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Including Examiner Comments R3101 PLANT TAXONOMY, STRUCTURE & FUNCTION Level 3 Wednesday 26 June 2013 09:30 – 11:00 Written Examination Candidate Number:…………………………………………………………………. Candidate Name:……………………………………………………………………. Centre Number/Name:……………………………………………………………… IMPORTANT – Please read carefully before commencing: i) The duration of this paper is 90 minutes. ii) ALL questions should be attempted. iii) EACH question carries 10 marks. iv) Write your answers legibly in the spaces provided. It is NOT necessary that all lined space is used in answering the questions. v) Use METRIC measurements only. vi) Use black or blue ink only. vii) Where plant names are required, they should include genus, species and where appropriate, cultivar. viii) Where a question requires a specific number of answers; only the first answers given that meet the question requirement will be accepted, regardless of the number of answers offered. ix) Please note, when the word ‘distinct’ is used within a question, it means that the items have different characteristics or features. . Ofqual Unit Code F/601/0993 Please turn over/….. ANSWER ALL QUESTIONS MARKS Q1 Describe the route that water follows through a plant from the soil to the atmosphere. 10 ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please see over/….. 2 MARKS ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Total Mark ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… Please turn over/….. 3 MARKS Q2 Draw a fully labelled diagram to show the tissue layout of a secondarily thickened dicotyledonous stem. 10 Please see over/….. 4 MARKS ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Total Mark ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please turn over/….. 5 MARKS Q3 a) Summarise the process by which sugar is made in the plant. 5 ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please see over/….. 6 MARKS b) NAME the sugar transported in the phloem. 1 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… c) State FOUR features of phloem tissue that allow the transport of sugar. 4 ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Total Mark ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please turn over/….. 7 MARKS Q4 a) Draw a clearly labelled diagram of a NAMED monocotyledon flower. 8 Name of monocotyledon flower : ……………………………………………………………………………………….... ……………………………………………………………………………………….... Please see over/….. 8 MARKS b) State TWO ways in which dicotyledonous and monocotyledonous flowers differ. 2 ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Total Mark ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please turn over/….. 9 MARKS Q5 a) Describe the differences between the processes of aerobic and anaerobic respiration in plants. 6 ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please see over/….. 10 MARKS ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… b) Explain the importance of anaerobic respiration in plant production. 4 ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… Total Mark ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………... Please turn over/….. 11 MARKS Q6 a) Distinguish between endogenous and synthetic growth regulators. 2 ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… b) 6 Describe THREE roles of gibberellic acid in plants. ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please see over/….. 12 MARKS ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… c) An anti-gibberellin is available for use in horticulture, state: i) ii) the effect this could have on the growth of plants; a horticultural situation where this could be used. 2 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... Total Mark ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please turn over/….. 13 MARKS Q7 a) Describe how plant roots respond to gravity. 6 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please see over/….. 14 MARKS b) Describe how a lily shoot (Lilium cv) will emerge successfully after planting the bulb on its side to avoid rotting. 4 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Total Mark ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… Please turn over/….. 15 MARKS Q8 Describe FIVE differences between conifers and flowering plants. 10 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… Please see over/….. 16 MARKS ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... Total Mark ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… Please turn over/….. 17 MARKS Q9 a) State TWO reasons for using the scientific (botanical) names of plants in horticulture. 2 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… b) Distinguish between an interspecific hybrid and an intergeneric hybrid using a NAMED example in EACH case. 6 ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please see over/….. 18 MARKS ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… c) Explain, with reference to ONE NAMED example, what is meant by a graft hybrid. 2 ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ……………………………………………………………………………………….... Total Mark ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… Please turn over/….. 19 MARKS Q10 a) Complete the following table to show the similarities and differences between moth and butterfly pollinated flowers: Moth pollinated flower Butterfly pollinated flower Similarity 1 1 Similarity 2 1 Difference 1 2 Difference 2 2 Please see over/….. 20 MARKS b) The diagram below shows a section through a flower. Identify FOUR features of this flower that show adaptation for bee pollination. 4 ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………………………………………………………………….... ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ******* 21 Total Mark DO NOT USE THIS PAGE 22 DO NOT USE THIS PAGE 23 ©These questions are the property of the Royal Horticultural Society. They must not be reproduced or sold. The Royal Horticultural Society, Wisley, Woking, Surrey GU23 6QB. Charity Registration Number: 222879/SC038262 24 R3101 PLANT TAXONOMY, STRUCTURE & FUNCTION Level 3 Wednesday 26 June 2013 Candidates Registered Candidates Entered Candidates Absent Candidates Deferred Candidates Withdrawn Q1 91 71 15 4 1 78.02% 16.48% 4.40% 1.10% Total Candidates Passed Passed with Commendation Passed Failed 61 32 29 10 85.92% 45.07% 40.85% 14.08% Describe the route that water follows through a plant from the soil to the atmosphere. There were some excellent, very detailed answers to this question which focused on the route or pathways that water follows through the plant after uptake from the soil by root hairs to eventual diffusion through stomata into the atmosphere. Details of the processes involved were not required. Marks were given for entry of water through root hairs, details of movement by apoplast and symplast pathways across the root cortex to the endodermis, control of movement in the apoplast pathway by the Casparian strip and transfer of water to the symplast pathway, before moving across the stele to the xylem vessels. Water then travels up the stem to the leaves in the xylem tissue, moves out of the leaf veins, either in the apoplast or symplast systems to the leaf mesophyll, circulates into air spaces in the leaf and diffuses through the stomata in to the atmosphere. Guttation through hydathodes was also credited. Some candidates confused the terms apoplast and symplast. 25 Q2 Draw a fully labelled diagram to show the tissue layout of a secondarily thickened dicotyledonous stem. In this question candidates were asked to draw a fully labelled diagram of a secondarily thickened dicotyledonous stem. The standard and accuracy of candidates’ diagrams varied; the best were large, clear and fully labelled showing the layout of all the tissues to be found in a secondarily thickened dicotyledon stem. No written explanation of the process of secondary thickening was required, neither was a series of diagrams asked for. Marks were awarded for clarity and accuracy of the tissue layout for the inner and outer tissues formed from the vascular cambium and cork cambium (phellogen). These included pith, primary xylem, secondary xylem, annual rings, secondary phloem, primary phloem, medullary rays, cortex, secondary cortex/phelloderm and cork (phellem). Q3 a) Summarise the process by which sugar is made in the plant. b) Name the sugar transported in the phloem. c) State FOUR features of phloem tissue that allow the transport of sugar. Many candidates showed detailed knowledge of the process of photosynthesis in answer to part a), which required a summary of the process of photosynthesis, but written in sufficient detail to gain five marks. Marks were gained for a detailed equation with formulae, an outline of the two stage reaction, and the processes that occurred within each stage. In the light reaction, light energy is captured by chlorophyll, photolysis of water occurs and oxygen is released, ATP is produced and hydrogen is carried by NAPH2. In the dark reaction carbon dioxide is converted using ATP and NADPH2 to glucose. In answer to the second part of the question, most candidates knew that glucose was an end product of photosynthesis but many were not aware that sucrose is the sugar transported in the phloem. The final part required knowledge of the structure and components of phloem tissue that allowed the transport of sucrose. Valid features were phloem sieve tube elements with few cell contents, perforated end walls or sieve plates, and stacked end on end to form a long tube. These are supported by companion cells with nuclei, linked by plasmodesmata, which assist in active transport and the loading and unloading of sugars. Strengthening tissues such as fibres and sclereids also physically support the sieve tubes. Q4 a) Draw a clearly labelled diagram of a NAMED monocotyledon flower. b) State TWO ways in which dicotyledonous and monocotyledonous flowers differ. 26 For part a), most candidates chose to draw a named bulbous monocotyledon flower such as Galanthus nivalis; a few drew named grass flowers. The standard of diagrams varied, some were very good but others poor with little resemblance to the named flower. Diagrams should be large, clear, labelled and preferably drawn in pencil (labelled in pen). Marks were given for the clarity of the drawing as well as the accuracy of the labelling. Marks were awarded for tepals, (or floret, glume, lemma, palea) receptacle, pedicel, and male parts of the flower such as stamen, anther, filament and female parts such as stigma, style and ovary. Most candidates were able to state in the second part of the question that monocotyledons had indistinguishable perianth segments or tepals in threes or multiples of three, whilst dicotyledons had separate whorls of sepals and petals in multiples of twos, or fives. Monoculpate pollen versus triculpate pollen was also an acceptable difference. General observations on the differences in leaf appearance or root formation between monocotyledons and dicotyledons were not acceptable. Q5 a) Describe the differences between the processes of aerobic and anaerobic respiration in plants. b) Explain the importance of anaerobic respiration in plant production. In general candidates knew the difference between aerobic and anaerobic respiration but not in sufficient detail to gain maximum marks. Those candidates who did gain maximum marks were able to state accurate equations for both processes and compare them in terms of whether oxygen was necessary, the yield of energy produced, the outputs from each process, where they occurred in the plant cell and the biochemical processes involved. Aerobic respiration Oxygen required High energy yield 38 ATP Carbon dioxide and water produced Cytoplasm and mitochondria Glycolysis, Krebs cycle, electron transport chain Anaerobic respiration No or very low oxygen levels Low energy yield 2 ATP Carbon dioxide and ethanol produced Cytoplasm only Glycolysis A most common mistake was confusing ethanol, C2H5OH, with ethylene, C2H4. The second part allowed candidates to apply their knowledge of anaerobic respiration to plant production and growing conditions. Most were aware that low energy yield from anaerobic respiration led to low or little growth, that ethanol was toxic and could kill plant cells, particularly roots, but that anaerobic conditions could occur in waterlogged or compacted soils, and overwatered, poorly draining growing media. 