( Jacobs and Timmer, 2005 ; Landis et al., 1989 ) may minimize elevated EC and/or potential leaching losses ( Landis et al., 1989 ) and nutrient runoff compared with fertigation with readily available nutrients. Media composition is another important
Mindy L. Bumgarner, K. Francis Salifu, and Douglass F. Jacobs
Mindy L. Bumgarner, K. Francis Salifu, Michael V. Mickelbart, and Douglass F. Jacobs
rubra L.) seedlings including foliar discolorations and reduced leaf dry mass production, suggesting the potential sensitivity of this species. In a previous study ( Bumgarner et al., 2008 ), we examined the effects of media composition and fertility on
Sandra B. Wilson, Nihal C. Rajapakse, and Roy E. Young
Hosta (Hosta tokudama Makeawa `Newberry Gold') plantlets were micropropagated photoautotrophically (without sucrose in medium) or photomixotrophically (with 2% sucrose in medium) for 3 weeks at 23 °C under 80 μmol·m-2·s-1 photosynthetic photon flux (PPF) prior to long-term storage. Plantlets were stored for 4, 8, or 12 weeks at 5, 10, or 22 °C in darkness or under white (400-800 nm), blue (400-500 nm), or red (600-700 nm) light at or near light compensation points. Illumination during storage was necessary to maintain dry weight and regrowth potentials of plantlets in vitro, but light quality had no effect on these parameters. All photoautotrophic plantlets stored in darkness were of poor quality at the time of removal from storage and died when transferred to the greenhouse. Dark-stored photomixotrophic plantlets survived storage for 12 weeks at 5 °C, but declined in appearance (visual quality) as the storage duration increased. Decline in visual quality was greater when plantlets were stored at 10 and 22 °C. Leaf dry weight of illuminated plantlets increased and percentage of leaf yellowing decreased as storage temperature increased. Recovery of illuminated plantlets from photomixotrophic storage was best when plantlets were stored at 22 °C. These plantlets were characterized by increased visual quality (color and form) and increased dry weight compared with those in other treatments. After 60 days in the greenhouse, the dry weight of these plantlets was similar for 4-, 8-, and 12-week storage durations, indicating flexibility in storage time if specific light and temperature provisions are met.
John E. Erwin and Debra Schwarze
Five cuttings from different node positions on stock plants were taken from each of 3 Clematis cultivars (Jackmani, Contesse de Bouchard, and Gypsy Queen) and Clematis purpurea plena elegans. Actively growing plants with 5 nodes were acquired. Node number increased from 1 at the base of the plant to 5 at the tip of the plant. Cuttings were treated with or without 0.1% IBA (indole-3-butyric acid) and placed in 1 of 5 different media: 100% washed sand (WS), 50% washed sand and 50% sphagnum peat (WP), 50% sphagnum peat and 50% perlite (SP), 100%) perlite (PT), or 50% sphagnum peat plus 25% perlite plus 25% vermiculite (PV). Rooting date, primary and secondary root number, and root dry weight were collected after 8 weeks. `Gypsy Queen' showed the earliest rooting with the greatest root development. Jackmani showed the worst rooting. Media WS and PT showed the best rooting whereas WP and SP showed the worst. Cuttings taken from the first 3 nodes rooted the best. As node position increased root number and dry weight decreased and time to root increased. Application of IBA had no significant effect on time to root or degree of rooting.
Laise S. Moreira and Matthew D. Clark
relies primarily on the media composition used during two phases. The first phase (heterotrophic, in which the pre-embryo depends on the endosperm if present) consists of incubating the fertilized ovules on the media to aid embryo formation and avoid
Myung Min Oh, Young Yeol Cho, Kee Sung Kim, and Jung Eek Son
·s −1 during the experiment, respectively. Measurement of water contents in different media compositions. Two mixtures of peatmoss and perlite [7:3 and 5:5 (v/v)] were used under four irrigation systems, NFW (5×), NFW (2×), NSW, and EBB. Three
Abraham Cruz-Mendívil, Javier Rivera-López, Lourdes J. Germán-Báez, Melina López-Meyer, Sergio Hernández-Verdugo, José A. López-Valenzuela, Cuauhtémoc Reyes-Moreno, and Angel Valdez-Ortiz
-Estrella et al., 2004 ). In tomato, plant regeneration is accomplished through organogenesis and it is affected by several factors such as genotype, explant characteristics (type, size, age, and orientation), media composition (growth regulators, carbon source
Patrick H. Kingston, Carolyn F. Scagel, David R. Bryla, and Bernadine Strik
Tukey’s honestly significant difference test at the 0.05 level in the “lsmeans” package ( Lenth, 2016 ; Pinheiro et al., 2016 ). Results Initial media composition. Initial physical and chemical characteristics differed among the 11 media ( Tables 2 and
Sandra B. Wilson, Keiko Iwabuchi, Nihal C. Rajapakse, and Roy E. Young
Broccoli (Brassica oleracea L. Botrytis group `Green Duke') seeds were cultured photoautotrophically (without sugar) or photomixotrophically (with sugar) in vitro for 3 weeks at 23 °C and150 μmol·m-2·s-1 photosynthetic photon flux (PPF). In vitro seedlings were stored for 0, 4, 8, or 12 weeks at 5 °C in darkness or under 5 μmol·m-2·s-1 of white (400–800 nm), blue (400–500 nm), or red (600–700 nm) light. Photosynthetic ability and soluble sugar contents were determined after removal from storage. Photomixotrophic seedlings contained approximately five times more soluble sugars than did photoautotrophic seedlings. Dark storage reduced soluble sugars in both photoautotrophic and photomixotrophic plants, but photosynthetic ability was maintained for up to 8 weeks in the latter whereas it decreased in the former. Illumination in storage increased leaf soluble sgars in both photoautotrophic and photomixotrophic seedlings. Soluble sugars in stems decreased during storage regardless of illumination, but remained higher in illuminated seedlings. Red light was more effective in increasing or maintaining leaf and stem soluble sugars than was white or blue light. Regardless of media composition or illumination, storage for more tan 8 weeks resulted in dramatic losses in quality and recovery, as well as photosynthetic ability. Seedlings stored for 12 weeks comletely lost their photosynthetic ability regardless of media composition or illumination. The results suggest that carbohydrate, supplied in the media or through illumination, is essential for maintenance of photosynthetic ability during low-temperature storage for up to 4 or 8 weeks.
Kee Yoeup Paek and Toyoki Kozai
We report the results of serial studies aimed at clarifying several factors affecting organogenesis in rhizome culture of temperate Cymbidium species and their hybrids. The growth patterns and regeneration ability of rhizomes derived from asymbiotic seed or shoot tip culture vary according to media composition, kinds and concentrations of plant growth regulators, culture conditions, and species and varieties. N6-benzyladenine was the best cytokinin for inducing shoot formation, for switching rhizome tissues into protocorm-like bodies, and for directly forming multiple shoots from branched rhizomes. Activated charcoal appeared to be necessary for producing healthy plantlets and for stimulating shoot growth at levels of 0.1% to 0.3% but concomitantly decreased rhizome growth. Sucrose at 5% was the most effective concentration for shoot induction from rhizomes. The above results support the conclusion that organogenic pathways between tropical, subtropical, and temperate Cymbidium species may be controlled by the genetic backgrounds of the species or cultivars.