Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

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Bibliography: leaves 153-156. / ix, 156 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the experiments conducted to determine the mechanisms that cause the decline in shoot Zn concentration and the responses of the wheat plant to Zn deficiency and chlorosulfuron stress. Root tip extension is used as a measure of wheat root growth during exposure to the sulfonylurea herbicide chlorsulfuron. Wheat plants differing in Zn efficiency are grown in HEDTA chelate-buffered nutrient solution in controlled conditions. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1997

Bibliography: leaves 153-156. / ix, 156 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the experiments conducted to determine the mechanisms that cause the decline in shoot Zn concentration and the responses of the wheat plant to Zn deficiency and chlorosulfuron stress. Root tip extension is used as a measure of wheat root growth during exposure to the sulfonylurea herbicide chlorsulfuron. Wheat plants differing in Zn efficiency are grown in HEDTA chelate-buffered nutrient solution in controlled conditions. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1997

Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2018. / Zinc deficiency on various soil types have been reported in arable soils of sub Saharan Africa (SSA) including South Africa. A pot trial was conducted at the Cape Peninsula University of Technology, Wellington campus to investigate the interaction of different application rates of Zn at various soil pH on the grain yield and quality of spring wheat in a completely randomized factorial design replicated three times. The four soil pH tested were: pHA: 5.1, pHB: 5.6, pHC: 6.1, pHD: 6.6 which correspond to lime application at 0, 0.5, 1 and 1.5 t/ha. Five Zn rates (Zn1: 3.5; Zn2: 4.5; Zn3: 5.5 Zn4: 6.5, and Zn5: 7.5 mg /kg soil which correspond to Zn1: 7; Zn2: 9; Zn3: 11; Zn4: 13 and Zn5: 15 kg /ha) were applied at two (planting and flowering) growth stages. Yield and yield component data collected were analyzed using SAS version 9.2 and means were separated by Duncun’s Multiple Range Test (DMRT). The results showed that grain yield and yield components were significantly affected by lime application pHC (6.1): 1t/ha at planting. Zn application at planting had no significant effect on the grain yield and yield components. However, at flowering, the simultaneous increase of Zn along with increase in lime positively affected grain yield and yield components. Plant analysis showed that at both stages (planting and flowering), Zn application, especially at pH 6.6, significantly increased P, K, Ca, Na, Mg Fe, Cu and B concentrations in wheat grain, but the concentrations of N, Mn, Zn and protein remained unaffected. Zn application had no effect on most nutrients due to the presence of lime. While the absence of lime, Zn4: 6.5mg/kg (corresponding to 13kg/ha) significantly increased the nutrients. In addition, Zn3: 5.5mg/kg (corresponding to 11kg/ha) promoted Zn absorption by grain in all treatments.

Soybeans (Glycine max L. Merr.) are a symbiont of two beneficial associations: biological nitrogen fixation (BNF) with Bradyrhizobium japonicum, and arbuscular mycorrhizal fungi (AMF). Within the Northern Great Plains of the USA, iron deficiency chlorosis (IDC) of soybean is a yield-limiting factor. The effects of IDC on BNF and AMF are not well defined. This study was conducted to determine the effects of IDC on BNF and AMF. A laboratory study was performed to compare three methods of measuring ureide-N, a product of BNF in soybeans. Field studies in soybean were performed at three locations at eastern N011h Dakota. The experimental design was a factorial combination of three cultivars and three treatments. The three cultivars, in order of decreasing chlorosis susceptibility, were NuTech NT-0886, Roughrider Genetics RG 607, and Syngenta S01-C9 RR. The three treatments were control, Sorghum bicolor L. companion crop planted with the soybean seed, and FeEDDHA applied with the soybean seed. Chlorosis severity was the greatest and least for the NuTech and Syngenta cultivars, respectively. The FeEDDHA treatment decreased chlorosis severity. Ureide levels were abnormally high in plants severely stunted by JDC. The excess accumulation of ureides in IDC-stunted plants suggests that plant growth was reduced more than the rate of nitrogen fixation. The AMF population \vas at an adequate level at all locations and not affected by cultivar or treatment, in general. In the laboratory study, the Patterson et al. method had greater ureide concentrations due to the non-specific measuring of ammonium compounds compared to the Vogels and Van der Drift and Goos methods. / North Dakota Soybean Council

