The Role of Phosphorus (P)

Phphosphorus_deficiency1osphorus is a vital component of adenosine triphosphate (ATP), the ‘energy unit’ of plants. ATP forms during photosynthesis, has P in its structure, and processes from the beginning of seedling growth through to the formation of grain and maturity.

Periodic Table of Crop Nutrients and Deficiencies

Periodic Table of Crop Nutrients

17 nutrients are essential for plant health. Optimal yields can only be produced when all these nutrients are in proper supply. According to the Law of Minimum, if one or more nutrients are lacking in the soil, crop yields will be reduced, even though an adequate amount of other elements is available.

Plumeria Nutrient Deficiencies

Not all plumeria problems are caused by insects or diseases. Sometimes an unhealthy plumeria is suffering from a nutrient deficiency or even too much of any one nutrient. Plumeria nutrient deficiencies often manifest as foliage discoloration or distortion. The following chart outlines some possible problems. Unfortunately many problems have similar symptoms and sometimes it is a combination of problems.

Be sure you eliminate the obvious before you kill your plumeria with kindness.

  • Check first for signs of insects or disease.
  • Foliage discoloration and stunted plants can easily be caused by soil that is too wet and drains poorly or soil that is too compacted for good root growth.
  • Exposure to cold or heat will slow plant growth and effect flowering.
  • Too much fertilizer can result in salt injury. Your plants may look scorched or they may wilt, even when the soil is wet.

Plumeria require a mix of nutrients to remain healthy. Nutrients that are needed in relatively large amounts are called the macronutrients. Plant macronutrients include: (N) nitrogen, (P) potassium, (K) phosphorus, calcium, sulfur and magnesium.

There are a handful of additional nutrients that are required for plant growth, but in much smaller quantities. These micronutrients include: boron, copper, iron, manganese, molybdenum and zinc.

All of these nutrients are taken in through the roots. Water transfers the nutrients from the soil to the Plumeria roots. So one requirement of sufficient Plumeria nutrition is water. A second requirement is the appropriate soil pH for the Plumeria being grown. Each Plumeria prefers a specific pH range to be able to access the nutrients in the soil. Some Plumeria are fussier than others, but if the soil pH is too acidic or alkaline, the Plumeria will not be able to take in nutrients no matter how rich your soil may be.

Primary Macronutrients

nutrient-deficiency-chart

Nitrogen (N) 

Nitrogen (N) is essential for plant growth and is part of every living cell. It plays many roles in plants and is necessary for chlorophyll synthesis. Plants take up most of their N as the ammonium (NH4+) or nitrate (NO3) ion. Some direct absorption of urea can occur through the leaves, and small amounts of N are obtained from materials such as water-soluble amino acids.

  • Symptoms: Lack of N and chlorophyll means the plant will not utilize sunlight as an energy source to carry on essential functions such as nutrient uptake. Older leaves, generally at the bottom of the plant, will yellow. Remaining foliage is often light green. Stems may also yellow and may become spindly. Growth slows. 
  • Sources: Any compound containing the words: ‘nitrate’, ‘ammonium’ or ‘urea’. Also manure.
  • Notes:
    • Many forms of nitrogen are water soluble and wash away.
    • Nitrogen is a component of vitamins, amino acids and energy systems within the plant, which form its proteins. Thus, N is directly responsible for increasing protein content in plants.
    • Nitrogen is necessary for chlorophyll synthesis and, as a part of chlorophyll molecules, is involved in photosynthesis.
    • Nitrate is very mobile in the soil and moves with soil water to root surfaces for plant absorption.

Phosphorus (P)

One of three primary nutrients, phosphorus (P) is essential for plant growth, and a plant must access it to complete its normal production cycle. Plants absorb P from the soil as primary and secondary orthophosphates (H2PO4 and HPO42-).

  • Symptoms: Small leaves that may take on a reddish-purple tint. Leaf tips can look burnt and older leaves become almost black. Reduced fruit or seed production.
  • Sources: Compounds containing the words ‘phosphate’ or ‘bone’. Also green sand.
  • Notes:
    • Very dependent on pH range.
    • The highest levels of P in young plants are found in tissue at the growing point. As crops mature, most P moves into the seeds, fruit, or both.
    • Under P deficiency, some crops, such as corn, tend to show abnormal discoloration.
    • Phosphorus is noted especially for its role in capturing and converting the sun’s energy into useful plant compounds.
    • Phosphorus promotes root development and early seedling growth.
    • Research associates specific growth factors with P: stimulated root development, increased stalk and stem strength, and improved flower formation and seed production.

Potassium (K)

Potassium (K) is one of the essential nutrients and is taken up in significant amounts by crops. Potassium is vital to photosynthesis, protein synthesis and many other functions in plants. It’s classified as a macronutrient, as are nitrogen (N) and phosphorus (P). Plants take up K in its ionic form (K+).

  • Symptoms: Older leaves may look scorched around the edges and/or wilted. Interveinal chlorosis (yellowing between the leaf veins) develops.
  • Sources: Compounds containing the words ‘potassium’ or ‘potash’.
  • Notes:
    • Potassium enhances many enzyme actions aiding in photosynthesis and food formation. It builds cellulose and helps translocate sugars and starches. Potassium is vital to producing grains rich in starch.
    • Potassium maintains turgor and reduces water loss and wilting.
    • Potassium is known as the “quality nutrient” because of its important effects on factors such as size, shape, color, taste, shelf life, fiber and other quality-related measurements.
    • In many high-yielding crops, the K content in the plant is comparable to the nitrogen (N) content.
    • Potassium is absorbed by plants in the ionic form, indicated as K+.
    • Plants deficient in K are less resistant to drought, extreme temperatures and other stressors. Plants lacking K are also more susceptible to pests, diseases and nematode attacks.
    • Ample K can increase root growth and improves drought tolerance.

Secondary Macronutrients

Magnesium (Mg)

Hidden in the heart of each chlorophyll molecule is an atom of magnesium (Mg), making the nutrient actively involved in photosynthesis. Magnesium also aids in phosphate metabolism, plant respiration and the activation of many enzyme systems.

