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- Author or Editor: Wagner Vendrame x
One of the largest horticultural trade shows in the United States, the Tropical Plant Industry Exhibition, takes place each January in Fort Lauderdale, Fla. The timing of this show coincides with the offering, during the spring semester, of an undergraduate horticulture course, Palm Production and Culture (ORH 4321C, 3 credits). We have developed a guided activity in which we assign the students to visit several preselected exhibits in this show, so that each exhibit in the show is visited by at least one student. The students complete a questionnaire for each exhibit in which they note the identity of the palm species present, the number of species present, the number of individuals of each species, and the total number of palms in each exhibit. Data in the questionnaires are compiled and used to augment and reinforce class discussions on morphology, cultural requirements, interiorscape management, species richness, species diversity, and field laboratory work in morphology and taxonomy. Procedures used have the potential for adaptation to other types of horticultural trade shows and other types of horticultural crops, as well as for other courses in horticulture.
The objective of this study was to evaluate greenhouse techniques for the production of jatropha (Jatropha curcas). Jatropha seedlings were transplanted into 1-gal containers filled with bark mix, coir, or peat-based substrate and fertilized with 0, 4.1, 5.9, or 8.3 oz/ft3 of a 15N–4.05P–9.96K controlled-release fertilizer (CRF). Plants were watered every 2, 3, or 4 days for 80 days in the greenhouse. Jatropha plants grown in peat-based substrate had greater stem diameter and shoot dry weight (SDW) than plants grown in bark mix. For each growing substrate, plants fertilized with 8.3 and 5.9 oz/ft3 of CRF had greater SDW than plants fertilized with 4.1 and 0 oz/ft3 of CRF. Similarly, for all three substrates, plants irrigated every 2 or 3 days had greater SDW than plants irrigated every 4 days. Although jatropha has been classified as a low–nutrient and water requiring plant, the results of this study suggest that increased inputs of fertilizer and water produce larger plants. Further research needs to be conducted on the benefit of larger plants from the greenhouse on subsequent oil production in the field.
The effects of four types of explants removed from 10-cm flower stalks of Doritaenopsis Purple Gem ‘Ching Hua’ (immature apical flower buds, immature lateral flower buds, flower stem nodes, and flower pedicel sections) and combinations of two plant growth regulators [naphthalene acetic acid (NAA) and thidiazuron (TDZ)] on direct in-vitro shoot induction and multiplication were studied. Immature apical flower buds were the only explants that showed induction and multiplication of shoots in vitro. NAA at 5.4 and 10.7 μm combined with either 4.5 or 9.1 μm TDZ provided the fastest and greatest percentages of shoot induction (27% to 40%) and the greatest numbers of shoot multiplication (111–160 shoots per explant). In vitro–induced shoots were rooted on medium containing 5.4 μm NAA and developed into plantlets with normal vegetative and reproductive morphology. Regenerated plantlets were acclimatized, showing 100% survival and establishment in greenhouse. Plantlets were grown to maturity and showed normal flower morphology. No floral off-types were observed. The high rates of shoot multiplication obtained offer a means for mass clonal propagation of this and possibly other related Doritaenopsis hybrids.
To investigate the effects of different cryoprotectants on germination and seedling development of jatropha (Jatropha curcas L.) seeds after cryopreservation, two experiments were performed under in vitro and ex vitro conditions. Nine treatments were used for both experiments, as follows: T1—No cryoprotectants (control); T2—glycerol 2 m (20 minutes); T3—sucrose 0.4 m (20 minutes); T4—glycerol 2 m (20 minutes) + PVS2 (10 minutes); T5—glycerol 2 m (20 minutes) + PVS2 + phloroglucinol 1% (10 minutes); T6—sucrose 0.4 m (20 minutes) + PVS2 (10 minutes); T7—sucrose 0.4 m (20 minutes) + PVS2 + phloroglucinol 1% (10 minutes); T8—glycerol 2 m (20 minutes) + sucrose 0.4 m (20 minutes) + PVS2 (10 minutes); and T9—glycerol 2 m (20 minutes) + sucrose 0.4 m (20 minutes) + PVS2 (10 minutes) + phloroglucinol 1% (10 minutes). After cryopreservation, seeds without cryoprotectants (T1) or with sucrose 0.4 m + PVS2 (T6) returned the best germination percentages after seven days of in vitro culture, 29.5% and 25%, respectively. However, they were not significantly different. For the ex vitro experiment, seed germination percentage was higher in organic substrate. These results indicate that cryopreservation of jatropha seeds can be accomplished without cryoprotectants, and faster germination is obtained in organic substrate.
