Vegetative Response of Saltcedar (Tamarix pentandra Pall.) to Photoperiod.

Saltcedar (Tamarix pentandra Pall.) stem cuttings responded vegetatively to various photoperiods of 11-, 14-, 17-, and 8 + 1-hour duration. Total stem length, average stem length, cuticle thickness, and xylem vessel member outside diameter were significantly maximal under a 14-hour photoperiod and less under photoperiods above and below this level. Numbers of stems and roots produced were significantly less in an 11-hour than under a 14-hour photoperiod; but neither was significantly different from responses under 17- and 8 + 1-hour photoperiods. Vegetative photoperiodic responses, except for cuticle thickness, were affected by a photoperiodic after-effect produced by cuttings collected on various dates. Average stem length, total stem length, and number of stems produced were significantly correlated with field photoperiods from November to May.