DEPARTMENT OF PLANT SCIENCE DEPARTEMENT PLANTKUNDE BOT 161 EXAMINATION / EKSAMEN DATE / DATUM : MARKS / PUNTE : 100

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1 DEPARTMENT OF PLANT SCIENCE DEPARTEMENT PLANTKUNDE BOT 161 EXAMINATION / EKSAMEN DATE / DATUM : MARKS / PUNTE : 100 TIME / TYD : 100 Min EXAMINERS / EKSAMINATORE: Prof JJM Meyer, Dr TE Tshikalange, Dr B Crampton, Dr PC le Roux Mr/Mnr HM Heyman, Mrs/Mev I Schoeman EXTERNAL EXAMINER / EKSTERNE EKSAMINATOR: Prof AE van Wyk The test paper consists of 10 questions on 14 pages. Die vraestel bestaan uit 10 vrae op 14 bladsye. Answer all questions in either blue or black ink. Do not write or draw in pencil. Beantwoord alle vrae in of blou of swart ink. Moenie in potlood skryf of teken nie. Do not use correction fluid (Tipp-Ex). Moenie korrigeervloeistof (Tipp-Ex) gebruik nie. QUESTION / VRAAG 1 : [5] Match the plant tissue with its description by writing the correct plant tissue with each description. Each term can only be used once. Pas die plantweefsel by die ooreenstemmende beskrywing deur die korrekte plantweefsel by elke beskrywing neer te skryf. Elke term kan net een keer gebruik word. (10 x ½) sclerenchyma / sklerenchiem cambial initials/ kambiuminisiale mesophyll / mesofil endodermis / endodermis collenchyma / kollenchiem pericycle / persikel periderm / periderm pith / murg 1.1 layer from which lateral roots originate laag waaruit laterale wortels ontstaan pericycle / persikel 1.2 tapered xylem cells with lignin in cell walls toegespitste xileemselle met lignien in selwande tracheids / trageïede 1.3 parenchyma cells in leaves containing chloroplasts parenchiemselle in blare wat chloroplaste bevat mesophyll / mesofil 1

2 1.4 protective coat consisting of cork and cork cambium beskermende laag wat uit kurk en kurkkambium bestaan periderm / periderm 1.5 bundles of long sclerenchyma cells bondels lang sklerengiemselle fibres / vesels 1.6 supporting cells with thickened primary walls ondersteuningselle met verdikte primêre wande collenchyma / kollengiem 1.7 parenchyma cells inside vascular ring in eudicot stems parengiemselle binne die vaatkring in eudikotiele stingels pith / murg 1.8 supporting cells with thick secondary walls ondersteuningselle met verdikte sekondêre wande sclerenchyma / sclerengiem 1.9 cells that produce secondary xylem and phloem selle wat sekondêre xileem en floëem vorm cambial or fusiform initials / kambiuminisiale of spoelinisiales 1.10 cell layer in roots regulating movement of solutes into vascular cylinder sellaag in wortels wat beweging van opgeloste stowwe tot in die vaatsilinder reguleer endodermis / endodermis QUESTION / VRAAG 2 : [5] Answer the following statements as TRUE or FALSE. If your answer is FALSE, motivate your answer. Beantwoord die volgende stellings as WAAR of ONWAAR. Indien jou antwoord ONWAAR is, motiveer jou antwoord. 2.1 Bark is associated with perennials but not annuals. Bas word met meerjarige plante en nie met eenjarige plante geassosieer nie. (1) True / Waar 2.2 A cladode is a flattened petiole that resembles a leaf blade. n Kladood is n afgeplatte petiool (blaarsteel) wat soos n blaarskyf lyk. (1) False phyllode is a flattened petiole (or cladode is a flattened stem) Onwaar fillood is n afgeplatte petiool (of kladood is n afgeplatte stingel) 2

