Search Results

You are looking at 51 - 60 of 131 items for :

  • scarification x
  • All content x
Clear All
Free access

Gary R. Bachman and Ted Whitwell

Southern seaoats (Uniola particulata) are difficult to propagate from seed due to low seed numbers produced and cold dormancy effects. To efficiently produce southern seaoats in the nursery industry the dormancy must be effectively broken to assure quick and even germination. 24 hr soaks in gibberillic acid (100 and 500 ppm) or scarification of the seed coat combined with GA soaks were compared. Seeds were planted in 50/50 peat/perlite medium 2.5 cm deep. 21 DAT both the 100 and 500 ppm GA soaks had higher germination rates. The 100 ppm GA was determined to he most effective (56% germination) with the seedlings being 3 cm in length. The 500 ppm treated seeds were 6 cm in length hut twisted from the GA causing excessive cell elongation.

Free access

J.C. Vlahos and P. Ververidis

Lupinus albus ssp. graecus, L. Fabaceae (Boiss. and Spruner) Franco and P.Silva, is being studied at the TEI of Heraklion since 1998 as a new plant with potential use in floriculture and ornamental horticulture. The plant has been recorded botanically; however, little is known about its physiology and genetic profile. Lupinus albus ssp. is a herbaceous annual plant 10 to 20 cm tall, growing at roadsides, field margins, vineyards, and olive groves up to 700 m altitude. The leaves are 5 to 11 cm wide, palmate shaped in alternate orientation, with five to nine leaflets 10 to 18 mm wide, all arising from the same point. The flowers are borne in terminal or lateral spike-like racemes 10 to 20 cm long. Florets are 15 mm long, dark blue occasionally with a white patch, stamens forming a tube. Pods are 60 to 70 mm long,with four to six black-spotted seeds. In the present work, seed germination studies were conducted combining chilling pretreatments with physical scarification (scratching). Mature seeds chilled at 5 °C for 6 weeks germinated readily (83%) when scarified with sand paper. Furthermore, we tested the effects of several plant growth regulators (chlorocholine chloride, paclobutrazol, maleic hydrazide and Ethrel 48) on young plants of Lupinus in order to obtain compact pot plants with more flowering racemes. Paclobutrazol at 5 and 10 mg/L achieved the best retardation effect, but did not affect flowering. In another trial with different potting media,the commercial potting soil proved the most suitable for growing lupins satisfactorily. It is concluded that Lupinus albus spp. graecus L. need further investigation in order to establish the best cultural conditions for its growth and development. Furthermore, due to its high genetic variability, selection and genetic improvement is required for optimal results.

Free access

Alison E. Heather, Hector E. Pérez, and Sandra B. Wilson

-germination viability assay. Seed viability was examined using a TZ staining test before germination experiments started. Viability testing procedures were adapted from Peters (2000) using protocols developed for other members of Polygoneaceae. Seeds were scarified at

Free access

Michael J. Tanabe and Nicole Wakida

Noni, Morinda citrifolia, is receiving a lot of attention for its potential medicinal effects. Hawaii is an ideal growing environment for this plant, where it has been used for many purposes, including medicinal ones, by ancient Polynesians. Currently, there is a rapidly developing noni industry in the state of Hawaii. Propagation of this plant is almost exclusively by seeds, and germination generally requires a couple of months without preconditioning or about a month if mechanically scarified. We developed an in vitro protocol that significantly improves percent germination rate by altering incubation temperature and the in vitro culture basal medium. Germination time was decreased to 4 days when the embryo was extracted and exposed to 31 °C. A basal medium containing 1/2 Murashige and Skoog (M&S) salts was the most effective in reducing germination time and increasing percent germination. Stem pieces obtained from in vitro-propagated seedlings produced callus when explanted in 1/2 M&S containing various levels of naphthalene acetic acid (NAA). The most effective treatment was 0.5 μm NAA and the least effective treatment was 2 μm NAA. Treatments without NAA did not produce callus. Calli treated with 4.40 μm 6-benzylaminopurine (BA) or 8.80 μm BA were the most effective in promoting caulogenesis. We also demonstrated that the number of first generation seedlings produced from each embryo could be increased by treatment with 8.80 μm BA.

Free access

Ing-Jiun Tom Wu, G.L. Wheeler, and F.H. Huang

Scarification treatments (a control, a 10-minute vacuum, or a 1.5-minute ultrasound), different media (modified Norstog and Van Waes) and growth regulators [benzyladenine (BA) at 0, 1, 1.5, or 2 mg·L-1 and 6-(r,r-dimethylallylamino)-purine riboside (2iPR) at 0, 1, 1.5 or 2 mg·L-1] were used in combination to increase seed germination of Cypripedium calceolus var. parviflorum. Seeds treated with ultrasound had higher germination (58.0%) than those treated with vacuum (27.4%) or controls (19.2%). Germination rates increased with 2iPR level and reached a maximum between 1.5 and 2 mg·L-1. Seeds on Van Waes medium, which were not transferred to fresh medium after germination, had a severe browning problem causing many protocorms to die. Those on Norstog medium continued to grow into seedlings with less browning. Germination rates of Calopogon tuberosus × Calopogon `Adventure' and Liparis liliifolia were determined on the different media and growth regulator treatments. Multiple shoots of Calopogon developed from single seeds on media containing growth regulators. Flower buds formed in vitro on Calopogon in media containing 1 mg·L-1 or higher BA 5 months after germination. L. Iiliifolia seeds in Norstog medium had a higher proportion of germination than those in Van Waes medium.

