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Jim Ault* and Sandy Siqueira

Shoot, root, and callus induction were examined in the North American lily, Lilium michiganense, in response to treatment with four auxins. Seed from controlled crosses were aseptically excised from slightly immature capsules and cultured in vitro on Murashige and Skoog basal medium and vitamins with 30 g/l sucrose, 7.0 g/l agar, and a pH = 5.7. Seed were maintained at 20 °C with a 14-h photoperiod. After 5.0-5.5 months, leaves and roots were removed from seedlings, the bulbs transversely sectioned, then the bulb sections cultured cut-surface down on the identical medium supplemented with 0.0, 1.0, 2.0, 4.0, or 8.0 μm dicamba, picloram, K-NAA, or 2,4-D. PGRs were added to medium prior to autoclaving except dicamba which was dissolved in 50% ethanol and added after medium autoclaving. 16 explants were utilized for each treatment. The experiment was conducted three times. Morphogenetic response (# of shoots produced, % of explants forming roots, and % of explants forming callus) was tabulated 4 months after treatment. Shoot formation was promoted by treatment with dicamba, picloram, and K-NAA in comparison to the control (2.5 shoots/explant). Shoot formation varied significantly in response to individual dicamba, picloram, and 2,4-D concentrations. A maximum of 7.9 shoots per explant was promoted by 4.0 μm K-NAA and 1.0 μm dicamba, respectively. Root and callus formation also varied significantly between auxin treatments. Root formation was inhibited by dicamba, picloram, and 2,4-D treatments in comparison with the control (100% rooting); callus formation was promoted by dicamba, picloram, and K-NAA treatments in comparison with the control (15% callusing).

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Marietta Loehrlein and Sandy Siqueira

Coreopsis rosea is important as a landscape plant and is of some impor-tance for restoration of native species. In both situations it is important to understand the breeding system so that the pollination process may be controlled for optimal seed production. The study of the incompatibility system is important to seed production. In commercial crops, seeds may be products of open pollination or F1 hybrids. In the former, genetic variability exists. In conservation and recovery programs of local flora, seeds with genetic variability are desirable. In development of commercial crops, uniform seeds and plants are desirable. Regardless of whether seeds will ultimately be used for commercial crops or for species restoration, an understanding of self-incompatibility will allow the pollination process to be manipulated for optimal seed production. The purpose of this research was to investigate the sexual reproduction mode in Coreopsis rosea. The objectives were to determine whether Coreopsis rosea operates with a self-incompatibility system, and, if so, to discover whether it is a sporophytic or gametophytic mode. The sporophytic form of self-incompatibility has been found in other plants in the Asteraceae family, but no one has studied self-incompatibility in Coreopsis rosea. The purpose of this research was to identify the self-incompatibility system in Coreopsis rosea. A series of self- and cross-pollinations were made in situ, and in vivo pollinations were made and the pistils studied under the microscope. Results indicate that Coreopsis rosea is self-incompatible and operates under the sporophytic mode.

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Marietta Loehrlein and Sandy Siqueira

Landscape and garden use of Coreopsisrosea has been growing recently. With the introduction of the new varieties of Coreopsisrosea `Sweet Dreams' and `Limerock Ruby', there are increased opportunities for commercial sales. While plants can be propagated by vegetative means, seed production is generally less expensive, seed can be stored, and hybrid development depends on seed production. As a result, it is beneficial to understand the reproductive process of the plant. The purpose of this research was to investigate the reproductive development of Coreopsisrosea. This research also seeks to identify, describe and record inflorescence morphological characters, which could be useful in plant systematic and phylogeny studies. To this end, the anthesis process of pink tickseed, Coreopsisrosea Nutt., was studied in 100 inflorescences from 10 plants. Inflorescences were tagged when they were first visible and measured daily for a month. The following measurements were taken: number of ray flowers, inflorescence diameter, diameter of the disc floret cluster (head), timing of anthesis, presence of pollen, and the longevity of opened flowers. The inflorescence anthesis process was 19.8 (±1.6) days long and was subdivided into 13 stages of development. During the 20 days of inflorescence anthesis, the flower was open 27.5% of the time (5.4 days). When the disc florets started to open, they did so from the outer layer of the cluster to the center of the cluster; therefore, florets in the head did not mature at the same time. Micrographs were taken using a dissecting microscope (Cobra dynascope) to illustrate the entire process.

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James Robert Ault and Sandy S. Siqueira

Shoot, root, and callus induction were examined in the North American lily Lilium michiganense in response to treatment with four auxin-type plant growth regulators (PGR). Seed from controlled crosses were aseptically excised from slightly immature capsules and cultured in vitro on Murashige and Skoog basal medium and vitamins with 30 g·L−1 sucrose, 7.0 g·L−1 agar, and a pH = 5.7. Seed were maintained at 20 °C with a 14-h photoperiod. After 5.0 to 5.5 months, leaves and roots were removed from seedlings, the bulbs transversely sectioned, then the bulb sections cultured cut-surface down on the identical medium supplemented with 0.0, 1.0, 2.0, 4.0, or 8.0 μm dicamba, picloram, K-NAA, or 2,4-D. Morphogenetic response was tabulated 4 months after treatment. Shoot formation was promoted by treatment with dicamba, picloram, and K-NAA in comparison with the control (2.5 shoots/explant). Shoot formation varied significantly in response to individual dicamba, picloram, and 2,4-D concentrations. A maximum of 7.9 shoots per explant was promoted by 4.0 μm K-NAA and 1.0 μm dicamba, respectively. Root and callus formation also varied significantly between PGR treatments. Root formation was inhibited by dicamba, picloram, and 2,4-D treatments in comparison with the control (100% rooting); callus formation was promoted by dicamba, picloram, and K-NAA treatments in comparison with the control (15% callusing).