Tjia Wai Mui. / Thesis submitted in: July 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 123-140). / Abstracts in English and Chinese. / Abstract (English) --- p.i / Abstract (Chinese) --- p.iii / Acknowledgement --- p.iv / Abbreviations --- p.v / Table of Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xii / Chapter Chapter One --- Literature Review / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Growth of L. edodes --- p.3 / Chapter 1.2.1 --- Life cycle of L. edodes --- p.3 / Chapter 1.2.2 --- Growth parameters of L. edodes --- p.6 / Chapter 1.2.2.1 --- Temperature --- p.6 / Chapter 1.2.2.2 --- Relative humidity --- p.7 / Chapter 1.2.2.3 --- Moisture content in substrate --- p.7 / Chapter 1.2.2.4 --- Light --- p.8 / Chapter 1.2.2.5 --- pH --- p.8 / Chapter 1.3 --- Cultivation of L. edodes --- p.9 / Chapter 1.3.1 --- History and development of artificial cultivation --- p.9 / Chapter 1.3.2 --- Use of forced fruiting --- p.11 / Chapter 1.4 --- Molecular studies of stress on fungi --- p.12 / Chapter 1.4.1 --- Studies of temperature stress in mushroom --- p.12 / Chapter 1.4.2 --- Studies of molecular chaperones in fungi --- p.13 / Chapter 1.4.2.1 --- Role of molecular chaperones --- p.13 / Chapter 1.4.2.2 --- Heat shock protein 70 (Hsp70) and their cochaperones --- p.13 / Chapter 1.4.2.3 --- Other chaperones --- p.15 / Chapter 1.4.2.4 --- Molecular chaperones and development --- p.16 / Chapter 1.5 --- Prospectus --- p.19 / Chapter Chapter Two --- The Effect of Stress on the Growth of L. edodes / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- Materials and Methods --- p.24 / Chapter 2.2.1 --- Strain and culture conditions --- p.24 / Chapter 2.2.2 --- Stress treatments --- p.24 / Chapter 2.2.3 --- Data collection --- p.25 / Chapter 2.2.4 --- Data analysis --- p.25 / Chapter 2.3 --- Results --- p.27 / Chapter 2.3.1 --- Reliability analysis --- p.27 / Chapter 2.3.2 --- Descriptive statistics --- p.28 / Chapter 2.3.3 --- Independent t-test (ANOVA) --- p.33 / Chapter 2.4 --- Discussion --- p.37 / Chapter Chapter Three --- Sequence Analysis of selected Stress Genes / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Materials and Methods --- p.40 / Chapter 3.2.1 --- Isolation of stress genes --- p.40 / Chapter 3.2.1.1 --- Construction of primordial cDNA library --- p.40 / Chapter 3.2.1.2 --- Screening of cDNA clones --- p.40 / Chapter 3.2.2 --- Sequence analyses of stress genes --- p.41 / Chapter 3.2.2.1 --- Amplification and purification of cDNA insert --- p.41 / Chapter 3.2.2.2 --- Full length DNA cycle sequencing --- p.42 / Chapter 3.2.2.3 --- Sequence analyses --- p.43 / Chapter 3.2.3 --- Screening of LeSSA (Inducible HSP70) --- p.45 / Chapter 3.2.3.1 --- PCR screening of LeSSA by degenerate primers and LeSSB specific primers --- p.45 / Chapter 3.2.3.2 --- Screening of LeSSA from cDNA library by hybridization --- p.49 / Chapter 3.3 --- Results --- p.51 / Chapter 3.3.1 --- Sequence analyses --- p.51 / Chapter 3.3.1.1 --- LeSSB --- p.51 / Chapter 3.3.1.2 --- LeMge1 --- p.57 / Chapter 3.3.1.3 --- LeSTI1 --- p.62 / Chapter 3.3.1.4 --- LeTCP1β --- p.69 / Chapter 3.3.1.5 --- LeTCP1γ --- p.74 / Chapter 3.3.2 --- Failure of isolating LeSSA (Inducible HSP70) --- p.80 / Chapter 3.4 --- Discussion --- p.82 / Chapter 3.4.1 --- Sequence analyses --- p.82 / Chapter 3.4.2 --- Screening of LeSSA --- p.84 / Chapter Chapter Four --- Characterization of stress genes upon different stresses / Chapter 4.1 --- Introduction --- p.86 / Chapter 4.2 --- Materials and Methods --- p.87 / Chapter 4.2.1 --- Strain and culture conditions --- p.87 / Chapter 4.2.2 --- Stress treatments --- p.87 / Chapter 4.2.3 --- Isolation of total RNAs --- p.87 / Chapter 4.2.4 --- Reverse transcriptase-polymerase chain reaction (RT-PCR) --- p.88 / Chapter 4.2.4.1 --- Reverse transcription --- p.88 / Chapter 4.2.4.2 --- PCR amplification by specific primers of stress genes --- p.89 / Chapter 4.2.5 --- Northern blot analyses --- p.91 / Chapter 4.2.5.1 --- RNA fractionation by formaldehyde gel electrophoresis --- p.91 / Chapter 4.2.5.2 --- Northern blotting --- p.91 / Chapter 4.2.5.3 --- Preparation of probes --- p.92 / Chapter 4.2.5.4 --- Hybridization and stringency washes --- p.93 / Chapter 4.2.6 --- Isolation of total protein --- p.94 / Chapter 4.2.7 --- Quantification of protein by Bradford method --- p.95 / Chapter 4.2.8 --- Western blot analyses --- p.95 / Chapter 4.2.8.1 --- Sodium dodecyl sulfate ´ؤ polyacrylamide gel electrophoresis (SDS-PAGE) --- p.95 / Chapter 4.2.8.2 --- Western blotting --- p.96 / Chapter 4.2.8.3 --- Immunodetection --- p.98 / Chapter 4.2.8.4 --- ECL detection --- p.98 / Chapter 4.3 --- Results --- p.99 / Chapter 4.3.1 --- Reverse transcriptase-polymerase chain reaction (RT-PCR) --- p.99 / Chapter 4.3.2 --- Northern blot hybridization --- p.106 / Chapter 4.3.2.1 --- Establishing an internal control --- p.106 / Chapter 4.3.2.2 --- Dig-labelling of stress genes --- p.106 / Chapter 4.3.2.3 --- Northern blot hybridizaton of stress genes --- p.106 / Chapter 4.3.3 --- Western blot hybridization --- p.111 / Chapter 4.4 --- Discussions --- p.113 / Chapter Chapter Five --- General Discussions --- p.118 / References --- p.123

Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Fruit size and the integrity of the rind are key components that determine the value of a citrus fruit. The application of 2,4-dichlorophenoxy acetic acid (2,4-D) to reduce splitting, a physiological disorder which entails cracking of the rind as well as to increase fruit size was conducted on three different split-susceptible mandarin and two split-susceptible orange cultivars. Treatments were applied directly after the physiological fruit drop period, as well as in January and February at 10 mg·L-1, alone or in combination with calcium (Ca), potassium (K) or gibberellic acid (GA3). Application of 2,4-D directly after physiological fruit drop, either alone or in a tank-mix with K, consistently reduced the number of split mandarin fruit, with later applications in January and February generally being ineffective. Post physiological fruit drop application of 10 mg·L-1 2,4-D significantly increased growth rate (mm.day-1) of all the mandarin cultivars, resulting in increased fruit size. Differences in sensitivity of cultivars to 2,4-D were evident, with the January application reducing the splitting in ‘Midknight’ Valencia. However, all the 2,4-D treatments reduced the fruit growth rate of the orange cultivars. The 2,4-D treatments, in terms of splitting, increased rind thickness, -strength and -coarseness of ‘Marisol’ Clementine, throughout fruit development. In addition fruit diameter and –length increased to such an extent that the fruit shape was altered (reduced d/l-ratio), reducing the potential of the rind to crack and the fruit to split, however rind coarseness of treated fruit was also increased. There were no major