Frustule characteristics of Staurosira construens Ehrenberg (order Fragilariales, class Bacillariophyceae) under varied light qualities and silicate concentrations

Staurosira construens is a benthic freshwater diatom distinguished by its elliptical valves with uniseriate rows of areolae, conspicuous marginal spines that often come in singles or in pairs between the areolae, and the apical pore fields that often appear rimmed. The research aimed to determine the effects on the frustule characteristics of S. construens under varied light qualities and silicate concentrations. Pure cultures of S. construens were obtained from the Microalgae Systematics and Applied Phycology Research Unit (MSAPRU) of De La Salle University – Manila. The cultures were grown under various light qualities (red, green, blue, and white) and silicate concentrations NaSiO3 [0.81M and 1.62M] in Binangonan Rizal SEAFDEC Philippines (BRSP) medium for 30 days to assess effects on frustule length and width (under LM), and the foramen density (under SEM). Results showed the interaction between silicate concentrations and varied light qualities do not promote significant differences in the length (p= 0.40), width (p=0.911) and foramen density (p=0.670) in S. construens