2023TrialShort answer

Q21 (a)

2 marks

Question

A plant pathologist observed brown spots developing on the leaves of a lemon tree and wanted to determine the cause of the disease. The pathologist suspected the tree was suffering from a bacterial disease, caused by infection with Xanthomonas citri.
Outline TWO plant adaptations for defence against pathogens.

Try the question before revealing the answer.

Solution

Criteria	Marks
• Clearly outlines at least two plant adaptations for defence against pathogens	2
• Clearly outlines one plant adaptation for defence against pathogens Or Identifies two adaptations/ outlines very briefly two adapations	1

Sample answer:

Plants deposit cell wall material around pathogens to seal them off from the surrounding tissue. Plants such as eucalypyts store oils in their leaves, which act as chemical defences against fungal and bacterial pathogens. Note – Cannot just state release chemicals, must be more specific.

Supplied marking guidance · human reviewed

Compare this with your working, not only your final sentence.

Syllabus alignment

Module 7 · Infectious Disease

Responses to PathogensInvestigate how a named Australian plant responds to a named pathogen.

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