R3101 PLANT TAXONOMY, STRUCTURE & FUNCTION

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1 Including Examiner Comments R3101 PLANT TAXONOMY, STRUCTURE & FUNCTION Level 3 Wednesday 10 February :30 11:10 Written Examination Candidate Number:. Candidate Name:.. Centre Number/Name: IMPORTANT Please read carefully before commencing: i) The duration of this paper is 100 minutes; ii) iii) iv) ALL questions should be attempted; EACH question carries 10 marks; 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) vii) viii) ix) Use black or blue ink only. Pencil may be used for drawing purposes only; Where plant names are required, they should include genus, species and where appropriate, cultivar; 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; Please note, when the word distinct is used within a question, it means that the items have different characteristics or features. Ofqual Unit Code H/505/2966 Please turn over/..

2 ANSWER ALL QUESTIONS Q1 a) Explain, using TWO NAMED plant examples in EACH case, how specific names can indicate: i) growth habit; ii) commemoration. 3 3 Please see over/.. 2

3 b) Explain the meaning and use of the term Plant Breeders Rights. 4 Total Mark Please turn over/.. 3

4 Q2 a) b) Define the term self-pollination. i) State the benefits of self-pollination to plants. 1 3 ii) State the limitations of self-pollination to plants. 2 4 Please see over/..

5 c) Explain TWO distinct methods by which plants limit self-pollination. 4 Total Mark Please turn over/.. 5

6 Q3 Describe the process of secondary thickening in the stem of a woody perennial from primary tissues to two years old Please see over/.. 6

7 Total Mark Please turn over/.. 7

8 Q4 a) b) Name THREE groups of plants within the angiosperms. Describe the reproductive characteristics of angiosperms that distinguish them from other vascular plant groups. 3 4 Please see over/.. 8

9 c) Name and describe the type of xylem cell found only in angiosperms. 3 Total Mark Please turn over/.. 9

10 Q5 a) In relation to photosynthesis, describe what is meant by EACH of the following terms: i) PAR (Photosynthetically Active Radiation); ii) light saturation point; iii) light compensation point Please see over/.. 10

11 b) Explain how a NAMED plant is adapted to grow in low light levels. 4 Total Mark. Please turn over/.. 11

12 Q6 a) Describe THREE effects of cytokinins in plants. 6 Please see over/.. 12

13 b) State what is meant by the following terms, giving a horticultural example for EACH: i) growth retardant; ii) growth inhibitor. 2 2 Total Mark Please turn over/.. 13

14 Q7 a) Define the following terms in relation to water movement in the plant: i) diffusion; ii) osmosis. 1 1 b) State TWO locations where EACH of the processes in a) occur in the plant. 4 Please see over/.. 14

15 c) Describe how the following processes aid water movement in the xylem tissue: i) cohesion; ii) adhesion. 2 2 Total Mark Please turn over/.. 15

16 Q8 a) Draw a labelled diagram of a legume flower. 4. Please see over/.. 16

17 b) Identify adaptations that promote insect pollination in the legume flower. 6 Total Mark Please turn over/.. 17

.. True or false fruit.. 1 ii) Type of fruit.

18 Q9 a) Identify EACH of the following types of fruit indicating whether they are true or false fruit. i) Type of fruit... True or false fruit.. 1 ii) Type of fruit... True or false fruit.. 1 iii) Type of fruit True or false fruit.. 1 Please see over/.. 18

19 iv) Type of fruit. True or false fruit... 1 v) Type of fruit... True or false fruit.. 1 b) Give a NAMED plant example for each fruit identified in a). 5 i).. ii).. iii).. iv).. v).. Total Mark Please turn over/.. 19

20 Q10 Describe how outdoor planting conditions affect root respiration for root growth Please see over/.. 20

21 . ******* 21 Total Mark

22 DO NOT USE THIS PAGE 22

23 DO NOT USE THIS PAGE 23

24 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: /SC

25 R3101 PLANT TAXONOMY, STRUCTURE & FUNCTION Level 3 Wednesday 10 February 2016 Candidates Registered 114 Total Candidates Passed % Candidates Entered % Passed with Commendation % Candidates Absent/Withdrawn % Passed % Candidates Deferred % Failed % Senior Examiner s Comments On the whole this paper was well answered with the majority of candidates attempting and completing all the questions. The following guidelines should be of help to future candidates. Where named plant examples are asked for, full botanical names (genus and species) are required to achieve full marks. Common names will not be given a mark. Use the command statements e.g. list or name (single words only), state (a few sentences), describe or explain (a fuller answer) together with the mark allocation, to judge the depth of the answer. Half marks are often allocated where the basic information given is correct but needs further qualification to gain the full mark. Where a number of answers are specified in the question, the examiner will not select correct answers from a list e.g. if the question states State TWO plant names, only the first two names given will be marked. Labels on diagrams should be correctly positioned to avoid ambiguity and diagrams should be clearly drawn and annotated. No marks will be awarded for artistic merit. Candidates should use unambiguous plant examples as reference sources from, for example, the RHS Find a Plant Service available on the RHS Website. 25

