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Jerry D. Cohen and Janet P. Slovin

The literature is full of different techniques and approaches to the isolation, purification and quantitative analysis of plant hormones. From this body of literature it is possible to deduce that 1) a lot of investigators are interested in how much of these compounds are in plants and 2) that the techniques for phytohormone analysis are still largely “under development”. This talk will discuss different approaches to hormone analysis, suitability of each approach, and criteria for the evaluation of techniques and results. The goal will be to highlight points that are important to obtaining reliable analytical information and knowing what to do when problems occur. Nevertheless, having reliable numbers is frequently only the first step in understanding hormonal systems involved in plant development, It is often the case that the expected results are not what is found in experiments involving plant hormone quantitation. We will consider experimental design, tissue localization, developmental stages, sampling and extraction procedures, and the limits of what to expect when “dogma confronts reality”. Work reported was supported by grants from the National Science Foundation DCB-8917378, USDA-CRGO 89-3721-4734, US-Israel BARD US-1362-87, and by funds from the USDA Argicultural Research Service,

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Jane Kahia, Peter Njenga, and Margaret Kirika

application of TDZ for in vitro propagation of anchote has not been reported. The aim of the study was to evaluate the effect of different phytohormones on in vitro propagation of anchote. Materials and Methods Anchote ( C. abyssinica ) tubers were collected

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Sanalkumar Krishnan and Emily B. Merewitz

). Creeping bentgrass also exhibits considerable susceptibility to other abiotic and biotic stresses such as summer stress and dollar spot [ Sclerotinia homoeocarpa ( Fry and Huang, 2004 )]. How the phytohormone profile of creeping bentgrass changes in

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Md. Aktar Hossain, Sooah Kim, Kyoung Heon Kim, Sung-Joon Lee, and Hojoung Lee

. Moreover, several studies have shown that phytohormones are involved in the sucrose-regulated expression of genes encoding anthocyanin biosynthetic enzymes in Arabidopsis seedlings ( Chen et al., 2007 ; Devoto et al., 2005 ; Loreti et al., 2008

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Hanan M. El-Hoseiny, Mohamed N. Helaly, Nabil I. Elsheery, and Shamel M. Alam-Eldein

of the narrow threshold between B deficiency and toxicity ( Yua and Ryan, 2008 ). Boron improves enzymes activity, promotes phytohormones and nucleic acids, activates nutrient uptake and mitigates plant tolerance to salinity, increases carbohydrates

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Jin Jiao, Xing Liu, Juyou Wu, Guohua Xu, and Shaoling Zhang

, CA) according to the manufacturer’s instructions. Pollen was hydrated and grown as previously described in germination medium (GM) for 1 h before challenged with temperature or phytohormones. For hormonal treatment, pollen was sprayed with five

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Takashi Hosoki

Effects of methyl disulfide (MeS2) on sprouting and phytohormones in dormant corms of spring-flowering gladiolus (Gladiolu×Tubergenii Hort. `Charm') were studied. Corms treated with MeS2 sprouted 30 days earlier than nontreated corms. The concentrations of endogenous promoters in the corm tissue increased and inhibitors decreased within 24 h of treatments. High concentration of inhibitors were present in the nontreated corms.

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Thomas L. Davenport

The reproductive phenologies of temperate fruit tree species are briefly introduced and compared to the reproductive phenologies of three tropical and subtropical fruit tree species. The impact of leaf and fruit development and the phytohormones they may produce on the reproductive or vegetative fate of bourse buds in apple spurs serves as the model to discuss temperate fruit flowering. In contrast, conceptual models of citrus (Citrus L.), mango (Mangifera indica L.), and lychee (Litchi chinensis Sonn.) flowering are described which propose physiological mechanisms for both flowering and vegetative flushing in trees grown in subtropical and tropical environments. Possible roles for auxin and cytokinins in shoot initiation and for gibberellins and a putative florigenic promoter in induction are discussed as they relate to the physiology of flowering and vegetative flushing of tropical species. Successful application of these conceptual flowering models through the use of growth regulators and other horticultural management techniques to control flowering of citrus, mango, and lychee is described.

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Sanalkumar Krishnan, Yingmei Ma, and Emily Merewitz

insect herbivory or fungal invasion. These responses all require significant modification of many phytohormones and energy to be performed. The preventative responses may only serve as a benefit to the plant if the plants are subsequently attacked by a

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Scott Schaefer, Ksenija Gasic, and Schuyler Korban

Peach shoots were grown in vitro for 0, 6, 12, 24, and 48 h on a basal medium containing one of several phytohormones or chemical elicitors, including abscisic acid (ABA), indolebutyric acid (IBA), indoleacetic acid (IAA), kinetin, gibberellic acid (GA3), aminocyclopropane-1-carboxylic acid (ACC), methyl jasmonate (MeJ), and salicylic acid (SA). Northern blot analysis was conducted using the 3' end of a peach-1,3-glucanase gene, PpGns1, used as a probe. Variations in levels of PpGns1 expression patterns were observed for each of the treatments. Shoots treated with ABA displayed high levels of transcripts at 12 and 24 h, followed by a sharp decline at 48 h. Shoots treated with ACC displayed a steady increase in transcripts throughout the 48 h period. The synthetic auxin IBA displayed a steady increase in mRNA accumulation for the first 24 h followed by a sharp decline at 48 h. Shoots treated with kinetin displayed low levels of transcripts after 24 h, while GA3 did not induce any accumulation of PpGns1 transcripts. Both SA and MeJA induced steady mRNA accumulation in peach shoots over the entire 48-h period. Induction of PpGns1 in response to SA, MeJ, and ACC also resulted in observed necrotic lesions on peach shoots, thus suggesting a different defense mechanism response.