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1 Introduction 1.1 PROPAGATION OF ROMULEA SPECIES FOR HORTICULTURAL AND CONSERVATION PURPOSES Romulea is a genus with many species of potential horticultural value. The fast growth, attractive growth forms, regular flowering and diverse flower variation with many aesthetically pleasing colours, makes species of this genus prime candidates for commercialisation as miniature potted plants and cut flowers (MANNING & GOLDBLATT, 1996; 1997; NIEDERWIESER et al., 2002). The Iridaceae is one of the most horticulturally important families of monocotyledons. Most of the cultivated ornamental species indigenous to South Africa have come from this family (COETZEE et al., 1999; NIEDERWIESER et al., 2002; REINTEN & COETZEE, 2002). The two genera of Iridaceae most in demand by the world market as floricultural crops are Gladiolus and Freesia (COETZEE et al., 1999). The production of cut flowers of Gladiolus and Freesia is a million dollar industry in many parts of the world (GOLDBLATT, 1991). These two genera are placed in the same tribe, Ixieae, as the genus Romulea (GOLDBLATT, 1990). The name Romulea was borrowed from the city of Rome, in vicinity of which the genus was first described by Maratti in a small taxonomic study published in 1772. He proposed that this species was distinct from Crocus, Colchicum, Sisyrinchium, Bulbocodium and Ixia (DE VOS, 1972). According to MANNING & GOLDBLATT (2001) there are approximately 90 species of Romulea. These species are found in sub-Saharan Africa, the Mediterranean basin, the Canary Islands, the Azores, and southern Europe (DE VOS, 1972; MANNING & GOLDBLATT, 2001). This attractive genus of the Iridaceae has its centre of diversity in the winter-rainfall zone of South Africa where 73 species are now recognized (MANNING & GOLDBLATT, 2001). Viewing the flowering plants in this area is an important tourist attraction. It attracts international tourists including world renowned botanists and nature lovers. Many South Africans also travel across the country each year to immerse themselves in the beauty of this floral spectacle, 1
Introduction where a great number of species of Romulea can be seen. Within the summer- rainfall zone of southern Africa, the species is restricted to upland and montane habitats (MANNING & GOLDBLATT, 2001). Species belonging to Romulea are deciduous perennial geophytes and the tunicated corms of these plants enable them to survive the dry season (DE VOS, 1972; MANNING & GOLDBLATT, 2001). At the start of the growing season, a group of adventitious roots are first formed near the base of the corm, after which the uppermost axillary bud develops into an inflorescence stem (DE VOS, 1972). According to HILTON-TAYLOR (1996) there are 18 rare, 10 vulnerable and 2 extinct species in the genus Romulea. RAIMONDO et al (2009) however lists this genus as having only 4 rare, 4 near threatened, 23 vulnerable, 7 endangered and 3 critically endangered species. In their book, RAIMONDO et al (2009) displays a photograph of the vulnerable Romulea sabulosa on the cover. This species was used in this study. Despite the fragile conservation status of many species in this genus, the area which hosts its centre of diversity is also under threat from climate change. The longer periods and higher intensity of drought in the Cape Floral Region is likely to have a large negative impact on the endemic flora (WEST, 2009). This study will form the groundwork for the commercialisation and conservation of this genus, as there has been no extensive work done on its ecophysiology and propagation. Micropropagation is an important tool for ornamental plant culture and breeding, which has been applied to almost all commercial geophytes (ZIV, 1997). It enables high propagation rates, which is especially useful for the commercialisation of new species (LILIEN-KIPNIS & KOCHBA, 1987; PIERIK, 1997). In many instances it has also been shown that micropropagation can play a vital role in plant conservation, especially when combined with methods such as cryopreservation (WOCHOCK, 1981; SARASAN et al., 2006; SHIBLI et al., 2006; WITHERS, 2008). 2
Page 1 and 2: Propagation of Romulea species Pier
Page 3 and 4: Contents 2.7 GERMINATION PHYSIOLOGY
Page 5 and 6: Contents 5.3.1 Explants from seedli
Page 7 and 8: Abstract The suitability of various
Page 9 and 10: Declarations I Pierre André Swart,
Page 11 and 12: Declarations DETAILS OF CONTRIBUTIO
Page 13 and 14: Publications from this thesis ASCOU
Page 15 and 16: List of Figures Figure 2.13: Suther
Page 17 and 18: was significantly different from th
Page 19 and 20: List of Tables Table 2.1: Names of
Page 21 and 22: List of Abbreviations 2,4-D 2,4-Dic
Page 23 and 24: Die vlakhaas spits sy oor hy het di
Page 25: As die mens dan ook so sy dankbaarh
Page 29 and 30: Introduction The subgenera Romulea
Page 31 and 32: 2 Literature review Leef van daad e
Page 33 and 34: Literature review Figure 2.2: Life
Page 35 and 36: Literature review Figure 2.4: Life
Page 37 and 38: Literature review The plants are sh
Page 39 and 40: Literature review flowers (DE VOS,
