Terrestrial Palaeoecology and Global Change

Chapter 7. Climate change
235
a
b
c
Fig. 96. Epidermal anomalies in gymnosperms from the Permian/Triassic “boundary clay” of Nedubrovo as
evidence of UF damage enhanced by loss of stratospheric ozone at the time of massive volcanic eruptions
(Krassilov et al., 1999a, 2000): (a) an irregular epidermal topography with linear and concentric configurations
of compressed cells in a peltasperm, Tatarina antiqua, reflecting erratic local bursts of meristematic
activity, (b) contiguous stomata and compact groups of small thick-walled cells derived from abnormally
developed stomatal initials (arrow) in a conifer, Ullmannia cf. bronnii, (c) an irregular configuration of
subsidiary stomatal cells distorted by intervention of ordinary cells in the same species, (d) a profuse division
of encircling cells of an aborted stoma in Tatarina antiqua.
d