Plant Diseases And Defences

Question 1

What do plants need from the soil?

Answer 1

Mineral ions

Question 2

If a plant does not have enough mineral ions, what can happen?

Answer 2

Plants suffer deficiency symptoms

Question 3

What are nitrates needed for in plants, and what happens if there is a lack of them?

Answer 3

Nitrates are needed to make proteins and therefore for growth. A lack of nitrates causes stunted growth

Question 4

What are magnesium ions needed for in plants, and what can happen if they aren’t enough?

Answer 4

Magnesium ions are needed for making chlorophyll which is needed for photosynthesis plants without enough magnesium suffer from chlorosis and have yellow leaves.

Question 5

What are aphids?

Answer 5

An insect that can cause huge damage to plants

Question 6

What are the signs that a plant has a disease?

Answer 6

Stunted growth, spots on the leaves, patches of decay (rot), abnormal growth (e.g. lumps), malformed stems or leaves, discolouration

Question 7

What 3 types of defences can plants have?

Answer 7

Mechanical, physical, and chemical

Question 8

Most plant leaves and stems have a what which provides a barrier to stop pathogens from entering?

Answer 8

Waxy cuticle

Question 9

How does the waxy cuticle defend a plant?

Answer 9

It creates a barrier to stop pathogens from getting in.

Question 10

What 3 things acts as a physical barrier in a plant?

Answer 10

Waxy cuticle, cell walls, layers of dead cells around stems (e.g. bark on trees)

Question 11

What 2 chemical defences can plants have?

Answer 11

Some can produce antibacterial chemicals which kill bacteria. Other plants produce poisons which can deter herbivores

Question 12

What are 3 mechanical defences that plants have?

Answer 12

Some plants have adapted to have thorn and hairs which stop animals from touching and eating them.

Other plants have leaves that droop or curl when something touches them. This means they can prevent themselves from being eaten by knocking insects of themselves and moving away from things.

Some plants can mimic other organisms.For example the passion flower has bright yellow spots on its sleeves which look like butterfly eggs. This stops are the butterflies from laying their eggs there.

Question 13

What term is used to describe yellow leaves on a plant?

Answer 13

Chlorosis