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Sheila A. Blackman and Eric E. Roos

The low quality of some seed lots received by germplasm repositories such as the National Seed Storage Laboratory can thwart efforts to regenerate seed for storage. This germplasm is in danger of irretrievable loss. The aim of this work is to promote the germination, and hence regeneration, of such low quality seeds through sterile culture of the isolated embryos. Hybrid (B73×LH51) maize seeds were aged 5 y at 32°C and 0.037 g H2O g-1 dry wt. Vigor - but not viability -declined under these conditions. The effects of four factors on growth and germination were systematically examined. These were: seed pretreatments; antibiotics and fungicides; nutrients; and growth substances. Amongst the pretreatments, none surpassed partial hydration of seeds for 24 hr to 0.55 g H2O g-1 dry wt at 25°C prior to embryo dissection. Thiram (2.4 mg mL-1) and kanamycin (50 ug ml1) effectively controlled bacterial and fungal growth with no deleterious effects on growth during culture of the isolated embryos. Exogenous sucrose (optimum 5 % wt/vol) significantly stimulated radicle growth in both deteriorated and non-deteriorated embryos. No other organic or inorganic nutrient stimulated growth. Naphthalene acetic acid did not affect growth while kinetin reduced radicle growth and stimulated coleoptile growth. Gibberellic acid (GA3 at 10-5M) significantly stimulated radicle growth in deteriorated embryos, whereas it promoted coleoptile growth in both deteriorated and non-deteriorated embryos. These data suggest GA or a GA-stimulated process may limit the growth of aged embryos.

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Khalid M. Ahmad, Syed M. A. Zobayed, Praveen K. Saxena, and David M. Hunter

Dionaeamuscipula Ellis commonly known as Venus fly trap is an important carnivorous plant with medicinal importance. It contains certain secondary metabolites like naphthoquinones and is used in anti-aid and anti-cancer drugs and other medicines like Cornivora. Increasing interest and use as an ornamental and medicinal plant, and dietary supplement have put it in an endangered state. Development of in vitro techniques for the preservation of germplasm that is on the brink of extinction is highly demanded. A regeneration protocol for the multiplication and micropropagation of Dionaeamuscipla Ellis was established. In vitro regeneration potential of leaf explants in different concentrations and combinations of plant growth substances was investigated in this study. Seeds were grown and leaf disc explants were excised and cultured under aseptic conditions on nutritional medium containing half strength Murashige and Skoog (MS) mix with combinations of 1.0–20.0 μm BA, 2.5.0 μm IBA, 1.0–10.0 μm 2iP and 0.1–0.5μm TDZ. The cultures were kept in growth cabinet with cool white light (40–60 μmol·m-2·s-1) under 16-h photoperiod. Regeneration was recorded after 60 days with the intervals of 15 days based on the degree of shoot organogenesis and somatic embryogenesis. 1/2 MS + 0.1 TDZ appeared to be efficient for somatic embryogenesis and simple MS for direct shoot organogenesis. 1/2 MS combined with 2iP appeared to be efficient for regeneration either by direct shoot organogenesis or by somatic embryogenesis. Plants were rooted well in Cape Cundew medium. These investigations will aid in the development of a model system for clonal mass propagation and in vitro regeneration of Dionaeamuscipla Ellis.

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Gary Gardner

most of the recent seminal discoveries in the field if not all of the details. The volume consists of 11 chapters; each of the first eight describes an individual class of endogenous plant growth substance, and the last three integrate research around

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Po-Hung Wu and Doris C.N. Chang

plant growth substance may be one solution to controlling spiking ( Wang, 1995 ). Phalaenopsis is unable to spike and bloom at high temperatures ( Lee and Lin, 1984 ; Wang et al., 2006 ). If a spiked phalaenopsis plant is moved to a high

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Ana Centeno and María Gómez-del-Campo

lanceolata (Rhodophyta) J. Phycology 35 493 500 Audus, L.J. 1953 Plant growth substances Leonard Hill Ltd London, UK Barranco, D. Trujillo, I. Rallo, L. 2005 Elaiografía hispánica

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Yasser Ismail El-Nashar and Yaser Hassan Dewir

with high temperature and NAA appears to increase germination. The role of PGR in overcoming the harmful effects on growth may be due to the change in endogenous growth substances that they initiate ( Hoque and Haque, 2002 ; Yoshida and Hirasawa, 1996

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John B. Workman, Patrick E. McCullough, F. Clint Waltz, James T. Brosnan, and Gerald M. Henry

: Roe, M., J. Burton, and R. Kuhr (eds.). Herbicide activity: Toxicology, biochemistry, and molecular biology. IOS Press, The Netherlands Struckmeyer, B. 1951 Comparative effects of growth substances on stem anatomy, p. 167–174. Plant growth substances

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Bing Wang and Alan R. Langille

( Booth, 1963 ). These processes in Solanum species, especially S. tuberosum subsp. andigena Hawkes, are controlled by environmental factors, primarily temperature and photoperiod, that regulate levels of endogenous growth substances. Rhizome growth

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Chad T. Miller and Mark P. Bridgen

growth substances and shoot emergence in Freesia hybrida corms J. Amer. Soc. Hort. Sci. 106 455 460 Harbaugh, B.K. Gilreath, J.P. 1986 Influence of rhizome harvest date, length of storage and GA 3 on sprouting and flowering of achimenes Proc. Florida

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Margarita Pérez-Jiménez, Alfonso Guevara-Gázquez, Antonio Carrillo-Navarro, and José Cos-Terrer

and chilling on abscesic acid content and germination in ornamental peach ( Prunus persica Batsch) seeds J. Hort. Sci. Biotechnol. 85 3 136 137 Raghavan, V. Torrey, J.G. 1964 Effects of certain growth substances on the growth and morphogenesis of