negative side effects on internal and external fruit quality, except for a possible reduction in juice content (%). Therefore, 10 mg·L-1 2,4-D can be applied directly after physiological fruit drop on ‘Marisol’ Clementine and ‘Mor’ mandarin to reduce fruit splitting. / AFRIKAANSE OPSOMMING: Vruggrootte asook die integriteit van die skil is belangrike aspekte in die bepaling van ʼn sitrusvrug se waarde. Die toediening van 2,4-dichlorofenoksie asynsuur (2,4-D) om vrugsplit, 'n fisiologiese defek wat tot die kraak van die sitrusskil lei, te verminder is getoets op drie mandaryn- en twee lemoenkultivars. Hiermee saam is die potensiaal van 2,4-D om vruggrootte te verbeter ook geëvalueer. Die 2,4-D behandelings is direk na die fisiologiese vrugval periode toegedien, asook in Januarie en Februarie, teen 10 mg·L-1, alleen of in kombinasie met kalsium (Ca), kalium (K) of gibberelliensuur (GS3). Al die mandarynkultivars het ʼn vermindering in die totale aantal gesplete vrugte getoon indien die 2,4-D (enkel of in kombinasie met K) toegedien was direk na fisiologiese vrugval. Suksesvolle behandelings het ook 'n toename in vruggrootte tot gevolg gehad. Toediening van behandelings in Januarie en Februarie was oor die algemeen oneffektief. Verskille in kultivar sensitiwiteit teenoor 2,4-D is gevind, met vrugsplit in ‘Midknight’ Valencia wat verminder was deur die Januarie toediening van 2,4-D. Al die 2,4-D behandelings het vruggrootte van die lemoenkultivars verlaag. Daar is bevind dat die 10 mg.L-1 2,4-D, enkel of in kombinasie met K, ‘n toename in beide skildikte en –sterkte van ‘Marisol’ Clementine teweeg bring asook ʼn growwer skil. Behandelings met 2,4-D het vrugdeursnee en –lengte laat toeneem, wat ʼn verandering in vrugvorm tot gevolg gehad het, tot so ʼn mate dat vrugte minder geneig was om gesplete te wees. Behalwe vir ʼn moontlike verlaging in die sapinhoud (%) van vrugte, was daar geen noemenswaardige negatiewe effekte op interne en eksterne vrugkwaliteit nie. Die toediening van 10 mg.L-1 2,4-D direk na fisiologiese vrugval kan dus aanbeveel word op mandaryn kultivars wat geneig is tot vrugsplit. / The Citrus Academy

La transformation de la paroi de l’ovaire en un péricarpe charnu implique une coordination entre les divisions cellulaires et l’expansion cellulaire. Des données considérables sur le développement et la maturation du fruit de tomate ont été établies, mais la coordination des divisions cellulaires, de l’expansion cellulaire et de l’endoréduplication durant la mise à fruit ainsi que durant la croissance du fruit de tomate reste grossièrement caractérisée au sein du péricarpe et de nombreuses questions ne sont pas résolues : comment ces deux processus sont-ils régulés et coordonnés durant le développement du fruit d’un point de vue cellulaire? Quand commence l’endoréduplication dans les tissus du fruit et quelle est sa fonction? La première partie de ce mémoire concerne la coordination des divisions cellulaires et de l’expansion cellulaire durant la fin du développement de l’ovaire et le début du développement du fruit. Une différenciation précoce des assises cellulaires composant la paroi de l’ovaire puis le péricarpe a été démontrée. Les divisions cellulaires se font principalement au sein de l’épiderme externe et montrent une synchronisation partielle tandis que l’expansion cellulaire se fait principalement dans le mésocarpe. L’endoréduplication semble être initiée avant l’anthèse. La