Please read the abstract in the section 00front of this document / Thesis (PhD (Agronomy))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

Solanine, the green substance in potato, Solanum tuberosum L., tubers, is a toxic glycoalkaloid that is a potential human health hazard. To control the formation of this glycoalkaloid a greater understanding of its site of synthesis is needed. Labelling of solanidine, a direct precursor in the biosynthesis of solanine, with digitonin may indirectly locate the site of solanine synthesis in tubers. A study using ultrastructural cytochemical techniques was initiated to explore this possibility. Sprouted tips and peridermal complex (periderm and cortex) tissue were fixed three different ways: (1) glutaraldehyde only, (2) osmium tetroxide and glutaraldehyde, and (3) glutaraldehyde-osmium tetroxide-digitonin mixture. The glutaraldehyde-osmium tetroxide-digitonin mixture provided the best fixation for this study and was used throughout. An alkaloid extract of potato tissues incubated with digitonin resulted in a precipitate being formed. Application of the alkaloid extract to TLC plates before and after incubating with digitonin indicated only solanidine was removed by the digitonin. In the electron micrographs the solanidine-digitonin complex was recognized as darkly stained needles or spicules. These spicules were observed mostly in the vacuoles in the sprouted tips. However, a few spicules were also noted in the cytoplasm. Relatively few spicules were observed in the peridermal tissue.

The aim of the experiment was to evaluate the effect of pig slurry applications in the growing crop of potatoes for industrial processing during the growing season. In 2015, he was at an altitude of 560 m based experiment, where the effect was evaluated by pig slurry at a variety Eurostarch experiment was divided into three variants, each variant had four repetitions, was a variant without application of slurry, 1 times applied manure and 2 times applied manure. For each experiment evaluated the proportion of emerged plants, tuber yield, starch content, average weight 1 tubers and the number of tubers in a bunch. In the reporting year and the effect of the application of manure. From the experimental results it is evident that the manure contributing to higher tuber yield, starch content and increased weight of tubers as the variant with one and two applications of slurry.

High temperature limit successful potato cultivation in the lowlands of tropical regions. One effect of high temperature may be an increase in gibberellin activity that is inhibitory to tuberization. Paclobutrazol blocks gibberellin biosynthesis and reduces its level in the plant. The effect of paclobutrazol on potato was examined under non-inductive conditions in a greenhouse and under field conditions in the hot tropical lowlands of eastern Ethiopia. Paclobutrazol was applied as a foliar spray or soil drench at rates equivalent to 0, 2, 3, and 4 kg a. i. per ha. Paclobutrazol increased chlorophyll a and b content, and photosynthetic efficiency, enhanced early tuber initiation, delayed physiological maturity, and increased tuber fresh mass, dry matter content, specific gravity and crude protein content. It reduced the number of tubers per plant and extended the tuber dormancy period. Paclobutrazol reduced shoot growth, and plant height, and increased the partitioning of assimilates to the tubers while reducing assimilate supply to the leaves, stems, roots and stolons. Stomatal conductance and the rate of transpiration were reduced. In addition, paclobutrazol treatment increased tuber N, Ca and Fe content while reducing P, K and Mg content. Growth analyses indicated that paclobutrazol decreased leaf area index, crop growth rate, and total biomass production. It increased specific leaf weight, tuber growth rate, net assimilation rate, and partitioning coefficient (harvest index). Microscopic observations showed that leaves of treated plants developed thicker epicuticular wax layers. The epidermal, palisade and spongy mesophyll cells were larger. It increased the thickness of the cortex and the size of vascular bundles and pith cells of the stem. It also increased the width of the cortex and favoured the formation of more secondary xylem vessels, resulting in thicker roots. Deposition of starch grains in the stem pith cells, and cortical cells of the stem and root, were stimulated in response to paclobutrazol treatment. In most instances the method of application did not affect the efficiency of paclobutrazol. The effect of cultivar and reproductive growth on growth, photosynthetic efficiency, water relations, dry matter production, tuber yield and quality of potato was also the subject of investigation. Non-flowering, flowering and fruiting plants of cultivars Al-624, Al-436, CIP-388453-3(A) and CIP-388453-3(B) were evaluated under field conditions of a sub-humid tropical highland of eastern Ethiopia. Cultivars exhibited differences with respect to leaf stomatal conductance, rate of transpiration, net photosynthesis, biomass production and allocation, tuber yield, tuber size distribution, specific gravity, dry matter content and nutrient composition. Fruiting plants had higher leaf stomatal conductance, and higher rates of transpiration and photosynthesis rates. The leaf area index, tuber growth rate, and partitioning coefficient (harvest index) of the fruiting plants were reduced, but crop growth rates and net assimilation rates were higher. Without affecting total dry matter production, fruit development reduced the amount partitioned to the leaves, stems, roots, and tubers. Fruit development reduced total and marketable tuber mass and tuber numbers. The effect of MCPA and paclobutrazol were studied under greenhouse and field conditions. Single foliar sprays were applied during the early and full bud development stages at rates of 0, 250, 500, and 750 g a.i. ha-1. Both MCPA and paclobutrazol greatly reduced the number of flowers and completely inhibited berry set. MCPA did not affect the number, yield, dry matter content and specific gravity of tubers. Without affecting the number of tubers, paclobutrazol increased tuber yield, dry matter content and specific gravity. / Thesis (DPhil (Horticultural Science))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

O sistema vascular de monocotiledôneas, incluindo Commelinaceae, tem sido estudado desde o sec. 17, sendo uma das maiores dificuldades em estudar esse sistema a grande quantidade de feixes vasculares e a complexidade de suas conexões, especialmente nas espécies que possuem plexo vascular nodal. As variações no sistema vascular não se restringem à relação caule/folha, uma vez que as raízes também podem apresentar certo grau de complexidade. Neste trabalho buscamos entender e apresentar uma arquitetura vascular em Commelinaceae baseado na reconstrução direta de análises tridimensionais dos sistemas caulinar e radicular. Para isto, foram analisadas amostras de caule (20 espécies) e raiz tuberosa (7 espécies) da família Commelinaceae, a partir de representantes das duas tribos de Commelinoideae (Commelineae e Tradescantieae). O rastreamento do sistema vascular no ápice caulinar mostrou que os feixes vasculares caulinares (em fase procambial) começam a ser distinguidos no 4º fitômero, a partir do ápice caulinar. A atividade meristemática do periciclo e o incremento foliar foram os principais fatores de espessamento primário do caule. A partir de análises tridimensionais complementares, como microscopia confocal, microtomografia computadorizada,vetorização gráfica e diafanização whole mount foram construídos modelos tridimensionais da arquitetura vascular em Commelinaceae. Nestes modelos foi possível verificar uma categoria de feixes ainda não relatada para Commelinaceae e que os feixes periféricos não são interrompidos ou terminam cegamente na periferia da medula. Três padrões de plexo vascular nodal são propostos, nos quais todos os feixes vasculares se conectam por meio de traqueídes. Para raiz tuberosa, dados morfométricos foram obtidos com auxílio do software ImageJ e vetorização gráfica foi utilizada para rastreamento do sistema vascular. Os resultados mostram quatro variações anatômicas do cilindro vascular e a quantificação morfométrica das características responsáveis por estas variações / The vascular system of monocotyledons, including Commelinaceae, has been studied since 17 th century, and one of the greatest difficulties in studying these systems is the great number of vascular bundles and the complexity of their connections, especially the species that have vascular nodal plexus. The variations in the vascular system are not restricted to the stem-leaf relation, since the roots can also present some degree of complexity. In this work we seek to understand and present a vascular architecture for Commelinaceae based on the direct reconstruction of 3D analyzes of shoot and root systems. Samples of stem (20 species) and tuberous root (7 species) of the Commelinaceae were analyzed including two tribes of Commelinoideae (Commelineae e Tradescantieae). The tracing of the vascular system in the shoot apex showed that the vascular bundles (in the procambial phase) begin to be distinguished in the 4th phytomer, from the apex. The meristematic activity of the pericycle (in the procambial phase) and the leaf increment were the main factors of primary stem thickening. From complementary 3D analyzes, such as confocal microscopy, computer microtomography, graphic vectorization and whole mount diaphanization, three-dimensional models of the vascular architecture were constructed from Commelinaceae. In these models it was possible to verify a category of bundles not yet reported for Commelinaceae and that the peripheral bundles are not interrupted or end blindly in the periphery of the vascular cylinder. Three patterns of nodal vascular plexus are proposed, in which all vascular bundles are connected by means of tracheids. For tuberous root, morphometric data were obtained by the aid of ImageJ software and graphic vectorization was used to trace the vascular system. The results show four anatomical variations of the vascular cylinder and the morphometric quantification of the characteristics responsible for these variations

