The effect of sea brine and bittern on survival and growth of mangrove <i style="">Avicennia marina </i> (Dicotyledones : Avicenniaceae)

Abstract

The effect of 25.5°B<img src=‘/image/spc_char/right_quote.gif’>e brine and 28.5°B<img src=‘/image/spc_char/right_quote.gif’>e bittern prepared from 3.5°B<img src=‘/image/spc_char/right_quote.gif’>e seawater was studied on the juvenile plants of the mangrove <i style="">Avicennia marina </i>(Forsk.) Vierh<i style=""> </i>under greenhouse conditions. The maximum in elongation growth and percentage increase in number of leaves in 5% concentration of brine was 35.0 mm and 200% respectively. However for 5% bittern they were 33.0 mm and 160% respectively. The 50% concentrations of brine and bittern were growth inhibitory while 100% concentration was lethal during 8 hours continuous exposure for 10 days. The highest growth of the <i style="">Avicennia marina</i> was observed when brine and bittern were diluted between 20 and 200 times. The undiluted and 50% diluted brine and bittern were lethal and growth inhibitory, respectively. The leaves were the best indicator of the inhibitory or lethal effects on the plants. The 1 to 5% brine promoted the growth of the leaves while other concentrations were inhibitory or lethal. However, the bittern in the range of 9 ml l^-1 and 1 to 50% were growth inhibitory for leaves, while 100% was lethal. The results indicate that discharge of brine and bittern in the marine environment, having semi diurnal tide cycle, will not be toxic or lethal to the plants.