deuxième partie est consacrée à l’analyse du RNA-seq nucléaire en fonction de quatre niveaux de ploïdie (4, 8, 16 et 32C). La majorité des gènes montrent une augmentation proportionnelle de leurs expressions en fonction des niveaux de ploïdie. Cependant, certains gènes révèlent une surexpression ou une sous-expression en fonction des niveaux de ploïdies. / The transformation of the ovary wall into a fleshy pericarp involves a coordinated pattern of cell division and cell expansion. Considerable data have been reported on tomato fruit development and ripening, but the pattern of cell division, cell expansion and endoreduplication at the tomato fruit set and during fruit growth remains grossly appreciated at the whole pericarp level and many questions are not yet resolved: How are cell division and cell expansion coordinated in tomato fruit a cellular level and according to developmental time? When does endoreduplication begin in fruit tissues and what is its function? The first part of this deals with the coordination of cell division and cell expansion during the end of tomato ovary development and the beginning of fruit growth. Evidence for early differentiation of cell layers in the ovary wall and then in fruit pericarp are presented. Cell division happens mainly in the external epidermis and shows partial synchronization, whereas cell expansion happens mostly in mesocarp cell layers. Endoreduplication is initiated as soon as before anthesis. The second part of this work is devoted to RNA-seq based transcriptome profiling of pericarp nuclei which have been sorted according to four ploidy levels (4, 8, 16 and 32C). We demonstrate that the expression of most of the pericarp-expressed genes shows a proportional increase according to ploidy level, on a nuclear basis. However, a significant amount of genes has been identified as over-expressed or under-expressed according to ploidy level.

by Ng Tak Pan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 151-168). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Abbreviations --- p.v / Table of Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xiii / Chapter Chapter One --- Literature Review / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Nutraceutical and Medicinal Properties of L. edodes --- p.4 / Chapter 1.2.1 --- Nutritional value --- p.4 / Chapter 1.2.2 --- Hypocholesterolaemic Effect --- p.5 / Chapter 1.2.3 --- Anti-tumor Effect --- p.5 / Chapter 1.2.4 --- Anti-viral Effect --- p.6 / Chapter 1.2.5 --- Immunopotentiating Effect --- p.6 / Chapter 1.3 --- Life cycle of L. edodes --- p.7 / Chapter 1.4 --- Environmental factors affecting mycelial growth and fruit body --- p.11 / Chapter 1.4.1 --- Nutrient requirement --- p.11 / Chapter 1.4.2 --- Physical and chemical factors --- p.12 / Chapter 1.5 --- Molecular studies on mushroom development --- p.15 / Chapter 1.5.1 --- Mating-type genes --- p.15 / Chapter 1.5.2 --- Hydrophobins --- p.19 / Chapter 1.5.3 --- Fruiting regulatory genes --- p.23 / Chapter 1.5.4 --- Molecular studies on fruit body development of I. edodes --- p.24 / Chapter 1.5.4.1 --- Identification of L. edodes genes --- p.24 / Chapter 1.5.4.2 --- Functional characterization of L. edodes genes --- p.27 / Chapter 1.5.4.3 --- Transformation in L. edodes --- p.28 / Chapter Chapter Two --- Expressed Sequence Tags (ESTs) of L. edodes / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- Materials and Methods --- p.33 / Chapter 