3 2.3 Within a woody stem that develops secondary growth, the cork cambium develops from the cortex. In n houtagtige stingel wat sekondêre groei ondergaan, ontwikkel die kurkkambium vanuit die korteks. (1) True / Waar 2.4 Monocots typically have a taproot rather than an adventitious root sytem. Monokotiele het tipies eerder n penwortelstelsel as n bywortelstelsel. (1) False Monocots have an adventitious root system Onwaar Monokotiele het n bywortelstelsel 2.5 Water can cross the cortex via the symplast or apoplast, but minerals moving via the apoplast must finally cross the selective membranes of endodermal cells. Water kan deur die korteks beweeg via die simplas en apoplas, maar minerale wat deur die apoplas beweeg moet uit eindelik deur die selektiewe membrane van endodermisselle beweeg. True / Waar (1) VRAAG / QUESTION 3 : [9] 3.1 How do the roots, stems and leaves in monocot and dicot plants differ morphologically from each other? Hoe verskil die wortels, stingels en blare van monokotiele en dikotiele plante morfologies van mekaar? (6) Roots: D: Tap-root system (1), M: Fibrous (adventitious) root system (1) Stems: D: Woody stem (1), M: Herbaceous stem (1) Leaves: D: Reticulate veined (has petiole, compound leaves) (1), M: Parallel veined (no petiole, simple leaves) (1) Wortels: D: Penwortel stelsel (1), M: Bywortel stelsel (1) Stingels: D: Houtagtig (1), M: Kruidagtig (1) Blare: D: Netarig (het blaarsteel, saamgestelde blare) (1); M: Parallel arig (geen blaarsteel, enkelvoudige blare) (1). 3.2 A couple carved a heart with their initials into a tree trunk 2 metres above ground level; the tree was 10 metres tall at the time. Ten years later the tree doubled in lenght to 20 metres. How far above the ground would the initials be after the tree double in length? Briefly explain your answer. n Paartjie het n hart met hul voorletters op die stam van n boom 2 meter bo die grondoppervlakte uit gekerf; die boom was op daardie stadium 10 meter hoog. Tien jaar later het die boom verdubbel in lengte tot 20 meter hoog. Hoe ver bo die grondoppervlakte sou die voorletters wees nadat die boom verdubbel het in lengte? Verduidelik jou antwoord kortliks. (3) The initials will still be at the same height (1) because only secondary growth occurs in this part of the tree (1). Primary growth occurs at the tips of the stem (1). 3

4 Die voorletters sal nogsteeds dieselfde hoogte wees (1) want net sekondêre groei vind hier plaas (1). Primêre groei vind op die einde van stingels plaas (1). VRAAG / QUESTION 4 : [8] 4.1 Explain, in logical full sentences, the pressure-flow hypothesis of sugar translocation in plants. Verduidelik, in logiese vol sinne, die druk-vloei hipotese van suikervervoer in plante. (6) The pressure-flow hypothesis explains translocation in phloem At the source, sucrose is moved into the companion cells of the phloem, utilizing ATP as an energy source and the co-transport of protons Sugars move from the companion cells to the sieve tube element through the plasmodesmata Water follows by osmosis, increasing the turgor pressure within the sieve tube element, thereby pushing the solution through the phloem At the sink, sugar is moved out of the sieve tube members, and water follows osmotically, decreasing the turgor pressure Die druk-vloei hipotese verduidelik vervoer in floëem By die bron, beweeg sukrose in die begeleidende selle van die floëem. ATP word as bron van energie gebruik en daar is ko-transport van protone Suikers beweeg vanaf die begeleidende selle na die sifvat elemente deur die plasmodesmata. Water volg d.m.v. osmose en vermeerder die turgordruk binne die sifvat element, en sodoende word die oplossing deur die floëem gedruk By die swelg, beweeg suiker uit die sifvat elemente en water volg d.m.v. osmose en die turgordruk neem af 4.2 Name two factors that can influence the opening and closing of the stomata. Noem twee faktore wat die opening en sluiting van die stomata kan beïnvloed. (2) Opening: - blue-light receptors in the guard cells stimulate the activity of ATP-powered proton pumps in the plasma membrane, promoting the uptake of K +. - depletion of CO 2 within air spaces of the leaf as photosynthesis begins. - stomatal opening is an internal clock located in the guard cells. Various environmental stresses can cause stomata to close during the day: - When the plant is suffering a water deficiency, guard cells may lose turgor and close stomata. - Abscisic acid, a hormone produced by the mesophyll cells in response to water deficiency, signals guard cells to close stomata. Oopmaak: 4