Die Qualität von Nutzpflanzen ist von zahlreichen Einflussfaktoren wie beispielsweise Lagerbedingungen und Sorteneigenschaften abhängig. Um Qualitätsmängel zu minimieren und Absatzchancen von Nutzpflanzen zu steigern sind umfangreiche Analysen hinsichtlich ihrer stofflichen Zusammensetzung notwendig. Chromatographische Techniken gekoppelt an ein Massenspektrometer und die Kernspinresonanzspektroskopie wurden dafür bislang verwendet. In der vorliegenden Arbeit wurde ein Gaschromatograph an ein Flugzeitmassenspektrometer (GC-TOF-MS) gekoppelt, um physiologische Prozesse bzw. Eigenschaften (die Schwarzfleckigkeit, die Chipsbräunung, das Physiologische Alter und die Keimhemmung) von Nutzpflanzen aufzuklären. Als Pflanzenmodell wurde dafür die Kartoffelknolle verwendet. Dazu wurden neue analytische Lösungsansätze entwickelt, die eine zielgerichtete Auswertung einer Vielzahl von Proben, die Etablierung einer umfangreichen Referenzspektrenbibliothek und die sichere Archivierung aller experimentellen Daten umfassen. Das Verfahren der Probenvorbereitung wurde soweit modifiziert, dass gering konzentrierte Substanzen mittels GC-TOF-MS analysiert werden können. Dadurch wurde das durch die Probenvorbereitung limitierte Substanzspektrum erweitert. Anhand dieser Lösungsansätze wurden physiologisch relevante Stoffwechselprodukte identifiziert, welche indikativ (klassifizierend) bzw. prädiktiv (vorhersagend) für die physiologischen Prozesse sind. Für die Schwarzfleckigkeitsneigung und die Chipseignung wurde jeweils ein biochemisches Modell zur Vorhersage dieser Prozesse aufgestellt und auf eine Züchtungspopulation übertragen. Ferner wurden für die Schwarzfleckigkeit Stoffwechselprodukte des Respirationsstoffwechsels identifiziert sowie Aminosäuren, Glycerollipide und Phenylpropanoide für das Physiologische Alter als relevant erachtet. Das physiologische Altern konnte durch die Anwendung höherer Temperaturen beschleunigt werden. Durch Anwendung von Keimhemmern (Kümmelöl, Chlorpropham) wurde eine Verzögerung des physiologischen Alterns beobachtet. Die Applikation von Kümmelöl erwies sich dabei als besonders vorteilhaft. Kümmelöl behandelte Knollen wiesen im Vergleich zu unbehandelten Knollen nur Veränderungen im Aminosäure-, Zucker- und Sekundärstoffwechsel auf. Chlorpropham behandelte Knollen wiesen einen ähnlichen Stoffwechsel wie die unbehandelten Knollen auf. Für die bislang noch nicht identifizierten Stoffwechselprodukte wurden im Rahmen dieser Arbeit das Verfahren der „gezielten An-/Abreicherung“, der „gepaarten NMR/GC-TOF-MS Analyse“ und das „Entscheidungsbaumverfahren“ entwickelt. Diese ermöglichen eine Klassifizierung von GC-MS Signalen im Hinblick auf ihre chemische Funktionalität. Das Verfahren der gekoppelten NMR/GC-TOF-MS Analyse erwies sich dabei als besonders erfolgversprechend, da es eine Aufklärung bislang unbekannter gaschromatographischer Signale ermöglicht. In der vorliegenden Arbeit wurden neue Stoffwechselprodukte in der Kartoffelknolle identifiziert, wodurch ein wertvoller Beitrag zur Analytik der Metabolomik geleistet wurde. / Several factors influence the quality of crops. These include particular storage conditions and cultivar properties. Minimization of quality defects requires the employment of comprehensive metabolic analysis to enhance the marketing potential of crops. From this point of view chromatographic techniques coupled either with a mass spectrometer or the combination with nuclear magnetic resonance spectroscopy have been successfully applied to solve the main tasks. In the present work, a gas chromatograph was coupled to a time of flight mass spectrometer (GC-TOF-MS) to analyze physiological processes and attitudes of crops like black spot bruising, chips tanning, physiological aging, and sprouting inhibition. For this purpose the potato tuber was employed as a model plant. Therefore, new analytical approaches were developed comprising the targeted analysis of a multitude of samples, the establishment of a comprehensive mass spectral reference library and the built up of a secure archival storage system. Furthermore, the sample preparation protocol was modified to analyze trace components with the help of GC-TOF-MS as well. This helped to extend the discovery of more endogenous metabolites. These analytical approaches were required to identify physiological relevant indicative and predictive metabolites. Consequently, a biochemical model was build up for the process of black spot bruising and chips tanning respectively. These models could be applied to an unknown breeding progeny. Metabolites of the respiratory chain were identified as relevant for the process of black spot bruising whereas amino acids, lipids and phenylpropanoids were of high importance for the process of physiological aging.  The process of physiological aging could be accelerated while applying higher temperatures and could be delayed while applying sprouting inhibitors, like caraway oil and chlorpropham. Compared to chlorpropham, caraway oil exhibited more advantages with respect to storage attitudes although it caused significant changes in the amino acid, sugar and secondary metabolism during a common storage period. However, the chlorpropham treated tubers showed a similar phenotype in comparison to the control tubers. In addition, several methods were developed with respect to the classification of yet unidentified signals. These cover the decision tree process, the targeted enrichment and depletion of specific metabolites with the help of solid phase extraction and the paired NMR and GC-MS analyses. The paired NMR and GC-MS analysis appears very promising because it allows for the identification of unknown GC-MS signals. Thus, this work makes a valuable contribution to the analytics of the metabolome, as new metabolites could be identified which are of physiological relevance for the potato tuber.

