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2 Polish Journal of Ecology

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The effect of the halophytic shrub Lycium ruthenicum (Mutt) on selected soil properties of a desert ecosystem in Central Iran

100%

Jalali G. A. , Akbarian H. , Rhoades C. , Yousefzadeh H.

nr 4

We compared soil properties beneath naturally-occurring patches of Lycium ruthenicum Murray (fam. Solanaceae) to evaluate the shrub’s potential to improve the fertility of saline soils. Soil pH, total nitrogen and carbon and extractable potassium, magnesium and phosphorus were respectively significantly higher in the A and B horizons of Lycium shrub patches compared to adjacent unvegetated soils. The influence of Lycium on these soil properties increased with shrub density. Total soil N and extractable Mg and K concentrations were 1.8, 2.6- and 6.6-fold higher under dense Lycium shrub patches compared to unvegetated, bare areas and soil pH was 0.5 units higher. In contrast, the presence of shrubs and shrub density had no clear affect on the EC, Na or CEC of the A horizon soils. The shrub effect extended to the gypsum-rich By horizon (20–50 cm depth) and underlying B horizon (30–80 cm depth) for several soil properties. Total soil C and N were 1.8- and 1.6-fold higher beneath dense Lycium patches than bare soil areas. Soil pH remained 0.4 units higher under dense Lycium than bare soil patches. In the B horizon total soil C was twice as high beneath dense Lycium patches compared to the other patch types. Lycium ruthenicum not only tolerates the saline and drought conditions, it also produces sufficient biomass to increase the nutrient and organic matter content of surface mineral soils in this arid ecosystem and may have potential to improve soil conditions, facilitate ecosystem development and slow desertification.

Inter - and intrapopulation variation of leaf morphological traits in natural stands of Buxus hyrcana [Pojark.] in Caspian Forests [Iran]

75%

Yosefzadeh H. , Tabari M. , Espahbodi K. , Jalali G. A. , Bussotti F. , Abdi E.

nr 2

291-301

The leaf morphology of Buxus hyrcana (Pojark.), shade-tolerant and evergreen species growing in understorey of Caspian Forest was studied in five natural Iranian populations in order to recognize the pattern of within- and among-population variation of selected leaf morphological traits. Fifteen traits were selected and measured or calculated – list in Appendix. Leaves were collected from different geographical (between 36°13′N and 53°15′E) populations of B. hyrcana growing in the Caspian Forests located in Mazandaran Province (northern Iran) in the similar vegetation and site conditions but on different altitudes. Ten mature trees from five relatively small areas (0.5–1 ha) were selected in June. Then ANOVA model was used with both crossed and nested effects. The results showed that variation among the populations was significant in 13 of 15 traits (P <0.05); variation among the trees in the population was significant in 14 of 15 traits (P <0.05). Among all characters measured, the greatest plasticity was found for weight, leaf area mass and specific leaf mass. Function 1 explained 30% of the total variance and Function 2 represented another 17% of the total variance. PCA analysis showed that the most important role in function 1 allocated to width of lamina and leaf figure ratio (length of lamina/width of lamina) and in function 2 to top of leaf figure (width of lamina in 0.1 its length/width of lamina). The results of the average linkage clustering method evidenced four distinct clusters. Generally, morphological traits of leaves of B. hyrcana showed low variation among the considered populations based on clustering analysis, although some trees inside the population showed significantly different values in comparison with other trees.