5 - blou-lig reseptors in die sluitselle stimuleer die aktiwiteit van ATP-gedrewe proton pompe in die plasmamembraan, wat die opname van K + bevorder. - verlaging van CO 2 in die lugholtes van die blaar wanneer fotosintese begin. - stomata opening is n interne horlosie wat in die sluitselle geleë is. Verskeie omgewings strestoestande kan veroorsaak dat die stomata in die dag toemaak: - Wanneer n plant aan waterverlies ly, verloor die sluitselle turgor en die stomata sluit. - Absisiensuur, n hormoon wat deur mesofilselle geproduseer word a.g.v. water tekort, sein dat die sluitselle die stomata moet toemaak. QUESTION / VRAAG 5 : [9] 5.1 Distinguish, in logical full sentences, between pollination and fertilization in flowering plants. Onderskei, in logiese vol sinne, tussen bestuiwing en bevrugting in blomplante. (2) Pollination is the transfer of pollen grains from an anther to a stigma (1) whereas fertilization involves the union of egg and sperm to form a zygote (1). Bestuiwing is die oordrag van stuifmeelkorrels vanaf die helmknop tot die stempel (1). Bevrugting is die versmelting van n eiersel en spermsel om n sigoot te vorm. (1) 5.2 After a pollen grain lands on a receptive stigma, it absorbs water and germinates by producing a pollen tube. Briefly explain the events that lead to double fertilization. Also mention what is meant by double fertilization. Wanneer n stuifmeelkorrel op n ontvanklike stempel land absorbeer dit water en ontkiem deur n stuifmeelbuis te vorm. Verduidelik kortliks die gebeurtenisse wat lei tot dubbelbevrugting. Meld ook wat met dubbelbevrugting bedoel word. (4) Pollen tube that grows down between the cells of the style toward the ovary. (1) The pollen tube discharges two sperm cells into the embryo sac. (1) One sperm fertilizes the egg, forming a zygote. (1) The other sperm combines with the two polar nuclei forming a triploid endosperm (1) Stuifmeelbuis groei af tussen die selle van die styl na die vrugbeginsel (1). Die stuifmeelbuis ontslaan twee sperm selle in die embriosak (1). Een sperm bevrug die eier en vorm die sigoot (1). Die ander sperm kombineer met twee polêre kerne en vorm die triploiede endosperm (1). 5.3 How does the plumule tip of maize and other grasses break through the soil? Hoe breek die plumulapunt van die mielie en ander grasse deur die grond? (1) The coleoptile pushes through the soil, and the plumule tip is protected as it grows upwards. (1) Die koleoptiel druk deur die grond, en die plumula ent is beskerm soos wat dit opwards groei (1). 5.4 Distinguish between the origin of a monofloral aggregate and a polyfloral aggregate fruit. Onderskei tussen die oorsprong van n monoflorale aggregaatvrug (versamelvrug) en n poliflorale aggregaatvrug (saamgestelde vrug). (2) 5

6 Monofloral aggregate fruit develops from many separate carpels of one flower (1), Polyfloral fruit develops from many carpels of the many flowers that form an inflorescence (1). Monofloraal aggregaat vrugte ontwikkel van baie aparte vrugblare van een blom (1). Polifloraal aggregaat vrugte ontwikkel van baie vrugblare van baie blomme in n bloeiwyse. (1) QUESTION / VRAAG 6 : [11] The modern system of naming living things orginated with the Swedish naturalist Carl Linnaeus, whose ambition was to name and describe all of the known kinds of plants, animals and minerals. Die moderne sisteem van benaming van lewende organismes het ontstaan by die Sweedse natuurkundige Carl Linnaeus, wat die ambisie gehad het om alle bekende plante, diere en minerale te benaam en te beskryf. 6.1 Name any three principles of the binomial system of nomenclature. Noem enige drie beginsels van die binomiale sisteem van nomenklatuur. (3) ANY THREE / ENIGE DRIE Name consists of the genus (generic) name and specific epithet (1) A genus name may be written alone but specific epithet never alone (1) Names of genera and species are printed in italics or are underlined when written or typed. (1) Genus starts with a capital letter (1) Specific epithet starts with a small letter (1) Naam bestaan uit n genus naam en n spesifieke epiteton (1) n Genusnaam kan alleen geskryf word maar nooit die spesifieke epiteton (1) Name van genera en spesies moet skuinsgedruk word of geonderstreep (1) Genus begin altyd met n hoofletter (1) Spesifieke epiteton begin altyd met n kleinletter (1) 6.2 The following names form part of the taxonomic classification of the legume crop, cowpea. Arrange the names according to the hierarchical system. Die volgende name vorm deel van die taksonomiese klassifikasie van die peulgewas, akkerboon. Rangskik die name volgens die hiërargiese rangorde. Fabaceae, Anthophyta, Plantae, Vigna unguiculata, Fabales, dicotyledons, Vigna, unguiculata, Eukarya (8 x ½) Domain / Domein Kingdom / Ryk Phylum / Filum Class / Klas Eukarya Plantae Anthophyta Dicotyledons 6