  • Symptoms: Slow growth and leaves turn pale yellow, sometimes just on the outer edges. New growth may be yellow with dark spots.
  • Sources: Compounds containing the word ‘magnesium’, such as Epson Salts.
  • Notes:
    • Magnesium is mobile within the plant and moves easily from older to younger tissues.
    • Plants require Mg to capture the sun’s energy for growth and production through photosynthesis.
    • When Mg deficiencies occur, the lower (older) leaves are affected first.
    • The most common source of Mg is dolomitic limestone, which provides both calcium and Mg, while neutralizing soil acidity.
    • Magnesium acts as a phosphorus carrier in plants, and is required for better root formation and thus for better nutrient and water efficiency in plants.

Calcium (Ca)

Calcium (Ca) is found all around us, and the very existence of plants and animals depends on it. Plants take up Ca as the Ca2+ cation. Once inside the plant, Ca functions in several essential ways.

  • Symptoms: New leaves are distorted or hook shaped. The growing tip may die. Contributes to blossom end rot in tomatoes, tip burn of cabbage and brown/black heart of escarole & celery.
  • Sources: Any compound containing the word ‘calcium’. Also gypsum.
  • Notes:
    • Not often a deficiency problem and too much will inhibit other nutrients.
    • Calcium deficiencies occur most often in acidic, sandy soils from which Ca leaches via rain or irrigation water.
    • Calcium helps balance organic acids within the plant as well as activates several plant enzyme systems.
    • Calcium helps form the compounds that make up part of cell walls, which in turn, strengthen the plant structure.
    • Calcium builds yields by indirectly improving root growth conditions and stimulating microbial activity, molybdenum (Mo) availability and uptake of other nutrients.
    • Calcium helps enable nitrogen (N)-fixing bacteria that form nodules on the roots of leguminous plants to capture atmospheric N gas and convert it into a form plants can use.
    • Calcium stimulates root and leaf development, and affects uptake and activity of other nutrients.

Sulfur (S)

Sulfur (S) is a part of every living cell and is important in the formation of proteins. Unlike the other secondary nutrients like calcium and magnesium (which plants take up as cations), S is absorbed primarily as the SO42- anion. It can also enter plant leaves from the air as dioxide (SO2) gas.

  • Symptoms: New growth turns pale yellow, older growth stays green. Stunts growth.
  • Sources: Compounds containing the word ‘sulfate’.
  • Notes:
    • More prevalent in dry weather.
    • Sulfur is present in several organic compounds that give the characteristic odors to garlic, mustard and onion.
    • Sulfur appears in every living cell and is required for synthesis of certain amino acids (cysteine and methionine) and proteins.
    • Sulfur is also important in photosynthesis and for winter crop hardiness.
    • Although S isn’t a constituent of cholrophyll, it’s still vital in chlorophyll formation.
    • Sulfur aids in seed production.
    • Leguminous plants need S for efficient nitrogen fixation.

Micronutrients

Boron (B)

Boron (B) is a micronutrient that is essential for cell wall formation and rapid growing points within the plant, such as reproductive structures. Interestingly, while higher plants require B, animals, fungi and microorganisms do not need this nutrient.

  • Symptoms: Poor stem and root growth. Terminal (end) buds may die. Witches brooms sometimes form.
  • Sources: Compounds containing the words ‘borax’ or ‘borate’.
  • Notes:
    • Boron improves seed set under stressful conditions.
    • Although required in small amounts, boron is a component of all cell walls in the plant.
    • Boron deficiencies are more pronounced during drought periods, when root activity is restricted.
    • The line between deficiency and toxicity is narrower than other essential nutrients. Farmers should apply at proper rate and with proper placement.
    • Plumeria most effectively uses boron when it’s applied through broadcast soil applications.

Chlorine (Cl)

Plants take up chlorine (Cl) as the chloride (Cl) anion. It’s active in energy reactions in the plant. Most Cl in soils comes from salt trapped in parent materials, marine aerosols and volcanic emissions. Classified as a micronutrient, Cl is required by all plants in small quantities.

  • Symptoms:
  • Sources:
  • Notes:
    • Stomata regulate the release of moisture from plants so they can minimize water loss during stressful dry periods. Chloride is key in stomatal regulation.
    • Chloride is involved in the chemical breakdown of water in the presence of sunlight and activates several enzyme systems.
    • Chloride plays an important role in plants as they acclimate to changing water availability (or make osmotic adjustments).
    • Chloride supports the transport of nutrients such as calcium, magnesium and potassium within a plant.

Copper (Cu)

Copper (Cu) activates enzymes and catalyzes reactions in several plant-growth processes. Vitamin A production is closely linked to the presence of Cu as well, and it helps ensure successful protein synthesis. Classified as a micronutrient, only a small amount of this essential nutrient is needed for plant survival.

  • Symptoms: Stunted growth. Leaves can become limp, curl, or drop. Seed stalks also become limp and bend over.
  • Sources: Compounds containing the words ‘copper’, ‘cupric’ or ‘cuprous’.
  • Notes:
    • Copper is the most immobile of the micronutrients.
    • Many vegetable crops show Cu hunger, with leaves that lose turgor and develop a bluish-green shade before becoming chlorotic and curling.
    • Copper is necessary to chlorophyll formation in plants and catalyzes several other plant reactions.
    • Other metals in the soil, such as iron, manganese and aluminum, affect the availability of Cu for plant growth.
    • Organic soils are the most vulnerable to Cu deficiency; heavy, clay-type soils are least vulnerable.

Manganese (Mn)

Manganese (Mn) functions primarily as part of enzyme systems in plants. It activates several important metabolic reactions and plays a direct role in photosynthesis. Manganese accelerates germination and maturity while increasing the availability of phosphorus (P) and calcium (Ca).

