on the germination percentage and speed, as well as seedling vigor for several mountain laurel hybrids. Our objective was to establish an efficient in vitro seed germination protocol for mountain laurel hybrid seeds to enable seed harvest before full
Natalia R. Dolce, Ricardo D. Medina, Luis A. Mroginski, and Hebe Y. Rey
opened for removing seed samples, bar = 2 cm. ( B ) 2,3,5-Triphenyltetrazolium chloride (TTC)–positive red coloration of viable seeds observed under a stereomicroscope (4×), bar = 1 mm. ( C ) In vitro seed germination and protocorm development (90 d after
Boris Andrés Bran Barrientos and Jong-Yi Fang
orchid species. Successful in vitro seed germination has been reported for S. plicata using various medium formulations. Hossain and Dey (2013) found that the maximum seed germination percentage was observed with the Phytamax medium (95%) followed by
Natalia R. Dolce, Ricardo D. Medina, and María T. González-Arnao
germination of cryostored and noncryostored seeds, depending on the Ilex species. In both cases (with and without cryostorage), the optimal condition coincides for in vitro seed germination of each species. Seedlings of the seven Ilex species tested
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.
Chad Finn, Kirsten Wennstrom, and Kim Hummer
Populations of 40 Rubus sp., representing the Malachobatus, Idaeobatus, Eubatus, and Anoplobatus, were planted in the field in 1994. To get a preliminary idea of how successful crosses between these species and standard cultivars would be, 58 crosses were attempted between standard cultivars and randomly selected genotypes of the 14 species that produced a significant number of flowers in 1995. Diploid species were crossed with `Tulameen' and `Meeker' raspberry and the tetraploid species with `Cherokee' and `Chester' blackberry. Twenty-two crosses produced seed lots ranging from 8 to 630 seeds. Crosses were successful with R. caesius, R. caucasicus, R. coreanus, R. georgicus, R. parvifolius, R. rosifolius, and R. sumatranus. Crosses were not successful with R. eustephanos, R. insularis, R. innominatus, R. lambertianus, R. sachalinensis, R. setchuenensis, R. swinhoei, and R. tsangorum. In vitro seed germination was attempted with all crosses. Larger seed lots were also germinated using standard procedures for Rubus. There is a great deal of variability in leaf morphology of the young seedlings within a cross that suggests that some or all of the seedlings are true hybrids. Seedlings that are not true hybrids could result from contaminant pollen or, as in R. armeniacus, pseudogamous embryo formation. Crossing results from 1995 and 1996, including crosses attempted and seed numbers per cross, will be presented along with, for the 1995 crosses, the number of germinated seedlings and our assessment of whether they appear to be true hybrids.
Qi Zhang, Kevin Rue, and Sheng Wang
Salinity tolerance of five buffalograss [Buchloe dactyloides (Nutt.) Englem.] cultivars (Texoka, Cody, Bison, Sharp's Improved II, and Bowie) and three blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] ecotypes (‘Lovington’, ‘Hachita’, and ‘Bad River’) was determined during in vitro seed germination and vegetative growth in a hydroponic system. Seeds were germinated on 0.6% agar medium supplemented with NaCl at 0, 5, 10, 15, and 20 g·L−1. Salinity reduced the final germination rate (FGR) and daily germination rate (DGR). Similarly, shoot dry weight (SDW), longest root length (LRL), and percentage of green tissue (PGT) of mature grasses declined with increasing salinity levels (NaCl = 0, 2.5, 5, 7.5, and 10 g·L−1). However, root dry weight (RDW) was not significantly affected by salinity. Blue grama exhibited a lower reduction in FGR and DGR than buffalograss at salinity levels lower than 10 g·L−1. Germination of all buffalograss cultivars and ‘Hachita’ blue grama was inhibited at salinity levels of 15 and 20 g·L−1 NaCl. However, buffalograss was more salt-tolerant than blue grama at the vegetative growth stage. Variations of salinity tolerance were observed within buffalograss cultivars and blue grama ecotypes, especially during the seed germination stage. Overall, buffalograss appeared to be salt-sensitive during germination but moderately salt-tolerant at the mature stage. However, blue grama was more salt-tolerant at the germination stage than the mature stage. Noticeable differences in salinity tolerance were observed between different germplasms. Therefore, salt tolerance of buffalograss and blue grama may be improved through turfgrass breeding efforts.
Alice Noemí Aranda-Peres, Lázaro Eustáquio Pereira Peres, Edson Namita Higashi, and Adriana Pinheiro Martinelli
Many different species of Bromeliaceae are endangered and their conservation requires specific knowledge of their growth habits and propagation. In vitro culture of bromeliads is an important method for efficient clonal propagation and in vitro seed germination can be used to maintain genetic variability. The present work aims to evaluate the in vitro growth and nutrient concentration in leaves of the epiphyte bromeliads Vriesea friburguensis Mez, Vriesea hieroglyphica (Carrière) E. Morren, and Vriesea unilateralis Mez, which exhibit slow rates of growth in vivo and in vitro. Initially, we compared the endogenous mineral composition of bromeliad plantlets grown in half-strength Murashige and Skoog (MS) medium and the mineral composition considered adequate in the literature. This approach suggested that calcium (Ca) is a critical nutrient and this was considered for new media formulation. Three new culture media were defined in which the main changes to half-strength MS medium were an increase in Ca, magnesium, sulfur, copper, and chloride and a decrease in iron, maintaining the nitrate:ammonium rate at ≈2:1. The main difference among the three new media formulated was Ca concentration, which varied from 1.5 mm in half-strength MS to 3.0, 6.0, and 12 mm in M2, M3, and M4 media, respectively. Consistently, all three species exhibited significantly higher fresh and dry weight on M4, the newly defined medium with the highest level of Ca (12 mm). Leaf nitrogen, potassium, zinc, magnesium, and boron concentrations increased as Ca concentration in the medium increased from 1.5 to 12 mm.
Song-jun Zeng, Zhi-lin Chen, Kun-lin Wu, Jian-xia Zhang, Cheng-ke Bai, Jaime A. Teixeira da Silva, and Jun Duan
sexual reproduction, although seeds germinate slowly and inefficiently as a result of the absence of an endosperm. In addition, germination usually requires symbiotic fungi ( Zeng, 2009 ). An in vitro seed germination protocol has been described for
Michael W. Bairu, Manoj G. Kulkarni, Renée A. Street, Rofhiwa B. Mulaudzi, and Johannes Van Staden
analyzed. In vitro seed germination and shoot induction. Some of the seeds collected from the University of KwaZulu-Natal Botanical Gardens were immediately used for in vitro germination tests. Six different types of germination media, namely distilled