Search Results
You are looking at 1 - 10 of 27 items for
- Author or Editor: Robert E. Lyons x
An undergraduate “Service Course” generally presents principles of a particular discipline in an uncomplicated manner needing no prerequisites. The target audience is typically students majoring outside the service course department or undeclared majors. The primary motives behind service courses are recruitment from within the university, providing non-mjors with a broad appreciation for a discipline, and providing graduate students with classroom teaching/management experience. `The structure, dynamics, success, and adaptability of “Indoor Plants,” a Virginia Tech Horticulture service course enrolling approximately 400 students per year, will be discussed. Comparisons with other service courses will be made.
An historic feature of the JC Raulston Arboretum (JCRA) is to identify new and unusual ornamental plant materials for landscape use through an active program of observing landscape performance at the JCRA in Raleigh. Introduction of plant materials into commerce occurs primarily through programs conducted in concert with the North Carolina Association of Nurserymen and through a unique policy of “open access” for nurserymen. One program, The JC Raulston Selections Program, returns revenues to the general operations and maintenance functions of the JCRA; others are not revenue generating, and are provided as a service to the industry. To a lesser extent, the general public may participate in receiving new plants via a special program offered through JCRA membership. The JCRA is also an official trial garden site for the All America Selections program and seed companies. Elements of these introduction and evaluation programs will be discussed within the context of the past, present, and plans for the future for program maintenance and possible changes.
Combinations of seed rate, spacing and weed control treatments were evaluated for their effect on the performance of The Virginia Tech Transplanted Meadow technique. The treatments consisted of seed rates of 112 g or 56 g per 90 m-2; within-row transplant spacing of 30, 45, or 60 cm; and mulch, oryzalin, or nothing applied for weed control. Plant competition alone was insufficient for effective weed control whereas oryzalin was the best but also reduced the plant stand and floral display. Mulch provided effective weed control with maximum floral display. Close transplant spacing within rows resulted in quick site coverage but this advantage disappeared after 8 weeks when no difference in floral display was observed. Seeding rate did not affect site coverage until the meadow reached maturity at 12 weeks. The lower seed rate allow ed more lodging, resulting in a more open appearance and greater light transmission through the canopy. Chemical name used: 4-(dipropylamino)-3,5dlnitrohenzenesulfonamide (oryzalin).
BA and GA4+7, were applied to vegetative, mature Rudbeckia hirta plants at the beginning of long days (LD). There were no synergistic effects, but BA inconsistently affected branching and had no effect on flowering. Floral initiation of the terminal inflorescence was promoted by GA4+7, although axillary inflorescences were not. Increasing GA4+7 levels decreased the time to terminal inflorescence anthesis. However, the interval between the terminal and second axillary inflorescence anthesis was increased. The net result was no significant effect on the time to second axillary inflorescence anthesis. Gibberellins may enhance the LD effect on the apical meristem of Rudbeckia, but axillary meristems, which initiate later, remained unaffected. Chemical names used: benzyladenine (BA), gibberellin4+7, (GA4+7).
Chrysanthemum × superbum, Coreopsis lanceolata, and Coreopsis grandiflora are LD flowering perennial plants. The end of juvenility could be defined as the minimum expanded leaf number required for fastest flowering once placed in LD. This research was conducted to compare juvenility and flowering requirements in dwarf and standard cultivars of these species. Plants were maintained under SD and transferred to LD upon reaching true leaf stages beginning with 0 (cotyledons only) and progressing at 2 or 3 leaf intervals to the 24 leaf stage. Coreopsis `Sunray' and Chrysanthemum `G. Marconi' were relatively unresponsive to LD whereas LD induced flowering in 70-100% of the plants in each leaf number treatment in Coreopsis `Early Sunrise'. Plants transferred at the 15 leaf stage required the least number of LD to reach anthesis. LD promoted complete flowering in Chrysanthemum × superbum `Snow Lady' plants and 90% of the SD control plants flowered as well. SD control plants from the other 3 cultivars remained vegetative. Effects of vernalization will also be presented.
A study was undertaken to determine the rate of floral initiation in Rudbeckia hirta. R. hirta plants were grown to maturity, 14-16 leaves, under short days (SD). Paired controls were established by placing half of the plants under long days (LD) with the remainder left under SD. Beginning at the start of LD (day 0), five plants were harvested daily from each photoperiod group for twenty days. Harvested meristems were fixed in 2% paraformaldehyde - 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.0) for 24 hrs, dehydrated in an ethanol series, embedded in paraffin and sectioned at 8 μm. Serial sections were stained with Methyl-green Pyronin, with adjacent sections treated with RNase for nucleic acid comparison. All events of floral initiation were identified, The results of limited inductive photoperiod indicate that 16-18 LD were required for flowering.
Gaillardia pulchella is an annual wildflower with ornamental potential native to the South and Southern West part of the U. S. This experiment attempted to further describe the long day (LD) flowering requirement, approximate the length of the juvenility phase, and characterize apical events during floral initiation. Plants were transferred from short day to LD at various leaf numbers and the time to first flower was recorded from the onset of LD. A quadratic response described the data and indicated that a minimum of 19-20 expanded leaves were needed to flower most rapidly (49 days) once placed in LD. Histological results characterizing apical events will also be discussed.