  • Symptoms: Growth slows. Younger leaves turn pale yellow, often starting between veins. May develop dark or dead spots. Leaves, shoots and fruit diminished in size. Failure to bloom.
  • Sources: Compounds containing the words ‘manganese’ or ‘manganous’
  • Notes:
    • Manganese plays a vital role in photosynthesis by aiding in chlorophyll synthesis.
    • Soybeans and wheat in particular require more Mn than many crops.
    • Manganese is very immobile in plants, so deficiency symptoms appear first on younger leaves, with yellowing between the veins. Sometimes a series of brownish-black specks appear.
    • Although Mn deficiencies are often associated with high soil pH, they may result from an imbalance with other nutrients such as calcium (Ca), magnesium (Mg), and Iron (Fe).
    • Manganese deficiencies are most common in high organic matter soils and in those soils with naturally low Mn content and neutral to alkaline pH.

Iron (Fe)

Iron (Fe) is essential for crop growth and food production. Plants take up Fe as the ferrous (Fe2+) cation. Iron is a component of many enzymes associated with energy transfer, nitrogen reduction and fixation, and lignin formation.

  • Symptoms: Plants deficient in Fe will often display a pale green leaf color (chlorosis), with sharp distinction between green veins and yellow interveinal tissues. Iron deficiencies may be caused by an imbalance with other metals such as copper (Cu), manganese (Mn) and molybdenum (Mo).
  • Sources:
  • Notes:
    • Iron deficiencies may be caused by an imbalance with other metals such as copper (Cu), manganese (Mn) and molybdenum (Mo).
    • Plants deficient in Fe will often display a pale green leaf color (chlorosis), with sharp distinction between green veins and yellow interveinal tissues.
    • Most Fe fertilizer sources work best applied as foliar sprays.
    • Iron is a catalyst to chlorophyll formation.
    • Iron acts as an oxygen carrier in the nodules of legume roots.

Molybdenum (Mo)

Molybdenum (Mo) is a trace element found in the soil and is required for the synthesis and activity of the enzyme nitrate reductase. Molybdenum is vital for the process of symbiotic nitrogen (N) fixation by Rhizobia bacteria in legume root modules. Considering Mo’s importance in optimizing plant growth, it’s fortunate that Mo deficiencies are relatively rare in most agricultural cropping areas.

  • Symptoms: Older leaves yellow, remaining foliage turns light green. Leaves can become narrow and distorted.
  • Sources: Compounds containing the words ‘molybdate’ or ‘molybdic’.
  • Notes:
    • Sometimes confused with nitrogen deficiency.
    • Molybdenum-deficiency symptoms show up as a general yellowing and stunting of the plant. A Mo deficiency can also cause marginal scorching and cupping or rolling of leaves.
    • Several materials supply Mo and can be mixed with nitrogen (N), phosphorus (P) and potassium (K) fertilizers applied as foliar sprays or used as a seed treatment. Seed treatment is the most common way of correcting Mo deficiency because of the very small amounts of the nutrient required.
    • Plants take up Mo as the MoO42- anion.
    • Molybdenum becomes more available as soil pH goes up, the opposite of most other micronutrients
    • Excessive Mo is toxic, especially to grazing animals.

Zinc (Zn)

Zinc (Zn) is taken up by plants as the divalent Zn2+ cation. It was one of the first micronutrients recognized as essential for plants and the one most commonly limiting yields. Although Zn is required in small amounts, high yields are impossible without it.

  • Symptoms: Yellowing between veins of new growth. Terminal (end) leaves may form a rosette.
  • Sources: Compounds containing the word ‘zinc’.
  • Notes:
    • Can become limited in higher pH.
    • Protein synthesis and growth regulation require Zn. Reduced hormone production due to a Zn-deficient plant will cause the shortening of internodes and stunted leaf growth.
    • Zinc is much less mobile within the plant, so deficiency symptoms first appear on the younger leaves.
    • Zinc aids synthesis of plant-growth substances and enzyme systems, and is essential for promoting certain metabolic reactions, which are particularly critical in the early growth stages.
    • As soil pH increases, zinc availability decreases.

Nickel (Ni) was added to the list of essential plant nutrients late in the 20th century. Plants absorb Ni as the divalent cation Ni2+. It is required in very small amounts, with the critical level appearing to be about 0.1 parts per million.

  • Notes:
    • No Ni deficienceies have been observed under crop-growing conditions, but in crop research settings, ag scientists have reproduced deficiency symptoms such as chlorosis of young leaves and dead meristematic tissue.
    • Nickel deficiency has been observed in some nursery plants and tree crops. Affected trees develop mouse-ear, a condition marked by small, curled leaves and stunted growth.
    • Nickel is a component of the urease enzyme and is, therefore, necessary for the conversion of urea to ammonia (NH3) in plant tissue, making it important in plant nitrogen (N) metabolism.

Non-fertilizer Elements

Hydrogen (H)

Hydrogen (H), derived almost entirely from water, is one of the 17 essential nutrients necessary for plant growth. Hydrogen, along with carbon and oxygen, are the three primary elements plants use in the largest amounts, and they perform as the building blocks for plant growth.

  • Notes:
    • Nearly all organic compounds also contain H atoms, which explains why plants need the H they get from water molecules through photosynthesis.
    • Hydrogen ions are vital in both aiding proton gradients to help drive the electron transport chain in photosynthesis, and for plant respiration.
    • Hydrogen is necessary for building sugars and other molecules to produce glucose for plant energy.
    • Known as a structural element, H is present in both the atmosphere and the growing environment.
    • Hydrogen is rarely a limiting nutrient.
    • Hydrogen is an element and can be a compound as well. As an element, H is the lightest, with one proton, one electron and usually no neutrons. Compound H forms when two H atoms share an electron pair, creating a covalent bond, which takes the form of a gas.

Carbon (C)

Carbon (C) is responsible for all life on earth. Carbon dioxide (CO2) released into the atmosphere is recycled endlessly as part of the carbon cycle. Plants take CO2 from the air and use the C for energy, helping to build essential biological compounds such as carbohydrates and proteins.

  • Notes:
    • Carbon is the primary energy source and building block for plant tissues.
    • Converted through photosynthesis into simple sugars, C helps plants build starches, carbohydrates, cellulose, lignin and protein.
    • Crop residues, green manures and animal wastes can be significant sources of organic C in the soil.
    • Almost half of the plant’s dry matter is comprised of C.

Oxygen (O)

Oxygen (O) is responsible for cellular respiration in plants. Plants acquire O by breaking down carbon dioxide (CO2) during photosynthesis and end up releasing the majority of it as an unnecessary byproduct, saving a small portion for future energy.

