SEPARATING LIVE AND DEAD FINE ROOTS USING COLLOIDAL SILICA - AN EXAMPLE FROM MANGROVE FORESTS

Separation of live and dead fine roots is a critical pro cess in studies of fine root dynamics, but many studies use subjective visual cues during time-consuming hand sorting of root samples, or do not attempt separation at all. Here we describe a method for separating fine roots from mangrove forests using solutions of colloidal silica. The method removed 96 +/- 2% (standard error) and 90 +/- 4% of the dead roots from root samples obtained from forests of Ceriops tagal and Rhizophora stylosa, respectively. Live roots of both plant species were separated with an efficiency of 94 +/- 2% when root samples contained greater than 1 g dry weight of live roots. Considerable variability was experienced with root samples containing less live roots. Separation efficiencies will need to be measured for roots from all different plant species.