7 Order / Orde Family / Familie Genus / Genus Fabales Fabaceae Vigna Species / Spesie Vigna unguiculata 6.3 Distinguish between a natural and an artificial classification system. Onderskei tussen n natuurlike en n kunsmatige klassifikasiestelsel. (2) Artificial: Plants classified according to plant growth forms and sexual systems. Usually concerns only one or a few characters. (1) Natural: Classifications to be an accurate reflection of the evolutionary relationships among organisms. Concerns many characters. (1) Kunsmatig: Plante geklassifiseer volgens plant groeivorme en die geslagtige sisteem. Gewoonlik net een of n paar kenmerke. (1) Natuurlike: Klassifikasie n akkurate weerspieeling van die evolusionêre verwantskappe tussen organisms. Gebaseer op baie kenmerke. (1) 6.4 Of what use is knowledge of the amino acid sequences of the proteins of various organisms to a taxonomist? Van watter nut is kennis van die aminosuurvolgorde van proteïene van verskeie organismes vir n taksonoom? (2) Amino acid sequences are of use in determining evolutionary relationships. The molecular clocks of proteins can be used to determine how much time has passed since 2 taxa branched from a common ancestor. Aminosuurvolgorde word gebruik om evolusionêre verwantskappe te bepaal. Die molekulêre horlosies van proteïene kan gebruik word om te bepaal hoeveel tyd het verby gegaan vandat 2 taksons vanaf n gemeenskaplike voorouer gebranch het. QUESTION / VRAAG 7 : [10] 7.1 A research team is undertaking a project to produce genetically modified maize for resistance to a fungus that causes Northern Corn Leaf Blight. Explain the role of the Molecular Biologist, the Tissue Culture Specialist and the Plant Pathologist in the project. n Span navorsers onderneem n projek om geneties gemodifiseerde mielies te produseer wat weerstand sal bied teen die fungus wat Noordelike Mielieblaarroes veroorsaak. Verduidelik die rol van die Molekulêre bioloog, die Weefselkultuurspesialis en die Plantpatoloog in die projek. (3) 7

8 7.2 Name three physiological characteristics of a plant that displays enhanced drought tolerance due to a mutation in the HD START protein. Noem drie fisiologiese eienskappe van plante met verhoogde droogte weerstandbiedenheid as gevolg van n mutasie in die HD START proteïen. (3) Answer (any 3 of the following) Deeper roots, more lateral roots, reduced stomatal density, higher abscissic acid and proline levels, increased resistance to oxidative stress 7.3 List four abiotic stresses that can reduce yield in plants. Lys vier abiotiese strestoestande wat die oesopbrengs van plante kan verlaag. (4) Any four below Drought Heat Cold Floods Nutrient deficiency Pollutants (incl. CO 2 ) QUESTION / VRAAG 8 : [9] 8.1 What is the name of the gene found in Bacillus thuringienses that encodes the Bt toxin protein, used in molecular biology to create insect resistant plants? Wat is die naam van die geen wat in Bacillus thuringienses voorkom wat vir die Bt-toksien kodeer wat in molekulere biologie gebruik word om insekweerstandbiedende plante te produseer? (1) Cry (1) gene 8.2 Name two different methods that can be used to transform plant material with a gene of interest. Noem twee metodes wat gebruik kan word om plantmateriaal met n spesifieke geen te transformeer. (2) 1. Biolistics / particle gun / gene gun / particle bombardment (1) 2. Agrobacterium mediated transformation (1) 8.3 Give the full scientific genus and species name of the model dicotyledonous plant used in molecular biology. Gee die volledige wetenskaplike naam (genus en spesie) van die dikotiele modelplant wat in molekulere biologie gebruik word. (1) Arabidopsis thaliana (1) 8.4 Describe the genome of the plant in 8.3 in terms of complexity (number of chromosomes, number of genes, size of genome). Beskryf die plant in 8.3 se genoomkompleksiteit (aantal chromosome, aantal gene, grootte van genoom). (3) 8