27 Q6 Some stated that anaerobic respiration allowed plants to survive short periods of anaerobic conditions and that it occurred during the early stages of seed germination. a) Distinguish between endogenous and synthetic growth regulators. b) Describe THREE roles of gibberellic acid in plants. c) An anti-gibberellin is available for use in horticulture, state: i) ii) the effect this could have on the growth of plants; a horticultural situation where this could be used. Endogenous growth regulators are naturally produced within the plant whilst synthetic growth regulators are manufactured and applied to plants. The roles of gibberellic acid most commonly described were cell elongation and division, particularly to extend internodes in stems, mobilisation of food reserves in seed germination, breaking dormancy in seeds, and promoting flowering or bolting in plants. Some candidates described promoting fruit set in specific crops by application of synthetic gibberellins. A description of each role was required for maximum marks. The most common answer to the third part of the question was that an anti – gibberellin is a dwarfing agent producing shorter, sturdier plants and that it is used in bedding plant production or pot plant production to produce compact plants and reduce transport damage. Q7 a) Describe how plant roots respond to gravity. b) Describe how a lily shoot (Lilium cv) will emerge successfully after planting the bulb on its side to avoid rotting. This question allowed candidates to demonstrate their knowledge of gravitropism/geotropism and the specific endogenous growth regulator that influenced directional growth. In general part b) was answered better than part a) showing that candidates understood the process of negative geotropism in shoots better than positive geotropism in roots. Geotropism is a directional growth response to gravity which is perceived in the root cap in cells called statocytes, containing statoliths which are pulled by gravity to the lower part of the cell where auxin accumulates. The auxin inhibits cell elongation in roots so that the opposite (upper) side of the root elongates and the root tip grows down towards the gravitational pull, exhibiting positive geotropism. Some candidates used diagrams to explain their answer. 28 The lily shoot is negatively geotropic and grows away from the force of gravity. Auxins accumulate on the lower side of the shoot which promote elongation of the shoot cells so that the shoot bends towards the surface. Some candidates explained the process of positive phototropism in terms of auxin movement to the shaded side of the stem having the same effect of directing the shoot towards the surface. This was also credited. Q8 Describe FIVE differences between conifers and flowering plants. Most candidates showed a wide range of knowledge of features of conifers and flowering plants, however some candidates were not able to describe five differences and others did not make direct comparisons between conifers and flowering plants. Many differences were credited including: Conifers Cones with cone scales Cones unisexual Pollination by wind Water transport by tracheids Flowering plants Flower with whorls of perianth parts Flowers usually hermaphrodite Pollination by variety of vectors Water transport mainly by xylem vessels Companion cells in phloem Leaves broad or strap-like, mesomorphic Seeds (ovules) enclosed in fruits (ovaries) Evergreen or deciduous Annual, biennial or perennial Woody and herbaceous Albuminous cells in phloem Leaves needle-like, xeromorphic Naked seeds Mainly evergreen Perennial Woody (secondary thickening) Q9 a) State TWO reasons for using the scientific (botanical) names of plants in horticulture. b) Distinguish between an interspecific hybrid and an intergeneric hybrid using a NAMED example in EACH case. c) Explain, with reference to ONE NAMED example, what is meant by a graft hybrid. This question required precise knowledge and understanding of botanical names specifically interspecific, intergeneric and graft hybrids. Most candidates made a good attempt at this question and the importance of botanical plant names for horticulturists was explained well, which included international communication, specification for planting and identification of taxa. 29 In the second part of the question credit was given for explaining that both interspecific and intergeneric hybrids are crosses between different species, for an interspecific hybrid the cross is made within the same genus and for an intergeneric hybrid between different genera, usually within the same family. Many candidates were able to give correct examples of each hybrid with their respective parents. Where examples of plant names are given these should be correctly spelt and written using the correct format. However in part c) many candidates confused grafting of fruit cultivars onto a rootstock from the same genus with a true graft hybrid which is grafting two plants of different genera together so that the tissues mix and form a chimaera. The standard example of this is + Laburnocytisus adamii formed from grafting Laburnum anagyroides with Cytisus purpureus. Q10 a) Complete the following table to show the similarities and differences between moth and butterfly pollinated flowers: b) The diagram below shows a section through a flower. Identify FOUR features of this flower that show adaptation for bee pollination. There were some excellent well informed answers to this question on flower adaptations for specific insect pollinators. Most candidates followed the format of the table in presenting their answers to part a) which included for similarities, copious nectar produced, long corolla tube, scented flowers and landing pads. For differences, moth pollinated flowers are large and pale in colour, open and produce scent during evenings/night, whereas butterfly pollinated flowers are brightly coloured and produce little scent throughout the day. Most candidates were able to identify four features of the flower that showed adaptation for bee pollination. These were easier to credit where the diagram had been labelled and included landing stage, nectar guides, tubular shape to the large corolla, stamens and stigma in a position to contact bee as it entered the corolla tube and nectaries at the base of tube. Flower adaptations for bee pollination such as colour that could not be seen on the diagram could not be credited. ©These questions are the property of the Royal Horticultural Society. They must not be reproduced or sold. The Royal Horticultural Society, Wisley, Woking, Surrey GU23 6QB. Charity Registration Number: 222879/SC038262 30