Although composting has been practiced for thousands of years, it was not until the 20th century that controlled scientific studies were published illustrating the benefits of compost use in crop production. These studies helped to spur increased interest in composting and compost use, and gave way to the development of commercial composting facilities that supply finished compost products to horticultural producers. Increasing composting activity and compost use encouraged the formation in the late 20th century of trade organizations, such as the U.S. Composting Council and similar organizations in other countries, that support research and applications work to determine ways to improve quality control of commercial compost products.
New guinea impatiens (Impatiens hawkeri) (NGI) `Pure Beauty Rose' (PBR) and `Paradise Orchid' (PO) were grown in full sun, 55% shade, or 73% shade and fertilized with a controlled-release fertilizer (CRF) [Nutricote Total 13-13-13 (13N-5.7P-10.8K), type 100] incorporated at rates of 2, 4, 6, 8, 12, 16, 20, 24, 28 and 32 lb/yard3 of growing media (1.2, 2.4, 3.6, 4.7, 7.1, 9.5, 11.9, 14.2, 16.6, and 19.0 kg·m-3). Plant quality rating, shoot dry weight, and flower number were measured at harvest and substrate samples were collected to analyze final substrate pH and electrical conductivity (EC). For both cultivars, light intensity and fertilization rate interactions were different for shoot dry weight and flower number, but there was no difference in plant quality rating between the light levels. Quality ratings of both PBR and PO plants increased as CRF rate increased to 12 to 16 lb/yard3 above these levels quality was not improved. Shoot dry weight of PBR plants grown in full sun increased as CRF rate increased to 28 lb/yard3 and then decreased, while shoot dry weight of plants grown with 55% and 73% shade increased as CRF rate increased to 20 and 16 lb/yard3, respectively, with no further increases. Shoot dry weight of PO plants grown in full sun and 55% shade increased as CRF rate increased to 28 and 24 lb/yard3, respectively, with no further increases, while shoot dry weight of plants grown with 73% shade increased as CRF rate increased to 24 lb/yard3 and then decreased. Flower number of PBR plants grown in full sun, 55% shade, and 73% shade increased as CRF rate increased to 24 lb/yard3 and then decreased. Flower number of PO plants grown in full sun increased as CRF rate increased to 28 lb/yard3 and then decreased, while flower number of plants grown in 55% and 73% shade increased as CRF rate increased to 24 lb/yard3 and then decreased.
Pollination effectiveness was evaluated for pollen (pollinia) from two Dendrobium hybrids, ‘Sena Red’ and ‘Mini WRL’, submitted to cryopreservation using a vitrification protocol. Parameters evaluated included pollinia exposure to a previtrification solution (PVS2) under ice (0 °C) or room (27 ± 2 °C) temperatures from 1 to 4 hours before cryopreservation (LN). On removal from cryopreservation, pollinia were used to pollinate flowers of the same hybrids to verify viability and germination. All pollinia showed high percentages of germination (greater than 80%) after crosses were performed, except for pollinia from Dendrobium ‘Sena Red’ submitted to 3 hours of precooling (0 °C) in PVS2 followed by LN (60%) and for pollinia submitted to PVS2 for 3 hours at room temperature with no precooling (70%). Capsules were formed for both hybrids and seeds were successfully produced. The seed viability test revealed high viability (90% to 95%) for all treatments for both hybrids. Seeds observed under a microscope contained well-formed embryos and no abnormalities were identified. Seeds from all treatments germinated. Germinating seeds developed into healthy seedlings with well-formed leaves and roots. Cryopreservation of pollinia was successfully accomplished either by direct storage in liquid nitrogen without cryoprotection treatments or by using a PVS2 vitrification protocol.