  • Notes:
    • All Oxygen available to life on Earth comes from plants.
    • Most of the Oxygen plants take in is expelled as a byproduct. Only a very small amount is actually used by the plant for respiration.
    • Plants don’t absorb Oxygen from the air, but instead acquire it during the breakdown of carbon dioxide (CO2) as part of photosynthesis.
    • Oxygen interacts with nitrogen (N) in a process called denitrification, and it affects other elements’ oxidation states as well.
    • Only the leaves and stems of a plant acquire Oxygen through photosynthesis. The roots of a plant are forced to take in Oxygen from the environment through air spaces in the soil.

Related Images:

The Role of Nitrogen (N)

Nitrogen (N) is essential for plant growth and is part of every living cell. It plays many roles in plants and is necessary for chlorophyll synthesis. Plants take up most of their N as the ammonium (NH4+) or nitrate (No3-) ion. Some direct absorption of urea can occur through the leaves, and small amounts of N are obtained from materials such as water-soluble amino acids.

Plumeria – Frangipani mosaic virus


196
August 1978
Family: Virgaviridae
Genus: Tobamovirus
Species: Frangipani mosaic virus
Acronym: FrMV

Frangipani mosaic virus

A. Varma – Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, New Delhi 110012, India

A. J. Gibbs – Research School of Biological Sciences, Australian National University, Canberra, Australia

Contents

Introduction
Main Diseases
Geographical Distribution
Host Range and Symptomatology
Strains
Transmission by Vectors
Transmission through Seed
Transmission by Grafting
Transmission by Dodder
Serology
Nucleic Acid Hybridization
Relationships
Stability in Sap
Purification
Properties of Particles
Particle Structure
Particle Composition
Properties of Infective Nucleic Acid
Molecular Structure
Genome Properties
Satellites
Relations with Cells and Tissues
Ecology and Control
Notes
References
Acknowledgements
Figures

Introduction

Described by Francki, Zaitlin & Grivell (1971).
Synonym
Temple tree mosaic virus. A virus with tubular particles 300 nm long and 18 nm in diameter. Sap transmissible. No vector known; is spread in cuttings of infected frangipani (Plumeria spp.). Restricted host range, grows best at 30-35°C.

Main Diseases

In Plumeria acutifolia the virus causes mosaic, ringspots, veinbanding and bronzing. In P. alba, it causes ringspots, leaf distortion and necrosis. No flower symptoms.

Geographical Distribution

Common in eastern Australia and northern India.

Host Range and Symptomatology

Host range not yet tested extensively, but seems restricted. More species become infected at temperatures above 25°C than below. At 35°C symptoms show in 3-6 days, at 22°C they take 2 weeks or more.

Diagnostic species
Datura stramonium. Chlorotic, necrotic or black lesions develop in inoculated leaves after 1-2 weeks in the glasshouse at 22°C. At 35°C, in controlled environment cabinets, similar symptoms develop in 3 days; one strain causes systemic necrosis along the veins and leaf margins.
Nicotiana glutinosa. At 22°C inoculated leaves develop chlorotic lesions in about 2 weeks. Not infected systemically.
N. tabacum (tobacco) cvs Samsun, Virginia Gold or White Burley. Rarely infected at 22°C. At 35°C all strains induce bright chlorotic or necrotic ringspots in inoculated and systemically infected leaves.
N. clevelandii x N. glutinosa. Not infected at 22°C. At 35°C inoculated leaves develop faint chlorotic lesions which become necrotic or develop ringspots. Not infected systemically.
Propagation species
Nicotiana glutinosa. Inoculated leaves give a good yield after 2-3 weeks at 22°C.
Assay species
Datura stramonium is the most reliable assay species.

Strains

Three distinct strains from different provenances have been distinguished by the symptoms they produce. They are the Adelaide strain (Adel) (Francki et al., 1971), and the Allahabad (Ald) and Delhi (Del) strains (A. Varma & A. J. Gibbs, unpublished data). Leaves of D. stramonium kept at about 22°C develop faint chlorotic lesions after inoculation with strain Adel, necrotic lesions after inoculation with strain Ald, and chlorotic lesions, later becoming black, after inoculation with strain Del. At 35°C symptoms developed more quickly and spread more: strain Adel gave necrotic lesions, strain Ald gave lesions with chlorotic haloes or ringspots, and strain Del gave spreading black necrotic ringspots and systemic veinal and marginal necrosis. N. tabacum cv. Virginia Gold was susceptible at 22°C to strain Del only, showing chlorotic and necrotic local lesions. At 35°C in the same tobacco cultivar, strain Adel gave faint necrotic ringspots, strain Ald gave bright necrotic ringspots and strain Del gave large ringspots both in inoculated and in tip leaves.

Transmission by Vectors

No vector is known.

Transmission through Seed

Not transmitted through seed of D. stramonium or N. tabacum cv. Samsun.

Serology

Particles of the virus are strongly immunogenic. They give flocculent precipitates in tube precipitin tests, and form one band of precipitate in gel diffusion tests.

Relationships

Properties, serological relationships and particle morphology place the virus in the tobamovirus group. The particles of frangipani mosaic virus are morphologically indistinguishable from those of other tobamoviruses. The Adel, Ald and Del strains are serologically closely related to each other. All three strains are related distantly to cucumber virus 4, cucumber green mottle mosaic virus, and an isolate of sunn-hemp mosaic virus from Queensland, Australia (but not one from West Africa); and even more distantly to TMV-type strain, TMV-U2 strain, tomato mosaic virus and ribgrass mosaic virus. (A. J. Gibbs & A. Varma, unpublished data; Franckiet al., 1971). There was no detectable serological relationship with Sammons’ opuntia virus even though comparisons of coat protein composition indicate a close affinity (Description No. 184).

Stability in Sap

Very stable. Sap from infected D. stramonium was not infective after heating to 95°C for 10 min, and lost 90% of its infectivity in 10 min at 90°C. The sap was still infective after 10 weeks at room temperature, and at dilutions up to 10-5.