2.2.1 --- Generation of expressed sequence tag --- p.33 / Chapter 2.2.1.1 --- Mushroom cultivation and RNA extraction --- p.33 / Chapter 2.2.1.2 --- Construction of primordium cDNA library --- p.34 / Chapter 2.2.1.3 --- Mass excision of pBK-CMV plasmid --- p.34 / Chapter 2.2.1.4 --- Random screening of mass excised cDNA clone --- p.38 / Chapter 2.2.1.5 --- Isolation of recombinant plasmid --- p.38 / Chapter 2.2.1.6 --- Generation of 3´ة end partially sequence --- p.39 / Chapter 2.2.1.7 --- Sequence analysis --- p.40 / Chapter 2.2.2 --- Reverse dot-blot Hybridization --- p.40 / Chapter 2.2.2.1 --- PCR amplification of cDNA clone --- p.40 / Chapter 2.2.2.2 --- Membrane preparation --- p.40 / Chapter 2.2.2.3 --- cDNA probe preparation --- p.41 / Chapter 2.2.2.4 --- Hybridization --- p.42 / Chapter 2.2.2.5 --- Stringent washing and autoradiography --- p.43 / Chapter 2.3 --- Results --- p.44 / Chapter 2.3.1 --- Construction of primordium cDNA library --- p.44 / Chapter 2.3.2 --- Screening of recombinant clone --- p.44 / Chapter 2.3.3 --- Isolation and reconfirmation of recombinant plasmid --- p.46 / Chapter 2.3.4 --- Generation of EST --- p.47 / Chapter 2.3.5 --- EST identity --- p.47 / Chapter 2.3.6 --- Reverse dot-blot hybridization --- p.56 / Chapter 2.3.7 --- Analysis of hybridization signal --- p.60 / Chapter 2.4 --- Discussion --- p.71 / Chapter Chapter Three --- Sequence Analysis and Transcriptional Profiling of Genes Encoding GTP-binding Proteins / Chapter 3.1 --- Introduction --- p.78 / Chapter 3.2 --- Materials and Methods --- p.82 / Chapter 3.2.1 --- Sequence manipulation --- p.82 / Chapter 3.2.2 --- Northern blot hybridization --- p.82 / Chapter 3.2.2.1 --- RNA fragmentation by formaldehyde gel electrophoresis --- p.82 / Chapter 3.2.2.2 --- RNA fixation by capillary method --- p.83 / Chapter 3.2.2.3 --- Probe preparation --- p.84 / Chapter 3.2.2.4 --- Hybridization --- p.85 / Chapter 3.2.2.5 --- Stringent washing and autoradiography --- p.85 / Chapter 3.2.3 --- Real-Time SYBR Green RT-PCR --- p.85 / Chapter 3.2.3.1 --- Primer design --- p.85 / Chapter 3.2.3.2 --- RT-PCR reaction --- p.86 / Chapter 3.3 --- Results --- p.88 / Chapter 3.3.1 --- Sequence manipulation --- p.88 / Chapter 3.3.2 --- Transcriptional analysis --- p.103 / Chapter 3.4 --- Discussion --- p.108 / Chapter 3.4.1 --- Heterotrimeric G proteins --- p.108 / Chapter 3.4.2 --- Ras-related protein Rab7 --- p.112 / Chapter 3.4.3 --- Developmentally regulated GTP-binding protein --- p.113 / Chapter Chapter Four --- Yeast Complementation and Over-expression tests of Le.Gβ1 and Le.Gγ1 / Chapter 4.1 --- Introduction --- p.115 / Chapter 4.2 --- Materials and Methods --- p.120 / Chapter 4.2.1 --- "Yeast strains, media and yeast vectors" --- p.120 / Chapter 4.2.2 --- Primer design --- p.121 / Chapter 4.2.3 --- RT-PCR Amplification of Le.Gβ1 and Le.Gγ1 --- p.121 / Chapter 4.2.4 --- Purification of PCR products --- p.122 / Chapter 4.2.5 --- Enzymatic digestion and purification --- p.122 / Chapter 4.2.6 --- Ligation and E. coli transformation --- p.122 / Chapter 4.2.7 --- PCR screening of E. coli transformants --- p.124 / Chapter 4.2.8 --- Plasmids extraction --- p.124 / Chapter 4.2.9 --- Yeast transformation --- p.124 / Chapter 4.2.10 --- Mating test --- p.125 / Chapter 4.3 --- Results --- p.129 / Chapter 4.3.1 --- Cloning of Le.Gβ1 and Le.Gγ1 --- p.129 / Chapter 4.3.2 --- Yeast transformation --- p.129 / Chapter 4.3.3 --- Mating test --- p.130 / Chapter 4.4 --- Discussion --- p.141 / Chapter Chapter Five --- General Discussion --- p.144 / References --- p.151

