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THE EFFECT OF WINTER FIELD CONDITIONS ON THE DISTRIBUTION OF TWO SPECIES OF UMBILICARIA
Author(s) -
SCOTT MARTHA G.,
LARSON DOUGLAS W.
Publication year - 1986
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.1469-8137.1986.tb00586.x
Subject(s) - thallus , biology , overwintering , lichen , photosynthesis , transplantation , botany , ultrastructure , starch , algae , habitat , pyrenoid , snow , chloroplast , ecology , biochemistry , medicine , physics , surgery , meteorology , gene
SUMMARY This paper describes the effects of transplantation on the ultrastructure and storage body distribution patterns in two saxicolous lichens which show a mutually exclusive distribution pattern. Umbilicaria vellea (L.) Ach., which grows in a snow‐free microhabitat, was transplanted into an adjacent habitat which received a deep winter snow cover and which supported populations of Umbilicaria deusta (L.) Baum. The reverse was done for U. deusta m the U. vellea habitat. Effects of transplantation on storage body distribution were evident for U. vellea , but not for U. deusta. At the ultrastructural level, thalli of U. vellea showed clear signs of disruption including senescence of the algal cells and an increase in the amount of stored starch which was negatively correlated with a decline in photosynthesis in the same replicates. Lipid deposits in U, vellea were initially few in number and did not change as a result of transplantation. Changes were not observed for either species in the number of pyrenoglobuli in the pyrenoid body. Algal cells of U. deusta contained significantly larger amounts of starch and lipid than those of U. vellea and no overwintering treatment disrupted the fine structure of the plant. However, numbers of starch grains declined seasonally while thalli were under snow. Storage body distribution was found to be a stable feature of the algal cells and not dependent on short‐term fluctuations in net photosynthesis. It is possible that U. deusta accumulates large amounts of photosynthetic products in the autumn and uses these to maintain low metabolic levels during the winter. It may be that U. vellea is excluded from snow‐covered habitats because its thalli lack the ability to store photosynthetic products and have a pattern of gas exchange unsuited to overwintering under deep snow.