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Symptoms of Deficiency In Essential Minerals -part 2

Definition Of Plant Terms: Plant Science Vocabulary

Following are terms commonly used to name plant parts or to describe how nutrient problems look on plants.

Note that plant leaves are the part of the plant where the effects of deficiencies are most easily seen.

Here are the terms:

Mottling – Patches of green and light, non-green areas on leaves.

Firing – Yellowing, followed by rapid death of lower leaves, moving up the plant and giving the same appearance as if someone torched the bottom of the plants.

Necrosis – Severe deficiencies result in the death of the entire plant or parts of the plant first affected by the deficiency. Plant tissue browns and dies. Tissue which has already died on a still living plant is called necrotic.

Necrotic – dead spots on leaves.

Chlorosis – Yellowing of leaf tissue. A common deficiency symptom because many nutrients affect the photosynthesis process directly or indirectly. If leaves are yellow, this is a sure sign that something is seriously wrong in your garden.

Interveinal Chlorosis – Yellowing between leaf veins but the veins themselves are still green. In grasses, this is called “striping.”

Rosetting – Very short internodes.

Stippling – Small spots or dots on leaves.

Axil – The angle between the upper side of the stem and a leaf, branch, or petiole.

Axillary bud – A bud that develops in the axil.

Flower – The reproductive unit of a female plant.

Flower stalk – Structure that supports the flower. Internode – The area of the stem between any two adjacent nodes.

Internode – The area of the stem between any two adjacent nodes.

Lateral Shoot (branch) – An offshoot of the stem of a plant.

Leaf – an outgrowth of a plant that grows from a node in the stem. Most leaves are flat and contain chloroplasts; their main function is to convert energy from sunlight into chemical energy (food) through photosynthesis. Healthy leaves are lime green.

Node – The part of the stem of a plant from which a leaf, branch, or aerial root grows; each plant has many nodes.

Petiole – The leaf stalk that attaches a leaf to the plant.

Root – A root is a plant structure that obtains food and water from the soil, stores energy, and provides support for the plant. Most roots grow underground.

Root cap – A structure at the ends (tips) of the roots. It covers and protects the apical meristem (the actively growing region) of the root.

Stem (also called the axis) – The main support of the plant.

Tap root – The main root of some plants. The tap root extends straight down under the plant.

Terminal bud – Located at the apex (tip) of the stem. Terminal buds have special tissue, called the apical meristem, consisting of cells that can divide indefinitely.

Symptom Descriptions

It is unusual to find any one leaf or even one plant that displays the full array of symptoms that are characteristic of a given deficiency. It is thus highly desirable to know how individual symptoms look, for it is possible for them to occur in many possible combinations on a single plant. Most of the terms used below in the description of deficiency symptoms are reasonably self evident; a few however have a distinct meaning in the nutrient deficiency field. For example, the term chlorotic, which is a general term for yellowing of leaves through the loss of chlorophyll, cannot be used without further qualification because there may be an overall chlorosis as in nitrogen deficiency, interveinal, as in iron deficiency, or marginal, as in calcium deficiency. Another term used frequently in the description of deficiency symptoms is necrotic, a general term for brown, dead tissue. This symptom can also appear in many varied forms, as is the case with chlorotic symptoms.

Nutrient deficiency symptoms for many plants are similar, but because of the large diversity found in plants and their environments there is a range of expression of symptoms. Because of their parallel veins, grasses and other monocots generally display the affects of chlorosis as a series of stripes rather than the netted interveinal chlorosis commonly found in dicots. The other major difference is that the marginal necrosis or chlorosis found in dicots is often expressed as tip burn in monocots.

Nitrogen – (N) (mobile in plant, mobile in soil)

Nitrogen deficiencies often appear first in older leaves, and will manifest as a light green overall appearance.

As symptoms progress, the leaves turn a yellow color and stems become weak and lower leaves drop off. Necrosis develops in older leaves. New growth becomes weak and spindly. Tops and roots grow poorly.

When plants are in the mid to later growth or flowering stages, older growth and large fan leaves may show nitrogen deficiency.

This is normal during the late stage of floral development because plants near the end of their lives are using up their nutrient and carbohydrate reserves. As leaves turn completely yellow, remove them from the plant.

Nitrogen excess turns foliage very dark green and can make plants susceptible to drought, disease and insect predation.

Nitrogen is crucial to photosynthesis and reproductive function. Nitrogen makes proteins and is essential to new cell growth. Nitrogen is mainly utilized for leaf and stem growth, as well as overall plant size and vigor.

Nitrogen moves easily to active young shoots and leaves and moves more slowly to older leaves. Nitrogen is involved in the structuring of amino acids, enzymes (specialized proteins that perform duties inside plants), proteins and nucleic acids. All of these are essential for cell division and most other plant functions. Obviously, nitrogen is essential to plant growth.