9 5 chromosomes (1) Approximately genes/ or (1) 120 Mb (1) Also correct: low complexity (1) fewer genes per Mb compared to most other plant species (1) small genome compared to most other plant species (1) 8.5 Name two characteristics of this plant that make it well suited to be a model plant. Gee twee einskappe van hierdie plant wat dit geskik maak om as n modelplant te dien. (2) Any two: Small plant, short lifecycle, many seeds per plant, small genome, selfpolinating QUESTION / VRAAG 9 : [15] 9.1 Which terms in column A fit those in column B the best? Provide you answer by writing down only the matching numbers of column A in column C. Watter terme in kolom A pas die beste by die van kolom B? Verskaf u antwoord deur slegs die passende nommers van kolom A in kolom C neer te skryf. (10) A B C 1 Alkaloids a Salicylic acid 2 Alkaloïede Salisielsuur 2 Natural form of aspirin b Tetrahydrocannabinol 7 Natuurlike vorm van aspirien Tetrahidrokannabinol 3 Sephadex c Isoprene units 6 Sephadex Isopreen-eenhede 4 Codeine d Contains 25 alkaloids 10 Kodeïen Bevat 25 alkaloïede 5 Phenolic compounds e Nitrogen containing compounds 1 Fenoliese verbindings Stikstofbevattende verbindings 6 Terpenoids f Benzene ring and an OH-group 5 Terpenoïede Benseenring en n OH-groep 7 Dagga g Chemical identification of compounds 8 Dagga Chemiese identifikasie van verbindings 8 NMR h Separate molecules on size 3 KMR Skei molekule op grond van grootte 9 Herbarium i Methyl ether of morphine 4 Herbarium Metieleter van morfien 10 Opium j Identification of plant species 9 9

10 Opium Identifikasie van plantspesies 9.2 Provide the names of five examples of groups of secondary compounds and also the name of one compound from each of the five groups. No chemical structure are required. Noem vyf groepe sekondêre verbindings sowel as die naam van een verbinding in elke groep. Geen chemiese struktuurformules hoef verskaf te word nie. (5) (half mark for groupname & another half mark for one example) Alkaloids e.g. morphine, cocaine,strychnine, nicotine,caffeine, quinine Non protein amino acids e.g. Dopa (dioh-phenylalanine) Phenols e.g. flavonoids, flavonol, tannins, lignins Terpenoids e.g. taxol, euphol, isoprene, essential oils, many insecticides Saponins and steroids e.g. digitalis, cholesterol QUESTION / VRAAG 10 : [19] 10.1 Name the three levels of biodiversity. Noem die drie vlakke van biodiversiteit. (3) Genetic, species and ecosystem diversity / Geneties, spesie en ekostelsel diversiteit 10.2 Name two major threats to biodiversity. Noem twee hoofbedreigings vir biodiversiteit. (2) Any two of / Enige twee van die volgende: Habitat destruction, loss or fragmentation / Habitatsverlies, -verandering of - fragmentering Species introduction (or alien or invasive species) / Uitheemsespesies Over-exploitation or over-harvesting / Oorbenutting Climate change / Klimaatsverandering Pollution or resource depletion / Besoedeling of hulpbron uitputting 10.3 Provide the term describing interspecific interactions where: Wat is die woord wat interspesifieke interaksies beskryf waar: (4) both species benefit (i.e. +/+ outcome) beide spesies bevoordeel word (dws +/+ resultaat) mutualism (or facilitation) / mutualisme (of fasilitasie) both species are negatively affected (-/- outcome) beide spesies negatief beïnvloed word (dws -/- resultaat) competition / kompetisie one species benefits and the other species is negatively impacted (+/- outcome)/ een spesie word bevoordeel en die ander spesie word benadeel (dws +/- resultaat) 10

11 predation, parasitism, herbivory, or disease (pathogen) / predasie, parasitisme, herbivorie of siekte (patogene) one species benefits and the other species is not affected (+/0 outcome) een spesie word bevoordeel en die ander spesie word nie beïnvloed nie (dws +/0 resultaat) commensalism / kommensalisme 10.4 Mention two biotic and two abiotic factors limiting species distributions. Noem twee biotiese en twee abiotiese faktore wat n spesie se verspreiding kan beperk. (4) Any two: Biotic factors = competition, predation, herbivory, parasitism, facilitation, pathogens Any two: Abiotic factors = temperature, water availability (or soil moisture or humidity or rainfall), sunlight (or cloudiness), wind (or climate in general), rocks and soils (physical substrate, including soil ph or calcareousness) 10.5 Define sustainable development. Definieer volhoubare ontwikkeling. (3) Sustainable development = meeting the needs of the present generation without jeopardising the ability of future generation to meet their needs. It has three components: social, environmental and economic sustainability. Volhoubare ontwikkeling = voorsien aan die behoeftes van die huidige generasie sonder om die vermoeë van toekomstige generasies in gevaar te stel om aan hulle behoeftes te voldoen. Dit het drie komponente: sosiale, omgewings-en ekonomiese volhoubaarheid What are the three characteristics of a biodiversity hotspot? Wat is die drie kenmerke van n biodiversiteitsfokusarea? (3) An area with high species richness, high endemism, and high threat (or vulnerability) n Gebied met hoë spesies rykheid, hoë endemisme en hoë bedreiging (of kwesbaarheid) TOTAL / TOTAAL :