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Water relations, thallus structure and photosynthesis in Negev Desert lichens
Author(s) -
PALMER ROBERT J.,
FRIEDMANN E. IMRE
Publication year - 1990
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1990.tb00544.x
Subject(s) - thallus , lichen , photosynthesis , botany , biology , dew , physics , condensation , thermodynamics
SUMMARY The role of lichen thallus structure in water relations and photosynthesis was studied in Ramalina maciformis (Del.) Bory and Teloschistes lacunosus (Rupr.) Sav. Water‐vapour adsorption and photosynthesis are dependent upon thallus integrity and are significantly lower in crushed thalli. Cultured phycobiont ( Trebouxia sp.) cells are capable of photosynthesis over the same relative humidity range (> 80 % RH) as are intact lichens. Thus, water‐vapour adsorption by the thallus and physiological adaptation of the phycobiont contribute to the ability of these lichens to photosynthesize in an arid environment. Despite differences in their anatomical structure and water‐uptake characteristics, their CO 2 incorporation is similar. The two lichens use liquid water differently and they occupy different niches.