Env Exp Biol (2011) 9: 83–90

Groth and mineral nutrition of two Triglochin species from saline wetlands: adaptation strategies to conditions of heterogeneous mineral supply

Abstract

In addition to soil salinity and tidal regime, soil nutrient disbalance and ion toxicity affect plant growth in coastal wetlands. The aim of the present study was to examine the effect of soil mineral nutrient availability and salinity on growth, mineral nutrition, and proline content of two closely related wetland monocotyledonous species, Triglochin maritimum and Triglochin palustre. Growth of leaves of T. maritimum was lowest in natural soil and increased towards optimum conditions, while the opposite was true for T. palustre. Growth at gradually decreasing soil concentration of N resulted in directly proportional decrease in tissue concentration of N in both studied species. In general, root tissues of both species accumulated significantly higher concentrations of micronutrients in comparison to leaf tissues. This was more pronounced for T. palustre, where root concentration of Fe, Mn, Zn and Cu was directly proportional to the respective substrate concentrations. However, both species accumulated identical concentrations of Fe, Mn, Zn and Mo in leaves. It is evident that in highly heterogeneous soil conditions T. maritimum and T. palustre can effectively regulate internal ion concentration without any negative consequences for growth. Proline content increased from optimum to natural soil conditions both in leaf and root tissues of both studied species. In conditions of highly heterogeneous soil nutrient availability as well as fluctuating soil salinity, both Triglochin species possess several mechanisms of adaptive value, including salinity-induced leaf succulence, accumulation of Na in vacuoles with counterbalancing high concentration of proline in cytoplasm, and preferential accumulation of micronutrients in roots.