Acta Botanica Croatica, Vol. 62 No. 1, 2003.
Izvorni znanstveni članak
Estimation of osmotic potential and free amino acids in some mangroves of the Sundarbans, India
Datta P. Nandy
M. Ghose
Sažetak
Osmotic potential (OP) of root and leaf was measured in 19 species of mangroves collected from the Sundarbans, India. Leaf OP was estimated in 11 taxa from among them, grown in fresh water and compared with that deriving from taxa grown in saline water.
Free amino acids were estimated from leaves of 16 mangrove species of the Sundarbans. The osmotic potential in leaves collected from their natural habitat was more negative than that from those grown in fresh water conditions. Seedlings grown without salt provided less negative leaf OPthan those treated with 0.1 mol dm–3 NaCl. The more negative OP was found in more saline soil, which might be related to adaptation to facilitate water uptake from a highly saline and frequently waterlogged anaerobic substratum. Aspartic
acid, alanine, proline, tryptophan, tyrosine and phenylalanine are the major free amino acids detected in the leaves. Leucine was recorded only in Avicennia spp., where phenylalanine content was negligible. Proline content was estimated in seven species. The positive
linear trend obtained between leaf OP and proline content points to its role as an osmoticum in mangrove leaves. Cysteine, aspartic acid, alanine and phenylalanine were determined in seedlings, while proline could be estimated only in X. mekongensis. Cysteine and proline content in seedling leaves were gradually reduced with increasing
soil salinity. Lack of cysteine in mature leaves and its decrease in more saline soil probably indicates salinity as a photorespiration restricting factor. A more or less inverse relationship was found between proline and alanine content both in seedlings and mature
plants.
Ključne riječi
Mangroves; osmotic potential; osmoticum; soil salinity; water uptake
Hrčak ID:
3540
URI
Datum izdavanja:
5.6.2003.
Posjeta: 2.059 *