abiotic stresses
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What are the main climate and environmental challenges for agriculture?
• Increased temperature • Droughts • Salinity • Pollution • Flooding • Increased population • Soil impoverishment • Soil erosion • Disease and pests
Why is there a need for a new green revolution?
• Due to increased human population and reduced crop productivity, a new green revolution is needed. • This requires developing stress-resilient crops, dependent on a better understanding of plant physiology.
What types of environmental stresses affect plants?
• Abiotic stresses: temperature, water, salinity, pollution, etc. Stress can be continuous or chronic, causing 30-50% crop loss. • Responses: Stress-specific or general, localized or systemic, short-term (minutes) to long-term (weeks).
What are the two main types of plant stress responses?
• Resistance: Adaptation of physiology and metabolism to reduce stress effects. • Avoidance: Perceiving stress but tolerating it by reducing growth.
What are the three types of plants based on stress responses?
• Stress-sensitive: Inadequate response to stress. • Stress-resistant: Adequate responses to mitigate stress effects. • Stress-tolerant: Constitutively prepared for stress.
What is water stress and how does it affect plants?
• Caused by critical water deficit leading to reduced growth. • Physiological effects: Osmotic imbalances, reduced photosynthesis, membrane porosity, etc. • Morphological responses: Stomatal closure, leaf wax production, root extension.
What are some adaptations of plants to water stress?
• Metabolism reduction upon water receipt. • Evasion: Short life cycles, water-dependent leaf production. • Root adaptations: Long roots for deeper moisture.
What are the effects and adaptations of plants to salt stress?
• Salt stress leads to osmotic imbalances and cellular toxicity. • Adaptations: Osmoregulation, bladder cells for salt storage, salt-excreting glands.
How do plants respond to temperature extremes (high and low)?
• High temperature: Stomatal closure, protective proteins, saturated fatty acids. • Low temperature: Dormancy induction, compatible solute production, unsaturated fatty acids.
What types of pollution stress affect plants and their responses?
• Air pollution: Inhibits stomatal movement, reduced photosynthesis. • Soil pollution: Inhibits photosynthesis and growth, toxic but some species thrive on contaminated land. • Adaptations: Detoxification enzymes, selective nutrient uptake, phytoremediation, phytomining.