Purification

The virus is easily purified from infected leaves of frangipani or N. glutinosa by several methods. The following methods give good yields:

1. Francki et al. (1971), based on McLean & Francki (1967) and Francki & McLean (1968). Homogenise infected leaves of N. glutinosa in 1.5 volumes of 0.2 M Na2HPO4, clarify by adsorption with charcoal and DEAE cellulose and filter through Celite. Sediment the particles by centrifuging at 44,000 g for 90 min. Resuspend pellets in distilled water and emulsify with equal volume of chloroform. Centrifuge at 12,000 g for 10 min. Collect aqueous layer and sediment the particles by centrifuging at 16,000 g for 30 min. Repeat chloroform extraction and sedimentation.

2. Based on Varma, Gibbs & Woods (1970). Triturate infected leaves mechanically with 2 ml/g of neutral phosphate-ascorbate buffer (equal volumes of 0.1 M disodium hydrogen phosphate and 0.05 M ascorbic acid). Add a quarter volume of chloroform, emulsify, centrifuge at 8000 g for 10 min, collect supernatant fluid and centrifuge for 1 h at 75,000 g. Resuspend the pellets in a small quantity of the buffer. Further purify by rate zonal centrifugation at 45,000 g for 75 min in gradients of 10-40% sucrose.

Properties of Particles

In dilute solutions the virus sediments as a single component with sedimentation coefficient (s20, w) of 188 S (R. D. Woods, unpublished data).A260/A280: 1.21.

Particle Structure

The virus has rod-shaped particles about 300 nm long and 17 nm wide. The preparations also contain shorter particles (Francki et al., 1971) (Fig.6).

Particle Composition

 Nucleic acid: The particles contain c. 5% RNA.Protein: Each subunit of the coat protein of strain Adel contains about 158 amino acid residues: Ala, 14; Arg, 11; Asx, 17; Cys, 1; Glx, 16; Gly, 9; His, 1; Ile, 11; Leu, 13; Lys, 4; Met, 0; Phe, 7; Pro, 4; Ser, 14; Thr, 13; Trp, 5; Tyr, 5; Val, 13 (Francki et al., 1971). Of the other tobamoviruses whose coat proteins have been analysed, Sammons’ opuntia virus has a composition most similar to that of frangipani mosaic virus..

Relations with Cells and Tissues

In the cytoplasm of infected parenchymatous cells of D. stramonium leaves, the particles of frangipani mosaic virus aggregate as microcrystals of various shapes and sizes. Particles were not seen in mitochondria, chloroplasts or nuclei although these organelles are not of normal appearance.

References

  1. Francki & McLean, Aust. J. biol. Sci. 21: 1311, 1968.
  2. Francki, Zaitlin & Grivell, Aust. J. biol Sci. 24: 815, 1971.
  3. McLean & Francki, Virology 31: 585, 1967.
  4. Varma, Gibbs & Woods, J. gen. Virol. 8: 21, 1970.

Related Images:

Over Watering your Plumeria

At one time or another we all over water our plumeria or you may live in a heavy rainfall area and had flooding problems. Over watering, prolonged heavy rainfall or flooding can cause havoc on your plumeria. Poor drainage can also contribute to this problem.  

Anaerobic Soil

Over watering your soil causes your soil to be waterlogged, not a healthy environment for plumeria to live. Much like we would not be comfortable living under water all the time.  We need to come up for air and the plumeria roots need oxygen too.  

Saturated soils with poor drainage can quickly become anaerobic, making the plumeria susceptible to diseases like root rot. When plumeria roots sit in excess water for too long, they start to rot or decay. As the roots deteriorate, they can’t take up water, so the plumeria wilts.  

Clues your soil or potting mix needs help

When too much water is around the roots, it is likely the beneficial microorganisms and soil life that were living in your pot and keeping your plumeria healthy have drowned or at best case, their numbers have greatly reduced.  If this is the case, the potting mix or soil may smell ‘sour’ or anaerobic.  Oxygen normally fills the gaps in between the soil crumb structure and all organisms and plumerias need air to live.  When plumeria roots start to decay, you may notice this unpleasant smell. 

If your potted plumeria show these tell-tale signs of over watering, there is a problem with the soil:

  • Your plumeria is wilting, dropping leaves
  • Your plumeria is looking unwell all of a sudden
  • Your plumeria is being attacked by pests or disease
  • Worms are coming up to the surface in great numbers (they are trying to save themselves from drowning)
  • Sometimes you might notice a scum or residue on the surface of the soil  

Here are some suggestions to help you from over watering your plumeria:

  • Adding coarse mulch material to the bottom of the pot will also help drainage
  • Mix your soil with 50% Perlite
  • Use pots with many drain holes
  • Add more drain holes in your pot
  • Locate your pots in well-drained areas
  • Or plant in the ground, when possible  

If the pot or container feels heavy and the plumeria is still wilting, the excess water may not be getting away fast enough.  If you have already drilled enough holes, you may need to actually remove your plumeria from the pot to save it.  Spread out a number of sheets of newspaper in a tray.  Lay the pot on its side and gently slide out the plumeria’s root ball. 

Allow the root ball to dry on the newspapers for about 12 hours or more, then using clean sharp scissors, trim off any dark-colored (brown rather than white) or slimy roots.  When you are finished, re-pot the plumeria in a clean container with some fresh potting mix as already outlined.  

Using Coarse Material in your pot:

We have found that putting an inch of two of coarse, decomposing mulch in the bottom of the pot helps with drainage and plumeria health.  

Most books and websites on container gardening recommend the addition of coarse material such gravel, sand, pebbles, pottery shards or polystyrene pieces to the bottom of pots to improve drainage, scientific studies have consistently demonstrated quite the opposite is true.  According to one scientist, Dr Chalker-Scott, Extension Horticulturalist and Associate Professor at the Washington State University:  

“Nearly 100 years ago, soil scientists demonstrated that water does not move easily from layers of finer textured materials to layers of coarser textured materials.  Since then, similar studies have produced the same results.  The coarser the underlying material, the more difficult it is for the water to move across the material’s face.  Gravitational water will not move from a fine soil texture into a coarser material until the finer soil is saturated.  Since the stated goal for using coarse material in the bottoms of containers is to “keep soil from getting water logged,” it is ironic that adding this material will induce the very state it is intended to prevent.”  

