4. Classification Flashcards
List four ways of classifying plant diseases.
- Based on host plants attacked
- Based on symptoms
- Based on plant organs attacked
- Based on causal agents
What two major types of causal agents can you have?
- Biotic - Infectious agents
2. Abiotic - Non-infectious factors
List three biotic infectious agents.
- Viruses
- Prokaryota
- Eukaryota
List five Eukaryota.
- Protozoa
- Chromista
- Mycota - Fungi
- Animalea - Nematodes
- Plantae - Higher plants
What are some examples of abiotic agents?
- too low or high temperature
- lack or excess of moisture, light
- lack of oxygen
- air pollution
- nutrient deficiency
- mineral toxicity
- pesticide toxicity
Are fungi more closely related to animals or plants?
Clearly more to ANIMALS
Order of classification.
L,D,K,P,C,O,F,G,S
What do viruses consist of?
Nucleic acid core of DNA or RNA and surrounded by coat of protein subunits=capsid
What shapes can viruses have?
rod, spherical or polyhedral
What are the transmission ways of viruses ?
- through host wound
- sap transmitted
- by animals and microbes
Do prokaryotes have DNA?
Yes, but not enclosed in a nucleus
What do bacteria cell walls contain?
glucans or glucose amines
How are bacteria without cell wall called?
phytoplasma or mycoplasma like organisms
What shapes can prokaryotes have?
- spherical (cocci)
- rods (bacilli)
- spiral (spirilla)
Prokaryote mode of reproduction is___
binary fission
Give an example of a Protozoa (specie)
Plasmodiophora brassicae
Are Protozoa fungus?
No, they are fungal-like organisms
What are the two kingdoms which are “pseudo” fungus?
Protozoa and chromista
Give two examples of chromistas (genus)
Phytophthora and Plasmopara
What is the body of the chromista made of?
Mycelium
What does mycelium contain?
Branches called hyphae
Are they unicellular?
No, they are generally multicellular and have cell walls.
What are the three main Fungi classes?
- Zygomycota
- Ascomycota
- Basidiomycota
What are two main characteristics of fungi cells?
- they do not have chlorophyll pigments
- cell wall contain chitin
What is chitin?
a long chain polymer of a N-acetylglucosamine a derivate of glucose
What are the fungi body composed of?
Mycelium
Give an example of a parasitic higher plant.
- Dwarf Mistletoe: have no chlorophyll so they parasite coniferous trees
- Dodder: a parasitic vine on alfalfa
- Striga: parasitic on sorghum, corn
What are nematodes?
Worms, invertebrate non-segmented round worms
Are they mostly parasitic?
No, most are free-living in soil, feeding on microbes. Some are animal and plant parasites.
Which systems do they have in their organism?
- alimentary
- reproductive
- nervous
Which systems do they lack?
- respiratory
- circulatory
What characteristic do all plant pathogenic nematodes have?
Stylet
BUT not all stylet nematodes are plant pathogenic
What do they use their stylet for?
To pierce plant cells and suck sap as the stylet is hollow.
What are two examples of air pollution affecting plants’ health?
- Ozone (O3)
- Acid rain
Where does O3 come from?
produced by a photochemical reaction between hydrocarbons and nitrogen dioxide primarily from auto-exhaust smog
Where does acid rain come from?
- factory emission releasing sulfuric acid from sulfur dioxide (coal) and nitrous oxides (auto engines)
- Forest decline smog, acid rain, winter kill, etc.
Which pH does acid rain have?
low, from pH=3-4
