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Multi-dimensional modelling of biomass energy flowsHemstock, Sarah Louise January 1999 (has links)
No description available.
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BIOMASS PRODUCTION FOR ENERGY IN DEVELOPING COUNTRY : Case Study: CHINA and NIGERIALiu, Xiaolin, Balogun, Kazeem January 2012 (has links)
Most developing countries of the world still uses biomass for domestic energy, this is mostly used in the rural areas and using our case study which is Nigeria and China. We have been able to establish the potential of biomass production energy use by looking at calorific values of some biomass such As-harvested wood, Dry wood, Straw Miscanthus Coal which was discussed on the introduction part of this thesis.
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The physiology of industrial yeast in continuous cultureWardrop, Forbes Robert January 1999 (has links)
The growth and physiology of <i>Saccharomyces cerevisiae</i> GB4918 (baker’s yeast) was studied under glucose-limitation in chemostat culture. Levels of lg/1 (0.1% w /v) glucose allowed cell growth while preventing fermentation in a defined medium (QEMM3). Metabolism of glucose by respiration or fermentation was shown to affect the mean cell volume, with fermentative use of glucose causing an increase in cell size. This was also a major physiological difference between <i>S. cerevisiae </i>GB4918 (a Crabtree positive yeast) and <i>Kliiyveromyces marxianus</i> DBVPG 6165 (a Crabtree negative yeast). The ability of the Crabtree positive yeast to substantially increase its mean cell volume was also reflected in a 5-fold greater consumption of glucose, reduced biomass yield and increased ethanol yield, compared with the Crabtree negative <i>K . marxianus</i>. Growth of both these yeasts was seen in 50g/l glucose in the presence of the respiratory inhibitor, antimycin A. This was evident by the switching to fermentation in <i>K . marxianus</i>, and the complete fermentation of glucose by <i>S. cerevisiae</i>. The growth and physiology of <i>S. cerevisiae</i> GB4918 was also established in glucose-limited chemostat cultures, with special regard to the intracellular macromolecular compounds that are relevant to industrial yeast biomass production. This showed that in respiring cultures of <i>S. cerevisiae</i>, increasing growth rate resulted in decrease in both trehalose and glycogen content, while increasing protein and RNA. This is true until μ<sub>max</sub> (in this context the growth rate at which respiro-fermentativemetabolism occurs) when accumulation of trehalose and glycogen is apparent. Once μ<sub>erit</sub> (growth rate at which washout of the culture begins) was reached then biomass significantly reduced. In describing the steady-state condition of baker’s yeast it was then possible to describe changes occurring in yeast when subjected to a variety of nutrient perturbations. With a lactic acid (2% v/v) perturbation there were dramatic effects on both growth and metabolism at a growth rate of 0.12h_1, but significant decreases in biomass and protein, and significant increases in trehalose and glycogen. At a higher growth rate (0.22h_1) the effect was much severer on protein content, and on reduced levels of trehalose and glycogen. The effect of perturbing the cultures with elevated levels of calcium was also most significant on reducing yeast trehalose and glycogen levels, probably due to inhibition of the biosynthesis of these compounds. Zinc additions to chemostat cultures acted to increase the levels of protein in the cells,while having little effect on any of the other cellular macromolecules. This suggests that increasing calcium levels during the latter stages of yeast propagations may produce a yeast with reduced stress responses. Increased zinc may also encourage a greater protein content, which would, in turn, provide a better nutritive content for both protein and amino acids in yeasts destined for use as a food additive.