Resist the Urge to Over water:

Resist the urge to water your plumeria without checking to see if they actually need water – it can actually make things worse!  Water logging and compaction can create ideal conditions for diseases such as phytopthora and other fungal attacks.  

Potted plumeria that have been inundated with water will also have likely leached out much of the plumeria food or fertilizer that was in the pot previously.  You will need to replace this food source with some more organic fertilizer to ensure your plumeria has the energy it needs to regain its health.  

If you notice discolored or yellowing leaves, this is often a sign your plumeria is crying out to be fed. This is because it is missing essential minerals!  A slow release, powdered or pelleted fertilizer and compost can help restore the nutrients.

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How to read a Fertilizer Label

 

You want to make sure your Plumeria are getting the nutrition they need, but there are so many choices when it comes to selecting fertilizer. How do you know what is really in the bag? There are certain rules that all fertilizer makers must follow when they label their products and understanding these rules can make comparing fertilizers much easier.

Major Ingredients: Most commercial fertilizers have 3 numbers on the front label, separated by dashes. For example: 11-11-13. This is the fertilizer analysis or percentage by weight of the 3 major nutrients plants need: nitrogen, phosphorus and potassium, in that order. These are abbreviated as N-P-K.

So if you purchased a 11 pound bag of fertilizer labeled 11-11-13, it would contain 11% nitrogen, 11% phosphorus and 13% potassium. The remaining 65% could be comprised of other nutrients and filler.npk-chart-e1412652821845

  • 1st Number = Nitrogen: The first number gives the concentration of nitrogen in the product. Nitrogen encourages foliage growth, among other benefits. A 11-11-13 fertilizer would contain 11% nitrogen by weight. So for every pound of fertilizer applied there is really only .11 pounds of nitrogen. (The 10 pound bag mentioned above would contain 1.1 lb. nitrogen.)
  • 2nd Number = Phosphorus: The middle number refers to the concentration of phosphorous. Phosphorous contributes to many fundamental plant processes such as rooting and setting flower buds. A 11-11-13 fertilizer would contain 11% phosphorous by weight or 1.1 pounds of phosphorous. (The 10 pound bag mentioned above would contain 1.1 lb. of phosphorus.)

    plantnutrients-232x300A good reference to get an idea if your Plumeria are Deficient in Nutrients

  • 3rd Number = Potassium: The final number states the concentration of potassium. Potassium contributes to the overall health and vigor of plants. Again, a 11-11-13 fertilizer would contain 13% potassium by weight or 1.3 pounds of potassium. (The 10 pound bag mentioned above would contain 1.3 lb. potassium.)

Complete Fertilizers: Fertilizers that contain all three major nutrients are considered complete fertilizers. There are specialized fertilizers which are called incomplete because they lack one or more major nutrients such as a fertilizer labeled 0-20-20.

Fertilizer Ratio (An easier comparison): An easier way to compare the numbers is to break them down to the fertilizer ratio or the amounts of the 3 major nutrients in relation to each other. A 5-10-5 fertilizer has a ratio of 1-2-1. This becomes important when looking for a fertilizer for a specific need. A 1-2-1 ratio is often recommended for vegetables, which need plenty of phosphorous to set fruit. 1-2-1 could be 5-10-5, 10-20-10 or any similar extrapolation.

Other Ingredients: Any additional ingredients will be listed on the side label. This may include other nutrients like calcium, magnesium, iron, micronutrients and even the percentage of organic matter.

Organic fertilizers: Organic fertilizers must specify which nutrient(s) is organic and it must be identified as either synthetic and/or natural, by percentage. For example: 20% of Nitrogen organic (6% synthetic, 14% organic). When something is labeled “organic”, it simply means it contains carbon atoms. However we have come to expect that organic fertilizer, like organic food, comes from natural processes and contains nothing synthetic. That tends to be the case, especially as consumers become more educated, but be sure to read the label before you make a purchase.

Tips:
ph-nutrients-availability1-1024x740-300x216If your PH is too high or too low you nutrients could be locked in the soil.

  • Having a soil test done before you start adding amendments will tell you what you actually need. If your soil pH is too high or too low, your plants will not be able to access some nutrients, even if they are present in the soil.
  • There is no one size fits all fertilizer. Fertilizer choice depends on the type of plant being grown and the soil it is being grown in.
  • Always follow the label instructions when using any registered garden product. Just because a little is good, it doesn’t follow that a lot is better.
  • You can use less of fertilizers with high analysis numbers than with lower numbers. Five pounds of 10-20-10 would give you the same nutrient value as 10 pounds of 5-10-5.
  • Organic fertilizers made from natural ingredients often have lower concentrations of the three major nutrients, so you will need to use larger amounts. However, they do contain many other nutrients that feed both the plant and the soil. If you are using a synthetic fertilizer, you should supplement with some type of organic matter such as compost or manure, to maintain soil health.

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Branching Inducers on Plumeria

Branching Inducers on Plumeria

By Milton Pierson, Suggested by Dr. Richard A. Criley, Univ. of Hawaii
Purpose:

To produce more branches per cut from a pruned plumeria limb. UH experiments suggest that lanolin pastes of cytokinins can improve the number of buds which break following pruning. It is desirable to increase lateral shoot production after pruning for cultural control both in commercial flower production and landscapes as well as for plants grown in containers (Kwon and Criley, 1991).

Procedure:

Apply 6-benzylaminopurine (BA) in a lanolin paste to pruned tips. Kwon and Criley (1991) used single stemmed 2 year old plants of P. rubra in 35 x 22 cm pots containing a medium of equal parts soil, peat, and perlite. The plants were decapitated at 30 cm above the soil line 3 weeks after repotting. Various concentrations of the growth regulator solution was then applied to be absorbed into the cut surface. We will use 2 mg/g and 4 mg/g (BA/lanolin) solutions (2000 and 4000ppm). Four plants should be used for each treatment plus 4 control plants. Data to collect are; (a)number of days to bud break for each plant, (b)number of shoots initiated and (c)surviving and (d)the length of these at 4 months after treatment.

