Effects usually local on older, lower leaves
a) Lower leaves mottled, usually with necrotic areas near top & margins. Yellowing beginning at margin & continuing toward center. Margins later becoming brown & curving under, older leaves dropping.		Potassium def.
b) Lower leaves chlorotic, usually necrotic in late stages. Chlorosis between veins, veins normal green. Leaf margins curling upward or downward with puckering effect. Necrosis between veins suddenly.		Magnesium def.