This genus in the Iridaceae has its center of diversity in the winter rainfall zone of South Africa. Ecophysiological techniques of soil sampling and analysis and germination physiology were used to determine the natural and ex vitro growth and development requirements of these plants, while biotechnological techniques were used to determine the in vitro growth and development requirements of these plants and to increase the rate. of multiplication and development. Crack cultures can be initiated in media supplemented with 2.3 to 23.2 M kinetin for all species that showed an in vitro response.
They studied the influence of various physical and chemical parameters on tuber formation in vitro and ex vitro acclimatization and growth. Although a case of in vitro flowering was observed during these experiments, these results could not be replicated. Although none of the tubers or plants planted ex vitro in the greenhouse survived, the low viability and the ex vitro acclimation experiment indicate that stem tubers grown in vitro are viable.
This thesis, Propagation of Romulea species, unless otherwise acknowledged in the text, is the result of my own research, under the guidance of Professor J.
Conference contributions
8 Figure 2.3: Life cycle of Romulea monadelpha, another species endemic to the winter rainfall region of South Africa (Modified from ASCOUGH (2008); 9 Figure 2.4: Life cycle of Romulea cameroniana, a species found in summer rainfall regions of Africa (Modified from ASCOUGH (2008);.104 Figure 4.2: Scanning electron microscopic images of seeds arranged from smallest to largest for size comparison.
130 Figure 5.8: Effect of three different concentrations of kinetin and mTR with or without 0.5 NAA on shoot production of hypocotyls and embryos of Romulea leipoldtii seedlings. 68 Table 2.6: Example of a matrix to establish optimal auxin to cytokinin ratios and their concentrations, where rows represent auxin levels and columns represent cytokine levels (Modified from Kyte and Kleyn (1996). 74 Table 2.7: Sources of explants and PGR' is used by different authors for direct shoots or meristimoid organogenesis in Iridaceae genera.
The lizard scrambles stiff-legged over scorching granite rock No shade trees here – the earth is flat – Tortoise seeks a small bush, others dig a hole.
1 Introduction
PROPAGATION OF ROMULEA SPECIES FOR HORTICULTURAL AND CONSERVATION PURPOSES
RAIMONDO et al (2009) states that this genus has only 4 rare, 4 near-endangered, 23 vulnerable, 7 endangered and 3 critically endangered species. In their book, RAIMONDO et al (2009) shows a photograph of the vulnerable species Romulea sabulosa on the cover. This study will be the basis for the commercialization and conservation of this genus, as no extensive work has been done on its ecophysiology and reproduction.
In many cases, it has also been shown that micropropagation can play a crucial role in plant conservation, especially when combined with methods such as cryopreservation (WOCHOCK, 1981; SARASAN et al., 2006; SHIBLI et al., 2006; WITHERS, 2008). . The overall aim of this study was to investigate the conditions that promote the growth and development of a number of Romulea species, both ex vitro and in vitro, in order to promote their commercialization and conservation. It was expected that there would be a correlation between geographical distribution and appropriate ex vitro and in vitro stimuli.
4 The subgenera Romulea and Spatulanthus were expected to have differential conditions suitable for ex vitro and in vitro growth and development.
GENERAL OVERVIEW OF THESIS CONTENT
- SPECIES SPECIFIC MORPHOLOGY AND DISTRIBUTION
- Romulea monadelpha
- Romulea pearsonii
- Romulea rosea
- Romulea sabulosa
- PHYLOGENY AND TAXONOMY
- CONSERVATION STATUS
- THE CLIMATE OF ROMULEA SPP. HABITATS
- Physical properties of soil
- Organic matter
- Soil nutrients
- Salinity
- Cation and anion exchange capacity and surface charges
- Soils of Namaqualand
- GERMINATION PHYSIOLOGY
- Seed structure
- Seed germination
- Measuring germination
- Promotion and inhibition of germination .1 Gibberellin and abscisic acid
- Phytochromes and light quality
- Scarification Mechanical scarification
- Seed longevity and viability
- After-ripening
- Embryo-excision as a tool for investigating mechanisms behind dormancy and testing viability
- Embryo and seedling morphology of Iridaceae
- Explant selection
- Explant preparation
- Medium composition
- Embryo-excision
- Organogenesis
- Somatic embryogenesis
- Hardening
- Applications of in vitro culture
- CORM PHYSIOLOGY
- IN VITRO PROPAGATION OF BULBOUS PLANTS
- IN VITRO PROPAGATION OF IRIDACEOUS SPECIES
- INTRODUCTION
- MATERIALS AND METHODS
- RESULTS
- SUMMARY
- MATERIALS AND METHODS
- Viability tests
- Scanning electron microscopy
- Ex vitro germination experiments
- Statistical analysis
- Water content and imbibition rate
- SUMMARY
- Explants from seedlings
- Explants from embryos
- Shoot multiplication
- Statistical analysis
- RESULTS
- Explants from seedlings
- Explants from embryos
- Explant comparison
- Shoot multiplication
- SUMMARY
11 Species belonging to Romulea are deciduous, perennial geophytes (DE VOS, 1972; MANNING & GOLDBLATT, 2001). Thanks to the corms of these plants, they can survive the dry season (DE VOS, 1972). The pH of the nutrient solution influences the solubility and availability of nutritional elements (DONAHUE et al., 1983). Not only the plant life, but also the soils of the Nieuwoudtville region are diverse (BRAGG et al., 2005).
