Monthly fluctuations in radial growth of individual lobes of the lichen Parmelia conspersa (Erhr. ex Ach.) Ach.


The radial growth (RG) of 120 lobes from 35 thalli of the foliose lichen Parmelia conspersa (Ehrh. ex Ach.) Ach. was studied monthly over 22 months in south Gwynedd, Wales, UK. Autocorrelation analysis of each lobe identified three patterns of fluctuation: 1) random fluctuations (58% of lobes), 2) a cyclic pattern of growth (23% of lobes), and 3) fluctuating growth interrupted by longer periods of very low or zero growth (19% of lobes). In 80% of thalli, two or three patterns of fluctuation were present within the same thallus. Growth fluctuations were correlated with climatic variables in 31% of lobes, most commonly with either total rainfall or number of rain days per month. Lobes correlated with climate were not associated with a particular type of growth fluctuation. RG of a lobe was positively correlated with the degree of bifurcation of the lobe tip. It is hypothesised that lobes of P. conspersa exhibit a cyclic pattern of growth due in part to lobe division. The effects of climate, periods of zero growth, and microvariations in the environment of a lobe are superimposed on this cyclic pattern resulting in the random growth of many lobes. Random growth fluctuations may contribute to the maintenance of thallus symmetry in P. conspersa.

Divisions: College of Health & Life Sciences > School of Optometry
College of Health & Life Sciences > Ophthalmic Research Group
College of Health & Life Sciences
College of Health & Life Sciences > Vision, Hearing and Language
College of Health & Life Sciences > Clinical and Systems Neuroscience
Additional Information: ©2009 Balaban, Philadelphia/Rehovot
Uncontrolled Keywords: parmelia conspersa,marginal lobes,temporal fluctuations,radial growth,lobe division,thallus symmetry,time series,autocorrelation,Agricultural and Biological Sciences(all)
Full Text Link: http://www.symb ... com/index.shtml
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2009
Authors: Armstrong, Richard A. (ORCID Profile 0000-0002-5046-3199)


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