Temperature effects on bulb growth and inflorescence development of Lachenalia cv. Ronina

Lachenalia cv. Ronina, a new flower bulb variety developed by the ARC-Roodeplaat Vegetable and Ornamental Plant Institute, has excellent characteristics as a flowering pot plant, but information on cultivation practices is limited. Temperature is the most important environmental factor regulating the growth cycle of this flower bulb, therefore three temperature regimes, representing a cool, moderate and warm winter climate, were chosen to manipulate floral development. During this study the bulb structure, development and growth were determined during the bulb preparation phase (year 1) and subsequently the morphology of the bulb was evaluated during the pot plant phase (year 2). Regarding the bulb structure and development, cultivar Ronina has a typical rhythmic, sympodial, modular growth. Bulb growth and module formation is affected by temperature. The low (L TR) and moderate (MTR) temperature regime, which represent the cool and moderate winter climate in South Africa were found to be the best temperature regimes for bulb production. The high (HTR) temperature regime caused bulbs to develop faster, but flower abortion occurred. At the end of the bulb preparation phase, daughter bulbs were observed in the axils of the leaf bases in bulbs of all three temperature regime treatments. Additional inflorescences from underdeveloped growth modules were detected in the axils of the inner leaf bases of bulbs of the high temperature regime. The bulbs as well as the roots are the main sinks for the carbohydrates, whereas the inflorescence and especially the leaves are the main source for soluble sugars. Due to the more stable temperature that was applied in the growth cabinets, the flowering date of bulbs in all three treatments flowered two months earlier than plants growing in the open. During this production phase, simultaneous flowering occurred more within bulbs that were subjected to the LTR during the bulb preparation phase. These bulbs also produced broader leaves with more spots on and better quality inflorescences with a longer keeping ability than those of the higher temperature regimes. A correlation was found between the leaf number and the number of inflorescences of plants in the pot plant phase, grown from LTR treated bulbs. The bulb fresh mass/size at the end of the bulb preparation phase cannot be used as a reliable criterion to predict the quality of the pot plant. By examining the bulb structure at the end of the bulb preparation phase, the quality of the pot plant can be predicted.Thesis (PhD Agric (Horticultural Science))--University of Pretoria, 2007.Plant Production and Soil Scienceunrestricte

In vitro multiplication of Protea cynaroides L. microshoots and the effects of high phosphorous concentration on explant growth

Protea cynaroides L. is a slow-growing, difficult-to-propagate plant. Due to problems such as phenolic browning and their sensitivity to the phosphorous nutrient, in vitro multiplication of P. cynaroides explants have not been successful. The present study was conducted to induce shoot proliferation of established P. cynaroides microshoots, and investigate the effects of high phosphorous concentration during explant multiplication. Microshoots with either one or two nodes were cultured on Murashige and Skoog (MS) medium containing modified macronutrients and full strength micronutrients. Two concentrations of NH4H2PO4 were tested: 0 mg L-1 NH4H2PO4, and a high P concentration of 1400 mg L-1 NH4H2PO4. Both growth media were also supplemented with gibberellic acid (GA3) (30 mg L-1), 6-benzylaminopurine (BAP) (2 mg L-1), ethylenediaminetetraacetic acid (EDTA) (50 mg L-1) and indole-butyric acid (IBA) (0.5 mg L-1). Results show that, contrary to what is often reported, the presence of a high phosphorous concentration in the growth media did not adversely affect P. cynaroides explants. The survival rate and mean axillary shoot length of explants cultured on growth media containing 1400 mg L-1 NH4H2PO4 were not significantly different from those grown on 0 mg L-1 NH4H2PO4. No phosphorous toxicity symptoms were observed in explants cultured on media with high phosphorous levels. Results also show that explants with two nodes had a higher survival rate and produced significantly longer axillary shoots than those with one node, irrespective of phosphorous concentration. Multiplication of P. cynaroides microshoots was successfully achieved for the first time.This work was supported by the National Science Council of Taiwan (R.O.C) in the form of a research grant (NSC 100-2313-B-343-001).http://www.academicjournals.org/AJBam201

Transient gene expression assays in rose tissues using a Bio-Rad Helios® hand-held gene gun

