Meristem culture and/or thermotherapy were used for virus elimination from ornamental Phlox paniculata L. (`Blue Boy', `Orange perfection' and `Starfire') mother plants. Shoot tip, leaf, node and flower ovary explants collected from greenhouse-maintained virus free plants were cultured in vitro for shoot initiation. Adventitious shoot initiation was observed on Murashige and Skoog (MS) medium containing the cytokinin BA with or without the auxin NAA. The addition of 0.4 mg·L-1 thiamine, 0.4 mg·L-1 folic acid, and 40 mg·L-1 adenine sulfate to the MS medium did not improve the regeneration rate. Multiplication and rooting were genotype dependent. Blue Boy and Orange Perfection cultivars regenerated the maximum number of shoots from leaf explants. `Blue Boy' leaf explants from in vitro plants had a lower regeneration rate than explants from greenhouse plants. Cultivar `Starfire' had the highest shoot formation with open flower ovary explants and failed to regenerate from leaf explants. In vitro rooting of adventitious shoots in the presence of auxins (IAA, NAA, or IBA) with or without BA was less effective than ex vitro rooting. Chemical names used: 6-benzyladenine (BA); indole-acetic acid (IAA); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA).
Margarita Fraga, Mertxe Alonso, and Marisé Borja
Gordon E. Holcomb, Rodrigo A. Valverde, and Dina L. Gutierrez
Erik S. Runkle, Royal D. Heins, Arthur C. Cameron, and William H. Carlson
Phlox paniculata Lyon ex Pursh `Eva Cullum' plants were grown under seven photoperiods following 0 or 15 weeks of 5 °C to determine the effects of photoperiod and cold treatment on flowering. Photoperiods were a 9-hour day extended with incandescent lamps to 10, 12, 13, 14, 16, or 24 hours; an additional treatment was a 9-hour day with a 4-hour night interruption (NI). Noncooled plants remained vegetative under photoperiods ≤13 hours; as the photoperiod increased from 14 to 24 hours, flowering percentage increased from 20 to 89. Flowering of noncooled plants took 73 to 93 days. Flowering percentage was 19, 50, or 100 when cooled plants were held under photoperiods of 10, 12, or ≥13 hours or NI, respectively. Time to flower in cooled plants progressively decreased from 114 to 64 days as the photoperiod increased from 10 to 24 hours. Reproductive cooled plants had at least three times more flowers, were at least 50% taller, were more vigorous, and developed seven or eight more nodes than did noncooled plants. Photoperiod had no effect on height of flowering plants.
Angela M. Madeiras, Thomas H. Boyle, and Wesley R. Autio
, 1993b , 1995 ), there is a paucity of scientific literature concerning germination in the perennial Phlox species. Several seed companies have published recommendations for germinating perennial Phlox seeds. For example, Prairie Moon Nursery (2004
Narendra Sankhla, Wayne Mackay*, and Tim Davis
Low concentration fumigation with nitric oxide (NO*) has been shown to extend the postharvest life of a range of flowers, fruits and vegetables by down-regulating ethylene production. Since ethylene is involved in flower abscission and leaf senescence of `John Fanick' phlox cut flower heads, a superior selection of perennial phlox (Phlox paniculata L.) bearing attractive long-lasting flowers, we have evaluated the effect of NO* delivered in vivo using sodium nitroprusside (SNP) as the source of NO* donor, on postharvest performance of `John Fanick' phlox flower heads. Although the presence of SNP (10-200 μmol·L-1) in the vase solution promoted the abscission of the open flowers, the young flower buds continued to open even in the presence of high SNP concentrations. On the other hand, at high SNP concentrations, the leaves became either yellow, or more frequently turned progressively black and senesced. Inclusion of sucrose in the vase solution, or pretreatment of flower heads with either 1-MCP or STS, significantly delayed the abscission of flowers and blackening of leaves. The pretreatment of flower heads with either 1-MCP or STS, or the presence of sucrose in the vase, together with SNP, greatly reduced the toxicity of the latter chemical resulting in improved postharvest display life. These results indicate that in `John Fanick' the leaves are relatively more susceptible to NO*-induced toxicity than the flowers. However, both sucrose and ethylene perception inhibitors are able to minimize the toxicity of high concentrations of NO* delivered in vivo via SNP.
Jayesh B. Samtani, Gary J. Kling, Hannah M. Mathers, and Luke Case
minimal or no injury to the crop plants. However, in another study, container-grown perennial phlox ( Phlox paniculata ) were injured 88% and 93% from oryzalin applications of 2.3 and 4.6 kg·ha −1 a.i., respectively ( Staats and Klett, 1993 ). In some
James E. Faust and Joanne Logan
photosynthetic daily light integral during root development J. Amer. Soc. Hort. Sci. 140 542 549 Enfield, A. Runkle, E. Heins, R. Cameron, A. 2003 Herbaceous perennials: Phlox paniculata Greenhouse Grower 21 6 66 74 Erwin, J.E. Warner, R.M. 2002 Determination of