I. Symptoms appearing first or most severely on new growth (root and shoot tips, new leaves)
A. Terminal bud usually dies. Symptoms on new growth.1. Basal part of young leaves and internal tissues of organs may become necrotic.
One of the earliest symptoms is failure of the root tips to elongate normally. Terminal shoot meristems also die giving rise to a witch's broom. Young leaves become very thick, leathery, and chlorotic; in some species young leaves may be crinkled because of necrotic spots on leaf edge during development. Young leaves of terminal buds become light green then necrotic and stem finally dies back at terminal bud. Rust colored cracks and corking occur on young stems and petioles, and flower stalks... boron deficiencyDifferentiating between calcium and boron deficiency symptoms: When calcium is deficient, there is a characteristic hooking of the youngest leaf tips. However, when boron is deficient, the breakdown occurs at the bases of the youngest leaves. Death of the terminal growing points is the final result in both cases.