fairly large and easy for students to manipulate during laboratory. The learning outcomes for this laboratory exercise are that a student will understand the role seed coverings play in maintaining seed dormancy, be able to explain the concept of embryo
Servet Caliskan, Sharon T. Kester and Robert L. Geneve
Jemma L. Hawkins, Kathryn J. Thirlaway, Karianne Backx and Deborah A. Clayton
instances, the opportunity for social interaction ( Sempik et al., 2005 ). It is likely that the physical exercise obtained during gardening activity will have benefits to health. There is evidence to suggest that is the case for the lower intensity leisure
Sin-Ae Park, Kwan-Suk Lee and Ki-Cheol Son
of indirect calorimetry; however, it is impractical outside a clinical or research laboratory setting. Therefore, a multistepped approach was used to determine the exercise intensities of gardening tasks in previous studies ( Park et al., 2008a
Geno A. Picchioni, Jagtar Singh, John G. Mexal and Ryan M. Goss
Undergraduate students generally have difficulty understanding plant water use in nursery conditions. A simple and reliable exercise to quantify evapotranspiration (ET) of containerized nursery plants is missing in the literature and could improve
Ron G. Goldy and Dana F. Moxley
A laboratory exercise is outlined and discussed for embryo culture of bean, corn, and pea embryos. Fresh, inexpensive material is generally available for these crop species throughout the year. The exercise gives students experience in embryo excision and exposure to some benefits of embryo rescue. Embryos from the three species are identified easily and can be removed without magnification, and data can be obtained within 3 weeks after culture. Further investigations using embryos are suggested.
Ursula K. Schuch
A two-part exercise was developed as part of the horticulture curriculum at Iowa State University to familiarize students with the American Standard for Nursery Stock (ASNS), and to allow them to practice and apply the ASNS with a variety of categories and types of ornamental plants. The first part of the exercise requires students to determine, according to ASNS standards, appropriate root ball/container size for plants to be moved from an existing immature landscape. During the second part, students evaluate whether root ball or container size of plants in a nursery is appropriate for the plant shoot dimensions. The exercise was designed for students to work in informal groups in a cooperative learning environment.
Sharon A. Duray and Fred T. Davies Jr.
A laboratory exercise is outlined and discussed for seed priming, or osmoconditioning. The exercise was developed using an easily constructed and inexpensive seed-priming system. A variety of horticultural seeds can be used to give students experience and exposure to some of the benefits of seed priming. Seed germination data usually can be obtained within 6 to 8 days, depending on the species used. The laboratory may be modified to stress various features of seed priming, including priming agents, optimal concentrations, and ranges of germination temperatures.
Thomas E. Marler and Haluk M. Discekici
A laboratory exercise is outlined in which breath is used as the source for elevating CO2. Single-plant enclosures are constructed by placing containers with stem cuttings within clear bags for maintaining high humidity during root initiation. These enclosures provide a restricted atmosphere in which elevated CO2 is adequately confined. The materials are inexpensive and readily available. The procedure is rapid, with results obtained in as few as 7 days. The increase in canopy and/or root growth as a result of elevated CO2 may be observed visually by younger audiences, or may be measured and analyzed in a manner dependent on the age group. The exercise generates an abundance of discussion and may be used to lead into many lectures on plant physiology, horticultural crop production, or global concepts of CO2 and the plant kingdom.
John E. Preece and Carl A. Huetteman
This exercise was developed for a plant propagation course to demonstrate, in a short time, the four stages of micropropagation, the effects of cytokinin concentrations, and the differences between adventitious and axillary shoots. Greenhouse-grown stock plants were brought into the laboratory, and 4- to 5-cm-long tips of runners were surface-dis-infested for 15 min in 0.5% NaClO with 1 ml of Tween 20/liter, followed by two 5-min rinses in sterile water. Working in the open laboratory near the bases of pairs of lit Bunsen burners, students placed either single-node or shoot tip explants (2 cm long, five replications) onto MS medium with 0, 1, or 10 μM BA. Cultures were in-cubated in parafilm-sealed culture tubes on open laboratory benches. Axillary shoots grew regardless of concentration of BA, and explants on medium with 10 μM BA produced the most callus and adventitious shoots. Microshoots were rooted and ac-climatized under mist in the greenhouse. This exercise can be performed in an open laboratory without the use of laminar flow hoods, specialized sterilizing equipment, or supplemental lighting.
Sharon A. Duray and Fred T. Davies Jr.
Plant propagation instructors are challenged to develop laboratory exercises that demonstrate the theoretical aspects of seed germination. Seed priming or osmoconditioning is a relatively new technigue that has been shown to improve seed performance in horticultural crops. An esaily constructed seed priming system was designed using a pair of 2-liter glass jars, 2 aquarium pumps and air tubing. Eight sets of 40 seeds were each wrapped in coffee filters and laced in aerated treatment solutions consisting of 50 mmole K H2P O4 or an untreated control of distilled water. All seeds were treated or 0, 1, 3 or 5 days. Upon completion, seeds were rinsed, dried and placed into petri dishes containing moist filter paper to observe germination. A good test species for this exercise is Vinca rosea which typically has a poor germination percentage and rate. Seeds primed for 3 and 5 days significantly enhanced both germination percentage and rate in Vinca.