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Towards the development of a starter culture for gari productionHaakuria, Vetjaera Mekupi 16 November 2006 (has links)
faculty of Science
School of Molecular and Cell Biology
9605145v
vhaakuria@yahoo.co.uk / Cassava is a food crop planted in many countries in Africa. Its tubers are a major
source of food and are processed to produce a variety of food products, one of which
is the fermented product called gari. This research report aimed to evaluate the
performance of three lactic acid bacteria for several properties with regard to the
fermentation of cassava to produce gari. Three organisms were used for the
evaluation, namely Lactobacillus plantarum, Lactobacillus fermentum and
Leuconostoc mesenteroides. The organisms were evaluated for viability, biomass
formation and glucose utilisation in static flasks, biomass formation and glucose
utilisation in 2 L fermenters, cell viability after dehydration processes and pH and
cyanide reduction in cassava substrate. In static flasks, the organisms were found to
retain above 80% cell viability after cryopreservation. Maximum biomass of 108
cells/ml was formed within the first 12 hours by all the organisms. While L.
fermentum, depleted glucose within 24 hours, L. plantarum formed the highest
biomass of 4 x 108 cells/ml. In 2 L Braunstat B fermenters, a cell count of 109 cells/ml
was obtained by L. fermentum and Leuconostoc mesenteroides within 12-15 hours.
Biomass formation for L. plantarum during the same period was 1010 cells/ml.
Glucose was depleted within 12 - 15 hours. The viability of cells between the
dehydration processes of centrifugation, glycerol and maltodextrin addition and
lyophilisation, was above 80% for all the organisms. However, this high cell viability
was influenced by concentration of cells during the centrifugation step. In cassava
substrate, L. fermentum, though heterofermentative, was found to be particularly acid
tolerant and reduced pH to 3.98. All the organisms were able to retain good viability
after lyophilisation. However, the results of cyanide reduction were inconclusive.
These results show that while cultures show promise for pilot scale studies of starter
culture development, further cyanide experiments need to be conducted, and synergy
between the organisms investigated.
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Assessment of leguminous cover crops for use in SaccharumHollowell, Dylan Mathis 12 May 2023 (has links) (PDF)
Cover crops play a part in improving sustainability by reducing negative environmental impacts such as soil erosion and nutrient runoff. Energycane could benefit from cover crops due to its row spacing. This study was conducted at the Bearden Dairy Research Center to determine differences in nitrogen accumulation, weed suppression, and energycane yield among treatments. Four cool-season species (planted in the fall of 2020 and 2021) [balansa clover (Trifolium michelianum), hairy vetch (Vicia villosa), white clover (T. repens) and winter pea (Pisum sativum subsp. arvense)], and four warm-season species (planted in the spring of 2021 and 2022 [alfalfa (Medicago sativa), alyceclover (Alysicarpus vaginalis), soybean (Glycine max), and sunnhemp (Crotalaria juncea)] plus negative and positive controls (0 and 168 kg N ha-1) were used. Regarding cool-season cover crops, significant differences were seen in all previously mentioned metrics. Warm-season cover crops only showed differences regarding nitrogen accumulation and weed suppression abilities.
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Demography, Biomass Production and Effects of Harvesting Giant Kelp Macrocystis pyrifera (Linnaeus) in Southern New Zealand.Pirker, John Georg January 2002 (has links)
This study examined the demography of giant kelp Macrocystis pyrifera (Linnaeus) and its interactions with understorey algae and invertebrates in southern New Zealand over two and a half years. Most of the study was done at two sites within Akaroa Harbour (Banks Peninsula) but ancillary sites at Tory Channel (Marlborough Sounds) were used for parts of the study. The kelp forests within Akaroa Harbour were generally highly productive, with a high annual turnover of giant kelp. Macrocystis plants were mostly annual and rarely reached ages greater than 12 months. Peak recruitment occurred in spring (November) during 1995-97, but lesser recruitment episodes occurred throughout the year. The maximum growth rates of Macrocystis fronds were comparable to rates reported elsewhere in southern hemisphere populations (22 mm - 24.5 mmlday), but considerably lower than those in northern hemisphere populations. The major experiment incorporated in the study tested the effects of the Macrocystis canopy and the understorey canopy of the stipitate laminarian Ecklonia radiata on macroalgae and invertebrates. The experiment was structured so that the effects of clearances at different times could be determined. One impetus for this experiment was the need to address issues relating to the commercial harvesting of giant kelp, its sustainability and its effects on other species. The effects of canopy removals on understorey algae, mostly juvenile Macrocystis, Ecklonia and Carpophyllum spp, were highly dependent on the timing of canopy removals and the combinations of canopies