Experiments were conducted during two different time periods to determine if hybrid phalaenopsis orchid (Phalaenopsis spp.) liners accumulate silicon (Si) and if this element can affect liner growth. A total of 800 liners were evaluated and Si fertilization was performed by applying potassium silicate (KSiO3) as a drench with three treatments (0.5%, 1.0%, and 2.0% v/v) and a control (water, no Si fertilization). The application of KSiO3 affected overall growth of phalaenopsis orchid liners, where Si content of the plant ranged from 0.5% to 1.7%. Overall, Si applied at 0.5% and 1.0% increased fresh weight and dry weight (DW) and at 1.0% Si significantly increased DW of root, shoot, and whole plant over the control. Increases in DW ranged from 27% up to 118%. Results from the second experiment were similar. Other plant parameters evaluated such as leaf number and size, root number, and length were unaffected by Si application. Although leaves of phalaenopsis orchid liners treated with Si appeared darker green when compared with the control, no significant differences were observed in chlorophyll content of leaves. Reduced growth was observed when 2.0% Si was applied affecting Si tissue concentrations and substrate electric conductivity. The data obtained from this study indicate that hybrid phalaenopsis orchid liners are Si accumulators and that this element influences their growth. Further studies are warranted to address the long-term effects of Si fertilization on the complete life cycle of hybrid phalaenopsis orchids.
Field evaluations were conducted of pecan [Carya illinoinensis (Wangenh.) C. Koch] trees regenerated via somatic embryogenesis to assess if the trees maintained clonal fidelity and exhibited true-to-type characteristics. Phenotypic and molecular comparisons were made of trees from two different tissue culture lines after 4 years in the field. Factors evaluated included shoot growth, leaf morphology, and susceptibility to fungal scab [Cladosporium caryigenum (Ellis & Langl.) Gottwald] and southern pecan leaf phylloxera (Phylloxera russellae Stoetzel). Genetic fidelity was examined using amplified fragment length polymorphism (AFLP) analysis. Statistically significant differences were observed between the culture lines in phenotypic leaf characteristics (i.e., specific leaf weight and leaf length-to-width ratio), number of shoots per 1-year-old branch, and in the frequency of scab lesions on leaves. No between-line differences were observed in trunk caliper, average and total shoot growth, shoot length per cross-sectional area, or presence of phylloxera galls. AFLP analysis readily detected differences between culture lines. Cluster analysis generally grouped trees together that were regenerated from the same line. Trees within a culture line usually exhibited similar leaf characteristics, but not shoot growth or tree height. A few trees exhibited more extreme leaf characteristics and differed from each other. However, they were statistically similar to most of the other trees in the population evaluated. AFLP data revealed that some trees exhibited greater divergence and less similarity than other trees from the same line. The nature and significance of such variation at this time are not related to any detectable phenotypic differences.
Myrciaria dubia (caçari or camu-camu) is a species with great relevance because of its high levels of bioactive compounds and antioxidant activity. The species is propagated mainly by seed, which leads to high genetic diversity. Producing plants that maintain their characteristics on a large scale at a low cost is a challenge for fruit species, especially in the Myrtaceae family. Therefore, this study aimed at assessing the effects of different plant growth regulators at various concentrations for the induction of somatic embryogenesis from caçari nodal segments and leaf disk explants. Two independent experiments were performed using nodal segments and leaf disks from plants grown in the greenhouse. In the first experiment, the combined effect of auxin and cytokinin at different concentrations was evaluated: 2,4-dichlorophenoxyacetic acid at 0, 1, 2, and 4 mg⋅L–1; and benzylaminopurine at 0, 0.25, 0.5, and 1 mg⋅L–1). In the second experiment, the application of different plant growth regulators (benzylaminopurine, kinetin, thidiazuron, and isopentenyl adenine) and their concentrations (0, 2, 4, and 6 mg⋅L–1) were evaluated. In both experiments, the basic culture medium was woody plant medium. Callus formation via nodal segments and leaf disks occurred in the first 30 d from cultivation and proved to be responsive to induction by 2,4-dichlorophenoxyacetic acid and benzylaminopurine. Auxin proved to be essential for somatic embryogenesis induction in nodal segments using 1 and 4 mg⋅L–1 of 2,4-dichlorophenoxyacetic acid alone. The results of this experiment will help advancing protocols for regeneration of somatic embryos and elucidating the physiological, molecular, and genetic mechanisms involved in the process of somatic embryogenesis for M. dubia. The development of an efficient protocol for in vitro clonal propagation of this species also lays the groundwork for further optimization of the system for genetic transformation.