Plant Stress, Abiotic Disorders, and Plant Hardinesss Flashcards
Water Related Plant Stress
Symptoms: stunt growth, small leaves, older yellow leaves, bluish, flagging, wilting, leaf drop
Reasons: low or too much water, compaction, damaged roots, soil salinity, atmospheric temp, and frozen soil
root rot, damping off of seedlings, vascular wilts can be results of too much water
Salinity Related Plant Stress
Symptoms: burnt leaf tips and chlorosis
Reasons: over fertilizing, water runoff, accumulate salts in soil, root damage, accumulate in leaf tips
Nutritional Related Plant Stress
Symptoms: interveinal chlorosis, marginal chlorosis, yellowing, and dwarfing of tissues
Reasons: using synthetic and micronutrient fertilizer, acidic soil, phosphorus toxicity (bonemeal)
Nutrient Mobility Related Plant Stress
mobile: in leaf tissues and can be transported to the newest growth when low availability, appears in old leaves
immobile: unable to be transported to new growth when availability is low, appears in newer leaves
Plant Stress
changes in colouration
necrotic/dead tissues
changes in normal development
internal and external factors
biotic and abiotic factors
Homeostasis
equilibrium in factors that contribute towards stable physiological processes, which plant stress can adversely disrupt.
Internal (Endogenous) Stressors
water, chemical/nutritional, and systemic pathogenic disease
External (Exogenous) Stressors
environment (temp, light, humidity, air, movement, pollution)
herbivory
mechanical (physical damage)
non systemic pathogenic disease
Biotic Factors
insects, fungi, bacteria, viruses
symptoms/signs: damage pattern non uniform, damage spreads over time, signs are visible.
Abiotic Factors
environmental stress and mechanical factors
symptoms/signs: damage pattern uniform, doesn’t spread over time, no signs visible.
Hardiness of Tissues
gradual cooling=hardening tissues
the hardier the plant, the better protected they are from cold injury.
Vernalization
ability to flower based on necessary exposure to cold, expressed in chill hours
Cold Stratification
necessary period of cold exposure that seed needs to break dormancy
artificial cold stratification: fridge
3 Categories of Cold Sensitivity
chilling sensitive
frost sensitive
cold hardy
Chilling Sensitive
injured by cold temps above 0 degrees C
either entire plant is sensitive or only the fruit/flowers
i.e. tropical plants
