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 studi es 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 fr om 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 t han 1 g dry weight of live roots. Considerable variability was experie nced with root samples containing less live roots. Separation efficien cies will need to be measured for roots from all different plant speci es.