Plant Anatomy and Physiology

Flashcards for Plant Anatomy and Physiology Lecture

Photosynthesis

Turns sunlight into food and generates oxygen.

Light-dependent reactions

Reactions that rely on direct light energy.

Light-independent reactions

Reactions that don't directly require light.

ATP

Activated form of energy.

ADP

Deactivated form of energy with two phosphates.

NADPH

Temporary storage for small amounts of energy.

Rubisco

Carbon dioxide is joined into a big organic molecule by this enzyme.

C4 photosynthesis

Separates carbon capture from the Calvin cycle, better when temperature is high or C02 is low.

Domestication

Adapting wild plants/animals for human use, reflecting genetic changes.

Artificial Selection

Humans interfere with crop evolution.

Monocots

One cotyledon in the seed.

Dicots (Eudicots)

Two cotyledons in the seed.

Primary meristems

Lengthen plant (shoot/root apical meristems).

Secondary meristems

Widen plant (cambiums).

Dermal

Outermost tissue system.

Vascular

Innermost, carries water/sugars.

Ground tissue

Tissue between dermal and vascular.

Phloem

Moves sugar.

Xylem

Moves water.

Petiole

Connects leaf to stem.

Stomata

Pores that let in carbon dioxide and let out water and oxygen, made of two guard cells.

Sporophyte

Diploid stage: makes spores.

Gametophyte

Haploid stage: makes gametes.

Complete flowers

Have petals, sepals, stamen (male), and carpals (female).

Incomplete flowers

Lack parts (e.g., eucalyptus without petals).

Perfect flowers

Have both male and female parts.

Imperfect flowers

Only have male or female parts.

Monoecious

Male and female flowers on the same plant (e.g., zucchini).

Dioecious

Male and female flowers on separate plants (e.g., cannabis).

Fruits

Enlarged ovaries, aid in dispersal (wind, water, animals).

Germination

Seed grows into a plant when conditions are suitable (water, oxygen, temperature, light).

Epigeal germination

Cotyledons emerge above ground.

Hypogeal germination

Cotyledons remain below ground.

Dormancy

Mechanism to prevent germination in unsuitable conditions.

C4 photosynthesis

Modification to overcome Rubisco's inefficiencies.

Xylem

Carries water and mineral nutrients from roots to shoots (one direction).

Phloem

Carries sugars from leaves to the rest of the plant (multidirectional), from sources (sugar makers) to sinks (sugar users).

Sieve elements

Have sieve plates at the end with sieve pores on the side which make up the continuous tubes; lack nuclei, most other organelles, and cytoplasm.

Companion cells

Support sieve elements by handling metabolic functions, including DNA transcription, translation, water storage, and phloem loading.

Symplastic route

Water travels through cells via plasmodesmata.

Apoplastic route

Water travels through cell walls (porous) until it reaches the endodermis.

Casparian Strip

Border control for the xylem.

Macronutrients

Needed in larger amounts.

Micronutrients

Needed in smaller amounts.

Sources

Tissues that make more sugars than they use (net photosynthesizers), e.g., mature leaves.

Sinks

Tissues that use more sugars than they make, e.g., seeds, fruits, roots, immature leaves.

Diffusion

Movement of a substance from high to low concentration.

Osmosis

Movement of water across a semipermeable membrane to equilibrate concentrations.

Carbohydrate Partitioning

Sugars compete for available sugars.

Source strength

How much net sugar a source produces.

Sink strength

How good a sink is at taking up sugar.

Phototropism

Auxin molecules are unevenly distributed across the plant tip.

Gravitropism

Growth in response to gravity.

Apical Dominance

Auxin produced at the shoot apex inhibits lateral bud growth.

Ethylene

Simple, volatile hormone involved in fruit ripening, leaf abscission, and flower senescence.

Gibberellins

Stimulate cell division and elongation, especially in internodes.

Cytokinins

Promote cell division and growth.

Abscisic Acid (ABA)

Stress hormone involved in response to abiotic stresses like drought and salt.

Red Light Sensing and Flowering Time

Plants flower in response to day length (photoperiod).

Florigen (FT protein)

Protein that moves from the leaf to the shoot apex to trigger flowering.