w6 Flashcards
What is the apoplast, and why is it important in plants?
The apoplast is the space outside the plasma membrane, allowing free movement of materials like water and solutes. It is crucial for diffusion across tissues or organs.
What are Casparian bands, and how do they function in plant defense?
Casparian bands are cork-like structures in vascular tissues that create a waterproof barrier, preventing bacterial invasion.
How do rhizobium bacteria benefit plants?
Rhizobium bacteria form symbiotic relationships with plants by fixing atmospheric nitrogen into a form usable by the plant, aiding growth.
Why do some plants reject their own pollen?
Some plants prevent self-pollination at the stigma to encourage genetic diversity and reduce inbreeding.
What chemicals do plants produce to combat environmental stresses?
Plants excrete various chemicals to counteract stresses like drought, heat, and insect attacks, improving their adaptability.
they can detect species of animal that are eating them
What is a bacterioid, and what role does it play in nitrogen fixation?
A bacterioid is a transformed bacterium in nitrogen-fixing plants, adapted to facilitate nitrogen fixation in anaerobic conditions.
they cant live without their host
What is leghemoglobin, and why is it significant?
Leghemoglobin removes oxygen to maintain the anaerobic conditions needed for nitrogen fixation in plant root nodules.
How do endomycorrhiza and ectomycorrhiza differ?
Endomycorrhiza penetrates plant cell walls without entering cell membranes, while ectomycorrhiza forms external interactions.
What are biotrophs, and how do they differ from necrotrophs?
Biotrophs feed on living cells and are highly specialized, while necrotrophs kill plant cells and feed on dead tissue.
What is a hemi-biotroph?
A hemi-biotroph exhibits a lifestyle that starts with biotrophy (feeding on living cells) and transitions to necrotrophy (feeding on dead cells).
What role do nematodes play in plant root systems?
Nematodes signal for cell growth in vascular tissues and extract nutrients, often causing damage to the plant.
they remain dormant in the soil until they sense a root
What distinguishes oömycetes from fungi?
Oömycetes are protists with fungal-like characteristics but lack hyphal septa (seperating parts of the hypha with cell walls), being unicellular instead.
What determines a plant’s susceptibility to pathogens?
being susceptable means a pathogen can affect the plant in some direct negative way. non susceptable means it cant even detect the plant as a soure of food.
What are resistance genes (R-genes) in plants?
R-genes enable plants to recognize specific pathogen effectors and trigger defense mechanisms to combat infection.
How do effectors suppress plant defenses?
Effectors are pathogen-produced molecules that disrupt the plant’s defense response by suppressing crucial steps. they can make it so the plant feeds the pathogen.
What is phytoalexin, and how does it aid plants?
Phytoalexin is an antibacterial compound produced by plants to resist bacterial infections.
How do plants detect fungal infections?
Plants detect fungal infections by recognizing chitin, a structural component in fungal cell walls, triggering defense responses.
chitin
What is the significance of the nitrogen cycle in plants?
The nitrogen cycle provides plants with essential nitrogen in usable forms like nitrate or ammonium, crucial for growth.
you need nitrogen to make proteins and dna
What is mycorrhiza symbiosis?
Mycorrhiza is a mutualistic relationship where fungi assist plants in nutrient uptake (like phosphorus), and plants provide carbohydrates in return.
What are the two types of mycorrhiza?
The two types are endomycorrhiza, which penetrates cell walls, and ectomycorrhiza, which forms external associations.
How do plants resist necrotrophic pathogens?
Plants produce defensive chemicals and strengthen their cell walls to limit pathogen spread and damage.
they can also kill off any infected parts to save the rest
What is the role of appressoria in fungal infections?
Appressoria are specialized fungal structures used to penetrate plant tissues by generating high turgor pressure.
What is a haustorium, and which pathogens use it?
A haustorium is a structure formed by biotrophic pathogens to extract nutrients from living plant cells without killing them.
What is RNA interference (RNAi) in plants?
RNAi is a defense mechanism where plants degrade double-stranded RNA from viruses to prevent infection.
What are the physical defenses of plants?
Plants use barriers like cuticles, trichomes, and spines to deter herbivores and pathogens.
raphides zijn micro splinters die schade veroorzaken als je het op eet
What are induced plant defenses?
Induced defenses are activated in response to an attack, such as producing phytoalexins or reinforcing cell walls.
What are parasitic plants, and how do they affect crops?
Parasitic plants, like Striga, extract nutrients from host plants using haustoria, often reducing crop yields.
plants growing on other plants
What is the significance of quorum sensing in bacterial infections?
Quorum sensing allows bacteria to coordinate infection strategies based on their population density.
What is a hypersensitive response in plants?
The hypersensitive response is a localized cell death mechanism to prevent pathogen spread.
What is induced systemic resistance?
Induced systemic resistance is a plant-wide defense response triggered by beneficial microbes or minor infections.
How do viruses spread within plants?
Viruses move through plasmodesmata and vascular tissues to infect different parts of the plant.
What are biotic and abiotic stresses in plants?
Biotic stresses include pathogens and herbivores, while abiotic stresses involve drought, temperature extremes, and salinity.
What is translocation in plants?
Translocation is the movement of sugars and nutrients through the phloem to support growth and development.
What is the role of trichomes in plant defense?
Trichomes are hair-like structures that deter herbivores and reduce water loss.
How do pathogens use effectors to bypass plant defenses?
Effectors suppress specific plant immune responses, enabling pathogens to invade.
What are necrotrophic effectors?
Necrotrophic effectors are molecules that kill plant cells, creating nutrients for necrotrophic pathogens.
How can breeding increase plant resistance?
Breeding introduces resistance genes or strengthens general defenses to improve a plant’s ability to withstand pathogens.
What is the significance of systemic acquired resistance?
Systemic acquired resistance provides long-term immunity throughout the plant after a localized infection.
What is the role of cuticles in plant defense?
The cuticle is a waxy layer that protects plants from water loss and pathogen entry.
What are macro and micronutrients in plants?
Macronutrients like nitrogen, phosphorus, and potassium are needed in large amounts, while micronutrients like zinc and iron are required in smaller quantities but are equally essential for plant health.
macro stikstof fosfoor kalium, micro zink ijzer
What is the role of stomata in abiotic stress responses?
Stomata regulate gas exchange and water loss. During stress like drought, they close to minimize water loss while balancing carbon dioxide uptake.
How does pH affect nutrient availability in soils?
Soil pH influences the solubility of nutrients, with certain nutrients becoming unavailable to plants in highly acidic or alkaline conditions.
the roots swap out electrolytes with its own particles to extract them from the soil
What is the significance of the nitrogenase enzyme?
Nitrogenase catalyzes the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃) during nitrogen fixation, a critical process for plant nutrition.
What are cleistothecia and oöspores in fungal pathogens?
Cleistothecia are closed fruiting bodies of some fungi, while oöspores are thick-walled sexual spores of oömycetes, both aiding in survival.
How do nematodes manipulate plant roots?
Nematodes induce gall formation in roots and extract nutrients, often weakening the plant.
How does induced systemic resistance differ from systemic acquired resistance?
Induced systemic resistance is triggered by beneficial microbes, while systemic acquired resistance follows pathogen attack, both providing whole-plant immunity.
What is the role of secondary metabolites in plants?
Secondary metabolites like alkaloids and flavonoids defend against herbivores and pathogens and mediate environmental interactions.
How do plants use phytohormones in stress responses?
Phytohormones like abscisic acid, salicylic acid, and jasmonates regulate responses to biotic and abiotic stresses.
