Above- and below-ground morphological responses of a citrus rootstock interfered with orange waste compost: an evaluation as a component of growing media

Composted orange waste was tested as a component of perlite-based pot media for growing a widely used citrus rootstock, Troyer citrange. This study also investigated both the leaf and root morphological traits response in Troyer citrange rootstock grown for 173 days in a compost amended substrate. After 127 days of pot cultivation, leaf number and stem height and, at lesser extent, the dry biomass of the citrange rootstock increased when treated with 7.5% (v/v) orange waste compost. The morphological analyses revealed a compost-induced increase of root length ratio (RLR) of both whole and 1st order lateral roots, indicating an improved plant’s ability to acquire the below-ground resources. Further, this compost-induced root increase was due to an improved “shape of the biomass” (high fineness) rather than the biomass allocation. Concluding, the results indicate that addition of orange waste compost not only stimulates the plant growth but also improves the quality of transplants of Troyer citrange rootstocks.