distilled water to remove excess HgCl 2 . Excised part of the cotyledons before seed embryos was placed on aseptic MS ( Murashige and Skoog, 1962 ) medium, which contained 0.65% agar and 3% sucrose, in glass tubes for germination. The seedlings were grown
Huan Xiong, He Sun, Feng Zou, Xiaoming Fan, Genhua Niu, and Deyi Yuan
James J. Camberato and S. Bruce Martin
Bermudagrass (Cynodon sp.) greens are overseeded annually with rough bluegrass (Poa trivialis L.) in the coastal southeastern United States, where irrigation water is often saline. Salinity may slow seed germination and delay turf establishment. Cultivar and seed lot differences in sensitivity to salinity may be substantial. Our objective was to determine the effects of salinity on germination of commercially available rough bluegrass cultivars and seed lots. To accomplish this, we examined the effects of salinity (0, 1.8, 3.4, and 5.0 dS·m-1 established with NaCl in deionized water) on germination of 33 cultivars/seed lots of rough bluegrass in vitro. Fifty seeds of each cultivar/seed lot were placed on pre-moistened germination paper in petri dishes, sealed with parafilm, and placed in growth chambers with 12-hours light/12-hours dark at 20/10 °C, respectively. Germination was scored from 4 to 25 days after seed placement. Rough bluegrass germination rate varied among cultivars/seed lots, ranging from less than three seeds/day to nearly seven seeds/day. Salinity slowed rough bluegrass germination rate from about six seeds/day at 0 dS·m-1 to five seeds/day at 5 dS·m-1. Increasing salinity reduced early germination of some cultivar/seed lots more than that of others. Impact was substantial in three cultivar/seed lots, where early germination at 5.0 dS·m-1 was less than 15% of that at 0 dS·m-1. For most cultivar/seed lots, the reduction in early germination with salinity at 5.0 dS·m-1 was about 50% of that at 0 dS·m-1. Final germination was reduced only 3% by increasing salinity. In view of differences in germination rate and response to salinity among seed lots of rough bluegrass cultivars, we suggest the planting of multiple cultivars and seed lots of rough bluegrass to insure rapid establishment.
D.W. Ramming, R.L. Emershad, P. Spiegel-Roy, N. Sahar, and I. Baron
assistance of Iris Sashitzky, ARO. Mention of trade products does not imply endorsement or recommendation over similar products not mentioned. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations
Denis Lauzer and Claire Laberge
The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.
Fred B. Perry Jr. and H. M. Vines
A method is proposed for the germination of fungal-free seeds of Magnolia grandiflora as a source of tissue for in vitro experiments. A combination sequence of a 16 hour water-soak at 25°C, hot water (52°C) for 1 hour, and then surface sterilization for 1 hour in 1:1000 aqueous mercuric chloride was the best treatment. Dips in 2.5% chlorox, 95% ethyl alcohol and concentrated sulfuric acid soak for 20 minutes were unsatisfactory. If seeds are selected carefully and treated as described, 60 to 90% of the seeds will germinate aseptically within 30 days.
Youzhi Chen, John M. Smagula, Walter Litten, and Scott Dunham
project include Donald Avery, Vanessa Lampke, Jennifer Martin, Jim Murray, Kim Turner, and Jessica Picucci. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby
Guochen Yang, Carl Niedziela, and Zhongge (Cindy) Lu
The goal of this study was to expedite galax seed germination in vitro. Galax seeds were collected from Yancey County, N.C., at an elevation of about 1100 m. Aseptic cultures were established using the tiny rust-colored seeds. In vitro seed germination was achieved under different pH conditions (4.2, 5.0, and 5.8). Seeds cultured in the medium with pH 4.2 tended to germinate early with a better rate than those cultured with a higher pH of 5.0 or 5.8 at the very beginning. Gradually, seeds from media with pH 5.0 and 5.8 caught up in germination. Eventually, seeds from all pH treatments produced a very similar germination rate. Attempts to use the matted and scaly rhizomes and very tender new growth as explant materials to establish aseptic cultures were not successful, due to severe contamination. However, our observations suggested that the very tender new growth could be a good source of explants once the optimum sterilization time is established.
Ikuo Miyajima, Adriana Kato, Juan Carlos Hagiwara, Diego Mata, Gabriela Facciuto, Silvina Soto, Alejandro Escandón, Marcela Mori, and Nobuo Kobayashi
2 Current address:Lab. Plant breeding, Fac. Life and Environmental Science, Shimane University, Matsue 690-8504, Japan. This research was funded by INTA–JICA project `The Horticulture Development Project in
Erika Szendrák and Paul E. Read
The temperate native terrestrial orchids are endangered species. Their propagation from seeds poses specific problems. It is well known that orchid seeds are devoid of endosperm and in nature they need microscopic fungi in a symbiotic relationship for germination. We developed a successful asymbiotic in vitro culture method for germinating seeds of several temperate orchid species and for maintaining the cultures of young plantlets. The medium used for both germination and seedling culture was a modified FAST medium. Seeds were surface-disinfested for 10 minutes in a 10% calcium hypochlorite solution. After sowing, the cultures were kept under dark condition at 10–12°C for 4 weeks. After that the cultures remained in the dark, but the temperature was raised to 25–26°C until germination occurred. Thereafter cultures required alternating seasonal temperatures: 25–26°C from the beginning of April to the end of September and 17–19°C from October to March. For the development of the young plantlets natural dispersed light and prevailing day-length was favorable. After 2 years of aseptic culture they were suitable for transfer ex vitro. Different stages of seed germination and plant development were observed using a scanning electron microscope and will be included in this presentation. Further observation of the effects of different environmental factors is currently under investigation.
Amy J. Moberg, James J. Luby, Carl J. Rosen, and Peter D. Ascher
Accessions of Vaccinium species (deliciosum, ovalifolium, membranaceum, parvifolium, scoparium) were evaluated for tolerance to higher pH in the root zone using an in vitro screening procedure. Seeds were germinated on media containing all essential nutrients with nitrogen in the nitrate form at pH 5 and pH 6 and evaluated for 21 weeks. Excess EDTA was used to buffer the micronutrients and pH was buffered by MES and succinic acid. Germination varied among species with V. ovalifolium being highest and V. parvifolium not germinating at all. Mortality was lower at pH 5. At pH 6, V. ovalifolium and V. membranaceum exhibited variation for growth while all other species suffered complete mortality.