Leaf trait relationships with species ecological optimum and sustainability across wetland plants

Abstract

Structural and functional parameters of leaves were studied in 19 dominant and abundant species growing in shallows and wet riversides at the mouth of the Maksimikha River (Barguzinsky district, Republic of Buryatia). To evaluate the species ecological optimum Tsyganov’ scales were used (Tsyganov, 1983). To assess the resistance, the potential ecological valence of the species on the illumination scale, as well as the climatic and soil tolerance indices of the species were applied (Zhukova et al., 2010). It was shown that the index of climatic tolerance of the species was negatively correlated with the leaf mass per area (LMA) (r = -0,68) and positively with the chlorophyll photosynthetic activity of (r = 0,51). A tendency was revealed to decrease in LMA and leaf dry matter content (LDMC) and increase in the chlorophyll photosynthetic activity in more thermophilic wetland plants. Leaf area positively correlated with the scores of the species optimum on the soil moisture and acidity scales (r = 0,59 and r = 0,72, respectively). LMA, the content and photosynthetic activity of chlorophyll correlated with the optimum scores on the soil nitrogen supply scale (r = -0,53, r = -0,50 and r = 0,72, respectively). The tolerance index of the species to soil factors was associated only with the content of chlorophylls (r = 0,68) and carotenoids (r = 0,55) per unit leaf area. The potential ecological valence of the species to illumination was positively correlated with leaf density and LDMC (r = 0,58 and r = 0,57, respectively). It was concluded that the thermoclimatic optimum of species of wetland plants, as well as their climate sustainability, are associated with changes in the LMA and chlorophyll photosynthetic activity. Edaphic factors had a greater influence on the structural and functional parameters of leaves than climatic ones, which manifested in a large number of relationships between soil scales and leaf traits. Wetland plant tolerance to a wider range of edaphic conditions was associated with a high content of chlorophylls and carotenoids.