Zinc and manganese have long been considered as essential micronutrients to plant growth, yet the interactions of the two nutrients on growth and development of plants have not been elucidated in their entirety. Silicon is not classed as an essential element, but has been found to improve growth of a number of crops, particularly of the Poaceae family. A simple water culture hydroponic system was developed to monitor the growth and development of a fruit crop (Cucumber – Cucumis sativus) under deficient, adequate and excessive applications of zinc and manganese. Plant growth parameters were monitored including leaf growth, plant height, plant fresh and dry mass, yield, fruit size and fruit mass. Nutrient uptake was also measured using inductively coupled plasma emission spectroscopy, whilst chlorophyll was determined spectrophotometrically. Plant nutrient analyses were also conducted using inductively coupled plasma emission spectroscopy. Silicon was found to have a beneficial effect on the growth of cucumbers and was incorporated as a treatment for this crop along with zinc and manganese since foliar silicon sprays were able to correct the occurrence of mineral deficiency symptoms. Along with plant growth measurements, nutrient uptake, plant nutrient analysis and chlorophyll determination, plant tissue was also analysed using transmission electron microscopy to establish the impact of silicon applications on the cell ultra-structure of cucumbers. Electron micrographs showed an increased presence of plasmodesmata in treatments excluding silicon. Such increased plasmodesmata connections under silicon deficient conditions could increase translocation of cell solutes due to reduced cell longevity. Results also confirmed the essentiality of zinc and manganese on plant growth and development as typical deficiency symptoms were observed. Typical toxicity symptoms were also recorded. Rates of uptake of nutrients corresponded with leaf growth and enlargement as well as yield. The chlorophyll concentration was not a clear indicator of nutrient application level. Typically, manganese and zinc interacted with iron, magnesium, calcium and potassium, affecting their uptake into the plant dependent on the level of manganese and zinc applied. Although non-essential, silicon improved plant growth, but had neither a relationship with the other nutrients evaluated nor affected the physical growth and development of the plants. Manganese and zinc, as essential to plant growth and development, affect the visual appearance of the plant as well as affect the plant biochemically due to their involvement in many growth and development processes. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Caractérisation de CCX2, un élément de la super-famille des antiports cationiques CaCA et de son rôle dans l’homéostasie minérale.<p><p>L'homéostasie des métaux est importante pour les fonctions cellulaires. Elle dépend de la régulation stricte des transports cellulaires d'ions métalliques et des espèces métalliques complexées. Nous rapportons ici l'analyse fonctionnelle chez Arabidopsis thaliana d'un élément de la superfamille CaCA, CCX2 (Calcium Cation eXchanger 2) qui n’est pas encore caractérisé dans les plantes. Nous avons pu observer en utilisant une fusion aves la protéine fluorescente GFP (Green Fluorescent Protein) que la protéine AtCCX2 était localisée dans le réticulum endoplasmique. L’expression de CCX2 est régulée par des traitements en métaux divers et par la carence en magnésium en particulier. De plus, l'expression du gène est régulée par la photopériode mais n’est probablement pas sous le contrôle de l'horloge circadienne. La caractérisation d'un mutant knock-out d’Arabidopsis a révélé que l’absence de l’activité CCX2 entrainait une meilleure croissance pendant la carence Mg (dans les conditions testées) mais pas de phénotype particulier sur les milieux aves excès de Zn ou de Cd ou induisant un stress osmotique. A ce stade, nous de pouvons apporter une explication au phénomène de tolérance pendant la carence Mg. Par ailleurs, le mutant ccx2 montre une réponse altérée à des hormones telles l’auxine et l’éthylène. Parce ce que le phénotype ccx2 mutant est relativement discret, des