The following passage is quoted from a letter from Dr. Richard A. Criley, dated September 16, 1994. It outlines where BA and lanolin may be obtained, how to mix them, how to apply the paste to plumeria, and addresses the question of the shelf life of the mixture.

“The application of chemical branch inducing substances in lanolin would be an interesting set of studies for PSA members to try. You can get plain old lanolin at many pharmacies or order it through chemical supply houses. It comes as a yellow, very sticky fatty substance. You can melt it in a double boiler and dissolve or suspend substances in it. My recommendation is to weigh out the stuff in the same container you want to melt it in – then you are sure of concentrations.

The benzyladenine is not water soluble to any great extent. I usually dissolve it in a small amount of acetone or alcohol or DMSO. You can also use 0.5 N HCL (small amount) to dissolve it, then dilute in water and add to the melted lanolin. Stir well to make a uniform mixture. Allow to cool. I use it by smearing a glob on the cut stump of a plumeria branch using a finger covered with a latex glove finger. Rates to try: 2 or 4 mg BA in 1 gram of lanolin. I have a mixture from 4 – 5 years ago that still has activity.

You can also pour the BA-lanolin paste mix while still liquid into plastic film canisters. This might be one way to share it around easily. (Maybe you could charge a few dollars per unit and recover the costs.)

The N-6-benzyladenine (BA) is also known as 6-benzylaminopurine.”

Summary:

  • Use 6-benzylaminopurine (BA) in a lanolin paste.
  • Apply paste to pruned tips. (1) 2 mg BA per gram lanolin. (2) 4 mg BA per gram lanolin.
  • These experiments would need control plants which receive a no N-6-benzyladenine . Both the experimental subject and control plant would have to be of the same cultivar to avoid inconsistencies in growth habit and flowering.

References:

Eunoh Kwon and Richard A. Criley (1991), Cytokinin and Ethephon Induce Greater Branching of Pruned Plumeria, Horticulture Digest; Hawaii Cooperative Extension Service, No. 93, March 1991, p. 6-8.

6-benzylaminopurine from Sigma Chemical Company; catalog # B 3408: 1 g, $10.65 + shipping. Lanolin from Sigma Chemical Company; catalog # L 7387: 1 kg, $32.80 + shipping.

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Phosphorus deficiency guide

 

phosphorusPhosphorus (K) deficiency guide

Phosphorus plays an important role for all living organisms and is an essential nutrient element for plants and animals. It has a key position in the combustion processes of the cell, and in the total energy transfer of the plant. It is also a “building block” of the cell walls, the DNA, and all sorts of proteins and enzymes.
 

For young plants, the presence of phosphate is indispensable; about 3/4 of the phosphorus consumed during a plant’s life cycle is absorbed in the first quarter of its life. The largest concentrations of phosphorus are found in the developing parts of the plant: the roots, the growth shoots and the vascular tissue.

 

About phosphorus in short

What is it and what does it do?
Phosphorus holds a key position in both cell processes and total energy transfer of the plant.
Also a “building block” of – among others – cell walls and DNA.
What can you see?
Small plant with purple/black necrotic leaf parts.
Leafs become malformed and shriveled.
What can you do?
Mix inorganic phosphate fertilizer THOROUGHLY through the potting mix or add extra liquid phosphate when growing in hydroponics.

Symptoms of a deficiency

Plants remain rather small with purple-black necrotic leaf parts, which later on become malformed and shriveled.

Development of a deficiency

  • At first, the plant becomes dark green – a different sort of dark green (blue/ green) as appears when there is a shortage of phosphorus.
  • The growth in height, and the development of the plant’s side shoots are inhibited.
  • After 2 to 3 weeks, dark purple-black necrotic spots appear on the old and medium-old leaves, making the leaves malformed.
  • The purple/black necroses expand to the leaf’s stem. The leaf turns, curls considerably and dies off.
  • The dead leaves are curled and shriveled, have a typical orange purple color, and fall off.
  • The plant flowers fully, but the yield will be minimal.

Reasons for a deficiency

Due to the low concentrations in which phosphate appears in nature, the affinity of plant cells for phosphorous allows easy absorption through the whole root. Therefore, shortages do not happen very often, except when:

  • The growing medium has a too high pH (higher than pH 7). In such cases the plant can not absorb phosphorus due to the fact that insoluble phosphorous compounds develop.
  • The ground is too acidic, or too rich in iron and zinc. This hinders the absorption of phosphate.
  • The potting mix has become fixated. Phosphate can not be absorbed any more.

Solutions to a deficiency

Always use inorganic phosphates as these are easy to absorb. Also always mix the phosphate fertilizer thoroughly through the potting mix.

  • When pH is too high, acidify the medium by using a thinned solution of phosphoric acid.
  • Choose products that have a guaranteed phosphate percentage on the packaging instead of alternative phosphate-containing products like guano or manure.

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Thrips – Pest

Pests & Diseases: Thrips

Thrips – Pests & Diseases

Thrips are recognizable by their small size and long flat shape. The adult thrips has four feathery wings. They can vary in color from gray to yellow or brown. Thrips are carriers of viruses, mainly of the genus Tospovirus. These viruses cause significant crop loss and are incurable.
 

About the pest in brief

 

What are Thrips?
When we use the term thrips, we are referring to a wide group of insects of the order Thysanoptera.
What can you see?
Because certain toxic substances are present in the saliva of thrips, you may see some deformations in the shoots or flowers of the affected plants.
What can you do?
Spray plants with ecological insecticides like potassium soap or plant extracts with pyrethrum.

Biological cycle of thrips

 

The first stage of the thrips’ life cycle is the egg, which will hatch much more quickly when temperatures are higher. The females lay eggs in plant tissues. The larvae that emerge from the eggs feed on the surrounding tissues. One of the characteristics of these insects is that they make the transition from pupa to adult in the soil or in the lower leaves. The larvae live in the leaves, but as soon as they reach the right stage of development, they fall to the ground or lower leaves where they live during the pre-pupal and pupal stages until a reproductive adult appears with fully developed wings. The whole life cycle lasts only a few weeks.

