GROWTH AND METABOLIC RESPONSE OF THE FRESH WATER UNICELLULAR ALGAE SCENEDESMUS DIMORPHUS, S. QUADRIQCAUDA AND ANKISTRODESMUS FALCATUS TO SALINE ENVIRONMENT.

GROWTH AND METABOLIC RESPONSE OF THE FRESH WATER

UNICELLULAR ALGAE SCENEDESMUS DIMORPHUS,

S. QUADRIQCAUDA AND ANKISTRODESMUS

FALCATUS TO SALINE ENVIRONMENT.

EZZAT A. IBRAHIM, A.S. SHAABAN* ANI> OLA E. TAHA

lnstitute of Oceanography and Fisheries. Algal Assay lab .•

El-Zamalek Fish Garden. Cairo. Egypt.

* Botany Department, Ain Shams University. Cairo, Egypt.
ABSTRACT
The effect of salinity on the growth and chemical constituents

of the freshwa ter ch1orophytes SCenedesaJs di_rphus (Trup. )

Kuetzing, SCenedesaJS quadrfcauda (Trup.) de Brebisson and

AnkfstrodesaJs falcatus (Corda) Ralfs are investigated. The results

indicate a I wide range of responses of the test algae and the

wide range of responses of the metabolic dopts within the same

species. The growth tolerance of the test algae to salinity

increases with Increasing exposure time. The 96-h EC50′ values,

however, of salinity for depression of growth in gil were: 2.25.

2.52 and 2.98 for S. df_rphus; 6, 6.5 and 6.64 for S. quadricauda;

and 1.27. 2.52 and 1.7 for A. falcatus after 48. 72 and 96 h

exposure, respectively. The dry weight per cell of all the test

algae increases with increasing salinity. Furthennore, total

chlorophyll a. b, total carotenoids, carbohydrate and protein

content per cell of S. df_rphus progressively decreases with

increasing salinity; the reverse is true with S. quadrfcauda and

A. falcatus only at low salinity.