doubles mutants avec les gènes homologues les plus proches (CCX1 et CCX3) ont été créés. Alors que les mutants ccx1 et ccx3 sont plus résistants à la carence en Mg et ccx1 plus résistant à la déficience Zn, aucun effet additif de ces mutations avec la perte de fonction de CCX2 n’a été observé. Les profils en minéraux du mutant ccx2 ne permettent pas de confirmer des différences significatives dans les concentrations d’éléments minéraux mesurés. Des tendances pour le Ca2+ en particulier sont observées et devraient être confirmés par d’autres expériences. La surexpression hétérologue dans la levure ou dans une suspension de cellules BY2 de tabac, la surexpression dans la plante et la production de protéine pour des études d’activité de transport dans des vésicules n’ont pu être possibles pour la caractérisation de CCX2. L’expression de CCX2 semble toxique pour les bactéries, la levure et les cellules de plantes; en effet les organismes hôtes sont morts lors de l'induction de l'expression (testé au niveau de la levure). Cet effet pourrait être lié à la perturbation de l’homéostasie du Ca2+ qui joue un rôle très important comme messager secondaire lors de la perception d’un stimulus et en particulier lors de l’apoptose. L’Analyse AhCAX8/CCX2 AhCCX2 est constitutivement plus exprimé dans les racines de l’hyperaccumulatrice de Zn et Cd, Arabidopsis halleri (accession d’Auby) par rapport à sa parente proche non tolérante non accumulatrice A. lyrata ssp petraea. L'expression plus élevée pourrait être liée à l'adaptation aux hautes concentrations de zinc et de cadmium dans le sol. Nous avons pu observer qu’avec une protéine GFP, AhCCX2 est également localisée au niveau du réticulum endoplasmique comme son homologue AtCCX2. Puisque une haute expression de CCX2 est toxique pour les organismes, nous avons exprimé la protéine sous le contrôle de son propre promoteur dans A. thaliana. Cette expression faible et spécifique a pu être atteinte sans signe de toxicité. La caractérisation de A. thaliana exprimant AhCCX2 dans le type sauvage ou le mutant ccx2 a montré une meilleure croissance lors d’une déficience Mg et, dans les plantes ccx2 qui expriment AhCCX2, une moins bonne croissance lors d’une carence en Zn. Les analyses minérales des plantes exprimant AhCCX2 n’ont pas montré de différence au niveau des concentrations en minéraux. Cependant, certaines tendances ont été observées pour les concentrations en Ca, Fe et Zn qui doivent être confirmées. Nos données suggèrent pour AhCCX2 un rôle dans l'homéostasie du Zn. Un niveau d'expression élevé d’AhCCX2 a un impact négatif sur la croissance lors d’une carence en zinc et pourrait être une partie des adaptations à un approvisionnement en Zn élevé. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

[Truncated abstract] Industrial processing to refine alumina from bauxite ore produces millions of tonnes of refining residue each year in Australia. Revegetation of bauxite residue sand (BRS) is problematic for a number of reasons. Harsh chemical conditions caused by residual NaOH from ore digestion mean plants must overcome extremely high pH (initially >12), saline and sodic conditions. At such high pH, manganese (Mn) is rapidly oxidised from Mn2+ to Mn4+. Plants can take up only Mn2+. Thus, Mn deficiency is common in plants used for direct BRS revegetation, and broadcast Mn fertilisers have low residual value. Added to this, physical conditions of low water-holding capacity and a highly compactable structure make BRS unfavourable for productive plant growth without constant and large inputs of water as well as Mn. However, environmental regulations stipulate that the residue disposal area at Pinjarra, Western Australia, be revegetated to conform with surrounding land uses. The major land use of the area is pasture for grazing stock. Hence, pasture revegetation with minimum requirement for fertiliser and water application is desirable. This thesis investigates a number of avenues with potential for maintaining a productive pasture system on BRS whilst reducing the current level of Mn fertiliser and irrigation input. Emphasis was placed on elucidation of chemical and physical factors affecting Mn availability to plants in BRS