Anatomical response of olive roots to dry and irrigated soils

Abstract

Root development was examined in roots of young olive trees (Olea europaea L., cv. Manzanillo) grown under wet and dry water regimes. Cross sections at sequential positions were observed along tbe roots axis from the apex up to 18 cm from the root tip at intervals of 3 cm. An index was established to facilitate development comparisons. Complete transition to secondary growth was found closer to the apex in the roots grown in dry soil (at 9 cm) than in the roots grown in watered soil (at 12 cm). Up to 5 cm from the root tip, the cortical tissue was wider in the roots grown in dry soil than in watered soil. Based on maturity stage, both total root and central cylinder radii were greater for the dry than the irrigated treatment. No difference between treatments was found in metaxylem vessel diameter.