TITLE:
Diagnostics of Epistomatal Wax of Californian Pine Needles, and Their Association with Ozone-Caused Chlorotic Mottle
AUTHORS:
Satu Huttunen, Andrzej Bytnerowicz, Michael J. Arbaugh, Katriina Bent, Marketta Karhu, Päivi Tuohimaa
KEYWORDS:
Pinus coulteri, P. jeffreyi, P. ponderosa, Epistomatal Wax Plugs, Scanning Microscopy (SEM)
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.12,
May
27,
2014
ABSTRACT: Tropospheric ozone is a
worldwide phenomenon causing injuries to forest trees. Californian ponderosa
and Jeffrey pines are well known for their sensitivity to ozone, while other
pine species have varied in their susceptibility. Sensitive pine species are
known for their chlorotic mottle and tip burn symptoms, caused by ozone air
pollution. Epistomatal wax plugs and filamentous waxes around stomata are
typical for pine needle surfaces. In this study, we investigated epistomatal
and epicuticular needle waxes in eight species of field-grown pines in 1985, 1986
and 2006. The epistomatal wax plugs were
present in asymptomatic needles without chlorotic mottle (23% of needles).
A lack of wax plugs in needles with chlorotic mottle and tip burn symptoms was
common (76% of needles). More abundant existence of mottling associated with
stomata without wax plugs in two-year-old needles, compared with one-year-old
needles (43% and 33%, respectively), indicated chronic injury development over
time.