removed. For example, winter harvests of the Macrocystis canopy alone enhanced the survival of post-settlement Macrocystis recruits, but had little effect on Ecklonia recruitment. However, when both Macrocystis and Ecklonia canopies were removed in spring, there was heavy recruitment of Ecklonia that grew to dominate the understorey. Strong inter and intraspecific interactions from the Macrocystis surface canopy appeared to have been reduced by physical factors including water turbidity, sedimentation and the deterioration of the surface canopy during summer. These physical factors were not as limiting in Tory Channel. Fine scale extrinsic factor effects including nutrients, light and grazing on the early life history of Macrocystis were investigated in small experiments. Results suggest that recruitment may be nutrient limited even at moderately low temperatures, and that small herbivorous gastropods are an important source of mortality in the early life stages of Macrocystis. Culturing and transplantation cultivation techniques were also examined as a means of supplementing algal supplies. Macrocystis was cultured successfully through its life cycle onto culture ropes, but generally failed to produce visible sporophytes when placed in the field. Cultured plants did grow in Tory Channel, however. Juvenile plants transplanted to ropes for on-farm cultivation showed little growth during summer, but the addition of nutrients significantly enhanced growth rates of these plants during warmer months when natural nutrient levels were low. Increased growth rates at the onset of winter and with the addition of nutrients during summer confirmed that low nutrient levels during summer are growth limiting. Akaroa Harbour kelp forests exhibited considerable variation in Macrocystis canopy biomass through time. For example, the 32,000 m2 kelp forest at Wainui had a biomass of 144 t in October 1995, which then decreased to 21 t in October 1996. Canopies tended to deteriorate during summer. Thus, at Ohinepaka Bay kelp forest had a biomass of 31 t during winter 1997, which decreased to 0.06 t the following summer. The greatest reduction in biomass, however, coincided with a period of hugely increased sediment, which smothered blades in the sea-surface canopy, covered the substratum, and prevented successful recruitment of kelp for over a year. Nutrient depletion was one of several factors thought to cause the summer deterioration of the Macrocystis sea-surface canopy, which has important ramifications for the commercial harvesting of Macrocystis pyrifera in summer. Management considerations and options are discussed in relation the commercial harvesting of Macrocystis in New Zealand. The major conclusion of this study is that although Macrocystis was able to form dense surface canopies during winter its ability to dominate kelp forests was constrained by physical factors, especially sedimentation, high turbidity, nutrients, and storms. The lack of strong interactions between Macrocystis and Ecklonia are also largely a result of their different life history characteristics. Overall, there appear to be no significant negative flow-on effects resulting from kelp harvesting and it appears that Macrocystis can be harvested sustainably.
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Demography, Biomass Production and Effects of Harvesting Giant Kelp Macrocystis pyrifera (Linnaeus) in Southern New Zealand.Pirker, John Georg January 2002 (has links)
This study examined the demography of giant kelp Macrocystis pyrifera (Linnaeus) and its interactions with understorey algae and invertebrates in southern New Zealand over two and a half years. Most of the study was done at two sites within Akaroa Harbour (Banks Peninsula) but ancillary sites at Tory Channel (Marlborough Sounds) were used for parts of the study. The kelp forests within Akaroa Harbour were generally highly productive, with a high annual turnover of giant kelp. Macrocystis plants were mostly annual and rarely reached ages greater than 12 months. Peak recruitment occurred in spring (November) during 1995-97, but lesser recruitment episodes occurred throughout the year. The maximum growth rates of Macrocystis fronds were comparable to rates reported elsewhere in southern hemisphere populations (22 mm - 24.5 mmlday), but considerably lower than those in northern hemisphere populations. The major experiment incorporated in the study tested the effects of the Macrocystis canopy and the understorey canopy of the stipitate laminarian Ecklonia radiata on macroalgae and invertebrates. The experiment was structured so that the effects of clearances at different times could be determined. One impetus for this experiment was the need to address issues relating to the commercial harvesting of giant kelp, its sustainability and its effects on other species. The effects of canopy removals on understorey algae, mostly juvenile Macrocystis, Ecklonia and Carpophyllum spp, were highly dependent on the timing of canopy removals and the combinations of canopies removed. For example, winter harvests of the Macrocystis canopy alone enhanced the survival of post-settlement Macrocystis recruits, but had little effect on Ecklonia recruitment. However, when both Macrocystis and Ecklonia canopies were removed in spring, there was heavy recruitment