Kiwifruit are of huge economic importance for New Zealand representing 29 percent of total horticultural exports. Fruit size is the biggest determinant of what consumers are willing to pay, and there is also a positive relationship between consumer preference for flavour and percentage dry matter. The two main cultivars exported from New Zealand are Actinidia chinensis ‘Hort 16A’ (gold kiwifruit) and A. deliciosa ‘Hayward’ (green kiwifruit). Under current commercial practice the only product allowed for use on kiwifruit to increase fruit size in New Zealand is Benefit®. Benefit® has been shown to induce different results when applied to A. chinensis and A. deliciosa, whereas synthetic plant growth regulators such as the cytokinin-like substance N-(2- chloro-4-pyridyl)-N’-phenylurea (CPPU) have been found to promote similar increases in fresh weight of fruit in both cultivars. Final fruit size is determined by both cell division and cell enlargement. It was been shown that fresh weight can be increased in both of the major Actinidia cultivars even though their physiology differs. Hormonal control of fruit size in relation to cell division and cell enlargement phases of fruit growth was studied in both A. chinensis and A. deliciosa. CPPU was applied to both cultivars in a growth response experiment where fruit were collected throughout the growing season. The objective of this experiment was to create growth curves, to compare and contrast the effect on A. chinensis and A. deliciosa, and to provide material for hormone analysis. Application of CPPU was found to significantly increase the fresh weight of both A. chinensis and A. deliciosa fruit (46.98 and 31.34 g increases respectively), and alter the ratio of inner and outer pericarps of A. chinensis fruit. CPPU and Benefit® were applied individually and together to both cultivars. It was found that only A. chinesis fruit were affected by the application of Benefit®; fresh weight was increased by 26.38 g, and percentage dry matter was significantly reduced. There was a statistically significant (p < 0.05) interaction between CPPU and Benefit® when applied to A. chinensis. 3,5,6-trichloro-2-pyridyloxyacetic acid (3,5,6-TPA) was applied to A. deliciosa on two application dates at three concentrations and was found to decrease fresh weight of fruit, but significantly increase percentage dry matter regardless of application date or concentration. Lastly CPPU and 1-naphthalene acetic acid (NAA) were applied to A. deliciosa at two application dates and in all combinations. Application date affected the response to both a low concentration of CPPU and NAA. A synergistic interaction was observed when CPPU was applied early plus NAA late (CPPU early (4.53 g increase) plus NAA late (13.29 g) < CPPU early plus NAA late (33.85 g). Finally endogenous hormone content was studied. Methods were developed and tested for the simultaneous analysis of both indole-3-acetic acid (IAA) and cytokinins. Freeze dried fruit were purified using Waters Sep-pak® cartridges and Oasis® columns then IAA was quantified by high pressure liquid chromatography. Preliminary results indicate a correlation between application of CPPU and endogenous IAA, high concentrations of IAA correlated well with periods of rapid fruit growth particularly for CPPU treated fruit.