Rose tissues of different varieties were transformed using a Bio-Rad Helios® hand-held biolistic gun. Parameters for optimum transient expression were optimized and included rose variety, flower age, tissue, gold particle size, DNA loading ratio. Smooth flowers without thick waxy layers and young unopened actively growing flowers were found to be better suited for the transient expression assays. The DNA amounts, gold particle amounts and size etc were not found to influence the efficiency of the transient transformation in these tissues. These studies indicate that biolistic transformation using hand-held guns can be used for successful transient expression assays in rose flower tissues. This is especially useful for a quick and easy analysis of genes and their expression before attempting stable transformation.http://www.elsevier.com/locate/saj

An investigation into using temporary immersion bioreactors to micropropagate Moringa oleifera Lam. callus, roots, and shoots

Moringa oleifera Lam., a tree naturally grown in the tropics, is becoming increasingly popular as an industrial crop due to its multitude of useful attributes. Therefore, this study tested the effect of temporary immersion system (TIS) bioreactors for mass micropropagation of Moringa oleifera Lam. callus, roots, and shoots. TIS are tissue culture systems that make use of timers to periodically immerse and drain plant cultures in a liquid nutrient medium instead of using solidified media. In initial studies, Moringa oleifera seeds were germinated in vitro, and in vitro seedling leaflets were then used as explant material for callus production on the pre-culturing media. Two experiments were conducted to improve the protocol for TIS bioreactor production. The first experiment investigated the effect of 6-benzylaminopurine (BA) and kinetin, whereas experiment 2 was conducted to improve shooting production. For the first experiment, leaf material was cultured onto a solidified medium consisting of half-strength Murashige and Skoog (MS) basal salts and 0.5 ppm 1-naphthaleneacetic acid (NAA) to initiate callus production before splitting it between solidified media and bioreactors for shooting. The shooting media consisted of full-strength MS basal salts and different treatments of kinetin and BA. A significant increase in callus production was observed with the use of TIS bioreactors, compared to solidified media, whereas root production had a highly significant interaction effect between the media and the cytokinin treatments. With shoot proliferation in mind, experiment 2 was performed, where microcuttings from in vitro-grown seedlings were excised and cultured onto a solidified MS medium, consisting of a control (0 ppm BA) and two different concentrations of 6-benzylaminopurine (BA) (0.1 ppm BA and 0.2 ppm BA) in the pre-culturing phase. Microcuttings were again excised after two weeks and transferred to the shooting media containing 0.1 ppm BA in TIS bioreactors and semi-solidified medium. Results showed TIS bioreactors to be effective in increasing both the amount and length of shoots produced. Shoot and callus fresh weights were also higher in explants cultured in TIS bioreactors. The results of this study also suggest M. oleifera sensitivities to plant growth regulators (PGRs). In conclusion, this study successfully produced callus, roots, and shoots in both the solidified media and TIS bioreactors, emphasizing the prospect of using TIS bioreactors for mass micropropagation of M. oleifera callus, roots, and shoots.The National Research Foundation (NRF) (Competitive program for Rated Researchers).https://www.mdpi.com/journal/agronomyam2023Plant Production and Soil Scienc

Transient gene expression assays in rose tissues using a Bio-Rad Helios® hand-held gene gun

Rose tissues of different varieties were transformed using a Bio-Rad Helios® hand-held biolistic gun. Parameters for optimum transient expression were optimized and included rose variety, flower age, tissue, gold particle size, DNA loading ratio. Smooth flowers without thick waxy layers and young unopened actively growing flowers were found to be better suited for the transient expression assays. The DNA amounts, gold particle amounts and size etc were not found to influence the efficiency of the transient transformation in these tissues. These studies indicate that biolistic transformation using hand-held guns can be used for successful transient expression assays in rose flower tissues. This is especially useful for a quick and easy analysis of genes and their expression before attempting stable transformation.http://www.elsevier.com/locate/saj

Role and significance of total phenols during rooting of Protea cynaroides L. cuttings

Phenolic compounds, which are known to regulate root formation, are found abundantly in difficult-toroot Protea cynaroides stem cuttings. In this study, analysis of total phenol content was carried out on blanched and unblanched cuttings to observe its fluctuation throughout the entire rooting period (120 days) and establish its relationship with root formation. Results showed that blanching significantly increased the total phenol content in the basal ends of the cuttings. The high total phenol content was associated with significantly higher rooting percentage and increased the number of roots formed. Blanching reduced the time needed for the cuttings to root sufficiently to be transplanted to the field by 30 days. Analyses of different parts of cuttings throughout the entire rooting period showed continuous increase in total phenols at the basal end, while decrease in total phenols was observed in the leaves.http://www.academicjournals.org/AJ

