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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #225895
Title: SOYBEAN AND TOBACCO FLORAL NECTARIES DIFFER DEVELOPMENTALLY AND FUNCTIONALLY TO PRODUCE NECTAR

Author
item HORNER, HARRY - ISU
item HEALY, ROSARIA - ISU
item THORNBURG, ROBERT - ISU
item Palmer, Reid

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/12/2008
Publication Date: 9/12/2008
Citation: Horner, H.T., Healy, R.A., Thornburg, R.W., Palmer, R.G. 2008. Soybean and Tobacco Floral Nectaries Differ Developmentally and Functionally to Produce Nectar [abstract]. Modern Variety Breeding for Present and Future Needs. p. 135-136.

Interpretive Summary:

Technical Abstract: Pollinator attraction and pollination of flowers are mediated by characters such as flower color (visual cue); flower shape (accommodation); flower opening and pollen dehiscence (timing); volatiles production (smell); and nectary gland and nectar secretion (reward). This gland and its complex secretory product represent two important aspects of a larger, basic-biological study dealing with production of hybrid soybean seed at Iowa State University. The cultivated soybean, Glycine max, is highly self-pollinated. Floral nectaries are diverse secretory glands that vary widely in their flower location, size, and ability to produce sufficient nectar to serve as a reward, and possibly as an attractant to a variety of pollinators. The pollinator vector involvement is vitally important in establishing cross-pollination, to produce hybrid seed for agronomic performance studies. Arabidopsis flower nectaries were not studied because they are very small structures that are essentially non-functional. However, very little comparative work has been done to assess differences between nectaries of self-pollinated and cross-pollinated species. To capitalize on this disparity, we are studying an ornamental tobacco (Nicotiana LxS8) that produces copious amounts of nectar and cross pollinates. The annual soybean cultivars that have relatively poor (Clark) and good (Raiden) pollinator attraction, and the perennial G. tomentella that outcrosses better than 50 percent of the time, represent prime subjects for our study which focuses on developmental and comparative anatomical results of nectaries of these taxa using histochemical, in situ hybridization, and immunocytochemical procedures. Our ongoing work with tobacco and the Glycine species demonstrates varying levels of nectary starch buildup, starch loss at a time of nectar production and secretion, expression of two tobacco nectary-specific genes (NEC 1 and NOX 1), and expression of a protein (NEC 1) associated with NEC 1 gene. Our hypothesis is nectar quantity and composition are of great importance to successful insect pollinator hybridization, especially in soybean.