plant physiology

Question 1

Basic anatomy

Answer 1

• Root
• Stem
• Leaves
• Flower
• Fruit

Question 2

Function of the root

Answer 2

Anchoring plant in soil and preventing it falling over. Absorbing water and salts which is needed for making food.

Question 3

Root systems

Answer 3

• Primary root with many lateral branch roots. Tap-root system
• No primary root, just all over the place. Fibrous root system

Question 4

Bottom of root

Answer 4

Called root cap. Continually replaced as fast as they are worn away when the root tip is pushed through the soil.

Question 5

Root hairs

Answer 5

Extra layer around root with fine hairs. Growing between soil particles and sticking closely to them. The root hairs take up water from the soil by osmosis and absorb mineral salts by active transport.

Large number of root hairs increases absorbing surface of root system.

Question 6

Structure of inside of root

Answer 6

Main tunnels:

**Xylem **& Phloem

Water enters via osmosis, nutrients enter via active transport. Glucose used for this. Gives off o2.

Question 7

Leaf anatomy

Answer 7

Leaf attached to stem by leaf stalk which continues into the leaf as a midrib. From midrib network of veins containing xylem/pholem transporting water n salts.

Question 8

Leaf epidermis

Answer 8

Epedermis is a single layer of cells on the upper and lower surfaces of the leaf. It helps to keep its shape. They reduce evaporation from leaf and prevent bacteria and fungi from entring. Thin waxy layer of epedermis is called cuticle.

Question 9

Leaf stomata

Answer 9

sing. stoma.

A pair of guard cells surrounding an opening.

Stomata open daytime and closed nighttime. Open allows for carbon dioxide to diffuse into the leaf. Closed co2 supply is cut off and photosynthesis stops.

Question 10

Leaf mesophyll

Answer 10

Tissue between upper and lower epidermis is

Question 11

Leaf veins

Answer 11

water brought to mesophyll via veins. the mesophyll takes in water via osmosis.

sugars passed to phloem and carried to stem.

Question 12

Stem epidermis

Answer 12

Same as leaf epidermis. In wooden stems, epidermis is replaced by bark, which is many layers of dead cells.

Question 13

Stem Vascular bundles

Answer 13

Group of specialized cells which conduct water, dissolved salts and food up or down the stem. Food substances travel in **pholem. **Water and salt travel in xylem. Xylem elongated tubes called vessels and pholem elongated tubes are called sieve tubes.

Question 14

Stem cortex and pith

Answer 14

Tissue between vascular bundle and epidermis is cortex. stores starch. the central tissue of the stem is called pith. packing tissue helping with structure.

Question 15

Flower anatomy

Answer 15

Sexual reproduction organs of flower. Flowers are hermaphroditic.

Female parts: style, stigma, ovary = pistil

The stigma is collection place for pollen (male gamete). very sticky.

_Male parts: _**stamen, anther. **anther is a pod of gametes, gives pollen. stamen stalk is filament.

Peduncle: stock of flower.

Sepal: not leaves. protects flowers yet to bloom.

Question 16

fruit

Answer 16

fertilized ovary of plants embryo.

not all fruit is edible.

parts of fruit:

seed: endosperm, embryo, seed coat.

pericarp: endocarp, mesocarp, exocarp.

Question 17

mechanisms for seed dispersal

Answer 17

• Parachute (dandelion)
• Winged (sycamore)
• Explosive (lupin)
• Hooked fruit (burdock/kardborre)
• Succulent fruits (fruit you eat. seed survives through stomach).

Question 18

adaptations to environment

Answer 18

spikes to ensure animals doesn’t take the cactus’ water.

Question 19

pollination

Answer 19

2 types:

**cross-pollination: **different genetic material (different plant carried by animal)

self-pollination: same genetic material. same plant.

Question 20

co-evolution of plans and pollinators

Answer 20