Le dernier rapport du GIEC confirme clairement des projections climatiques prévoyant une augmentation des températures et de leur variabilité à la fin du XXIème siècle. Les effets de ces changements sur la production et la qualité des fruits ont été étudiés dans le cadre du projet CAQ40(INRA). Les expérimentations menées sur des pêchers en pot placés sous différents climats (témoin,+2°C et +5°C), ont permis d’identifier les processus (phénologie, développement, croissance,photosynthèse, métabolisme) les plus sensibles à l’élévation des températures et leurs conséquences sur le développement et la composition des fruits et la pérennité de la production.L’élévation de température a augmenté la demande climatique entraînant une diminution du potentiel hydrique des arbres, ce qui a pu entrainer une concentration des composés d’intérêt dans le fruit. La réduction du taux de photosynthèse des feuilles dans des conditions de forte température est liée à une inhibition de la photosynthèse par les températures élevées et à un contrôle stomatique lié au statut hydrique.Après floraison, l’élévation de température accélère la croissance végétative, induisant une mise en place de la surface foliaire anticipée. Cette croissance végétative précoce a eu pour conséquence (i) une dynamique très rapide d’élongation des axes en pousse longue (ii) une dominance apicale plus marquée, (iii) une diminution de la ramification des axes axillaires,contrairement aux traitements thermiques plus tardifs qui ont eu un effet défavorable sur l’initiation et la différenciation des bourgeons floraux réduisant le potentiel de production l’année suivante.En outre, l’augmentation de température après floraison a entraîné un raccourcissement très marqué de la durée de croissance du fruit, avec une date de récolte anticipée de près de 3semaines. Ce raccourcissement de la durée de croissance du fruit a entraîné une diminution du flux entrant de carbone dans le fruit, pénalisant sa croissance et sa qualité. Le climat très différent entre les deux années expérimentales a entrainé une forte variabilité de la composition des fruits entre les deux années d’expérimentation. En 2014, une élévation de température précoce ou continue a conduit à récolter des fruits de petites tailles ayant des concentrations et des teneurs en saccharose plus importantes. En 2015, la durée de développement entre floraison et maturité était encore plus courte qu’en 2014 ce qui pouvait être lié au climat plus chaud de 2015 et les fruits ont été moins sucrés et plus acides que ceux de 2014. Toutefois, l’élévation des températures en fin de développement en 2015 a augmenté les teneurs et les concentrations en hexoses et en sorbitol liées à un effet concentration mais également à un effet sur le métabolisme. L’élévation des températures en milieu et en fin de cycle a également favorisé l’accumulation d’acide malique et citrique. Les fortes températures n’ont pas eu beaucoup d’effet sur la vitamine C et ont soit augmenté ou diminué les teneurs en composés phénoliques. Les effets d’une élévation de la température sur le métabolisme sont donc très dépendants du stade de développement du fruit.L’utilisation de modèle à l’échelle du fruit (Virtual Fruit) et à l’échelle de l’arbre (QualiTree)pourrait permettre de simuler à la fois l’effet de l’environnement et des pratiques culturales sur la croissance et la qualité du fruit, et donner une vision plus intégrée du fonctionnement de la plante sous contraintes environnementales. / The latest IPCC report clearly confirms the climate projections for increasing temperaturesand their variability at the end of the 21st century. The effects of climate changes in fruit yield andquality have been studied in a project funded by INRA (project CAQ40, Metaprogramme ACCAF).Experiments carried out on potted peaches placed in different climates (control, +2 ° C and + 5 ° C),allowed the identification of the processes (phenology, development, growth, photosynthesis,metabolism) most sensitive to rising temperatures and their consequences on the development andcomposition of fruits and the sustainability of production.Higher temperature has increased the demand for water, leading to a decrease in the waterpotential of the trees, which may have led to a concentration of the compounds of interest in thefruit. The reduction of leaf photosynthesis under high temperature conditions was related to theinhibition of photosynthesis by high temperatures and stomatal control related to water status.After flowering, the rise in temperature accelerates the vegetative growth, triggering a more rapidestablishment of leaf area. This early vegetative growth resulted in: (i) very rapid dynamics ofelongation of the axes in long shoot (ii) a more pronounced apical dominance, (iii) a decrease in theaxillary axial branching. In contrast the later heat treatment had an adverse effect on the initiationand differentiation of floral buds reducing the production potential in the following year.In addition, the increase in temperature after flowering resulted in a marked shortening ofthe fruit growth period, with an expected harvest date almost 3 weeks earlier. This shortening offruit growth duration has led to a decrease in the flow of carbon entering the fruit, penalizing itsgrowth and quality. The very different climates between the two experimental years resulted in ahigh variability in fruit composition between the two years of experimentation. In 2014, increasedtemperature during the early stage of fruit development or continuously led to the harvest ofsmaller fruit with higher concentrations and higher sucrose content. In 2015, the time durationbetween flowering and maturity was even shorter than in 2014, which could be linked to thewarmer climate of 2015. In 2015 fruits were less sweet and acidic than those of 2014. However, therise of temperatures at the end of fruit development in 2015 increased the levels andconcentrations of hexoses and sorbitol; this increase was partially due to a concentration effect butalso to an effect on fruit metabolism. Increased temperatures in the middle and at the end of fruitdevelopment also favoured the accumulation of malic and citric acid. The high temperatures did nothave much effect on vitamin C and either increased or decreased the levels of phenolic compounds.The effects of an increase in temperature on the metabolism are therefore very dependent on thestage of fruit development.The use of a Fruit‐scale model and a tree‐level (QualiTree) model could simulate both the effect ofthe environment and cultural practices on the growth and quality of the fruit, and give a moreintegrated view of the plant's functioning under environmental constraints.

