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The relationships between community structure and soil properties (pH, P, N, Ca, Mg, CaCO₃ and clay content) were examined in a swamp forest from the northern part of Turkey. Statistically significant correlations were found between the soil variables and three different associations (Fraxino excelsioris-Fraxinetum angustifoliae, Carpino orientalis-Pterocaryetum fraxinifoliae, Acero campestris-Alnetum glutinosae) according to CCA ordination. P, Mg, Ca and clay content of soil were found as four significant variables for species composition in the studied forest.
We investigated the effects of sexual reproduction on vegetative propagation and relative somatic cost in Arum maculatum L. (Araceae). Two groups were selected as control and experimental. The spadices of individuals in experimental group were removed to test the relationship between sexual reproduction and vegetative propagation. Statistically significant differences were found between initial and final tuber weight in individuals with sexual organs removed. No significant differences were found between initial and final tuber weight in naturally reproducing (sexual organs not removed) individuals. However, the statistically significant differences were found between control and experimental group with respect to above-ground biomass but not in terms of below-ground biomass. The differences between two groups in terms of above-ground and below-ground nitrogen concentrations were also significant. Relative somatic cost of sexual reproduction (RSC) was observed in above-ground parts, but not in below-ground parts in terms of biomass and in both above- and below-ground parts in terms of nitrogen concentration.
The effects of pH, electrical conductivity (EC), soluble cations (Na⁺, K⁺, Ca²⁺, Mg²⁺), and soluble anions (HCO₃⁻, Cl⁻, SO₄²⁻) on vegetation zonation in a salt-marsh community (Black Sea coast) were investigated on two localities at Black Sea Coast differing as to the altitude, community composition and zonation. Three zones (25–80 m wide) – lower, middle and upper were distinguished in each locality along 150 m transect and according to the vegetation types which were analysed with Braun-Blanquet method. The dominant species were following: Juncus acutus L., Salicornia prostrata Pall., Spergularia marina (L.) Gris, Hordeum geniculatum All., Plantago coronopus L. subsp. coronopus, Carex capitellata Boiss. and Bal, Artemisia santonicum L. and Juncus littoralis C. A. Mey. Soil samples were taken down to 50 cm. The results of soil analysis were evaluated by using Canonical Correspondence Analysis (CCA) from winter 1999 to autumn 2000. HCO₃⁻ concentration and inundation depth (2.22–21.44 cm) are the environmental variables that correlate the best with axis 1, whereas K⁺ concentration and inundation depth (2.22–21.44 cm) correlate the best with axis 2 during the study period. During winter 1999, HCO₃⁻ concentration showed the highest correlation with the canonical axis 1 and associated zone was H. geniculatum. In spring, summer and autumn 2000, inundation depth (3.44–19.11 cm) was the most prominent factor correlated with the first and second axes, respectively, with associated zone of C. capitellata. EC, Na⁺ and Cl⁻ concentrations were decreased during autumn in all vegetation zones except for C. capitellata and Artemisia santonicum zones in which Na⁺ and Cl⁻ concentrations and EC, respectively were increased during autumn. The C. capitellata (Cyperaceae) zone was located on the positive site of axis 1 during autumn 2000 and followed the gradient of inundation depth. S. prostrata, S. marina, H. geniculatum and P. coronopus subsp. coronopus seems to be adapted to the most saline soils, whereas C.capitellata indicates the wettest soils in the studied salt marsh. The Juncus littoralis zone followed the gradient of maximum salinity during autumn of the year 2000, but the zone was not related to the measured increase in soil salinity during winter, summer and spring. In both localities EC, Na⁺ and Cl⁻ concentrations were tended to decrease at upper zones. Inundation regime, K⁺ concentration, and HCO₃⁻ concentration are key factors affecting vegetation zonation in studied salt marshes.
Gallery forests in Central Black Sea Region are dominated by Platanus orientalis L. The studies were performed in four sites (Mert River, Adalar, Kurupelit and Taflan Regions) located in V-shaped river valleys and differing with soil conditions. Nutrient concentrations were measured in green and senescent leaves in selected sympatric tree species. Foliar nutrient resorption efficiency (RE; as the ratio of the resorbed amounts of nutrient losses during the leaf senescence to its prior amount deposited in the leaves) and proficiency (RP; the level to which nutrient content per unit leaf mass, mg g⁻¹, has been reduced in senescent leaves) were examined in several sympatric species. The high nitrogen resorption efficiency (N-RE) (62%) were found in Hedera helix L., while the lowest (40%) – in Salix alba L. The phosphorus resorption efficiency (P-RE) ranged between 35% (Rubus discolor Weithe and Nees) and 50% (S. alba) and that of potassium (K-RE) ranged between 49% (S. alba) and 62% (Robinia pseudoacacia L.). The different trend was observed in the values of proficiency (RP). The high nitrogen resorption proficiency (N-RP) ranged between 10 mg g⁻¹ (Clematis vitalba L.) and 18 mg g⁻¹ (R. discolor). The high phosphorus resorption proficiency (P-RP) was found in R. discolor (0.5 mg g⁻¹) similar to N-RP. The lowest P-RP was found in R. pseudoacacia (0.3 mg g⁻¹) like K-RP (5 mg g⁻¹). The high K-RP (10 mg g⁻¹) was found in H. helix. There is no significant difference between four study sites. Soil N, P and organic matter concentrations were significantly correlated with green-leaf N, P and K concentrations. Significant correlations were also found between K-RP and soil nutrient concentrations and soil moisture. However, no significant correlations were found among green-leaf nutrient concentrations, RE, RP and soil nutrient concentrations and moisture.
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