Leaf demography of <Emphasis Type="Italic">Festuca pallens</Emphasis> in dry grassland communities |
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Authors: | Monika Janišová |
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Institution: | (1) Slovak Academy of Sciences, Institute of Botany, Dúbravská cesta 14, SK-84523 Bratislava, Slovakia |
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Abstract: | Leaf blade parameters and leaf demography of Festuca pallens Host were studied in two types of dry grasslands. The field work was carried out in the Považsky Inovec Mts (Western Carpathians)
during 1993–1995. The permanent plot in the Poo badensis-Festucetum pallentis was located on a steep, strongly eroded S-facing slope covered with dolomite outcrops, scree and sparse vegetation (20%)
dominated by Festuca pallens. The permanent plot in the Festuco pallentis-Caricetum humilis was located on the even ridge plateau with shallow stony soil and vegetation covering about 70% dominated by Carex humilis and Festuca pallens.
In comparison to other grasses Festuca pallens had a very low rate of leaf turnover. The highest leaf birth rates and the lowest leaf death rates were observed in June.
Leaf mortality was uniformly distributed in time without a distinct minimum or maximum. For the surviving tillers the leaf
production exceeded the leaf mortality during the whole growing season. The steady net gain of leaves in tillers was not interrupted
by the parallel process of tillering. Among the leaf cohorts the leaves produced in May had the longest leaf blades. Leaves
grew during the whole year. The winter cold and summer drought might slow down the growth rate or interrupt the growth. The
growth of a leaf blade took five to eight weeks. Leaf life span was estimated to 150–200 days (time from leaf appearance at
the apex to the complete loss of its green assimilating parts). In comparison to other grasses Festuca pallens belongs to the species with the longest leaf life span. The effect of environmental factors on leaf demography was followed
by the comparison of two populations belonging to two phytosociological associations differing mostly in habitat xericity.
Differences were revealed in the following characteristics: length of leaf blade in cohorts born during May and June, maximum
length of a leaf blade in a tiller and daily increments in May and June. The course of leaf natality and mortality was similar
in the studied populations. |
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Keywords: | dry grasslands leaf blade parameters leaf turnover leaf life span |
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