The contamination of process pea (Pisum sativum L.) crops by the immature fruit of black nightshade (Solanum nigrum L.) and hairy nightshade (S. physalifolium Rusby var. nitidibaccatum (Bitter.) Edmonds) causes income losses to pea farmers in Canterbury, New Zealand. This thesis investigates the questions of whether seed dormancy, germination requirements, plant growth, reproductive phenology, or fruit growth of either nightshade species reveal specific management practices that could reduce the contamination of process peas by the fruit of these two weeds. The seed dormancy status of these weeds indicated that both species are capable of germinating to high levels (> 90%) throughout the pea sowing season when tested at an optimum germination temperature of 20/30 °C (16/8 h). However, light was required at this temperature regime to obtain maximum germination of S. nigrum. The levels of germination in the dark at 20/30 °C and at 5/20 °C, and in light at 5/20 °C, and day to 50 % germination analyses indicated that this species cycled from nondormancy to conditional dormancy throughout the period of investigation (July to December 2002). For S. physalifolium, light was not a germination requirement, and dormancy inhibited germination at 5/20 °C early in the pea sowing season (July and August). However, by October, 100% of the population was non-dormant at this test temperature. Two field trials showed that dark cultivation did not reduce the germination of either species. Growth trials with S. nigrum and S. physalifolium indicated that S. physalifolium, in a non-competitive environment, accumulated dry matter at a faster rate than S. nigrum. However, when the two species were grown with peas there was no difference in dry matter accumulation. Investigation of the flowering phenology and fruit growth of both species showed that S. physalifolium flowered (509 °Cd, base temperature (Tb) 6 °C) approximately 120 °Cd prior to S. nigrum (633 °Cd). The fruit growth rate of S. nigrum (0.62 mm/d) was significantly faster than the growth rate of S. physalifolium (0.36 mm/d). Because of the earlier flowering of S. physalifolium it was estimated that for seedlings of both species emerging on the same date that S. physalifolium could produce a fruit with a maximum diameter of 3 mm ~ 60 °Cd before S. nigrum. Overlaps in flowering between peas and nightshade were examined in four pea cultivars, of varying time to maturity, sown on six dates. Solanum physalifolium had the potential to contaminate more pea crops than S. nigrum. In particular, late sown peas were more prone to nightshade contamination, especially late sowings using mid to long duration pea cultivars (777-839 °Cd, Tb 4.5 °C). This comparison was supported by factory data, which indicated that contamination of crops sown in October and November was more common than in crops sown in August and September. Also, cultivars sown in the later two months had an ~ 100 °Cd greater maturity value than cultivars sown in August and September. Nightshade flowering and pea maturity comparisons indicated that the use of the thermal time values for the flowering of S. nigrum and S. physalifolium can be used to calculate the necessary weed free period required from pea sowing in order to prevent the flowering of these species. The earlier flowering of S. physalifolium indicates that this species is more likely to contaminate pea crops than is S. nigrum. Therefore, extra attention may be required where this species is present in process pea crops. The prevention of the flowering of both species, by the maintenance of the appropriate weed free period following pea sowing or crop emergence, was identified as potentially, the most useful means of reducing nightshade contamination in peas.