Anatomy and Morphology of Field-Sampled Citrus Fibrous Roots as Influenced by Sampling Depth and Rootstock1

Abstract

Abstract Roots of ‘Orlando’ tangelo (Citrus paradisi MacF. × C. reticulata Blanco) on rough lemon (C. jambhiri Lush.), sour orange (C aurantium L.), sweet orange (C. sinesis (L.) Osb.) and Rusk citrange (C. sinensis × Poncirus trifoliata Raf.) were field-sampled from depths extending to 2.5 m in a well-drained sandy soil and from about 3 m in an underlying sandy clay layer of undetermined thickness. Root anatomy and morphology were examined by light and scanning electron microscopy respectively. Epidermal hairs and radially elongated groups of hypodermal cells were observed on all roots. Root hairs differed in size and shape and hypo-dermal hairs seemed to occur more frequently on surface roots. Fibrous root bunches tended to be less branched and individual roots were smaller in diameter as sampling depth increased. General root anatomy was similar to previous descriptions.