coastal Louisiana : a community profile. Marsh ecology -- Louisiana; Wetlands -- Louisiana. D. spicata c E o CO O o (A a> 3 z g a cc O CO OQ < cc. NaCI (mM/l) Figure 46. Effects of NaCl concentration in the root medium on the rate of Rb absorption by excised root tissue of S. alterniflora and D. spicata (1 mM Rb; 2 mM Ca; reprinted from Bot. Gazette, 1981, by Parrando, Gosselink, and Hopkinson with permission of The Univer- sity of Chicago). the concentration of other ions such as K (Smart and Barko 1978). Finally, the plant leaves have secretory glands called hydathodes which selectively secrete cer- tain ions. All this regulatory activity requires extra energy expenditure by the plant. It is not surprising then that the growth rate decreases as the external salt concentration increases. The problem of anoxia is complex because it affects not only the plant Itself but also the microblally mediated biochemical reactions that occur in the soil around the roots. Oxygen is required as an electron acceptor in aerobic cell respiration. Its presence allows the efficient oxidation of organic sugars to carbon dioxide and water to produce high energy-reduced organic compounds and the cell's ready energy currency adenosine triphosphate (ATP). In the absence of oxygen, cell metabolism is incomplete; less energy is released from an equivalent amount of sugar (1 mole of glucose yields 2 moles of ATP under anaerobic conditions compared to 36 moles under aerobic conditions); and organic "waste products" like ethanol and lactic acid accumulate because they cannot be oxidized to carbon dioxide (Figure 47). In the surrounding root medium, when oxygen is depleted, other materials act as electron acceptors, almost always through some microbial intermediary rather than through strictly inorganic chemical transfonnations. Many ionic species are reduced. The reduced form of metallic ions such as manganese and iron is more so
Size: 1318px × 1895px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbio, booksubjectwetlandslouisiana
