Iron content during lime‐induced chlorosis with two citrus rootstocks

Abstract

A greenhouse experiment was conducted to evaluate the influence of varying soil moisture stress in inducing chlorosis in citrus root‐stocks cultivated in calcareous soil. Two rootstocks: Citrus aurantium, tolerant, and Poncirus trifoliata, non‐tolerant to calcareous soil were simultaneously planted in pots containing one of three types of soils that differed in their native CaC0₃ content:88% (Soil I), 30% (Soil II) and 0.5% (Soil III). In each soil three moisture levels were maintained: Sm₁ at field capacity, Sm₂ at 80 cb and Sm₃ at 230 cb. The association of excessive moisture regime (Sm₁) with high lime soil (Soil I) induced symptoms of line chlorosis in C. aurantium, whereas these symptoms appeared in P. trifoliata when planted in Soils I and II irrespective of the soil moisture status. The iron content in the chlorotic leaves of C. aurantium is reduced, yet it remains within.the optimum range at about 60 ppm. On the other hand, the chlorotic leaves of P. trifoliata contain more iron than the green leaves. The roots of the two citrus rootstocks accumulated less iron in the chlorotic than in the non‐chlorotic state.

Key words:

• Lime‐induced chlorosis
• iron chlorosis
• citrus rootstocks
• calcareous soil
• soil moisture stress
• iron nutrition