Studies on copper deficiency in mango, guava and jackfruit

The copper deficiency effects at 0.00065 mg Cu l⁻¹ were first observed at week 35 in mango, at week 24 in guava and at week 48 in jackfruit. The depression in dry matter owing to copper deficiency was highest in jackfruit and lowest in guava. The acutely deficient (0.00065 mg Cu l⁻¹) leaves of mango contained 4, those of guava had 2.1–3.0 and those of jackfruit contained 4.2–5.7 μg Cu g⁻¹ dry matter in comparison to 7.4–10.2, 9.6–12.4 and 13.5–19.1 μg Cu g⁻¹ dry matter from Cu sufficient (0.065 mg l⁻¹) leaves of mango, guava and jackfruit respectively.