The “salts” commonly used as a source of nitrogen are: potassium nitrate (KNO3), ammonium nitrate (NH4N03) and calcium nitrate (Ca (N03)2.4H2O).

Nitrate is transported via xylem to all parts of the plant, where it participates in nitrogen assimilation. Nitrate is stored in cell vacuoles and fulfills important functions in the osmo-regulation and anion-cation balance in plant cells.

Inorganic nitrogen is reduced to ammonia and incorporated in organic molecules. Ammonium in the roots is most commonly stored as organic nitrogen.

This reaction is carried out by two enzymes, nitrate and nitrite reductases. Nitrate is first converted into nitrite by nitrate reductase; then, nitrite is reduced into ammonia by nitrite reductase.

Conversion of nitrate into nitrite occurs in the cytoplasm. Nitrate reductase consists of FAD, cytochromes [Fe2/Fe3] and molybdenum [Mo(V)/(VI)].

These components form integral parts of the electron transport chain through which electrons are used to reduce nitrate to nitrite. If high nitrate concentrations are present it can also be transported to the leaves where it is then reduced.

Glutamine synthetase and glutamate synthase are key enzymes in conversion of ammonium into glutamine. It is then converted into asparagine, arginine and allantoin act as basic sources of nitrogen for all macromolecules biosynthesis.

You should daily monitor your plants, focusing on their leaves. If you see pale leaves with a yellow tinge like the picture, you may have a nitrogen deficiency. Such deficiency can slow growth, decrease harvest size and damage the overall health of your plants.

The best ways to avoid nitrogen deficiency are to use quality products, and to keep your root zone pH in the ideal 5.8 to 6.3 range.

Phosphorus – (P) (mobile in plant, immobile in soil)

Phosphorus deficiencies show up in older growth first. You will see leaf tips curling downwards.

When phosphorus is deficient, slow and spindly plants with reduced growth will result.

Phosphorus deficiency leaf damage often shows itself as patches that are dull dark green to bluish green. In severe cases, older leaf and petioles turn reddish purple.

Younger leaves appear yellowish green with purplish veins when nitrogen is deficient, but will have dark green veins when phosphorus is deficient.

Necrotic spots occur on leaf margins in advanced stages of phosphorus deficiency. Leaf tips look like they have been burnt.

Phosphorus deficiency is most common when ph is above 7 or below 5.5. Phosphorus will bind with soil very easily and this can cause excess phosphorus. Excess phosphorus can create deficiencies of zinc and iron.

Plants use phosphorus for photosynthesis, respiration, storing carbohydrates, cell division, energy transport (ATP, ADP), nucleic acids, enzymes and phospholipids.

Phosphorus builds strong roots and is vital for seed and flower production. Highest levels of phosphorus are needed during germination, early seedling growth and flowering.

Some crops require lots of phosphorus, but most require more potassium and nitrogen and magnesium than phosphorus. Several types of hydroponics plants need far more phosphorus during flowering than during vegetative growth phase.

Excess phosphorus causes decrease in the uptake of zinc, iron and copper- which starts a chain reaction of other macro and micro nutrient deficiencies.

When temperatures drop below 55 degrees Fahrenheit (12 degrees Celsius), plants have a hard time uptaking phosphorus.

Phosphorus is present in the plant as inorganic phosphate (Pi), or bound to a carbon atom. Phospholipids in bio-membranes contain a large amount of phosphorus. In these molecules phosphorus makes a connection between a diglyceride and an amino acid, amine or alcohol via a phosphate- ester bond.

Phospholipids consist of a hydrophobic tail, the diglyceride, and a hydrophilic head containing PO4. Membranes consist of two monolayers of phospholipids known as a lipid bilayer. The hydrophilic end of the phospholipids are oriented towards water (outward) while the hydrophobic ends are orientated inwards.

Phosphorous plays a very central role in determining the total energy metabolism of the plant because it forms energy-rich phosphate esters (C-P) such as glucose-6-phosphate.

Energy released during the glycolysis, oxidative phosphorylation or photosynthesis is used to synthesize ATP and this energy is liberated during the hydrolysis of ATP in ADP and inorganic phosphate. ATP is unstable and therefore turns over rapidly.

Plant cells contain two different forms of phosphate storage. Within the metabolic storage, phosphate is primarily stored as phosphate esters which can be found in the cytoplasm and mitochondria of the cell.

With non-metabolic storage, phosphate is stored as inorganic phosphate (Pi) in vacuoles.

Phosphorus regulates starch production in chloroplasts. ADP-glucose-pyrophosphorylase, an enzyme involved in the synthesis of starch, is inhibited by Pi and stimulated by triose-phosphates.

Phosphorous availability has a direct affect on the energy balance in the cell and nucleic acid biosynthesis.

Phosphorus deficiency can cause reduction in growth rate and show up as dark-green coloration of leaves, caused by accumulation of chlorophyll in leaves.

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