Full access

Belinda Love, Wayne S Johnson, and George C.J. Fernandez

Germination of purple sage [Salvia dorrii (Kellogg) Abrams] seed was evaluated under 21 temperature combinations (day temperatures from 5 to 30C and night temperatures from 5 to 30C) in two experiments: 1) cool-moist stratification; and 2) sandpaper scarification, leaching with water, or gibberellic acid (GA3). The quadratic responses of weighted germination percentage (WGP), a combined index of germination percentage and speed of germination, were significant (P ≤ 0.05) for all treatments. The interaction of day and night temperatures was significant (P ≤ 0.05) only for the 2-week stratification treatments and for the Expt. 2 control. Stratification increased WGP over the control. Optimal WGP for all stratification treatments ranged from 46% to 51%. Optimal WGP was the same for both GA3 treatments. Optimal WGP for 0.29 mmol GA3 occurred at 16C night temperature and 22C day temperature, and for the 1.44 mmol GA3 treatment at 18C night and at 30C day temperature.

Free access

Jyotsna Sharma* and William R. Graves

Rhamnus alnifolia and Rhamnus lanceolata are shrubs of modest size with lustrous foliage. We evaluated seed germination of both species and propagated R. alnifolia by using softwood cuttings collected in early June. For R. alnifolia, cold stratification for up to 90 d resulted in 48% germination and a germination value of 1.9, whereas only 7% germination occurred among seeds stratified for 120 d. Seeds of R. alnifolia did not germinate if they were untreated or if scarified and stratified. Rhamnus lanceolata required 120 d of stratification to germinate, but percentages were low (≤ 5). Survival of germinants of both species was 90 to 100% regardless of prior seed treatment. Seedlings grew uniformly and had a mean leaf count of 11 and a mean height of 20 cm after 102 d. Application of 3000 and 8000 mg/L indole-3-butyric acid (IBA) in talc led to 85% rooting of R. alnifolia, whereas rooting was ≤ 15% after use of solutions with those IBA concentrations. While 75% of untreated cuttings rooted, fewer roots formed without IBA. More roots developed in 100% vermiculite than in 1 vermiculite: 1 perlite (by volume), which also diminished the number and apparent health of leaves on cuttings during the rooting period. We conclude that talc-based IBA and vermiculite should be used to root softwood cuttings of R. alnifolia, and that both species can be propagated from stratified seeds. Rhamnus lanceolata is more recalcitrant than is R. alnifolia and merits further study to optimize germination success.

Free access

Lorna C. Wilkins and William R. Graves

Development of half-sib Gleditsia triacanthos inermis Willd. (honey locust) seedlings was studied during exposure to osmotic and high root temperature stress. Seven days after seed scarification, seedlings of uniform fresh weight were transferred to static hydroponic culture vessels in a growth chamber. Three days later, vessel solutions were replaced with polyethylene glycol 8000-amended solutions with osmotic potentials (ψπ) of -0.05, -0.10, or -0.20 MPa at 23C. Within each ψπ treatment, root temperature was increased from ambient (23C) to 35C for 0, 6, 12, or 24 hr day-1 for 20 days. Root and shoot dry weights decreased with increasing exposure to 35C among seedlings in the -0.05 MPa solution and decreased for seedlings in -0.10 and -0.20 MPa solutions in all temperature regimes. Epicotyl expansion tended to decrease with decreasing ψπ and increasing exposure to 35C. However, for plants in the -0.20 MPa solution, epicotyl length was greatest when roots were exposed to 35C for 6 hr day-1.

Free access

David Tay*

In plant germplasm conservation, “orthodox” seed (i.e. seed that survives drying down to low moisture content) is the most suitable propagule for long-term storage. In general, high quality seeds of around 5% seed moisture content can be stored for 5-15 years at 2°C and 15-50 years at -18°C. Globally, there are some 1,300 genebanks and 6.1 million accessions of food and industrial crops in conservation. When collecting and conserving plant germplasm, seed science and technology have to be applied during germplasm collection; seed regeneration-germination, seedling establishment, flower synchronization, pollination, harvesting, drying, processing and packaging; seed storage and conservation; characterization and evaluation; and finally, distribution. Some of the seed science knowledge and technology skills encompass seed sampling strategy, sample size, seed health, germination and vigor testing, dormancy breaking, scarification, stratification, vernalization, photoperiod treatment, isolation and pollination techniques, harvesting, threshing, drying, hermetic packaging, storage facility design, etc. The goal is to produce seed lots that fulfill the required genetic, physical, physiological and health quality. A summary was presented to relate germplasm conservation activities to seed science and technology. Some of the seed production, processing and testing equipment used were highlighted. Seed research in germplasm conservation is therefore crucial to streamline the operation and management of a genebank to make it more cost effective and attractive for funding.

Full access

Servet Caliskan, Sharon T. Kester, and Robert L. Geneve

students treated seeds, petri dishes with germination paper (treated with or without the hormone solution), and a razor blade. Eastern redbud seeds can be purchased from a seed company or collected from local trees. All seeds should be previously scarified