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Sahar Dabirian and Carol A. Miles

cotyledon to remain on the rootstock to ensure graft success ( Bisognin et al., 2005 ; Hassell et al., 2008 ). However, to prevent rootstock growth with these methods, the meristem tissue at the base of the rootstock cotyledon must be completely removed

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R.J. Griesbach and J. Milo

Most methods developed to transform plants either require tissue culture to regenerate a whole plant from transformed tissue or the transformation of reproductive tissue. These approaches are not applicable to vegetatively propagated crops or crops that can not be tissue-culture propagated. We have modified a procedure that was developed to transform zygotic meristems for use with whole plant meristems. We developed a method to introduce DNA via electrophoresis into the cells of axillary meristems of whole plants growing in soil. About half of the treated meristems developed into shoots. Of those shoots, up to half had some level of GUS marker gene expression. We were able to transform Cercis, Chrysanthemum, Capsicum, and Prunus. In Capsicum, the GUS gene was inherited.

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Ying Gao, Hao Liu, and Dong Pei

) immunolocalization of walnut stamens: ( A ) longitudinal sections of staminate catkin during bract differentiation (bar = 200 μm), high levels of IAA signals were observed around shoot apical meristem and flower primordium. ( B ) Longitudinal sections of staminate

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Sarah A. Masterson, Megan M. Kennelly, Rhonda R. Janke, and Cary L. Rivard

reliance on the healing chamber, which could potentially facilitate more grafting success for a propagator with limited facilities. In addition to reducing water stress, the removal of the entire scion meristem could expedite the process of growing a plant

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Bruce W. Wood

.g., sucrose) acting in the environment of the axillary meristems during, or just after, vernalization preceding anthesis ( Wood, 2011 ). Like with many other tree-fruit species ( Schmidt et al., 2009 ), florally induced bud primordia on heavy cropload trees (i

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Senay Ozgen, James S. Busse, and Jiwan P. Palta

primary injury from calcium deficiency is localized in the expanding pith cells below the apical shoot meristem and injury is characterized by the collapse of the walls of subapical cells in potato. These results suggest that strontium may be able to

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Naza Azizbekova, Christia M. Roberts, Stefanie Butland, and Brian Ellis

Scilla peruviana is a bulbous plant whose distribution extends from South Africa, into Europe and Asia. It belongs to the family Liliaceae (subclass Monocotyledonae). S. peruviana is an attractive floral species with excellent commercial potential, but it does not produce many bulblets and its multiplication rate is very low. Increasing the multiplication rate, and regulation of its growth and development, cannot be achieved without knowledge of its basic patterns of ontogenesis. We studied the annual growth and development of S. peruviana, from initiation until differentiation, giving special attention to cytological changes at the apical meristem. We also investigated the cytophysiological changes occurring in scales during ontogenesis. Two generations of daughter bulbs are present in each mother bulb. Flowering of the mother bulb coincides with vegetative development of the apical meristem of the primary daughter bulb (March-April). During gradual senescence of leaves and roots of the mother bulb, the apical meristem of the primary daughter bulb undergoes a transition from vegetative to prefloral development (June). Intensive flower organ differentiation occurs in the daughter bulb during the mother bulb's rest period (July–August). Initiation of the apical meristem of the secondary daughter bulb occurs within the primary daughter bulb, which is itself enclosed within the mother bulb (August). The development of the apical meristem of a daughter bulb, from its initiation until flowering, thus occurs without interruption and takes ≈20 months. By modifying external factors such as temperature and growth regulators, we can now control time of flowering and increase the multiplication rate of S. peruviana.

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Mokhles A. Elsysy and Peter M. Hirst

genes, gibberellin oxidase genes, and meristem identity genes ( Guitton et al., 2012 ). This finding supported the hypothesis that GAs influence flower formation, and further research on the interaction between growth regulators and molecular floral

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Tomoya Esumi, Ryutaro Tao, and Keizo Yonemori

Japanese pear (Pyrus pyrifolia) and quince (Cydonia oblonga), both classified in the subfamily Maloideae, show differences in inflorescence architectures despite of the fact that they are genetically closely related. We previously isolated flowering related genes, LEAFY (LFY) and TERMINAL FLOWER 1 (TFL1) homologues, from these species and showed that they had two types of homologues for each gene. In this study, we examined the expression pattern of LFY and TFL1 homologues in these species by in situ hybridization and RT-PCR. The floral bud was dissected to small pieces under stereomicroscope; apical meristem, scales/bracts, pith, floral meristem, and inflorescence; and then used for RT-PCR. The LFY homologues were expressed in apical meristem and scales/bracts before the floral differentiation in both Japanese pear and quince. After floral differentiation, the expression was observed in floral meristem, scales/bracts and pith in both the species. The TFL1 homologues were strongly expressed in the apical meristem, but their expression was drastically decreased just before floral differentiation. It is considered that the decrease of expression of TFL1 homologues is a sign of floral initiation. The expression of TFL1 homologues was transiently increased at the beginning of floral differentiation in both species. Moreover, one of TFL1 homologues in Japanese pear was continuously expressed in the inflorescence part in the floral primordia, whereas expression of TFL1 homologues in quince almost completely disappeared after a solitary floral meristem was initiated. It was suggested that TFL1 homologues may also be involved in the inflorescence development of Japanese pear.

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Theoharis Ouzounis and Gregory A. Lang

to: 1) characterize natural N remobilization from leaves to reproductive and vegetative meristems in sweet cherry during fall and winter; 2) determine the effect of fall foliar urea applications on storage N levels in flowering spurs; 3) determine