of Ecklonia that grew to dominate the understorey. Strong inter and intraspecific interactions from the Macrocystis surface canopy appeared to have been reduced by physical factors including water turbidity, sedimentation and the deterioration of the surface canopy during summer. These physical factors were not as limiting in Tory Channel. Fine scale extrinsic factor effects including nutrients, light and grazing on the early life history of Macrocystis were investigated in small experiments. Results suggest that recruitment may be nutrient limited even at moderately low temperatures, and that small herbivorous gastropods are an important source of mortality in the early life stages of Macrocystis. Culturing and transplantation cultivation techniques were also examined as a means of supplementing algal supplies. Macrocystis was cultured successfully through its life cycle onto culture ropes, but generally failed to produce visible sporophytes when placed in the field. Cultured plants did grow in Tory Channel, however. Juvenile plants transplanted to ropes for on-farm cultivation showed little growth during summer, but the addition of nutrients significantly enhanced growth rates of these plants during warmer months when natural nutrient levels were low. Increased growth rates at the onset of winter and with the addition of nutrients during summer confirmed that low nutrient levels during summer are growth limiting. Akaroa Harbour kelp forests exhibited considerable variation in Macrocystis canopy biomass through time. For example, the 32,000 m2 kelp forest at Wainui had a biomass of 144 t in October 1995, which then decreased to 21 t in October 1996. Canopies tended to deteriorate during summer. Thus, at Ohinepaka Bay kelp forest had a biomass of 31 t during winter 1997, which decreased to 0.06 t the following summer. The greatest reduction in biomass, however, coincided with a period of hugely increased sediment, which smothered blades in the sea-surface canopy, covered the substratum, and prevented successful recruitment of kelp for over a year. Nutrient depletion was one of several factors thought to cause the summer deterioration of the Macrocystis sea-surface canopy, which has important ramifications for the commercial harvesting of Macrocystis pyrifera in summer. Management considerations and options are discussed in relation the commercial harvesting of Macrocystis in New Zealand. The major conclusion of this study is that although Macrocystis was able to form dense surface canopies during winter its ability to dominate kelp forests was constrained by physical factors, especially sedimentation, high turbidity, nutrients, and storms. The lack of strong interactions between Macrocystis and Ecklonia are also largely a result of their different life history characteristics. Overall, there appear to be no significant negative flow-on effects resulting from kelp harvesting and it appears that Macrocystis can be harvested sustainably.
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Genotypic Variation in Yield Performance under Tropical Environments of Soybeans with Temperate and Tropical Origins / 温帯産および熱帯産ダイズ品種の熱帯環境下における収量の遺伝子型間変異Andy, Saryoko 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21141号 / 農博第2267号 / 新制||農||1058(附属図書館) / 学位論文||H30||N5115(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 稲村 達也, 教授 縄田 栄治 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
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Strategic raw material supply for the particleboard-producing industry in Europe : Problems and challengesTrischler, Johann January 2016 (has links)
Particleboard was invented to increase the utilization of wood and it soon became an important core material for furniture production. Nowadays, other industries such as the pulp and papermaking industry and the thermal energy recovery industry claim the same type of raw material. This leads to increasing competition and higher prices than in the past when that kind of wood raw material was widely available and of low price. The particleboard-producing industry is therefore seeking opportunities to reduce the competition and ensure the future supply of lignocellulosic raw material for their products. The purpose of the work summarised in this thesis was to investigate the strategic supply of lignocellulosic raw materials for particleboard production and to evaluate alternatives for the supply of lignocellulosic raw material for particleboard production. To encompass the complex field of strategic raw material supply, several publications have considered different stages along the supply chain. These papers range from empirical studies to practical tests on a laboratory scale. In this thesis, some of the papers are linked together, building the base for the overall results. The results show that the task of increasing the supply of lignocellulosic raw material as primary raw material source is limited by several factors, but that improved product design coupled with a suitable recycling concept can greatly increase the availability of lignocellulosic raw material as a secondary source. Alternatively, the use of non-wood plants might be an opportunity to substitute wood as raw material but there are still some problems relating to the particle properties which must be overcome first.
