Ethylene involvement in silique and seed development of canola, Brassica napus L.

A wide range of plant hormones, including gibberellins (GAs) and auxins are known to be involved in regulating seed and fruit growth and development. Changes in ethylene biosynthesis are also associated with seed and fruit development, but ethylene's role in these processes is poorly understood, as is its possible interaction with the other plant hormones. A major complication of investigating ethylene-induced regulation of developmental processes is ethylene's biphasic mode of action. To investigate ethylene's actions and interactions we used a 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase transgenic canola line. This line evolves significantly less ethylene from its siliques and seeds, relative to plants from a wild type (WT) background. Plants of the transgenic line also had smaller siliques which were associated with reductions in both seed size and seed number. Application of ethephon, a compound that produces ethylene, to plants of the transgenic line restored the WT phenotype for both siliques and seeds. Application of the same dose of ethephon to WT plants diminished both silique and seed development, showing ethylene's biphasic effect and effectively producing the ACC deaminase transgenic phenotype. There were significant decreases in endogenous concentrations of GA(1) and GA(4) and also of indole-3-acetic acid (IAA), between WT seeds and seedless siliques and seeds and siliques from the transgenic line plants. These differences were emphasized during early stages (10-20 days after pollination) of seed and silique development. The above results strongly suggest that ethylene interacts with other endogenous plant hormones in regulating silique and seed development and growth in WT lines of canola.

Growth and ethylene evolution by shade and sun ecotypes of Stellaria longipes in response to varied light quality and irradiance.

Plants growing in the shade receive both low light irradiance and light enriched in far red (FR) (i.e., light with a low red (R) to FR ratio). In an attempt to uncouple the R/FR ratio effects from light irradiance effects, we utilized Stellaria longipes because this species has two distinct natural population ecotypes, alpine (dwarf) and prairie (tall). The alpine population occupies the open, sun habitat. By contrast, the prairie population grows in the shade of other plants. Both 'sun' and 'shade' ecotypes responded with increased stem elongation responses under low irradiance, relative to growth under 'normal' irradiance, and this increased growth was proportionally similar. However, only the shade ecotype had increased shoot elongation in response to a low R/FR ratio. By contrast, the sun ecotype showed increased stem elongation in response to increasing R/FR ratio. Varying the R/FR ratios had no significant effect on ethylene evolution in either sun or shade ecotype. Under low irradiance, only the sun ecotype showed a significantly changed (decreased) ethylene evolution. We conclude that R/FR ratio and irradiance both regulate growth, and that irradiance can also influence ethylene evolution of the sun ecotype. By contrast, R/FR ratio and irradiance, while having profound influences on growth of the shade ecotype, do not appear to regulate these growth changes via effects on ethylene production.

Developing a virtual community for health sciences library book selection: Doody's Core Titles.

PURPOSE: The purpose of this article is to describe Doody's Core Titles in the Health Sciences as a new selection guide and a virtual community based on an effective use of online systems and to describe its potential impact on library collection development. SETTING/PARTICIPANTS/RESOURCES: The setting is the availability of health sciences selection guides. Participants include Doody Enterprise staff, Doody's Library Board of Advisors, content specialists, and library selectors. Resources include the online system used to create Doody's Core Titles along with references to complementary databases. BRIEF DESCRIPTION: Doody's Core Titles is described and discussed in relation to the literature of selection guides, especially in comparison to the Brandon/Hill selected lists that were published from 1965 to 2003. Doody's Core Titles seeks to fill the vacuum created when the Brandon/Hill lists ceased publication. Doody's Core Titles is a unique selection guide based on its method of creating an online community of experts to identify and score a core list of titles in 119 health sciences specialties and disciplines. RESULTS/OUTCOME: The result is a new selection guide, now available annually, that will aid health sciences librarians in identifying core titles for local collections. EVALUATION METHOD: Doody's Core Titles organizes the evaluation of core titles that are identified and recommended by content specialists associated with Doody's Book Review Service and library selectors. A scoring mechanism is used to create the selection of core titles, similar to the star rating system employed in other Doody Enterprise products and services.

Assessing reference staff competency in the electronic environment.

This paper shows how the Galter Health Sciences Library of Northwestern University's Feinberg School of Medicine developed and implemented a program to assess reference staff competencies for assisting users in the electronic environment after completing a new training program. The first phase was a year-long assessment of reference questions to identify the types of questions received at the desk. Next, a training program for reference was developed and implemented with an emphasis on answering the most common questions identified such as remote access, access privileges, holdings information, and database searching. The program included individualized instruction on library policies, electronic resources, access restrictions, and troubleshooting. The next phase was to create instruments to test staff competencies in answering questions after training. Based on the scores, additional training was individualized and provided to the appropriate staff member to enhance their skills where needed. The training system that was developed has proven to be effective as most staff scored better than 92% on initial testing. As a result, library management can be certain that users' questions are being answered correctly and that the staff has the skills required to work in an electronic environment.