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Partial Turgor Pressure Regulation in Chara canescens and its Implications for a Generalized Hypothesis of Salinity Response in Charophytes
Author(s) -
Winter U.,
Kirst G. O.
Publication year - 1991
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1991.tb00191.x
Subject(s) - turgor pressure , salinity , osmotic pressure , euryhaline , osmoregulation , sucrose , botany , chara , biology , horticulture , chemistry , zoology , ecology , biochemistry
Concentrations of ions and sucrose in the vacuolar sap of Chara canescens growing in an oligohaline lake (1.5 ‰) were estimated over the main growth period of the plants. During fructification vacuolar sap contained a mean of 41 mol m −3 (range 10.2–61.8) sucrose. The mean turgor pressure was 239 mosmol kg −1 (range 219–264). In long‐ and short‐term experiments these plants were subjected to increasing salinities up to 22 ‰. When salinity was increased from 1.5 to 4.4 ‰ turgor pressure was restored to only 80 % of the initial value. This reduced level of turgor pressure was maintained up to a salinity of 22 ‰. The increase in vacuolar osmotic potential was due to the monovalent ions Na + , K + and Cl − . The relative amounts of Na + and K + participating in the regulation process were dependent on external salinity. The regulatory mechanisms observed in the brackish water species Ch. canescens are compared with those reported from freshwater and euryhaline species.