Plant Physiology Quiz

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Questions and Answers

What is the term used for the areas in a plant where sugars are produced or stored?

Sources (correct)

Sinks

Translocation zones

Phloem vessels

Which tissue is primarily responsible for the transport of assimilates in plants?

Xylem

Phloem (correct)

Epidermis

Cortex

What type of plant movement is determined by the direction of the environmental stimulus?

Nastic movement

Phototropism (correct)

Geotropism (correct)

Thigmotropism

During translocation, what is the primary function of the sink locations in a plant?

To store and utilize sugars Signup and view all the answers

Which of the following is an example of nastic movement?

Epinasty Signup and view all the answers

Which of the following statements correctly defines essential nutrients for plants?

They're necessary for both vegetative and reproductive stages. Signup and view all the answers

What is the main process by which fluids move upwards from the roots to the leaves in a plant?

Transpiration Signup and view all the answers

What mechanism allows plants like cacti to preserve water?

Closing stomates at night Signup and view all the answers

Which adaptation helps plants survive in environments with limited light penetration?

Abscission of leaves Signup and view all the answers

What term describes the condition of deterioration with age in plants?

Senescence Signup and view all the answers

Which of the following is NOT an example of a physiological adaptation in plants?

Presence of Pneumatophores Signup and view all the answers

What particular adaptation helps some plants respond to sudden temperature changes?

Heat-shock proteins Signup and view all the answers

Which term refers to the upward bending of plant parts in response to stimuli?

Hyponasty Signup and view all the answers

What characterizes plant growth?

It results from cell division and enlargement. Signup and view all the answers

Which type of growth is termed 'determinate'?

Growth of organs that stop after reaching a certain size. Signup and view all the answers

How do plants differ from animals in terms of growth?

Plants exhibit indeterminate growth throughout their life. Signup and view all the answers

What is differentiation in plants?

The transformation of undifferentiated cells into specialized cells. Signup and view all the answers

What is dedifferentiation?

When mature cells lose specific characteristics and become undifferentiated. Signup and view all the answers

What is a key characteristic of the growth curve of plants?

It exhibits a sigmoid pattern. Signup and view all the answers

What defines the indeterminate growth of plants?

Growth that continues for the entirety of the plant's lifespan. Signup and view all the answers

Which statement is true regarding cell differentiation?

Differentiated cells can become undifferentiated through dedifferentiation. Signup and view all the answers

What adaptation allows the Azolla plant to flow easily in water?

Reduced roots and absence of root hairs Signup and view all the answers

What does the Law of Limiting Factors state?

Output is determined by the least productive resource Signup and view all the answers

What happens according to the Law of Diminishing Returns?

Beyond an optimal level, additional factors yield smaller output increases Signup and view all the answers

What is photosynthesis primarily responsible for in plants?

Converting sunlight into sugar Signup and view all the answers

What does the First Law of Thermodynamics state?

Energy cannot be created or destroyed, only transformed Signup and view all the answers

What characterizes the Second Law of Thermodynamics?

Entropy increases over time, and heat flows from hot to cold Signup and view all the answers

Which of the following forms of energy is considered light?

Electromagnetic radiation, including X-rays and microwaves Signup and view all the answers

What is primarily produced by cellular respiration in plants?

ATP Signup and view all the answers

How does turgor pressure influence guard cells?

It allows them to expand or contract, opening or closing stomates. Signup and view all the answers

What primarily controls turgor pressure in plants?

Salt uptake and extrusion Signup and view all the answers

Which environmental factor increases the rate of transpiration by warming the leaf?

Temperature Signup and view all the answers

How does high humidity affect transpiration rates?

It reduces transpiration due to decreased water vapor gradient. Signup and view all the answers

What happens when a plant's water loss is not compensated by soil water absorption?

The turgor loss causes the stomata to close, reducing transpiration. Signup and view all the answers

What is translocation in plants?

The transport of assimilates from sources to sinks. Signup and view all the answers

Which factor contributes to a higher transpiration rate?

Greater leaf surface area Signup and view all the answers

What effect does wind have on the rate of transpiration?

Wind carries away humid air, replacing it with drier air, increasing transpiration. Signup and view all the answers

What percentage of water loss is attributed to stomatal transpiration?

90% Signup and view all the answers

Which type of transpiration accounts for the least percentage of water loss?

Lenticular transpiration Signup and view all the answers

What is a significant impact of transpiration on plant temperature?

It cools the leaf below the ambient temperature. Signup and view all the answers

Which phenomenon primarily drives transpiration in plants?

Continuum of water in the plant Signup and view all the answers

What element primarily enables the adherence of water molecules to the xylem?

Polarity of water Signup and view all the answers

How does transpiration contribute to nutrient uptake in plants?

It draws nutrients up from the root zone to the shoot. Signup and view all the answers

What role do guard cells play in transpiration?

They control the opening and closing of stomata. Signup and view all the answers

What is the daily water loss for a tropical palm?

