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John E. Erwin and Gerard Engelen-Eigles

Interaction between simulated shipping and rooting temperature and harvest year was studied on Lilium longiflorum. Bulb dormancy and maturity appear to be separate phenomenon and are affected by temperature differently. Shoot emergence (an indicator of release from dormancy) was hastened by 10 °C shipping and 10 to 20 °C rooting temperatures in both years. Flower induction was affected differently by simulated shipping and rooting temperatures during 1992 and 1993, indicating that bulb maturity differed between the 2 years. Final leaf and flower number decreased because of shipping or rooting temperature, but only when bulbs were mature and received cool temperatures (<16 °C) before a 6-week vernalization treatment. Immature bulbs (at harvest) are unresponsive to vernalizing shipping and rooting temperatures. Prevernalization handling temperature and vernalization treatment length should vary with year based on degree of bulb maturity to achieve consistency in final morphology. Internode length is associated more with the time elongation is suppressed after dormancy is broken than with flower induction (where internode length increases as the length of time elongation is suppressed after breaking of dormancy increases).

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Arend-Jan Both, Bruce Bugbee, Chieri Kubota, Roberto G. Lopez, Cary Mitchell, Erik S. Runkle, and Claude Wallace

. Example of the proposed product label for a light-emitting diode (LED) lamp specifically designed for plant growth applications. PSS is the phytochrome photostationary state, using values from Sager et al. (1988) , which is a dimensionless ratio indicated

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Diego A. Mata and Javier F. Botto

spectrum by specialized photoreversible receptors called phytochromes. The action of the phytochromes is a function of the relative amounts of the active and the inactive forms (Pfr and Pr, respectively) established in the plant tissues, and it positively

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Michael P. Dzakovich, Celina Gómez, Mario G. Ferruzzi, and Cary A. Mitchell

properties of edible plant tissues. Alterations in metabolic flux in response to light are mediated by a host of proteins including the phytochromes, cryptochromes, phototropins, and UVR8, among others ( Galvão and Fankhauser, 2015 ; Gyula et al., 2003

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William R. Okie and Bryan Blackburn

greenhouses using natural daylight. Erez et al. (1966) suggested that peach leaf budbreak is phytochrome-dependent and thus needs a light stimulus in contrast to flower budbreak, which was inhibited by light during budbreak in their study. Phytochrome is a

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D. Michael Glenn and G.J. Puterka

and Loughrin, 2004 ) through phytochrome-mediated processes. Colored netting, while reducing light, can also increase yield ( Shahak et al., 2004 ). Despite the increased light levels in the canopy from reflective films, increased fruit size is

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Takanori Takeuchi, Miwako Cecile Matsushita, Soichiro Nishiyama, Hisayo Yamane, Kiyoshi Banno, and Ryutaro Tao

, respectively ( Table 4 ). These genes were annotated based on a BLAST search and five genes encoded transcription factors. The annotations indicated that MD09G1146000 , MD09G1009100 , MD14G1126900 , MD16G1140800 , and MD15G1369700 encode PHYTOCHROME

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Kevin R. Cope and Bruce Bugbee

ratio and phytochrome photoequilbria). These results were reviewed by Yorio et al. (1998) . Later, Dougher and Bugbee (2001a) examined the effects of blue light on growth and development of lettuce, soybean, and wheat using high-pressure sodium (HPS

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Gary R. Bachman and Margaret J. McMahon

It is theorized that photomorphogenic reductions in stem elongation are similar to thermomorphogenic plant response, i.e. increased red:far-red light response is similar to –DIF (day temperature < night temperature). The long hypocotyl (hy) mutants of Arabidopsis thaliana Landsberg are phytochrome mutants that are less responsive to light quality than wild type. These include mutants of phytochrome chromophore biosynthesis (hy 1, hy2, hy6), phytochrome B (hy3), blue-light receptor (hy4), and signal transduction (hy5). These mutants were grown in growth chambers with temperatures of 18C day/24C night (–DIF) and 24°C day/18°C night with a 14-h photoperiod. Lighting consisted of both incandescent and fluorescent lamps. Growth measurements of five of the mutants were consistent with reported effects of DIF. The height of these plants were significantly greater in the +DIF regime when compared to –DIF. The hy5 mutant showed little difference in the height measurements of plants grown in either -DIF or +DIF. This mutant has a phytochrome signal transduction deficiency. This result indicates that a functional photoreceptor is required, even in reduced quantities as in the phytochrome chromophore biosynthesis mutants, to signal perception of DIF temperature conditions.

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Sandra L. Barbour, Margaret J. McMahon, John J. Frett, and Dennis R. Decoteau

Similarities exist between the effects of phytochrome and cytokinins on plant growth and development (e.g., chloroplast development, amaranthin synthesis. seed germination, photomorphogenesis). It is unclear, however, if and how these two systems interact.

As a beginning step to determine cytokinin-phytochrome interactions, we developed a strategy utilizing ipt -transgenic tobacco in phytochrome/light treatment investigations. The sour-cc of the ipt gene was Agrobacterium tumefaciens Ti plasmid 15955. This gene encodes for isopentenyl transferase which is an enzyme active in cytokinin biosynthesis.

Ipt -transgenic tobacco cultures (grown on MS medium supplemented with kanamycin but no plant growth regulators) were treated with end-of-day red or far-red light for 15 minutes. After 30 days of treatment, the plant tissue was harvested and either homogenized for SDS-PAGE or fixed for transmission electron microscopic analysis.

Results from immuno-gold labelling using polyclonal antibodies specific to iptase will he used to Indicate the influence of phytochrome on cytokinin activity. Also, structural changes at the ultra-cellular level will be determined.