Symptoms of Deficiency of Nutrients in Plants

After reading this article you will learn about the symptoms of deficiency of nutrients in plants. The nutrients whose symptoms of deficiency has been discussed are: 1. Nitrogen 2. Phosphorus 3. Potassium 4. Calcium 5. Magnesium 6. Sulphur 7. Iron 8. Manganese 9. Copper 10. Zinc 11. Molybdenum 12. Boron.

1. Nitrogen:

Nitrogen deficient plants have a stunted and spindly growth, the stem is erect but lateral buds do not develop. So tillering is reduced in cereals. Leaves make an acute angle with the main stem. First, older leaves become pale green or yellowish green. This starts from the apex of older leaves and moves towards the base.

These pale green or yellow green areas often develop brilliant tints of lemon, yellow or orange or less frequently reddish purple. Later younger leaves are affected if the deficiency continues for a sufficiently long period when older leaves become completely dry. This is called firing.

2. Phosphorus:

Growth of phosphorus deficient plants is severely restricted. They are thin, erect and spindly. Lateral buds do not develop and so tile ring is reduced in cereals. The bluish-green older leaves become bronzed or develop reddish brown or purple tints.

These effects appear first on the apex of older leaves and then gradually spread towards the base. The severely affected apical portions of leaves may become rolled. Leaves may be shed prematurely and flowering and fruiting may be delayed.

3. Potassium:

Potassium deficient plants have a stunted and bushy growth. Pale green older leaves develop chlorosis between veins and light grey to bronze, reddish brown or brown colouration along the leaf apex and the apical margin. The leaf tip and apical margin of the leaf become scorched and necrotic. Thin brown roots are poorly developed; the small leaflets of the potato are crinkled and curved downwards.

4. Calcium:

The first symptoms of calcium deficiency are chlorosis of young leaves, followed by distortion of the growing points of the stem. In crops belonging to the genus Brassica, young leaves forming the terminal bud do not expand, but become hooked. The leaves near them become cupped and the growing point dies. In wheat and barley, the upper parts of younger leave fail to unroll and appear thread-like.

5. Magnesium:

The normal green colour of the foliage fades, resulting in chlorosis between veins, leading to chlorotic stripping in the parallel veined leaves and chlorotic mottling in the reticulate veined leaves. These chlorotic areas later develop brilliant tints of orange, red, purple or mauve. The area between the veins may turn brown and necrotic if a severe deficiency continues for long time.

6. Sulphur:

The most common symptom is the fading of the normal green colour of younger leaves followed by chlorosis. The young leaves of sulphur deficient plants i.e. cereals exhibit chlorotic striping between veins.

Brassica crops are susceptible to sulphur deficiency the symptoms of which are curled leaves and a non-development of apical bud older leaves exhibit wrinkled and inwardly raised areas. They may be tinted with orange or red colour and shed prematurely. The plant becomes brittle.

7. Iron:

Chlorosis appears first at the basal part of younger leaves and later spreads towards the apical portion. Veins remain green. A continuous deficiency may result in the total bleaching of leaves.

8. Manganese:

Small chlorotic patches appear between the veins of middle leaves. Later, these chlorotic patches unite, resulting in a chlorotic striping between the veins in parallel veined leaves, and chlorotic mottling in reticulate veined leaves. The chlorotic areas of leaves turn reddish-brown and necrotic.

9. Copper:

A copper deficiency results in first young leave exhibiting chlorosis and drying, and a distortion of the terminal leaves. The shoot apex may die prematurely, resulting in the development of several auxiliary buds. Apices of young leaves often dry up. Young leaves of cereals may turn severely chlorotic, fail to unroll and wither.

In species of Brassica e.g. cauliflower and cabbage, young leaves develop fine chlorotic mottling between the veins; mottled areas often develop white necrotic patches, particularly along the veins and leaf margins.

10. Zinc:

The commonest symptoms of zinc deficiency are chlorosis between veins, reduction in the sizes of young leaves, which are often clustered and a bronzing, purple, violet reddish brown or brown colouration of the foliage.

11. Molybdenum:

In most plants with reticulate venation, the first symptoms of Molybdenum deficiency is chlorotic mottling between the veins of old or middle leaves, or all over the surface when nitrogen is supplied to the crops in the form of nitrates.

Crops like cauliflower, a species of Brassica, exhibit chlorotic mottling and a cupping of the middle leaves. A drying of severely affected leaves begins from the margin and covers the whole leaf, leaving only the petioles. Later, younger leaves are also affected and fail to expand fully; ultimately the growing point becomes necrotic and further growth ceases.

12. Boron:

The commonest symptoms of boron deficiency exhibited by crops include necrosis of the softer tissue, particularly phloem and the death of the growing points. In heart rot of sugar beet, young leaves at the centre of the crown fail to expand fully and become curled.

The petiole and the basal part of the mid rib turn brown or black and become brittle. The young terminal leaves of the growing points and later, the entire crown become necrotic.