Exam 2 Flashcards
Cytokinins are responsible for promoting cell elongation in stems.
False
Abscisic acid improves fruit quality in grapes by regulating sugar accumulation.
True
2, 4-D is a synthetic herbicide that kills broadleaf weeds by mimicking the plant growth hormone auxin.
True
Plant hormones are chemical messengers that regulate plant growth development and responses to stimuli.
True
Gibberellins can cause grapes to elongate and become oval-shaped.
True
Cytokinins are used in horticulture to enhance fruit set and size in tomatoes.
True
Ethylene is involved in the process of postharvest handling of climacteric fruits.
True
Abscisic acid is widely used to break seed dormancy in agriculture.
False
Cytokinins are used to induce rooting in tissue culture applications.
False
Auxins play a significant role in phototropism and gravitropism.
True
Gibberellins are used to promote uniform germination in seeds.
True
Cytokinins promote cell division and delay leaf senescence.
True
Gibberellins are primarily involved in the abscission of leaves and fruits.
False
Ethylene is a gaseous hormone that facilitates fruit ripening.
True
Plant hormones are also known as phytohormones.
True
Gibberellins are used in agriculture to enhance fruit size in grapes.
True
Abscisic acid regulates stomatal closure during water stress conditions.
True
Ethylene is used to delay ripening in non-climacteric fruits.
False
Auxins are commonly used in horticulture to stimulate rooting in plant cuttings.
True
Major Plant Hormones are:
Auxins
Gibberellins
Cytokinins
Abscisic Acid
Ethylene
True
The process of vernalization is triggered by temperatures above 50°F.
False
Fruit trees exposed to insufficient chilling hours may produce more fruit.
False
The length of the chilling period does not influence the timing of flowering in vernalization-dependent crops.
False
Temperature is a critical environmental factor affecting plant growth and development.
True
Dormancy is typically broken by exposure to light not cold temperatures.
True
Chilling hours vary depending on the species and cultivar of the plant.
True
A damage caused by low non-freezing temperatures (32–45°F) is called chilling injury.
True
The minimum, optimum, and maximum temperatures for plant growth are called cardinal temperatures.
True
Chilling hours are measured in hours of exposure to temperatures below freezing.
False
Insufficient chilling hours can lead to delayed flowering and poor fruit set.
True
Limited water exacerbates the effects of heat stress.
True
Dormancy is a state of inactivity that protects plants from cold damage.
True
Wind Machines mix warm upper air with cold surface air during radiation freezes and offer crop protection.
True
Plants that are exposed to inadequate chilling hours might not experience full bud break.
True
Plants requiring chilling hours will flower later if they experience too many chilling hours.
False
A damage caused by ice formation in tissues (<32°F) is called freezing damage.
True
For dormancy to be broken, all plants must experience a minimum of 1,000 chilling hours.
False
Radiation freeze occurs on clear, calm nights when the ground loses heat rapidly, cooling the surface below freezing.
True
Tree Wrapping protects young trees from advective freezes.
True
Cold stress causes membrane damage, reduced photosynthesis, and yield loss.
True
Cold stress affects plants by causing cellular dehydration and metabolic disruption.
True
Irrigation provides latent heat during freezing as water transitions to ice.
True
Chilling hours accumulate when the temperature is consistently below freezing.
False
It has been estimated that because of stress resulting from climatic and soil conditions (abiotic factors) that are suboptimal the yield of field-grown crops in the United States is only 22% of the genetic potential yield.
True
Advection freezes occurs when we have overcast skies and strong winds.
True
Vernalization only affects the vegetative growth of plants.
False
Frequent and shallow watering during heatwaves is a common strategy to mitigate heat stress.
True
Smudge pots were an old way to warm up the orchard/grove by burning oil.
True
Low-chill cultivars are often bred for areas with warmer climates.
True
The process of dormancy involves a plant’s physiological response to warm temperatures.
False
A warm winter can result in inadequate chilling hours and delayed bud break in temperate crops.
True
Chilling hours are accumulated in the temperature range of 32°F to 45°F.
True
Heat stress reduces pollen viability and fruit set.
True
Vernalization requires exposure to cold temperatures to break dormancy.
False
Chilling hours are essential for breaking dormancy in most temperate fruit trees.
True
Peach trees have a low chilling requirement compared to apples.
True
Heat stress in plants can cause reduced photosynthesis and yield loss.
True
Apple trees require more chilling hours than peach trees.
True
Chilling hours do not influence flowering in subtropical crops like citrus.
True
Chilling hours are only important for fruit trees and not for vegetables.
False
Far-red light inhibits stem elongation and is unnecessary for most plants.
False
Short-day plants can be forced to flower by extending daylight using artificial lights.
False
Phytochromes are photoreceptor proteins that detect red and far-red light.
True
Light quantity is measured in terms of PAR and expressed as PPFD or DLI.
True
LEDs can be used to manipulate both light quantity and light quality for plant growth.
True
Photoperiod manipulation is commonly used to control flowering in horticultural crops.
True
Supplemental lighting is commonly used in greenhouses to compensate for low light during winter.
True
Photoperiodism refers to a plant’s ability to respond to changes in temperature.
False
Blue light is essential for stomatal regulation and compact plant growth.
True
Lettuce is an example of a short-day plant.
False
Poinsettias flower in the winter when the days are short and the nights are long.
True
Seasonality does not influence the quality of light plants receive.
False
Summer provides higher DLI compared to winter due to longer days and stronger sunlight.
True
Plants use circadian rhythms to optimize photosynthesis and flowering times.
True
Day-neutral plants require a specific photoperiod to flower.
False
Changes in leaf chlorophyll concentration represent a light acclimatization strategy.
True
Indoor farming uses LED lights to mimic natural light conditions for crops.
True
Plants under low light conditions will often exhibit shorter stems and smaller leaves.
False
Light quality refers to the total amount of light energy received by plants.
False
Phytochromes regulate flowering and seed germination in plants.
True
Accurate management of light quantity and quality can improve yields.
True
Day-neutral plants like tomatoes are unaffected by photoperiod manipulation.
True
Chrysanthemums require long-day photoperiods to induce flowering.
False
Red light primarily promotes photosynthesis and flowering.
True
Plants grown under high DLI conditions generally have higher photosynthetic rates and biomass.
True
In order to flower, poinsettias need to be kept in complete darkness for 12–15 hours a day, for 2-3 months.
True
DLI stands for Daily Light Integral and represents the cumulative PAR a plant receives over a day.
True
Lettuce farming in vertical systems relies on manipulating the light spectrum.
True
Excessive light can result in photoinhibition and leaf scorching.
True
PAR measures the photosynthetically active light.
True
Pfr is the inactive form of phytochrome.
False
Short-day plants flower when the nights are longer than a critical length.
True
Light acclimatization is the process by which plants adapt to changes in light intensity and quality.
True
Chrysanthemums flower in response to shorter nights.
False
In vertical farming systems adjusting the ratio of blue and red light can optimize lettuce growth.
True
Seasonal variations in light quality can affect flowering and fruiting cycles.
True
The effects of light quality on plant growth are uniform across all species.
False
Photoperiod can be defined as the physiological reaction of plants to the length of day and night.
True
Light quantity influences flowering, fruiting, and nutrient uptake
True
Shading nets can help prevent excessive light stress on plants.
True
