stomatal and non-stomatal limitations to photosynthesis Plant Cell Environ. 8 95 104 Kim, J. van Iersel, M.W. 2011 Slowly developing drought stress increases photosynthetic acclimation of Catharanthus roseus Physiol. Plant. 143 166 177 Lynch, J.P. 2007a
Krishna Nemali and Marc W. van Iersel
Karen L. Panter, Steven E. Newman and Michael J. Roll
Catharanthus roseus plants were grown in three media, each containing one of two by-products of shredded waste tires. The media were no. 1) 1 rubber*: 1 peat moss, no. 2) 1 rubber*: 1 vermiculite: 2 peat moss, and no. 3) 2 rubber*: 1 vermiculite: 1 peat moss (by volume) where rubber* indicates either 0.6 cm shredded rubber or a fibrous by-product. Control plants were grown in 1 peatmoss: 1 rockwool and 1 vermiculite: 1 peatmoss (by volume). Catharanthus roseus cv. Peppermint Cooler plants were grown for 7 weeks in 10-cm containers at a commercial Denver-area greenhouse. Data taken included plant heights, plant widths, flowers per stem, and dry weights. Visually, plants grown in the no. 2 mix, with either fiber or 0.6-cm rubber, were similar to the controls and superior to the other two mixes. Ending plant heights were similar among the two controls and no. 2 with fiber and were taller than all other combinations. Flower numbers were greater in the 1 rockwool: 1 peat moss control and no. 2 mix with fiber than any other treatment. The same was true for stem number and dry weight. Results indicate that the no. 2 mix of 1 fiber: 1 vermiculite: 2 peatmoss has potential for container crop production.
Assunta Bertaccini, Robert E. Davis and Ing Ming Lee
A collection of mycoplasma-like organisms (MLOs) was maintained in plant tissues micropropagated in vitro. MLO-infected plants included Chrysanthemum frutescens L. with chyrsanthemum yellows disease, Gladiolus sp. L. with “germ fins,” Hydrangea macrophilla (Thunb.) DC. with virescence, Rubus fruticosus L. with rubus stunt, and periwinkle [Catharanthus roseus (L.) G. Don] singly infected by the following MLOs: Italian periwinkle virescence, chrysanthemum yellows, North American aster yellows, Italian periwinkle stunt, American periwinkle little leaf. Shoots micropropagated in vitro exhibited symptoms of little-leaf and/or abnormal proliferation of axillary shoots resulting in “witches' broom” appearance that resembled symptoms in grafttransmitted greenhouse-grown or naturally infected field-collected plants. These symptoms, typical of infection by MLOs, were not observed in micropropagated healthy shoots of the same plant species, and, compared with the healthy ones, varied with MLO strain and host plant species. Dot hybridizations with a nonradioactive cloned DNA probe provided evidence for the presence of MLOs in propagated tissues through serial subcultures.
D.M. Quinn, B.K. Behe, J.L. Witt and R.S. Roark
Our objective was to determine heat tolerance and performance of 245 summer-flowering annual plant cultivars installed 16 Mar. 1995 in beds receiving full sun located at the E.V. Smith Research Center in Shorter, Ala. (lat. 32°30′N, long. 85°40′W). No maintenance, with the exception of one midseason pruning of petunias, was performed. Catharanthus roseus L. `Blush Cooler' had the highest mean rating (4.1 of 5.0). Salvia farinacea Benth. `Victoria Blue' and Petunia ×hybrida `Fantasy Pink' both performed well with 3.5 mean ratings. `Purple Wave', a compact spreading cultivar of P. ×hybrida, had a 3.1 mean rating, but had a 5.0 rating before pruning. We do not recommend pruning `Purple Wave'. Of the 34 marigold cultivars evaluated, Tagetes erecta L. `Antigua Mixed' had the highest mean rating. Tagetes erecta `Inca Yellow' and `Perfection Gold' tied with the second highest mean rating.
D.W. Burger, T.K. Hartz and G.W. Forister
Seed germination and crop growth characteristics were determined for Tagetes spp. L. `Lemondrop', marigold; Catharanthus roseus Don. `Little Pinkie', vinca; Petunia hybrida Vilm. `Royalty Cherry', petunia; Dendranthema×grandiflorum (Ramat.) Kitamura `White Diamond', chrysanthemum; Pittosporum tobira Ait. `Wheeleri', sweet mock orange; Photinia ×fraseri Dress., photinia and Juniperus sabina L. `Moon Glow', juniper grown in various size containers containing blends of composted green waste (CGW) and UC Mix. Seed germination, plant height, and stem and root fresh and dry mass were lowest in unamended CGW. For most plants studied, a CGW: UC Mix blend containing at least 25% UC Mix was required for adequate growth and development. Germinating seeds and young seedlings were most adversely affected by unamended CGW. As plants grew and were transplanted into larger containers (10- and 15-cm pots, 530 and 1800 mL), they were better able to grow in media with higher CGW content.
T.K. Howe and W.E. Waters
Nineteen vinca (Catharanthus roseus) cultivars were evaluated for days to flower, flower diameter, flower color, plant dimensions, and appearance during the summer and fall of 1993. Summer: Days from sowing to flower ranged from 58 days for `Pretty in Pink' to 64 days for `Pretty in Rose'. Flower diameter ranged from 4.3 to 5.8 cm for `Orchid Cooler' and `Parasol', respectively. `Parasol' produced the largest flower. The `Carpet' entries (creeping types) were shorter than all others. Appearance ratings were similar among all entries at 85 and 109 days after sowing. Fall: Days from sowing to flower ranged from 51 days for `Grape Cooler' to 58 days for `Tropicana Rose'. Flower diameter ranged from 4.3 to 5.1 cm for `Orchid Cooler' and `Parasol', respectively. `Peppermint Cooler', `Grape Cooler' and `Orchid Cooler' were the only entries with significantly smaller flower size than `Parasol'. Appearance ratings at 109 and 141 days after sowing were similar for all entries, however at 166 days `Dawn Carpet' and `Pink Carpet' had significantly lower ratings than 15 other entries due to frost damage.
