Photosynthesis and Plant Hormones

These flashcards cover key concepts related to photosynthesis, plant hormones, and their functions as discussed in the lecture.

What is the primary function of photosynthesis?

To convert light energy into chemical energy stored in glucose.

What are the three main pathways of photosynthesis?

C3 pathway, C4 pathway, and CAM pathway.

Which plant hormone is primarily involved in stem elongation?

Gibberellins.

What is the role of auxins in plant development?

Auxins promote cell elongation and inhibit the growth of axillary buds.

Define photoassimilate distribution.

The process by which photosynthates (sugars) are transported and distributed within the plant.

What effect does ABA (abscisic acid) have on stomata?

ABA induces stomatal closure to reduce water loss during drought conditions.

What is the main byproduct of the light reactions of photosynthesis?

Oxygen (O2).

What is the main enzyme involved in the C3 photosynthesis pathway?

Rubisco (ribulose bisphosphate carboxylase/oxygenase).

What type of plants perform C4 photosynthesis?

Plants like corn, sugarcane, and sorghum that usually thrive in high temperatures.

How do CAM plants differ from C3 and C4 plants?

CAM plants fix CO2 at night and store it as malate, releasing it during the day.

What is the primary transport tissue for photosynthates in plants?

Phloem.

What is the impact of high CO2 concentration on Rubisco activity?

It increases the efficiency of carbon fixation while limiting photorespiration.

What happens during photorespiration?

O2 is fixed instead of CO2, leading to a loss of energy and carbon.

What are cytokinins primarily involved in?

Promoting cell division and growth in plant tissues.

In what part of the plant is gibberellin primarily synthesized?

In developing stems, leaves, and seeds.

What triggers stomata to open?

Light and low carbon dioxide concentrations trigger stomatal opening.

Which plant hormone promotes lateral bud growth?

Cytokinins.

What is the significance of the C4 pathway in photosynthesis?

It allows plants to efficiently capture CO2 and minimize water loss at high temperatures.

How do plants primarily transport water?

Through the xylem tissue.

What is the role of guard cells in stomatal function?

Guard cells control the opening and closing of stomata to regulate gas exchange and water loss.

What are the consequences of ringbarking a tree?

It disrupts phloem flow, leading to the death of the roots and upper plant parts.