Equisetum arvense is an evolutionary old species that is common as a perennial weed in Europe, North America and Australia. It reproduces vegetatively via rhizomes and tubers and due to this it spreads efficiently below ground after initial establishment. The aim of this study was to increase the knowledge of performance during early growth of the species. This included differences between clones along a gradient throughout Sweden, development of tubers and rhizomes, local adaptation and the overall variation within the species. Rhizomes of E. arvense were collected from three different places in each of four regions, up to 1000 km apart, in Sweden. Clones from the twelve places were planted in spring for a common garden study. During summer the plants were watered when needed and during late summer the plants were harvested every second week until late autumn. Data recorded were tuber and rhizome biomass, aboveground biomass, number of tubers and three different tuber characteristics. The results showed clone specific phenotypes, but no gradient response or adaptation to regions, e.g. the clone with the highest and the clone with the lowest tuber biomass in relation to the rhizome biomass were from the same region. During early growth, the plants developed continuously with rapid increase of belowground biomass after development of aboveground photosynthetic parts. Tuber productions differed a lot between clones. The relationship between tubers and rhizomes may affect the clone’s possibility to be competitive in different environments. Management advice may need to be based on clone specific knowledge.

Potato production in tropical and subtropical countries suffers from damage caused by the potato tuber moth (PTM), Phthorimiaea operculella. Development of a germline transformation system and the identification of genes that are differentially expressed within the PTM midgut are the main goals of this research. We tested three components that are critical to genetic transformation systems for insects; promoter activity, marker gene expression, and transposable element function. We compared the transcriptional activities of five different promoters, hsp70, hsp82, actin5C, polyubiquitin and ie1, within PTM embryos. The ie1 promoter flanked with the enhancer element, hr5, showed a very high level of transcriptional activity compared with the other promoters. The expression of the enhanced green fluorescent protein (EGFP) was detected under UV-illumination within the embryonic soma demonstrating that it can be used as an effective marker gene for PTM. The transpositional activities of the Hermes, mariner and piggyBac transposable elements were tested in interplasmid transposition assays. The piggyBac element was shown mobile within the embryonic soma with a transposition frequency of 4.2 X 10-5 transposition/donor plasmid. The piggyBac mobility has been enhanced by incorporating a transactivator plasmid expressing the IE1 protein from the bacoluvirus Autographa californica nuclear polyhedrosis virus. Seven transformation experiments were performed. The experiments failed to produce a transgenic PTM. The insect midgut is a rich region of molecular targets involved in food processing that could be potentially used to design a new control strategy. The suppression subtractive hybridization (SSH) method was used to identify differentially expressed genes from the PTM midgut. From this subtracted library, 2984 clones were collected and screened. Of these clones, 637 clones are candidate differentially expressed genes within the PTM midgut. Sixty-nine cDNA clones were randomly selected for DNA sequencing. Tweleve clones were selected for further analysis using RT-PCR and Northern blot techniques. Eleven of the clones resulted in positive results for midgut expression. Five clones, showing homology with insect immune peptides, were used in the challenge experiment which revealed that these cDNAs are constitutively expressed in the midgut, as well as being up-regulated due to bacterial or viral challenge.