Irrigation amounts affect the compositional changes of Moringa oleifera seeds throughout different developmental stages

The compositional development of Moringa oleifera seed across a range of growth stages was monitored at three irrigation treatments, simulating total annual rainfall of 900 mm, 600 mm and 300 mm/annum over two consecutive growing seasons (24 months). Fruit developmental stages were categorized according to fruit diameter (0 mm – 28 mm) at 2 mm increments. Starch was the first to accumulate during the initial histo-differentiation phase (fruit diameters of 0 mm-12 mm), while oil levels remained comparatively low. During the subsequent expansion phase (fruit diameters of 12 mm – 24 mm) however, stored starch was mobilized and used in oil biosynthesis, reducing the starch content. The bulk of oil and protein were synthesised throughout this phase with their content increasing sigmoidally. As the seed moisture content decreased during the final maturation phase (fruit diameters of 24 mm – 28 mm), the average oil content reached 24.8%, while the protein contents were 24.8% and the starch contents were 8.7%. The different irrigation treatments had less of an effect on the final starch, oil and protein content than on the time and rate of their synthesis throughout seed development. Higher irrigation levels principally favoured oil biosynthesis. The highest final oil contents were measured at the intermediate irrigation treatment (600 mm/annum), suggesting that both lower and higher irrigation levels could possibly reduce final oil contents. The reduction in irrigation amount delayed the onset of oil biosynthesis and as a result the starch content reached higher levels prior to its remobilization during oil biosynthesis.© 2014 Friends Science Publishershttp://www.fspublishers.orgam201

Germination and ultrastructural studies of seeds produced by a fast-growing, drought-resistant tree: implications for its domestication and seed storage

Seed ageing during storage is one of the main causes of reduction in seed quality and this results in loss of vigour and failure to thrive. Finding appropriate storage conditions to ameliorate deterioration due to ageing is, therefore, essential. Ultrastructural changes in cellular organelles during storage and seed germination rates are valuable indices of damage that occurs during seed ageing. There is increasing interest in Moringa oleifera Lam. because of its multiple uses as an agroforestry crop. Seeds of this species lose their viability within 6–12 months of harvest but no scientific information is available on the longevity of seed stored in the fruit (capsules). Inmost undeveloped countries, seeds are still stored inside the fruit by traditional methods in special handmade structures. In this experiment we tried to simulate these traditional storage conditions. Capsules of Moringa were stored at ambient room temperature for 12, 24 and 36 months. The ultrastructure, solute leakage and viability of seed were investigated. The ultrastructure of 1-year-old seed showed no sign of deterioration. It was evident, however, that some cells of the 3-year-old seed had deteriorated. The remnants of the outer and inner two integuments that remain tightly attached to the cotyledons probably play a role in seed dormancy. No significant difference was found between germination percentage of fresh and 1-year-old seed. The germination percentage decreased significantly from 2 years of storage onward. The decrease in seed viability during storage was associated with a loss in membrane integrity which was evidenced by an increase in electrolyte leakage. Our findings indicate that the longevity of M. oleifera seeds can be maintained if they are stored within their capsules.National Research Foundation, South Africahttp://aobpla.oxfordjournals.orghb201

Effect of storage conditions on Moringa oleifera Lam. seed oil : biodiesel feedstock quality

