Leaf morphology and macronutrients in broadleaved trees in central Italy

Abstract

As part of an intensive monitoring programme (MON.I.TO, Intensive Monitoring of Forests in Tuscany), a 3-year survey was carried out, which included three tree species (beech, Fagus sylvatica L.; Turkey oak, Quercus cerris L.; holm-oak, Quercus ilex L.) located at six different sites. Leaves were sampled annually and analysed for nutrient concentrations (nitrogen, sulphur, phosphorus, magnesium, calcium, potassium and sodium) and morphological parameters (leaf area, dry weight, leaf mass per area, leaf thickness and leaf density). Results indicated considerable interannual variation of all the parameters. Differences between sampling sites indicated that, of all parameters measured, leaf mass per area could explain best the differences in field performance under conditions of stress. In fact, leaf mass per area was greater in the drier sites or when sea salt deposition occurred. Nevertheless, the variation of leaf mass per area over the 3 years did not reflect the differences in rainfall. Higher leaf mass per area was accompanied by lower concentrations of phosphorus and nitrogen, which could be a dilution effect due to an increase of structural carbon compounds in sclerophyllous leaves, as revealed by the total foliar content of these elements. Leaf mass per area as a measure of sclerophylly reached very high values among mesophile vegetation. Long-range transport of sea salt from coastal areas to mountain areas was mirrored in sodium concentrations of leaves.

Warming and drought alter C and N concentration, allocation and accumulation in a Mediterranean shrubland

“…The increase in the C/N leaf concentration ratio formed in the dominant non-N-fixing species in response to warming and drought is a widely observed phenomenon (Groom & Lamont, 1999;Bussotti et al, 2000). These effects were due to a decrease in N concentrations under warming and to an increase in C concentrations and a decrease in N concentrations under drought.…”

“…These effects were due to a decrease in N concentrations under warming and to an increase in C concentrations and a decrease in N concentrations under drought. This usually results from an increase in structural compounds rich in carbon and poor in N, such as lignin, in order to protect leaf tissues from water deficit (Bussotti et al, 2000). With further drought, an increase in leaf C concentrations and stem N concentrations and content can be expected in non-N-fixing shrubs in order to improve the plant's capacity to withstand drought.…”

Sources of variability in tissue chemistry in northern hardwood species

“…Foliage has been well studied for variation in nutrient concentrations within the tree (Le Tacon and Toutain 1973; Van den Driessche 1974;Ellis 1975;Morrison 1985;Erdmann et al 1988), from tree to tree (Ellis 1975;Morrison 1985;Erdmann et al 1988), and from year to year within a 5-year period (Alban 1985;Duquesnay et al 2000;Bussotti et al 2000). Other tissues such as boles and branches are less often studied and are more difficult to sample repeatedly but are more important to forest nutrient budgets due to their greater biomass (Pardo et al 2004;Paré et al 2013).…”

Preliminary Study on Taxonomic Review Using Histological Sections of Some Iberian Species from the Genus <i>Quercus</i> L. (Fagaceae)

“…But in addition to these characteristics, there is also an influence of ecological factors, phenological cycles, growth rhythms, etc. [13] [14], which call for the utmost care when collecting samples for taxonomic studies. As far as it is practical, it is necessary to unify the greatest possible number of variables.…”