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The effects of the synthetic strigolactone GR24 on Arabidopsis thaliana callus cultureMdodana, Ntombizanele Thobela 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Plant growth promoting substances (PGPS) are emerging as useful tools in the
investigation of important plant growth traits. Two PGPS, smoke-water derived from
burning plant material and a synthetic strigolactone analogue, GR24, have been
reported to regulate a wide variety of developmental and growth processes in plants.
These PGPS are beginning to receive considerable attention in the area of improving
plant biomass yield and production. Variation in growth between plants is a major
impediment towards the complete understanding of the intrinsic processes that
control biomass production. Callus cultures of the model plant Arabidopsis thaliana
could overcome some of these hindrances. However, the suitability of these callus
cultures as a model system for plant biomass production must be established first.
This study aimed at using A. thaliana callus cultures as a platform to study the plant
growth promoting activities of smoke-water and GR24.
The first part of this study was conducted to develop an optimal protocol for inducing
A. thaliana callus formation. Wild-type A. thaliana Col-O, as well as strigolactone
deficient and insensitive mutants (max1-1, max2-1, max2-2, max3-9 and max4-1)
were cultured for callus induction. Hypocotyl and leaf explants were cultured onto
MS media supplemented with different hormone concentrations of 2,4-D and kinetin
(2:2 mg/L 2,4-D:kinetin and 0.5:0.05 mg/L 2,4-D:kinetin). Both media proved suitable
for callus induction of all genotypes, with max1-1 showing the highest efficiency
(83.33% and 92.22%) of callus induction. Calli were then used as a platform for
future investigations into the effects of smoke-water and GR24. Secondly, this study examined the effects of smoke-water and GR24 on wild-type A.
thaliana Col-O callus. Basic physiological studies were conducted to determine if
these two compounds would positively affect callus growth, as was shown in
previous studies using whole plants. Calli cultivated on MS media containing the two
different hormone concentrations were transferred onto the same fresh MS medium,
supplemented with either smoke-water or GR24. Growth promotion by smoke-water
and GR24 in calli was characterized by a significantly increased mass (biomass).
Calli were additionally transferred onto MS medium containing either auxin only or kinetin only and supplemented with GR24 or smoke-water. In the auxin only system,
increased mass was recorded for both GR24 and smoke-water treatments, while
these two compounds seemed to reduce growth in the kinetin only system. The
positive growth stimulatory effect observed for the auxin only system could be
attributed to the synergistic relationship between auxin and strigolactones, whilst the
reduced mass in the latter system could be due to the antagonistic interaction
between strigolactones and cytokinins.
Finally, this study has discovered a dual role of strigolactones in biomass
accumulation and adventitious root formation for Arabidopsis thaliana callus. On an
auxin- and cytokinin-free MS medium supplemented with GR24, calli of Arabidopsis
thaliana strigolactone deficient mutants (max1-1 and max4-1) and the wild-type Col-
O, but not the strigolactone response mutant (max2-2), showed enhanced biomass
accumulation. In addition to this, the max4-1 mutant and wild-type Col-O
demonstrated enhanced adventitious rooting, which was not apparent in max2-2.
Together these data suggested that the biomass accumulation and the adventitious
rooting activities of GR24 in Arabidopsis thaliana calli are controlled in a MAX2-
dependent manner. The interaction between strigolactone, auxin and cytokinin
signalling pathways in regulating these responses appears to be complex. Gene
expression profiling showed regulation of stress-related genes such as B-box
transcription factors, CALCINEURIN B-LIKE and RAP4.2 Genes encoding hormones
associated with stress (ABA, ethylene) and defence mechanisms (JA) were upregulated.
