PLANT SPEEDRUN

Which type of growth increases plant girth?

Secondary growth.

Which meristem causes secondary growth?

Vascular cambium and cork cambium.

Which meristem produces secondary xylem and phloem?

Vascular cambium.

What is the outer protective layer of young plants called?

Epidermis with cuticle.

What is the correct order from outside to inside in a dicot stem cross section?

Epidermis → phloem → xylem → pith.

If phloem cells in a stem are killed, what transport stops?

Sugar transport (phloem).

Does killing phloem stop water transport in xylem?

No, xylem transport continues.

Main driver of upward water movement in xylem?

Low water potential at top of xylem + cohesion of water molecules.

Theory explaining upward movement of water in xylem?

Cohesion-Tension theory.

What factor causes a sudden spike in transpiration rate in a graph?

Warm moving air over leaves.

Which environmental factors match: X = Humidity, Y = Temperature, Z = Light intensity?

C (Humidity, Temperature, Light intensity).

Pollination type for bright, colourful, scented flowers with nectar?

Insect pollination.

What is phototropism?

Growth of shoots toward light due to auxin movement to shaded side.

In coleoptile experiments, when does bending occur toward light?

When tip is exposed to light.

How does auxin cause bending toward light?

Accumulation on shaded side → cell elongation → bending toward light.

What is geotropism?

Growth response to gravity; roots positive, shoots negative.

Effect of auxin in shoots vs roots?

Stimulates elongation in shoots, inhibits elongation in roots.

Which hormone induces seed dormancy and closes stomata?

Abscisic Acid (ABA).

Which hormone promotes fruit ripening and leaf abscission?

Ethylene.

Which hormone promotes stem elongation and germination?

Gibberellin.

Which hormone promotes cell division and delays leaf senescence?

Cytokinin.

What happens to transpiration and water uptake in response to environment?

They follow same pattern, water uptake lags behind transpiration.

Which process produces microspore tetrads?

Meiosis of microspore mother cell.

What happens to microspores after meiosis?

Separate into pollen grains; each undergoes mitosis → tube nucleus + generative nucleus.

What happens to the generative nucleus after pollination?

Mitosis → 2 male gametes.

Steps of double fertilisation in angiosperms?

1 sperm + egg = zygote; 1 sperm + 2 polar nuclei = triploid endosperm.

Importance of double fertilisation?

Endosperm forms only if fertilisation occurs, prevents waste of nutrients.

After fertilisation, ovule becomes what?

Seed.

After fertilisation, ovary becomes what?

Fruit.

Advantage of seed dispersal?

Reduces competition with parent plant.

Wind-pollinated flower features?

No petals/nectar, smooth light pollen, feathery stigma.

Insect-pollinated flower features?

Coloured petals, sticky pollen, nectar, scent.

Can pollination occur without fertilisation?

Yes.

Can fertilisation occur without pollination?

No.

What is apical dominance?

Suppression of lateral buds by auxin from shoot apex.

How to increase plant bushiness?

Remove apical bud or use auxin inhibitor.