plant responses

What name is given to the growth response of plants to light?

How does this growth response benefit plants?

Name any other type of growth response in plants.

Gro wth regulators are important in plants. Explain the term growth regulator.

Describe the mechanism of any one plant growth response to an external stimulus.

Give one example of the use of plant growth regulators, e.g. by horticulturists.

Plants have adaptations that help in protection. Give any two methods plants use to protect themselves.

Answer the following based on investigating the effect of IAA on plant tissue.

1. Name a suitable plant tissue you used.

2. Describe how you measured the effect of IAA on plant tissue.

Name the substance that causes the change in mass of the plant tissue.

What term is given to the movement in and out of the plant tissue of the substance you named in part (a) (i) above?

What term is used to describe the condition of the plant cells that have been soaked in the 0 g/100 cm3 sugar solution?

Explain how plant cells maintain the condition you named in part (a) (v) 1. above.

Explain in detail why the mass of the plant cells reduces in the 12 g/100 cm3 sugar solution.

What do you think would happen to an animal cell in the 0 g/100 cm3 sugar solution?

State a location in plants where growth regulators are produced.

How are growth regulators transported around a plant?

Name a suitable plant tissue you used in this investigation.

Describe how you set up the investigation on the effect of IAA growth regulator on a plant tissue

Describe how you measured the effect of IAA on the plant tissue.

Describe any one result of your investigationof IAA experiment

describe one safety precaution you took in carrying out this investigation of IAA experiment

tropism

2 examples of tropisms in plants

describe in detail the mechanism of one plant tropism

give 2 uses of commercial plant growth regulators

germination

dispersal

dormancy

how does dormancy in seeds benefit plant species

2 roles of water in process of germination

2 possible food stores in seeds

3 factors necessary for germination

Answer the following questions in relation to an investigation you carried out to show digestive activity during seed germination.       

State whether your used starch agar or skimmed milk (protein) agar. 

Why were the seeds soaked in water prior to the investigation? 

Describe how you further prepared the seeds and added them to the agar plate(s).  

Under what conditions did you store the plate(s) containing the seeds to allow  germination to occur? 

How did you test to show that digestion had occurred? 

State the result that showed digestion had occurred.

Where precisely in plants are auxins produced? 

What is the precise benefit to the plant that the shoot is positively phototropic?

Give two uses in agriculture or horticulture of plant growth regulators.

State two reasons why the action of an auxin is considered to be similar to   the action of a hormone in the human body.

note on phototropism in plants

auxin

a precise location in plants where auxins are produced

example of an inhibitory function of auxin

exactly how does an unequal concentration of auxin in the elongation zone affect the growth of a shoot and a root

suggest what could cause unequal concentration of auxin in a shoot and a root

state 2 uses in horticulture of auxins or relate compounds

reasons why dispersal is important to plants

way in which knowledge of seed dormancy is useful to humans

 Other than water, name two essential environmental requirements for successful germination of seeds.

What is the role of digestion and the role of respiration in seed germination? 

The graph below shows variations in the dry mass of peas over a period of time after germination. Give a reason for:  

1.The initial decrease in mass          

2. The subsequent increase in mass.    

Place the letter X on your diagram, to show the part of the leaf in which most photosynthesis occurs and explain why it occurs mostly there. 

State two other ways in which the leaf is well adapted for photo synthesis.

 Name three substances which are involved in leaf metabolism and which pass  through the stomata. 

The concentration of which gas influences the diameter of the stomata?

dormancy

how does digestion contribute to successful seed germination

State whether you carried out this investigation using starch agar or skimmed milk (protein) agar.

Name a type of enzyme in the seed that carries out this digestion.

Why were the seeds soaked in water at the start of the investigation?

When preparing the seeds, they were also split and sterilised.

Why is it recommended that you sterilise the seeds?

When preparing the seeds, they were also split and sterilised.

Why were the split seeds placed open-side down on the agar?

How did you know that digestive activity had occurred on one of your investigation plates?

How did you know that digestive activity had not occurred on one of your investigation plates?

What name is given to the regions of plants which secrete growth regulators?

Give an example of a growth regulator which has a negative effect on plant growth.

thigmotropism.

Following fertilisation, from precisely which part of the flower is the seed formed?

What is meant by the term monocotyledonous?

Name two biomolecules stored in endosperm or cotyledon tissue.

Give one way knowledge of seed dormancy has been useful to humans.

Name a part of a seed in which food for germination is stored.

Name the three factors necessary for seeds to germinate.

At the start of the investigation to show digestive activity during germination the seeds were sterilised. 1. Why is this necessary?

2. How did you sterilise the seeds?

Name the substance that is used as a medium on which to germinate the seeds.

What substance, to be digested by the seeds, was added to the above medium?

What control did you use in this demonstration?

How did you demonstrate that digestive activity had taken place?

How did you demonstrate that digestive activity had taken place?

Name a plant growth regulator that promotes growth and give a precise location for a site of its action.

through which part of a stem are growth promoters transported?

Outline two uses of growth promoters in horticulture.

Give an example of a growth regulator that inhibits growth.

adverse external environment

Give two ways in which plants protect themselves from adverse external environments.

Name the group of substances in plants which control responses to external stimuli.

What name is given to the regions in plants in which these substances are produced?

Give locations for two of these regions.

positively phototropic.

Explain the mechanism of response by a plant to a named external stimulus.

State two ways in which hormones are similar to the group of substances referred to in (b)(i).

plant growth regulator

dormancy

how does dormancy of seeds benefit plants

Water, oxygen and a suitable temperature are all required for the germination of seeds. In the case of each of these factors describe its effect on the process of germination.

Which part of the embryo in a germinating seed gives rise to each of the following parts of the seedling?

• The root 2.

• The shoot.