Expression of stress related genes indicated clues on some kind of stress
mediation that might be involved during the regulation of the rhizogenic response.
Conversely, smoke-water treatment could not enhance the biomass of the calli and
nor could it induce adventitious rooting in the absence of auxin and cytokinin. This
observation strongly emphasized the distinct roles of these two compounds, as well
as the importance of the interaction and ratio of auxin and cytokinin in callus growth.
This study has demonstrated a novel role of strigolactones in plant growth and
development, i.e. enhancement of biomass production in callus cultures. Secondly
the enhanced adventitious rooting ability is in agreement with recently published
literature on the role of strigolactones in regulating root architecture. In vitro callus
production is advantageous to plant sciences. It creates an opportunity for increasing plant material for cultivation and offers the use of cell cultures that accurately mimic
specific growth responses. It could greatly contribute to the study of intricate
regulatory and signalling pathways responsible for growth and development in
plants. Because the regulation of plant biomass production is very complex and the
molecular mechanisms underlying the process remain elusive, it is of paramount
importance that further work be done in order to gain more in-depth insights and
understanding of this aspect and subsequently improve efficiency and returns when
applying biotechnology tools on commercially important crop plants. / AFRIKAANSE OPSOMMING: Verbindings wat plantgroei bevorder (PGBV) het as nuttige alternatief ontstaan om
plant groei te ondersoek. Rook-water, afkomstig van verbrande plant material, en ‘n
sintetiese strigolaktoon analoog, GR24, wat ‘n α, β-onversadigde furanoon
funksionele groep in gemeen het, is vir die regulering van ‘n wye verskeidenheid
ontwikkelings- en groei prosesse in plante verantwoordelik. Tans ontvang hierdie
PGBVs aansienlik aandag in die area van die verbetering van plant biomassa
opbrengs en -produksie. Die variasie in groei tussen plante is ‘n groot hindernis om
die intrinsieke prosesse wat biomass produksie beheer, volledige te verstaan. Deur
gebruik te maak van kallus kulture van die model plant Arabidopsis thaliana kan van
hierdie hindernisse oorkom word. Tog moet die geskiktheid van kallus kulture as ‘n
model sisteem vir plant groei biomass produksie eers gevestig word. Die doel van
hierdie studie was om A. thaliana kallus kulture as ‘n platform vir die studie van die
plantgroei bevorderingsaktiwiteite van rook-water en GR24 te gebruik.
Die eerste deel van die studie is uitgevoer ten einde ‘n optimale protokol vir die
induksie van A. thaliana kallus produksie te ontwikkel. Wilde tipe Col-0, asook
strigolaktoon afwesige en onsensitiewe mutante (max1-1, max2-1, max2-2, max3-9
en max4-1) is vir kallus induksie gekultiveer. Hipokotiel en blaar eksplante is op MS
medium wat verskillende hormoon konsentrasies van 2,4-D en kinetien (2:2 mg/L
2,4-D:kinetien en 0.5:0.05 mg/L 2,4-D:kinetien) bevat, oorgedra. Beide media was
geskik vir kallus induksie van al die genotipes, met max1-1 wat die hoogste
effektiwiteit (83.33% en 92.22%) van kallus induksie getoon het. Kalli is daarna as ‘n
platform vir toekomstige navorsing i.v.m die effek van rook-water en GR24 gebruik. Tweedens ondersoek die studie die effek van rook-water en GR24 op wilde tipe Col-0 kallus. Basiese fisiologiese studies is uitgevoer om te bepaal of die twee
verbindings ‘n positiewe effek op kallus groei toon soos aangedui in vorige studies
waar intakte plante gebruik is. Kallus wat op MS medium wat die twee verskillende
hormoon konsentrasies bevat gekultiveer was, is op dieselfde vars MS medium, wat
addisioneel óf rook-water óf GR24 bevat, oorgedra. Die stimulering van groei van
kalli deur rook-water en GR24 is deur ‘n merkwaardige toename in massa
(biomassa) gekenmerk. Kallus is additioneel op MS medium wat slegs óf ouksien óf kinetin bevat
(gekombineer met GR24 of rook-water behandeling), oorgedra. In die sisteem waar
slegs ouksien toegedien is, is ‘n toename in massa waargeneem vir beide GR24 en
rook-water behandelinge. In teenstelling hiermee, het die twee verbindings in die
sisteem waar slegs kinetin toegedien is, ‘n vermindering in groei meegebring. Die
positiewe groei stimulerende effek wat waargeneem is vir die sisteem waar slegs
ouksien toegedien is, kan toegedra word aan die sinergistiese verhouding tussen die
ouksien en strigolaktone; terwyl die verlaagde massa in die laasgenoemde sisteem
aan die antagonistiese interaksie tussen strigolaktone en sitokiniene toegedra kan
word.