Augalo derlingumo didinimas ir derliaus kokybės gerinimas – vienas iš svarbiausių žemės ūkio mokslų prioritetų. Valgomoji bulvė (Solanum tuberosum L.) – svarbus maisti-nis augalas, kurio auginimo ir paplitimo geografija didesnė nei kukurūzų, ryžių ir kviečių. Pagrindinė bulvių produkcija – stiebagumbiai, kurie naudojami ne tik maistui, pašarui, bet ir alternatyviems tikslams: bioplastikų, krakmolo, spirito gamybai (Šlapakauskas, Du-chovskis, 2008). Bulvių pasėlio augimas labai priklauso nuo sėklai naudojamų stiebagumbių koky-bės. Pagal fiziologiją bulvė sudėtingas augalas, kurio augimo, vystymosi bei stiebagumbių laikymo sąlygos įtakoja jų dygimą (Cristiansen et al., 2006). Bulvių stiebagumbių dygi-mas – vienas iš svarbiausių veiksnių, nulemiančių kero stiebų skaičių, kurie yra derlių įtakojantis faktorius (Allen et al., 1992). Siekiant paankstinti derlių, suformuoti tankų, produktyvų pasėlį stiebagumbių daigi-nimui gali būti naudojami egzogeniniai augimo reguliatoriai – sintetiniai fitohormonų analogai, kurie leidžia pakeisti augalo hormonų statusą, modifikuoti metabolizmo proce-sus. J. Lazauskas (2001) teigia, kad geriausia bulves daiginti natūraliomis šviesos sąlygo-mis, ne aukštesnėje nei 17 oC temperatūroje, 35–45 dienas iki sodinimo, tuomet jų daigai būna trumpi ir stiprūs. Tačiau kai stiebagumbių daiginimo metu trūksta šviesos ar būna netinkama temperatūra, pumpurai būna ne vienodo dydžio, silpni. Mokslininkai plačiai tiria abiotinių veiksnių (šviesos, temperatūros)... [toliau žr. visą tekstą] / Research problem. Plant productivity enhancement and yield quality improvement are one of the top priorities for agricultural sciences. The potato (Solanum tuberosum L.) is a staple crop, whose cultivation and distribution geography is larger than that of maize, rice and wheat. The main potato produce is tubers which are used not only for food and feed but also for alternative purposes – production of bioplastics, starch and spirits (Šlapakauskas, Duchovskis, 2008). Potato crop performance is highly reliant on the quality of tubers used as seed material. In terms of physiology, the potato is a complex plant whose growth, development and tuber storage conditions influence sprouting (Cristiansen et al., 2006). Potato tuber sprouting is one of the prime factors determining the number of stems per potato plant, which is also a factor, which influences potato yield (Allen et al., 1992). Seeking to advance potato maturity and harvesting and to achieve a dense, productive stand, exogenous growth regulators can be used for tuber sprouting. These growth regulators are synthetic analogues of phytohormones that enable changes in plant hormonal status and modification of metabolic processes. J. Lazauskas (2001) suggests that to achieve short and strong sprouts, it is most efficient to sprout potato tubers under natural light conditions at a temperature no higher than 17 oC, 35–45 days prior to planting. However, a shortage of light during tuber sprouting or inadequate temperature result... [to full text]

The black truffle (Tuber melanosporum Vitt.) industry in Australia is relatively new and has enormous potential but some truffières (truffle farms) fail to meet anticipated harvest projections. Inappropriate soil conditions and climate, and the management of such factors are suggested as the primary reasons for inadequate yield. In addition, requirements for ascocarp initiation and development and the role of the host plant in such processes are unknown. This study examines interactions between European hazel (Corylus avellana L.) and the ectomycorrhizal (ECM) black truffle symbiont in a commercial truffière (Hazel Hill) in south-western Australia. Specific studies were initiated to examine the interactions of host physiology, mycorrhizal infection and the interaction with abiotic factors. The study related specific physiological processes of the host plant to the known life cycle of the black truffle to determine the role of the host plant in ascocarp production, if any. The work also examined the effect of silvicultural treatments intended to increase truffle production. A review of existing literature was undertaken to determine the key soil and climatic factors required for successful truffle production. Climatic conditions appeared more important than soil chemistry and structure in Western Australia, with significant seasonal variation in air and soil temperatures required plus irrigation to supplement summer rainfall. This information was used to define areas with potential for truffle production in the south-west of Western Australia: the cooler, high rainfall regions (>1000 mm annual rainfall) where there is sufficient seasonal variation in soil temperature and availability of adequate quantities of quality water for irrigation. Subsurface soil acidification and salinity, as well as groundwater salinity, are constraining factors. Lime amendment is necessary to create sufficiently high pH and CaCO3 levels required by the truffle fungus. A field trial was established to