Page 41 and 42: Literature review often found on cl
Page 43 and 44: Literature review flowers of R. lei
Page 45 and 46: Literature review flattened upper s
Page 47 and 48: 2.2.16 Romulea tabularis Literature
Page 49 and 50: Literature review extinct, R. papyr
Page 51 and 52: Literature review R. leipoldtii occ
Page 53 and 54: Literature review Figure 2.8: Calvi
Page 55 and 56: Literature review Figure 2.14: Fras
Page 57 and 58: Figure 2.20: Nieuwoudtville weather
Page 59 and 60: Literature review Figure 2.26: Grah
Page 61 and 62: Literature review Figure 2.29: Diag
Page 63 and 64: Literature review Figure 2.30: A te
Page 65 and 66: Literature review Macronutrients ca
Page 67 and 68: Literature review The soils of the
Page 69 and 70: Literature review The embryo is the
Page 71 and 72: Literature review Phase 2 is seen a
Page 73 and 74: Literature review endogenous gibber
Page 75 and 76: Literature review tolerable level (
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Literature review these channels pe
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Literature review 2.8.7 Seed dorman
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Literature review the embryo (COPEL
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Literature review germinated under
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Literature review (COPELAND, 1976).
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2.9 BRIEF REVIEW OF IN VITRO CULTUR
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Literature review (DEBERGH, 1994).
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Literature review PIERIK (1997) sta
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Literature review The distinguishin
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Literature review The essential fun
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2.9.3.4 Abscisic acid Literature re
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Table 2.6: Example of a matrix to e
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Literature review Young embryos req
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Literature review and the addition
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Literature review organ is then pro
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Literature review environmental str
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2.11 IN VITRO FLOWERING Literature
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Literature review higher regenerati
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Subfamily Ixioideae (continued) Tri
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Literature review Table 2.8: Corm i
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3 Investigation into the habitat of
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Soil sampling and analysis The firs
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Soil sampling and analysis Table 3.
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4 Germination physiology 4.1 INTROD
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4.2.2 Water content and imbibition
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Germination physiology (-N), phosph
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Germination physiology rosea seeds
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Germination physiology Figure 4.4:
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Germination (%) 50 40 30 20 10 0 77
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Germination (%) 100 80 60 40 20 0 c
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Germination physiology The relative
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Germination physiology seeds of R.
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5.2 MATERIALS AND METHODS In vitro
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In vitro culture initiation and mul
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5.2.3 Explant comparison In vitro c
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5.4 DISCUSSION In vitro culture ini
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6 In vitro corm formation and flowe
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In vitro corm formation and floweri
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6.3 RESULTS 6.3.1 Corm formation In
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Commercialization potential of Romu
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Commercialization potential of Romu
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BASKIN, C. C., and BASKIN, J. M. (1
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Literature cited DOWLING, P. M., CL
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Literature cited HILTON-TAYLOR, C.
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Literature cited KUMAR, A., SOOD, A
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Literature cited PIERIK, R. L. M. (
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Literature cited STEINITZ, B., COHE
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