Laastens het hierdie studie het ‘n gelyktydige rol van strigolaktone vir biomassa
akkumulasie en bywortelvorming in Arabidopsis thaliana kallus ontdek. Kallus van
A. thaliana strigolaktoon afwesige mutante (max1-1 en max4-1) en die wilde tipe
Col-0 (maar nie die strigolaktoon reagerende mutant (max2-2) het op ‘n ouksien en
sitokinien vrye MS medium wat GR24 bevat ‘n verhoogde biomassa akkumulasie
getoon. Die max4-1 mutant en wilde tipe Col-0 het verhoogde bywortelvorming
getoon, wat nie so opmerklik by max2-2 was nie. Hierdie data het tesame
voorgestel dat die biomassa akkumulasie en die bywortelvormingsaktiwiteite van
GR24 in Arabidopsis thaliana kallus op ‘n MAX2-afhanklike wyse beheer word. Die
interaksie tussen strigolaktoon, ouksien en sitokinien sein transduksie paaie vir die
regulering van hierdie reaksies blyk kompleks te wees. Die geen uitdrukkingsprofiel
het die regulering van stres verwante gene soos B-boks transkripsie faktore,
CALCINEURIN B-LIKE en RAP4.2, getoon. Gene wat vir hormone wat aan stres
(ABA, etileen) en verdedigingsmeganismes (JA) verwant is, is opgereguleer. Die
uitdrukking van stress verwante gene dui op tekens van ‘n ander tipe stres
bemiddeling wat dalk by die regulering van die risogeniese reaksie betrokke kan
wees. In teenstelling, rook water behandeling kon nie die kallus biomassa verhoog
nie en dit kon ook nie die bywortelingvorming in die afwesigheid van ouksien en
sitokiniene induseer nie. Hierdie waarneming is ‘n sterk bevestiging vir die
uitsonderlike rol van die twee verbindings, asook die belang van die interaksie en
verhouding van ouksien en sitokinine vir die groei van kallus. Hierdie studie toon op ‘n nuwe rol van strigolaktoon in plant groei en ontwikkeling,
d.w.s die verhoogde biomassa produksie in kallus kulture. Tweedens, die
verhoogde bywortelvormingsvermoë is in ooreenstemming met literatuur wat
onlangs gepubliseer is i.v.m die rol van strigolaktone in die regulering van wortel
argitektuur. Die in vitro produksie van kallus is voordelig in plant wetenskappe. Dit
skep ‘n geleentheid vir die vermeerdering van plant materiaal vir kultivering en bied
die gebruik van selkulture wat spesifieke groei reaksies op ‘n merkwaardige wyse
akkuraat namaak. Dit kan grootliks bydra tot die studie van die delikate
regulatoriese en sein transduksie paaie wat vir groei en ontwikkeling van plante
verantwoordelik is. Aangesien die regulering van plant biomassa produksie baie
kompleks is en die molekulêre meganismes vir die proses onbekend bly is dit van
grootskaalse belang dat meer werk gedoen word om ‘n meer in diepte insig en
kennis van die aspekte en gevolglike verbetering van effektiwiteit en wins te kry deur
die toepassing van biotegnologiese metodes op die gewas plante wat van
kommersiêle belang is.
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