M.W. van Iersel, R.B. Beverly, P.A. Thomas, J.G. Latimer and H.A. Mills
Good fertilizer management is important in plug seedling production of bedding plants to prevent nutrient deficiencies and toxicities. We determined the effect of N, P, and K nutrition on the growth of plugs of impatiens (Impatiens wallerana Hook. f.), petunia (Petunia ×hybrida Hort. Vilm.-Andr.), salvia (Salvia splendens F. Sellow ex Roem.& Schult.), and vinca (Catharanthus roseus L.). For all four species, shoot N concentration was correlated linearly with shoot dry mass of the seedlings at transplant. Phosphorus or K concentration in the nutrient solution or shoot tissue had little or no effect on the shoot growth of seedlings, but shoot P levels increased with P concentrations in the fertilizer solution (luxury consumption). Salvia was the only species that also exhibited luxury consumption of K. Results of this study indicate that seedling growth of these species is mainly determined by N and this should probably be the main focus of fertility programs in the plug industry, while P and K applications can be reduced.
M.R. Evans and G. Li
The annual bedding plants `Dazzler Rose Star' impatiens (Impatiens wallerana), `Cooler Blush' vinca (Catharanthus roseus), `Orbit Cardinal' geranium (Pelargonium × hotorum), `Janie Bright Yellow' marigold (Tagetes patula) and `Bingo Azure' pansy (Viola tricolor) were grown on germination papers treated with deionized water (DI), 2500 or 5000 mg·L-1 (ppm) humic acid (HA) or nutrient control (NC) solutions. Seedlings grown on HA-treated germination papers had higher dry root weights than those grown on DI or NC-treated germination papers. Except for impatiens, seedlings germinated on HA-treated germination papers had higher lateral root numbers and higher total lateral root lengths than those grown on DI and NC-treated germination papers. Impatiens grown on NC-treated germination papers had higher lateral root numbers than those grown on DI or HA-treated germination papers. Overall, lateral root numbers for impatiens were higher for seedlings germinated on HA-treated papers than DI or NC-treated papers and highest lateral root numbers occurred on those impatiens germinated on papers treated with 5000 mg·L-1 HA. Except for geranium, seedlings grown in HA-amended sphagnum-peat-based substrates had similar dry root and dry shoot weights as those grown in unamended substrates. Geranium seedlings grown in HA-amended sphagnum peat-based substrates had significantly higher dry root weights than those grown in unamended substrates. However, dry shoot weights of geranium grown in HA-amended sphagnum peat-based substrates were similar to those grown in unamended substrates.
R. Crofton Sloan, Richard L. Harkess and William L. Kingery
Urban soils are often not ideal planting sites due to removal of native topsoil or the mixing of topsoil and subsoil at the site. Adding pine bark based soil amendments to a clay soil altered soil bulk density and soil compaction which resulted in improved plant growth. Addition of nitrogen (N) or cotton gin waste to pine bark resulted in improved plant growth compared to pine bark alone. Growth of pansies (Viola × wittrockiana) during the 1999-2000 winter growing season was enhanced by the addition of pine bark plus nitrogen at 3- and 6-inch (7.6- and 15.2-cm) application rates (PBN3 and PBN6) and pine bark plus cotton gin waste at the 6 inch rate (CGW6). Plant size and flower production of vinca (Catharanthus roseus) were reduced by pine bark amendments applied at 3- or 6-inch rates (PB3 or PB6). Crapemyrtle (Lagerstroemia indica) grown in plots amended with 3 or 6 inches of pine bark plus cotton gin waste (CGW3 or CGW6) and pine bark plus nitrogen at 3- or 6-inch rates (PBN3 or PBN6) produced greater shoot growth than other amendment treatments. In some instances PB3 treatments suppressed growth. High levels of N and soluble salts derived from CGW and PBN soil amendments incorporated into the soil probably contributed to the improved plant growth observed in this experiment.
Michael R. Evans
Aggregates produced from finely ground waste glass [Growstones (GS); Earthstone Corp., Santa Fe, NM] have been proposed to adjust the physical properties of peat-based substrates. The GS had a total pore space (TPS) of 87.4% (by volume), which was higher than that of sphagnum peat and perlite but was similar to that of parboiled fresh rice hulls (PBH). The GS had an air-filled pore space (AFP) of 53.1%, which was higher than that of sphagnum peat and perlite but lower than that of PBH. At 34.3%, GS had a lower water-holding capacity (WHC) than sphagnum peat but a higher WHC than either perlite or PBH. The bulk density of GS was 0.19 g·cm−3 and was not different from that of the perlite but was higher than that of sphagnum peat and PBH. The addition of at least 15% GS to sphagnum peat increased the AFP of the resulting peat-based substrate. Substrates containing 25% or 30% GS had a higher AFP than substrates containing equivalent amounts of perlite but a lower AFP than substrates containing equivalent PBH. Substrates containing 20% or more GS had a higher WHC than equivalent perlite- or PBH-containing substrates. Growth of ‘Cooler Grape’ vinca (Catharanthus roseus), ‘Dazzler Lilac Splash’ impatiens (Impatiens walleriana), and ‘Score Red’ geranium (Pelargonium ×hortorum) was similar for plants grown in GS-containing substrates and those grown in equivalent perlite- and PBH-containing substrates.