26 Q1 a) Explain, using TWO NAMED plant examples in EACH case, how specific names can indicate: i) growth habit; ii) commemoration. 3 3 b) Explain the meaning and use of the term Plant Breeders Rights. 4 Q1a) Candidates who gave two plant examples with appropriate specific epithets, rather than generic epithets or cultivar names gained marks. Full marks were obtained where candidates gave an explanation of the epithet as well as an example. For i) some incorrectly gave plant characteristics or life cycles rather than growth habits. Suitable examples included Cotoneaster horizontalis, indicating horizontal branching and Betula pendula which has pendulous or weeping branches. For ii) many candidates were able to name two commemorative epithets, often relating to a plant s discoverer for example, Berberis darwinii or Buddleja davidii. Better candidates gave more information such as the name relates to Charles Darwin or Father Armand David, rather than just commemorates Darwin or David. Q1b) Candidates who scored highly recognised that PBRs give plant breeders legal rights over their newly developed cultivars and are issued by an appropriate authority such as the Plant Variety Rights Office in the UK (not the ICN or ICNCP which are rulebooks for applying plant names). Propagation by a third party is not allowed unless authorised by the breeder and royalties paid. New plants must be tested for distinctness, uniformity and stability and the cultivar name approved and registered. Marks were also awarded where candidates mentioned that plants undergoing testing for PBR may have a code name and a selling name or trade designation and that plant labels show the cultivar name with the suffix PBR. Q2 a) Define the term self-pollination. 1 b) i) State the benefits of self-pollination to plants. ii) State the limitations of self-pollination to plants. 3 2 c) Explain TWO distinct methods by which plants limit self-pollination. 4 Q2a) When defining self-pollination, candidates needed to say more than just a plant that pollinates itself, to gain a mark. It is the transfer of pollen from an anther to a stigma in the same flower or on the same plant or between two genetically identical plants. Q2b) Candidates gave a good range of benefits e.g. a successful genotype is maintained, seed production is ensured, the plant is not reliant on vectors for pollen dispersal and isolated populations are more likely to survive. Similarly the limitations were well known e.g. genetic variability will be reduced together with hybrid vigour, detrimental characteristics may appear and the anthers and stigmas must mature simultaneously for success. Q2c) Among the methods limiting self-pollination, protandry or protogyny where the stamens or stigmas mature at different times and dioecy, separate male and female plants, were the most popular choices. Many also mentioned heterostyly in Primula and genetic self-incompatibility. 26

27 Q3 Describe the process of secondary thickening in the stem of a woody perennial from primary tissues to two years old. 10 Q3 Some very good descriptions of the process of secondary thickening were given, both with and without accompanying diagrams. Diagrams without text were acceptable as long as they were annotated to describe the process. Descriptions or drawings of the features of woody stems rather than the process of how they are formed, gained less marks. Where candidates used diagrams, a cross section of a dicotyledonous stem at the start of secondary thickening was helpful to show the position of the primary xylem and phloem and the vascular cambium/intrafascicular cambium. Further diagrams could show the development of the interfascicular cambium in the cortex between the vascular bundles and the eventual formation of a ring of vascular cambium giving rise to secondary xylem and phloem displacing the primary xylem and phloem. Additional marks were gained by describing the development of the cork cambium (phellogen) in the cortex, not in the epidermis, giving rise to the outer cork layer (phellem) and inner secondary cortex (phelloderm). Marks were also awarded for mention of medullary rays, lenticels, bark (all the layers outside the secondary phloem) and the development of annual rings, two of which would be visible in the secondary xylem at the end of two year s growth. Q4 a) Name THREE groups of plants within the angiosperms. 3 b) Describe the reproductive characteristics of angiosperms that distinguish them from other vascular plant groups. 4 c) Name and describe the type of xylem cell found only in angiosperms. 3 Q4a) Candidates were able to list three groups of flowering plants although some incorrectly mentioned gymnosperms, bryophytes or ferns. Answers varied according to the classification system used and any recognisable group within Angiosperms was accepted. The commonest choices were dicotyledons and monocotyledons (and their equivalent taxons e.g. Magnoliopsida and Liliopsida), eudicots and basal angiosperms, together with suitable Orders e.g. Rosales or Families e.g. Rosaceae. Groups based on life cycles e.g. annuals, biennials or perennials or plant type e.g. shrubs, trees, evergreens were not accepted as these can be found in non-angiosperm plants. Q4b) Candidates who scored highly recognised that this was a comparison between vascular plant groups, so between angiosperms, gymnosperms and pteridophytes, not bryophytes. Suitable answers included double fertilisation and the development of endosperm, the production of flowers, seeds enclosed in fruits, pollen vectors and seed dispersal mechanisms other than by wind, all unique to angiosperms. Q4c) Candidates who correctly named xylem vessels rather than describing xylem tissue in general, or tracheids, also found in conifers, gained marks. Characteristics included their shape, lack of end walls, lignified walls with pits and a central lumen without living contents. 27