Moringa seed oil is known as Ben oil. Recently research by several authors illustrated the potential use ofBen oil for biodiesel production. Oil quality is directly related to the physiological condition of the seedsfrom which it is extracted. Oil extracted from damaged and deteriorated seed can compromise fuel quality.The aim of the study was to investigate the effect of various storage conditions and—duration on Moringaoleifera seed oil quantity and quality as a potential source of biodiesel. Firstly, oil was extracted from freshseeds and stored in dark bottles at room temperature. Secondly, Seeds were stored following a factorial2 × 4 × 3 experiment with two types of containers (paper and aluminium bags), four temperatures (−19,4, 20 and 30◦C) and three storage periods (6, 12 and 24 months). From the experimental results, it wasobserved that the oil content of moringa seed did not change significantly (p < 0.05) after 12 monthsof storage but decrease significantly in seed stored at 4◦C in paper bags and those at 20◦and 30◦C inaluminium bags at 24 months. The free fatty acid increased significantly (p < 0.05) after 12 months at allstorage conditions and continued to increase above the recommended value (2%) for biodiesel parent oilat 24 months, except for that of seed stored at −19◦C in aluminium bags. The density of moringa seed oilremained unchanged throughout storage. The viscosity of oil extracted from seed stored in paper bags at−19◦C and that of the oil stored in dark bottle at room temperature decreased significantly at 24 months.Based on these results, moringa seed can be stored at any of the applied conditions for six months, butif they are stored beyond this period, the use of low temperature such as −19◦C and 4◦C and sealedcontainers are recommended. It is not advisable to store the extracted oil for more than 6 months.National Research Foundation, South Africahttp://www.elsevier.com/locate/indcrop2017-06-30hb2016Plant Production and Soil Scienc

The variation in antimicrobial and antioxidant activities of acetone leaf extracts of 12 Moringa oleifera (Moringaceae) trees enables the selection of trees with additional uses

BACKGROUND : The aim of this study was to evaluate the variation in antimicrobial and antioxidant activities of the leaf acetone extracts of 12 Moringa oleifera trees harvested in order to select the best material for clonal propagation. METHODS : A two-fold serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against a panel of fungal (Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans) and bacterial (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa) species. The radical scavenging capacity was determined using 2,2 diphenyl-1-picryhydrazyl (DPPH). RESULTS : There was a large variation in antimicrobial activities with MICs between 0.04 and 2.50 mg/ml against bacteria and from 0.16 to N2.50 mg/ml against fungi. For samples harvested in winter: trees L3 and LP2 had significant activity against E. faecalis (MIC 0.08 mg/ml) and E. coli (MIC 0.04 mg/ml). Trees L5, LP1 and LP6 had weak activity against E. coli (MICs 1.25 and 2.50 mg/ml), S. aureus (MIC 1.25 mg/ml), and E. faecalis (MIC 2.50 mg/ml), while other samples had moderate activity against the four bacteria (MICs 0.16–0.63 mg/ml). From samples collected in summer: L5 (MIC 0.08 mg/ml), L6 (MIC 0.08 mg/ml after 1 h incubation), LP1 (MICs 0.08 mg/ml), LP2 (MICs 0.08 mg/ml after 1 h incubation), LP4 (0.08 mg/ml) and LP5 (MICs 0.04 and 0.08 mg/ml) had significant activity against E. faecalis (L5, L6, LP1, LP2, LP4, and LP5), S. aureus (LP1, and LP5), and E. coli (LP2, and LP5), respectively. Other extracts had weak antibacterial activity with MICs ranging from 0.16 to 0.63 mg/ml. Most of the samples harvested in winter had moderate antifungal activity: L1, L2, L3, L4, L5, L6, LP1, LP2, and LP3 had moderate activity against C. albicans (ATCC strains) with MIC of 0.63 mg/ml in all cases while L2, L3 and L4 as well as L6, LP1, LP2, LP3, LP5 and LP6 against A. fumigatus (MICs 0.63 mg/ml) and C. neoformans (MICs 0.63 mg/ml), respectively. Apart from L1 (MIC 0.31 mg/ml), L2, L3 and LP6 (MICs 0.63 mg/ml in all cases) with moderate activity, all the samples collected during summer had weak activity against A. fumigatus (MICs 1.25–2.50 mg/ml). All the extracts had a low radical scavenging activity with the IC50 values ranging from 34.72 to 109.62 μg/ml, compared to the reference standard L-ascorbic acid (IC50 2.41 μg/ml). This may be related to the extractant used. CONCLUSION : The large variation in antimicrobial activity and antioxidant activities of 24 acetone leaf extracts of 12 M. oleifera trees may lead to the selection of clonal material to serve as a source of propagation materials. Successful propagation and growth of tree LP with very good activity against E. coli and a high total activity could provide an additional use of this valuable plant species to rural people.The Limpopo Department of Agriculture (LDA), the National Research Foundation and MDA received a Postdoctoral Fellowship from the University of Pretoria. Open Access funded by SAAB.http://www.elsevier.com/locate/sajbhb2017Paraclinical Science