Efficient callus initiation from leaf of mangrove plant, Bruguiera sexangula in amino acid medium: Effect of NaCl on callus initiation

Experimental conditions for efficient callus initiation from mangrove plants were investigated. As a source exptant, leaf of Bruguiera sexangula was used. Mangrove plant is one of the most famous woody plants which can grow at the salty area. The initiated callus can be a suitable material for the investigation of salt tolerant mechanisms of mangrove plants. Leaf pieces cultured in an Amino Acid medium supplemented with 2 μM 2,4-dichlorophenoxyacetic acid and 2 μ M N-(2-chloro-4-pyridyl)-N'-phenylurea at 30 C developed calluses. Microscopic observation suggested that the callus was initiated from the tissue in the vascular bundles in the leaf. We also examined the effect of NaCl on callus initiation and short-term culture of the calluses on the leaves. Callus initiation rate decreased with increasing NaCl concentration higher than 100 mM in the culture media. The medium containing 100 mM NaCl produced the largest callus on the leaf, compared with higher or lower concentrations of NaCl. Mangrove is a general term for salt-tolerant woody plants found growing at the seashore in tropical and subtropical areas. More than 100 species in several families (Tomlinson 1986), including the genus Bruguiera, belong to this group of plants. There are many reports addressing the mechanisms of salt tolerance of mangrove plants at the organ level (Ball and Farquhr 1984a, b, Werner and Stelzer 1990).