The axis further consists of the embryonic root (radicle), the hypocotyl with attached cotyledons and the shoot tip with the first true leaves (plumules) attached (BEWLEY & BLACK, 1994). This stage is associated with changes in the cells of the radicle and radicle elongation (JANN & AMEN, 1977; BEWLEY & BLACK, 1994). In the case of morphological dormancy, germination is prevented at the time of maturation due to the morphological characteristics of the embryo.
Successful and sufficient rooting is essential for plant survival during establishment and transfer to soil (AHLOOWALIA et al., 2002). The approach to developing an appropriate medium will depend on the purpose of the culture (SMITH, 2000b). High-quality water should be used as a component of the plant culture medium (PIERIK, 1997; BEYL, 2005).
The type and concentration of plant growth regulators used varies according to the purpose of the culture (PIERIK, 1997). Such reprogramming results in dedifferentiation and then redifferentiation into a new developmental pathway (GABA, 2004). The mechanism of dedifferentiation is not understood (GABA, 2004). Cultivation of callus is often performed in the dark, as light can induce callus differentiation (SLATER et al., 2003).
Dry weight measurements are more accurate but involve destruction of the sample (PHILLIPS et al., 1995). In the next phase, the morphological differentiation and development of the nascent organ takes place (SCHWARTZ et al., 2004). The good and sustainable health of leaves is therefore essential for the acclimatization and survival of the plant (HUYLENBROECK et al., 1998).
Stomatal aperture can be measured by applying nail polish to the abaxial surface of the mature leaf (ROBERTS et al., 1990). This is due to vitrification and abnormal growth of shoots grown in BA supplemented media. All but one set of shoots formed on media supplemented with 23.2 µM kinetin failed to root (Data not shown).
INTRODUCTION
MATERIALS AND METHODS
- Corm formation
- Corm formation
The rest of these shoots were multiplied for a further 4 months and then used in an experiment to test the effect of growth retardants on garlic formation in R. This was done by multiplying the proportion of garlic induction by the mass of the tubers produced (mg) and dividing this number by one hundred according to the methods of ASCOUGH et al. The product of tuber induction and tuber mass indicates that placing the shoots at 10°C on a medium with 6% sucrose results in the best combination of both proportion induction and tuber mass, followed by the shoots placed at 20°C media is placed with 9%.
The addition of 17.0 and 34.0 M PP3 resulted in the greatest percentage of tiller induction and tiller size (Table 6.2). No tuber formation was observed at any temperature and medium tested for R. When 100 bottles of shoots propagated on BA-supplemented media placed at 25°C were not subcultured for 6 months, no tuber formation or basal thickening was observed.
The highest percentage of multiple corm formation was observed at 15°C in a medium supplemented with 23.2 μM kinetin, while the highest number of corms per shoot was observed at 10°C in a medium with 3 % sucrose. This shows the percentage of corm formation in crops in which corm formation was observed (Total Corm Crops) and the average number of corms produced in cases of multiple corm formation. The highest number of cases of multiple corm formation for R. sabulosa was also observed at 10 and 15°C.
In a study by ASCOUGH et al. 2008) on Watsonia vanderspuyiae (in the same subfamily, Ixioideae), the highest percentage of garlic induction was observed for shoots placed at low temperatures. This study showed no significant difference between garlic induction percentages of shoots placed on MS media supplemented with sucrose at 10 and 20 °C. Clump formation at low temperatures has been observed in vitro for many genera in the Iridaceae (ASCOUGH et al., 2009).
However, it was shown by HOMES et al. 1987), that tuber formation of Crocus sativus also occurred at 30°C, a temperature that totally inhibits tuber formation of R. 148 supplemented with BA after 6 months, shows that this chemical inhibits tuber formation for this genus.
SUMMARY
The flowers are attractive not only because of their wide variety of colors, including yellow to white, pink, orange, apricot, red, magenta, lilac and purple, but also because of the interesting shape of some flowers such as R. Germination of the seeds of some however, some of the most attractive species in this genus are few. Apart from the increased propagation rate in vitro compared to conventional propagation, in vitro techniques such as embryo rescue established for these species will also be useful in the commercialization of these species.
Embryo rescue enables embryo development in vitro if the endosperm is underdeveloped (HARTMANN & . KESTER, 1965). She speculated that this was due to failure of endosperm development, suggesting that the embryo might be viable and that embryo rescue and in vitro culture techniques could be used to grow these hybrids (DE VOS, 1972). 154 large, beautiful and fragrant flowers that can be cloned in vitro using the protocols established in this study.
Embryo rescue and in vitro culture techniques can also be used to cross such a phenotype with a widespread species such as R. Plant-derived smoke and smoke extracts stimulate seed germination of the fire climax grass Themeda trianda. Plants of the Nyika Plateau: an account of the vegetation of the Nyika National Parks of Malawi and Zambia.
A smoke-induced alteration of the sub-testa cuticle in seeds of the post-fire recruit, Emmenanthe penduliflora Benth. Totipotency in tissue explants and calluses of some members of the Liliaceae, Iridaceae and Amaryllidaceae. Seed dormancy: changing concepts and theories In: The Physiology and Biochemistry of Seed Dormancy and Germination.
In vitro conservation of endangered plants: progress over the past decade. In vitro cellular and developmental biology. Thirty-fifth Annual Conference of the South African Association of Botanists (SAAB), 19 to 22 January, University of Johannesburg, Drakensberg.