28 Q5 a) In relation to photosynthesis, describe what is meant by EACH of the following terms: i) PAR (Photosynthetically Active Radiation); ii) light saturation point; iii) light compensation point b) Explain how a NAMED plant is adapted to grow in low light levels. 4 Q5a) Full marks were gained where candidates defined the terms and gave some extra information. For example, PAR is the wavelengths of light between 400nm and 700nm which are absorbed by chlorophyll and are therefore useful for photosynthesis. The light saturation point is the level of light intensity beyond which there is no further increase in photosynthesis. This is because the photosynthetic apparatus is functioning at its maximum and not because other factors become limiting as some candidates stated. The light compensation point was not generally well understood. It is the light level at which the amount of carbon dioxide fixed by photosynthesis matches the amount of carbon dioxide lost through respiration so there is no net gain of carbohydrate and therefore no growth. Q5b) Most answers named a suitable shade plant, the most popular being Fatsia japonica, Helleborus spp. and Hosta spp. Better candidates described adaptations to shade specific to their chosen plant rather than generic characteristics. Examples of adaptations included thin leaves with a large surface area for light absorption, low light saturation and light compensation points, fewer palisade layers, chloroplasts evenly distributed through the mesophyll or dissected leaves to allow light through to leaves below. Examples of shade avoidance rather than shade adaptation e.g. spring flowering plants or plants which climb were not credited. 28

29 Q6 a) Describe THREE effects of cytokinins in plants. 6 b) State what is meant by the following terms, giving a horticultural example for EACH: i) growth retardant; ii) growth inhibitor. 2 2 Q6a) Most candidates were able to describe at least one effect of cytokinins in plants, with higher marks being given for fuller answers. Examples included: promotion of cell division in apical and lateral meristems, initiation of shoots in micropropagation, retardation of leaf senescence so prevention of development of autumn colour due to either stimulation of chlorophyll or inhibition of its breakdown, growth of lateral buds, with cytokinin acting antagonistically to auxin and overcoming apical dominance. Q6b) The terms which relate to synthetic PGRs applied exogenously, were less well known. A growth retardant obviously slows growth but does so through inhibiting the action of gibberellins so reducing internode length and this effect is reversible. Growth inhibitors, by contrast, stop growth by preventing cell division at the apical meristem and have an irreversible effect. Active ingredients such as paclobutrazol or trinexapac ethyl, or trade names were accepted e.g. Chlormequat, Bonzi are both growth retardants used to produce bushy pot plants. For growth inhibitors maleic hydrazide and ethylene are used to prevent sprouting in potatoes and onions. Q7 a) Define the following terms in relation to water movement in the plant: i) Diffusion; ii) Osmosis. 1 1 b) State TWO locations where EACH of the processes in a) occur in the plant. 4 c) Describe how the following processes aid water movement in the xylem tissue: i) Cohesion; ii) Adhesion