monitor the seasonal C dynamics of European hazel in the context of the life cycle of the black truffle. Maximum translocation of sucrose in the phloem sap coincided with the period of anticipated rapid growth of the truffle ascocarp implicating the use of current photosynthate in C nutrition of the ascocarp. Sampling of non-structural carbohydrates (NC) of above and belowground plant material indicated maximum storage of C in the host coincides with maturation of the ascocarp. These observations provide evidence of a synchronous growth habit of the plant host and the ascocarp. The C allocation patterns of European hazel in response to liming a loamy soil, taken from near the Hazel Hill truffière, and inoculation with ECM fungi (T. melanosporum, Hebeloma sp. and Scleroderma sp.) were examined in a glasshouse pot trial. Liming increased biomass allocation to the shoot and induced deficiencies of phosphorus and manganese. Colonisation by ECM fungi significantly increased net photosynthesis, indicating the sink strength of these fungi, but there was no relationship between the level of mycorrhizal infection and fine root NC. The maximum rate (40 g lime kg-1 soil) reduced infection by Hebeloma and Scleroderma and had no impact on T. melanosporum. Further, infection rates of T. melanosporum did not increase in response to lime suggesting lime is not necessary for ECM development in this soil type. Fertiliser is widely used in commercial truffières in Australia but the consequences for truffle production are unknown. In a field trial, the growth and physiological response of European hazel to forms of phosphorus (34 and 68 kg ha-1 apatite-P and 68 kg ha-1 triple super phosphate -P) and nitrogen (50 kg ha-1 of NO3- and NH4-N) were examined as well as the mycorrhizal response to fertiliser. Apatite-P increased phloem sap sucrose concentrations which was attributed to increased root biomass and associated sink capacity. Fertiliser application did not change fine root NC concentrations suggesting no increase in allocation of C to ECM structures. The highest rate of apatite-P decreased mycorrhizal infection rates of T. melanosporum and, most likely, was the result of increased infection rates of Hebeloma. In contrast to the literature relating to indigenous Australian ECM fungi, the highest rate of soluble-P did not decrease ECM infection rates in T. melanosporum. Nitrogen treatments increased foliar N content and improved gas exchange efficiency of plants, and had no adverse impact on the level of ECM infection. Fertilisation with N significantly increased soil respiration rates suggesting N limits mineralisation at this site. Some truffières manage the canopies of the host tree to ensure maximum exposure of the soil surface in order to increase soil temperatures. As there are no published data on the effect of pruning on black truffle production, a field trial was established to document the impact of canopy pruning on host physiology and soil temperature. The removal of 65% of canopy leaf area reduced phloem sap sucrose concentrations, soil respiration rate and the soluble: insoluble NC ratio of fine roots in the short term (1-3 weeks). There was no compensatory response of leaf gas exchange parameters as a result of pruning. Generally, there was no long term impact on plant physiological parameters as a result of pruning. Long term effects on soil temperature were observed as a result of pruning. Mean annual temperature and amplitude increased significantly beneath pruned trees and spring, summer and autumn soil temperatures increased as did diurnal variation as a result of pruning. Pruning did not increase winter soil temperatures and therefore would probably not impact on ascocarp maturation during this period. This research has provided insight into the C physiology of hazel associated with the black truffle and the consequences for truffle production. The results provide anecdotal evidence of direct C transfer between the host and the developing truffle, contrary to the existing paradigm that the ascocarp is saprotrophic for the majority of its growth and development. There is a need to validate this finding as there are consequences for management of commercial truffières. Liming of loam duplex soils can reduce the abundance of the most common competitor ECM fungi and should be encouraged in commercial truffières. Applying phosphorus and nitrogen to commercial truffières will improve growth rates of planted trees without adversely impacting on ECM infection by black truffle fungi, although the impact on truffle production remains unknown. It is anticipated truffle production will improve in the longer term as a result of pruning and prudent canopy management. Management options should include tree removal to reduce planting density and increase soil exposure in truffières. There is a need for longer term trials to be established to determine the C nutrition of the truffle ascocarp and to clearly define the key stages of the black truffle life cycle in Western Australia.