Disease Incidence

Plant pathology and quarantine terminology

Abiotic

pertaining to physical and inorganic components. For example, diseases/disorders in plants can be caused by abiotic factors such as extremes of heat, light, moisture, lack of nutrients etc.

Appressorium (pl. Appressoria)

an enlarged fungal filament that adheres to the surface of the host, prior to penetration.
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Avirulent

unable to cause disease; lacking virulence (see virulent); nonpathogenic.

B

Biotic

pertaining to life and therefore living organisms. For example, plant diseases of a biotic origin are caused by living organisms such as insects, nematodes, etc.

Biotroph

an organism that can live and reproduce only on another living organism. A biotroph is completely dependent on the host organism as a source of nutrients, i.e. it is an obligate parasite. Compare with necrotroph.

Blight

A disease characterised by rapid and widespread death of plant tissue. Blight may take the form of extensive spotting, discoloration, wilting, or destruction of leaves, flowers and stems.
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C

Canker

a sunken necrotic lesion often of a main stem, branch or root.
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Chlorophyll

the green pigment found in chloroplasts of plant cells and algae. Chlorophyll is the receptor of light energy in photosynthesis. Chlorophyll is also found in photosynthetic bacteria.

Chloroplast

a disk-shaped structure in plant and algal cells that contains chlorophyll and is the site of photosynthesis.

Constitutive

constantly present, whether there is demand or not.

Cork

the external protective tissue of a stem or root. It is made up of polygonal-shaped cells that are non-living at maturity. The cell walls of cork tissue contain a fatty material (suberin) that makes them impermeable to water and gasses. Cork cells form the outermost layer of bark.

Cultivar

a cultivated plant variety or cultural selection; a plant type within a species that has recognizable characteristics as a result of deliberate genetic manipulation. Distinguishable characteristics may include colour, flower shape, fruits, seeds and height.

Cuticle

the waxy or fatty layer covering epidermal cells of plant surfaces exposed to air such as leaves, stems and fruit. The cuticle is water-repellent and aids the plant in conserving water by reducing the amount of water vapour lost to the air from plant surfaces, particularly the upper surface of leaves.In zoology, cuticle also refers to the non-cellular outer layer of an insect or a nematode.

D

Damping off

the collapse and rot of seedlings near soil level before emergence or soon after emergence. Damping off is caused by fungi: Pythium spp., Phytophthora spp., Fusarium spp., and Rhizoctonia spp.
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Defensins

antimicrobial proteins that inhibit the growth and development of pathogens. Plant defensins are found throughout the plant kingdom and are released upon seed germination, creating an antimicrobial environment around the seed while it germinates.

Dieback

progressive death of shoots, branches and roots, sometimes even leading to complete death of the plant.
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Disease

any malfunctioning of host cells and tissues that results from continuous irritation by a pathogenic agent or environmental factor which leads to the development of symptoms;
- abnormal functioning of physiological processes of an organism.

Disease Incidence

the number of plants affected by a disease within a population.

Дата добавления: 2015-10-31