Ecological and functional leaf morphology of species of the genus Aquilegia L.

Abstract

The functional leaf morphology of 13 species and one subspecies of the genus Aquilegia L. was studied in the steppe zone of Ukraine: A. oxysepala Trautv. & C. A. Mey. var. kansuensis Brune, A. buergeriana Sieb. et Zucc., A. flabellata Sieb.et Zucc., A. aurea Janka, A. nigricans Baumg., A. pyrenaica DC., A. canadensis L., A. skinneri Hook., A. chaplinii Standley ex Paysch., A. alpina L., A. einseleana F.W. Schultz, A. sibirica Lam., A. olympica Boiss. There are some common features in all investigated species of this genus introduced in the steppe of Ukraine: 1) a higher leaf indentation (Iz) and correlation of fresh weight to leaf area (m/S) related to increase in the total solar radiation in June, annual precipitation (Is), the sum of temperatures above 10 °C and the duration of period with temperature above 5 °C; 2) higher correlation of fresh and dry weight (m2/m) in the species from dry habitats; 3) higher correlation of fresh leaf weight to petiole length (m/Lp) in the species from warmer habitats; 4) higher correlation of leaf area to petiole length (S/Lp) related to decrease in the total solar radiation in June; 5) higher correlation of leaf petiole length to its diameter (Lp/dp) related to the increase of annual precipitation variation and duration of the period with temperature above 15 °C in their natural habitats. The correlation of dry leaf weight to its area (m2/S) is characterized by the same correspondences as m/S, except for solar radiation. There are significant differences in some parameters in North-American alpine forest species as the steppe climate of Ukraine is much more dry and cold than that of their natural habitats. This causes the adaptive morphologic modification of the leaf. We observe a higher leaf indentation, correlation of fresh weight (m/S) and dry weight (m2/S) to leaf area, correlation of fresh leaf weight to petiole length (m/Lp) in North-American alpine forest species in comparison to highland sub-alpine and lowland forest species of Eurasian origin. The correlation of the leaf area to petiole length (S/Lp) and correlation of fresh and dry weight (m2/m) is higher in the group of subalpine species. The correlation of leaf area to petiole length (S/Lp) is higher in alpine forest species. Highland and lowland forest species are characterized by increase of leaf blade indentation (Iz), a smaller leaf area (S) related to increase in the total solar radiation in June in their natural habitats. They are also characterized by increase in a length of petiole (Lp) and a lower m2/m, related to increase of the difference in annual precipitation and evaporation. Sub-alpine and alpine forest species are characterized in a region of introduction by increase of leaf blade indentation (Iz) and the correlation of fresh weight to leaf area (m/S) related to increased annual precipitation evaporation. Such parameters as Iz, m/S and m2/S are higher in subalpine and alpine forest species from warmer habitats. We have identified the following morphological leaf features which provide its normal functioning in the changing growth conditions: indented edge of the leaf blade, a sufficient accumulation of plastic substances (m2/S) – it is higher in the species from warmer regions with high evaporation. Leaves of the species from warmer regions accumulate more water. The species from warmer regions and warm regions with high evaporation are the most adapted to steppe conditions of Ukraine.