Molybdenum is required for this reduction, and if molybdenum is deficient, nitrate may accumulate to a high level in the plant, and at the same time the plant may exhibit nitrogen deficiency symptoms. Molybdenum differs from other trace nutrients in that many plants can develop in its absence provided that ammonium nitrogen is present. Molybdenum appears to be essential for the nitrate-reducing enzyme to function. Molybdenum deficiencies are commonly found in Northeastern Washington. Foliar marginal necrosis is the most common symptom of fluoride toxicity along with Chlorosis along and between the veins occurs in fluorine-sensitive plants.
Symptoms appear on older leaves at base of plant.
Plant dark green a. At first, all leaves are dark green and growth is stunted. Visual symptoms of phosphorus deficiency are not always definite, but many phosphorus deficient plants exhibit off-color green foliage with purple venation, especially on the underside of leaves, and plants are stunted and remain stunted even when fertilizers supplying potassium and nitrogen are applied. Older leaves assume a purple-bronze color. Phosphorus is phloem retranslocated from older leaves to new growth.