Comparative Study of Effects of Growth Conditions on Ion Components in the eaves of Some Mangrove Species from Thailand

Abstract

Ten species of mangrove plants collected from Phang Nga forest of Southern Thailand were analyzed for inorganic ions (anions and cations) and organic acids. Moreover, the relationships between mangrove plants species and their growing areas are also examined. Transplantation of collected mangrove viviporous seeds from Phang Nga forest to Iriomote, Okinawa, for comparative study on cultivation between Thailand and Okinawa, is discussed. Inorganic ions in 4 species of these mangrove species were analyzed for comparison of amount of inorganic ions and organic acids between the Thailand and Okinawa growth conditions.
Accumulations of Na⁺ and Cl^- ions in the leaf of each mangrove species are affected by the degree of sea water tide and its concentration. Species directly affected by sea water such as Rhizophora mucronata and Avicennia alba indicated higher amounts of Na⁺ and Cl^- ions than species distributed in inner mangrove forest areas and a low concentration of sea water (NaCl concentration).
Amounts of anions and cations in all old leaves were higher than in young-stage leaves. However, the amounts of anions and cations in young-stage leaves of Avicennia spp. were higher than in old-stage leaves. Analyzed mangrove plant leaves of December samples showed higher accumulation of ions than April samples. December in Phang Nga of Southern Thailand is the summer dry season, and the end of April is the start of the rainy season. Concentration of organic acids in mangrove leaves is dependent on species zonation of mangrove plants in the mangrove forest. The front of Mangrove forest and river-mouth area mangrove plant species indicated a higher concentration of organic acids than those not affected by sea water or which had a low concentration of sea water affecting the mangrove plants. Results of Okinawa cultivated mangrove leaves (transplanted plant leaves) indicated a lower accumulation of inorganic ions than Thailand mangrove leaf samples. The accumulation of these inorganic ions by mangrove plants may be dependent on environmental conditions of growth areas (temperature, light, sea water, soil, season and others).