30 Q7 Q7a) Most candidates found parts a) and b) of this question quite difficult. Full marks were awarded to candidates who recognised that the question was about water movement not gases or solutes. i) Thus diffusion is the movement of water molecules from a high concentration to a low concentration. The most popular examples of diffusion in the plant were: the evaporation from leaf cell surfaces into the air spaces of the spongy mesophyll, loss of water vapour through the stomata by transpiration, the movement of water from cell to cell through the plasmodesmata. ii)better candidates defined osmosis fully as the diffusion of water molecules through a partially permeable membrane rather than just a membrane, from a high water or low solute concentration to a low water or high solute concentration, specifying water or solute. Any location where water crosses a membrane involves osmosis so the following examples could be used: soil water entering a root hair cell (not simply a root hair), water movement between epidermal and guard cells, water entering or leaving the cell vacuole, water entering sieve tube cells at phloem loading sites, water entering the endodermal cells of the root. Q7b) Simply stating that water passes across or through cells could not be credited as this could be through the cell walls (the apoplast) i.e. not osmosis. The roles of the endodermis and Casparian strip were not well understood with many candidates stating that water passes through the latter. The Casparian strip is a waxy layer in the endodermal cell wall which prevents water passing through the wall and between cells forcing it to cross the cell membrane by osmosis and enter the endodermal cell itself. Q7c) Most candidates correctly identified cohesion as the attraction between water molecules and adhesion as the attraction between water molecules and the inner surface of tracheids or xylem vessels. Mention of the mechanism i.e. the polarity of water molecules leading to hydrogen bonding between molecules, and bonding between water molecules and charges in cell walls gained extra marks. Cohesion aids water movement by enabling a continuous column of water to form and be pulled up in the transpiration stream without breaking (through high tensile strength), whilst adhesion enables water columns to climb against the force of gravity through capillary action. 30

31 Q8 a) Draw a labelled diagram of a legume flower. 4 b) Identify adaptations that promote pollination in the legume flower. 6 Q8a) The majority of candidates were able to draw and label good diagrams of a legume flower. The commonest flower chosen was Lathyrus odoratus and marks were awarded for correctly labelling standard (banner), wing and keel petals, 9 fused stamens and one free, the elongated ovary with many ovules and the upwards bending style and stigma. Q8b) Most candidates identified bees as the main pollination vector in legume flowers and gave a good range of adaptations. These included colourful petals but not red, nectar guides leading to nectaries at the base of the petals, provision of nectar rich in sucrose as a carbohydrate source, scent to attract bees, the keel petal acting as a landing pad, the bee s weight opening the flower to expose stamens and stigma which brush against the bee s body, large pollen grains with a rough outer exine to adhere to the bee and a strong pedicel to support the weight of the bee. Q9 a) Identify EACH of the following types of fruit indicating whether they are true or false fruit. i) 1 ii) 1 31

These were, in order, a nut (Quercus robur), a follicle (Aquilegia vulgaris), a capsule (Papaver somniferum), a berry (Solanum lycopersicum) and a pome (Malus

32 iii) 1 iv) 1 v) 1 b) Give a NAMED plant example for each fruit identified in a). 5 Q9a) If candidates knew their fruits and could give suitable named plant examples this was a high scoring question. These were, in order, a nut (Quercus robur), a follicle (Aquilegia vulgaris), a capsule (Papaver somniferum), a berry (Solanum lycopersicum) and a pome (Malus sylvestris) all of which were true fruits except for the pome which is a false fruit. Names were accepted other than those stated above as long as they were a correct example of the type of fruit shown. Q9b) Marks were lost due to incorrect spellings, not giving a full binomial name or using a common name. 32

33 Q10 Describe how outdoor planting conditions affect root respiration for root growth. 10 Q10 Many candidates failed to notice that this was a question about root respiration, not photosynthesis or water relations in plants. The best approach was to focus on the environmental factors which affect respiration in the root zone i.e. oxygen supply and temperature in the soil. Most candidates gave a good account of the need for a good oxygen supply for aerobic respiration. This is provided by soils with good drainage, high porosity and good structure. Description of soil conditions which prevent this such as poor soil structure, compaction and waterlogging were also credited together with mention of anaerobic respiration and its effects. Comparison of the energy released by aerobic and anaerobic respiration, together with production of ethanol toxic to root cells in anaerobic conditions all gained marks. A number of candidates described plant adaptations to waterlogging in detail which was not required. Fewer candidates mentioned the effects of temperature whereby increasing soil temperature increases the rates of respiration in root cells and oxygen diffusion in the soil. Better candidates made the connection between higher rates of aerobic respiration leading to better root establishment, root growth and mineral nutrient uptake. Mention of any methods used to improve root respiration such as use of mulches to raise soil temperature or the need for a good supply of phosphorus for ATP production were also rewarded. 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: /SC

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R2101 PLANT CLASSIFICATION, STRUCTURE & FUNCTION

R2101 PLANT CLASSIFICATION, STRUCTURE & FUNCTION WITHOUT EXAMINERS COMMENTS R0 PLANT CLASSIFICATION, STRUCTURE & FUNCTION Level Monday 5 February 08 09:30 0:50 Written Examination Candidate Number: Candidate Name: Centre Number/Name:.. IMPORTANT Please