 

Thrips

 

Symptoms of the pest

The adult thrips eats a varied diet based mainly on pollen, but the larvae feed on plant tissues and it is the larvae that are responsible for the majority of plant damage. The larvae suck the liquid from plant cells, mainly from the leaves, but also the petals, shoots and fruits. Early symptoms include an almost transparent or clear discoloration of the leaf with black dots (which are caused by fecal secretions). They have rasping, sucking mouthparts that look like combs and make a soup from the tissue which is then sucked up. Usually the top layer of the tissue is undisturbed and a window of clear tissue is seen in the middle of the area of discoloration.

 

Because certain toxic substances are present in the saliva of thrips, some deformations may occur in the shoots or flowers of affected plants. In cases of very severe infestation, the leaves may dry up entirely. At the same time, some thrips like Frankliniella occidentalis secrete a few drops of a substance when they are threatened by predators. These excretions contain decyl acetate and dodecyl acetate – pheromones that serve as a warning signal for other nearby thrips.

 

How to prevent the pest?

 

Because of the thrips’ ability to transmit viruses, it is important to monitor our crops for thrips and detect them as early as possible. The classic method for doing this is by using adhesive traps. These traps are blue in color, because thrips are strongly attracted to blue. The traps should be examined every few days using a magnifying glass to see if any thrips (usually winged adults) have gotten stuck to them.

 

Thrips

 

Solutions for controlling the pest

 

If you detect thrips, appropriate treatments need to be administered to minimize the risk of an infestation. These treatments include ecological insecticides such as potassium soap or plant extracts with pyrethrum, in places where these are allowed by law. Plants must be sprayed thoroughly all over because the thrips will take refuge under the veins of the leaves, making it difficult for the insecticide to come into contact with all the insects.

 

It is also possible to use entomophagous fungi to combat thrips. Beauveria bassiana is one fungi that is typically used to combat thrips. It is also important to make sure that you clean up and remove any plant or soil residues from the floor or worktops.

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Aphids – Pest

 Aphids – Pests & Diseases

Aphids are no longer than about 4 mm, have a bulbous abdomen and can be many different colors. They are among the most destructive pests to affect cultivated plants in temperate regions. Winged aphids are especially dangerous for your crops, since they destroy plants much faster than regular aphids
 

About the pest in brief

What are aphids?
When we refer to aphids, or plant lice, we usually mean a super family of insects which includes over 4.000 species of plant-specific parasites.
What can you see?
Aphids can cause decreased growth rates, mottled leaves, yellowing, stunted growth, curled leaves, browning, wilting, low yields and death in plants.
What can you do?
There are several cultivation techniques that we can use to prevent or minimize an attack of aphids.

Biological cycle of aphids

Aphids can be winged or wingless. Usually, the first generation to hatch after winter is wingless. However, after several generations there can be a lack of space on the host plant. This triggers the birth of a generation of winged aphids, which can migrate to other hosts. All the aphids born from the winter eggs are females. Several more generations of female aphids are born during spring and summer. Females can live for 25 days, during which they can each produce up to 80 new aphids. Spring and summer reproduction occurs asexually – without males.

Aphids

Symptoms of the pest

The aphids feed on phloem sap, which weakens the plant and causes a metabolic imbalance, twisting of the leaves and, in extreme cases, causing leaf loss. Leaf loss affects the quantity and quality of the final harvest. Aphids also introduce toxins into the plant, systemically altering its development.

Furthermore, the honeydew secreted by the aphids is an ideal culture medium for a range of various fungi, which form a barrier on the leaf, stopping it from taking in all the light that hits it.

However, the most harmful effect of aphids is the transmission of viruses. Aphids can transmit dozens of viruses from a diseased plant to healthy one in just a few seconds, especially the winged generations. The biggest problem with viruses is that there is no remedy for them, so the infection of a plant that is not tolerant or resistant to the virus leads inevitably to a decline in the final production.

Aphids

CONTROL AND PREVENTION

HOW TO GET RID OF APHIDS

  • Try spraying cold water on the leaves, sometimes all aphids need is a cool blast to dislodge them.
  • If you have an aphid invasion, dust plants with flour. It constipates the pests. 
  • Use commercially available biological controls or by spraying with insecticidal soap or horticultural oil.
  • You can often get rid of aphids by wiping or spraying the leaves of the plant with a mild solution of water and a few drops of dishwashing detergent such as Ivory.
  • Stir together 1 quart of water, 1 tsp of liquid dish soap and a pinch of cayenne pepper. Do not dilute before spraying on plants.
  • Organic controls include soapy emulsion, horticultural oil (read the directions), and pyrethrum spray. Soapy water should be reapplied every 2-3 days for 2 weeks.
  • Use homemade garlic or tomato-leaf sprays.

There are several cultivation techniques that we can use to prevent or minimize an infestation of aphids.

These include:

  • Eliminating weeds that can serve as a reservoir of eggs and adults
  • Using insect nets (sometimes insecticide-impregnated) to cover crops
  • Avoiding the excessive use of nitrogenous fertilizer
  • Removing crop residues
  • Establishing plant species that can serve as a reservoir for predators (banker plants)

PREVENT APHIDS

  • For fruit or shade trees, spray dormant oil to kill overwintering eggs.
  • You can purchase beneficial insects, such as lady beetles, lacewings, and parasitic wasps, which will feed on aphids. These are usually ordered via mail—check the Internet for labs. They should keep the aphid populations controlled in the first place.
    • You can also plant flowering groundcovers in home orchards to attract predators.
  • Companion planting can be very helpful to keep aphids away from your plants in the first place. For example:
    • Aphids are repelled by catnip.
    • Aphids are especially attracted to mustard and nasturtium. You can plant these near more valuable plants as traps for the aphids. 
    • Nasturtiums spoil the taste of fruit tree sap for aphids and will help keep aphids off broccoli.
    • Garlic and chives repel aphids when planted near lettuce, peas, or rose bushes. 

Solutions for controlling the pest

The natural enemies of aphids include ladybird beetles (or ladybugs) and lacewings. Green lacewing larvae (Chrysoperla sp.) are voracious predators of aphids.

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