500 liters/day Signup and view all the answers

Study Notes

Crop Science Module 4: Physiological Processes Affecting Crop Production

This module covers physiological processes affecting crop production, specifically focusing on concepts of growth and development, plant movements/crop adaptation, and plant life processes (photosynthesis, respiration, transpiration, and translocation)

Concepts of Growth and Development

Plant growth is an irreversible change in cell and organ size, resulting from cell division and enlargement.
Plant development involves progression from seed germination to maturation.
Determinate growth occurs when an organ or part stops growing after reaching a specific size (e.g., leaves, flowers).
Indeterminate growth means cells of an organ, part, or organism continue dividing indefinitely (e.g., plants as a whole).
Plant growth follows a sigmoid curve: lag phase, exponential phase, and stationary phase.

Concepts of Growth and Development (cont.)

Differentiation is the process where undifferentiated cells transform into specialized cells with distinct morphological and physiological characteristics.
All plant cells have the same genetic makeup, but differentiation causes differences in morphology and physiology.
Dedifferentiation is the opposite of differentiation; mature cells revert to undifferentiated states, often in response to damage, and can then re-differentiate.
Unlike animals, plants exhibit indeterminate growth, meaning plants continue growing throughout their lifespan.

Plant Movements/Crop Adaptation

Tropisms are plant movements where the environmental stimulus determines the direction of the movement.

Tropisms (Examples)

Phototropism is movement in response to light.
Geotropism (or Gravitropism) is movement in response to gravity and, for example, root growth down.
Heliotropism (Solar tracking) refers to the flat blade of a leaf always being nearly at a right angle to the sun throughout the day.

Crop Adaptation

Adaptations in morphology include pneumatophores (breathing organs) or modified roots—for example, in trees growing in marshes and modified petioles to float, in water hyacinth
Adaptations in physiology include closing stomates (pores) to reduce water loss, abscised leaves to reduce loss, and abscission of branches to reduce competition in forested areas where light penetration is limited

Biochemical adaptations

Mutations in target genes can lead to glyphosate resistance in weeds.
Plants can increase heat-shock proteins in response to sudden suboptimal or supraoptimal temperatures.

The Law of Minimum

Liebig's Law of the Minimum states that if one growth factor (nutrient) is deficient, plant growth is restricted even if other factors are adequate.
Growth is improved by increasing the level of the deficient factor.

The Law of Optima and Limiting Factors (Blackman)

This is a modification of the Law of Minimum.
A process's rate is limited by the slowest factor, often involving various factors such as CO2, light, chlorophyll, water, and temperature (optimal ranges exist).

The Law of Diminishing Returns

This economic concept predicts that adding an additional production factor (like fertilizer or water) after reaching optimal capacity will produce smaller increases in output.

Plant Life Processes (Photosynthesis)

Photosynthesis (PS) is the process in which plants use sunlight to produce sugar; cellular respiration converts this sugar into ATP (energy).
This process uses chlorophyll to convert unusable sunlight energy into usable chemical energy.
The overall reaction of PS is: 6CO2 + 12H2O + light --> C6H12O6+ 6O2 + 6H2O
raw materials = CO2 and water with light's energy
products = glucose and oxygen

Plant Life Processes (Photosynthesis) (Cont.)

Leaves' anatomical structures are designed for efficient PS (e.g., large surface area, vascular system, pigments for light absorption).

Plant Life Processes (Respiration)

Respiration is an enzyme-assisted process to break down food into CO2 and H2O releasing energy.
It's critical for the metabolic reactions, like photosynthesis. Glucose entirely converted into CO2. Total yield of ATP = 38 ATPs
The first process , glycolysis, is an anaerobic process that takes place in the cytoplasm. A six carbon sugar (glucose) is broken down into two three-carbon molecules of pyruvic acid and a small amount of ATP energy.
Pyruvic acid enters the mitochondria, where the Krebs cycle and the electron transport chain are involved creating more ATP energy.

Plant Life Processes (Transpiration)

Transpiration is the loss of water vapor from plant parts (e.g., leaves) through stomata (pores).
Different types of transpiration—lenticular, cuticular and stomatal— exist.
Factors affecting transpiration include environmental factors such as light, temperature, humidity, and wind, and internal physiological factors such as the size of stomata, the size and surface area of the leaf, and the construction of the xylem vessels.
importance: Plants lose a substantial amount of water throughout their lives via transpiration. Its importance includes cooling the plant, drawing nutrients upwards in xylem and creating pressure to move water,

Plant Life Processes (Translocation)

Translocation is the transport of assimilates (photosynthesis's products) from the source to the sink (storage or growth areas). Assimilates travels through the phloem vessels.
Transpirational stream is the process of moving nutrients upwards in xylem of plants, from roots to shoots.

Nutrient Requirements

Essential nutrients are needed for completion of vegetative and reproductive stages, and their deficiency is correctable only by the specific essential nutrient; there are no substitutes.

Nutrient Deficiencies (Specific Examples)

Deficiencies of nitrogen, phosphorus, sulfur, magnesium, calcium, and iron can cause specific visual symptoms in plants.

Soil Fertility Decline

Reasons for soil fertility decline include crop removal, soil erosion, and the conversion of nutrients into unavailable forms (e.g., insolubility formed from combinations with other elements, transformation by microbes, volatilization, and leaching).

Plant Reproduction

Sexual reproduction uses seeds, while asexual reproduction uses other parts of the crop (excluding seeds).

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Description

Test your knowledge on plant physiology with this quiz. Explore important concepts such as sugar production, nutrient transport, and plant adaptations. Each question challenges your understanding of how plants interact with their environment.