View/Open - ResearchSpace - University of KwaZulu-Natal

More documents

Recommendations

Info

In vitro corm formation and flowering and ex vitro acclimatization During this period new axillary buds are formed. The axillary buds gradually form their own corm at the base as conditions for growth becomes less suitable at the end of flowering in September. During September and October the averaged daily minimum temperatures are 6.3 ± 0.7°C and 8.2 ± 0.3°C and the averaged daily maximum temperatures are 21.3 ± 0.7°C and 25.6 ± 0.4°C. The maximum temperature of periods of vegetative growth and corm induction is close to 15°C and the minimum and maximum temperatures are close to 10 and 20°C during periods of senescence, when accumulated carbohydrates may be reallocated to the corm in the natural habitat of R. sabulosa. Although such an explanation is plausible, the interactions of factors that influences the climate of Namaqualand is very complex and it is therefore a difficult topic (DESMET, 2007). The corm production rate of various Gladiolus cultivars was also increased by a two step bud-culture technique, involving short-term exposure to a medium with plant growth regulators and subsequent withdrawal from plant growth regulators in a liquid medium (SEN & SEN, 1995). The specific temperature needed for carbohydrate accumulation for R. sabulosa, compared to that of Tritonia gladiolaris may be explained by its very restricted distribution compared to that of the widespread T. gladiolaris. An adaptation to accumulate carbohydrates above a certain temperature and to induce corms below this temperature would allow a species to spread to a variety of habitats where this temperature is observed, whereas a specific carbohydrate accumulation temperature range will limit the populations to an area with periods of this temperatures long enough to accumulate sufficient carbohydrates to be able to survive the dry seasons underground in a dormant state and to produce enough vegetative growth in the next season for the accumulation of additional carbohydrates. The fact that corms did not flower in vitro is probably because these plants need much colder minimum temperatures (below 5°C) such as in their natural environment for growth and development. The one corm of R. minutiflora which flowered in vitro at 20°C was perhaps a mutation. Plantlets of Romulea species develop viable corms after 6 months, which can be commercialized as propagation units. Corm formation speeds up the 149
In vitro corm formation and flowering and ex vitro acclimatization micropropagation and seedling establishment process and it is also cost-effective, as there is no need for hardening or acclimatization of plants. 6.5 SUMMARY • Low temperature significantly increased corm formation in R. minutiflora and R. sabulosa • A two step corm formation protocol involving placing corms at either 10 or 20°C for a few months and then transferring these cultures to 15°C should be used for R. sabulosa • When PP3 and ABA is added to the medium on which R. minutiflora shoots were placed, these shoots develop corms at 25°C, a temperature that totally inhibits corm formation when these growth retardants are not present • BA inhibited corm formation in R. leipoldtii • Corms of Romulea sabulosa formed at 10°C are viable • Corms can be commercialized as propagation units to grown in winter-rainfall areas with minimum temperatures below 5°C during winter 150
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 and 26:
As die mens dan ook so sy dankbaarh
Page 27 and 28:
Introduction where a great number o
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 (
Page 77 and 78:
Literature review these channels pe
Page 79 and 80:
Literature review 2.8.7 Seed dorman
Page 81 and 82:
Literature review the embryo (COPEL
Page 83 and 84:
Literature review germinated under
Page 85 and 86:
Literature review (COPELAND, 1976).
Page 87 and 88:
2.9 BRIEF REVIEW OF IN VITRO CULTUR
Page 89 and 90:
Literature review (DEBERGH, 1994).
Page 91 and 92:
Literature review PIERIK (1997) sta
Page 93 and 94:
Literature review The distinguishin
Page 95 and 96:
Literature review The essential fun
Page 97 and 98:
2.9.3.4 Abscisic acid Literature re
Page 99 and 100:
Table 2.6: Example of a matrix to e
Page 101 and 102:
Literature review Young embryos req
Page 103 and 104:
Literature review and the addition
Page 105 and 106:
Literature review organ is then pro
Page 107 and 108:
Literature review environmental str
Page 109 and 110:
2.11 IN VITRO FLOWERING Literature
Page 111 and 112:
Literature review higher regenerati
Page 113 and 114:
Subfamily Ixioideae (continued) Tri
Page 115 and 116:
Literature review Table 2.8: Corm i
Page 117 and 118:
3 Investigation into the habitat of
Page 119 and 120:
Soil sampling and analysis The firs
Page 121 and 122:
Soil sampling and analysis Table 3.
Page 123 and 124: 4 Germination physiology 4.1 INTROD
Page 125 and 126: 4.2.2 Water content and imbibition
Page 127 and 128: Germination physiology (-N), phosph
Page 129 and 130: Germination physiology rosea seeds
Page 131 and 132: Germination physiology Figure 4.4:
Page 133 and 134: Germination (%) 50 40 30 20 10 0 77
Page 135 and 136: Germination (%) 100 80 60 40 20 0 c
Page 137 and 138: Germination physiology The relative
Page 139 and 140: Germination physiology seeds of R.
Page 141 and 142: 5.2 MATERIALS AND METHODS In vitro
Page 143 and 144: In vitro culture initiation and mul
Page 145 and 146: 5.2.3 Explant comparison In vitro c
Page 159 and 160: 5.4 DISCUSSION In vitro culture ini
Page 163 and 164: 6 In vitro corm formation and flowe
Page 165 and 166: In vitro corm formation and floweri
Page 167 and 168: 6.3 RESULTS 6.3.1 Corm formation In
Page 173: In vitro corm formation and floweri
Page 177 and 178: Commercialization potential of Romu
Page 179 and 180: Commercialization potential of Romu
Page 181 and 182: BASKIN, C. C., and BASKIN, J. M. (1
Page 183 and 184: Literature cited DOWLING, P. M., CL
Page 185 and 186: Literature cited HILTON-TAYLOR, C.
Page 187 and 188: Literature cited KUMAR, A., SOOD, A
Page 189 and 190: Literature cited PIERIK, R. L. M. (
Page 191 and 192: Literature cited STEINITZ, B., COHE
show all

View/Open - ResearchSpace - University of KwaZulu-Natal

Create successful ePaper yourself

Delete template?

Save as template?