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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #145768
Title: A GLYCINE MAX FLORAL NECTARY: A FASCINATING SECRETORY ORGAN WITH UNUSUAL SUBCELLULAR STRUCTURES AND MANNER OF SECRETION

Author
item HEALY, ROSEANE - ISU
item HORNER, HARR - ISU
item Palmer, Reid

Submitted to: Iowa Academy of Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/24/2003
Publication Date: 1/24/2003
Citation: HEALY, R.A., HORNER, H.T., PALMER, R.G. A GLYCINE MAX FLORAL NECTARY: A FASCINATING SECRETORY ORGAN WITH UNUSUAL SUBCELLULAR STRUCTURES AND MANNER OF SECRETION. IOWA ACADEMY OF SCIENCE MEETING. 2003. Abstract No. 10.

Interpretive Summary:

Technical Abstract: The floral nectary is a short-lived discoid gland around the base of the gynoecium. It consists of an epidermis, with prominent guard cells, that covers a mound of special parenchyma innervated by fingers of phloem. When the nectary reaches its maximum size, special parenchyma around the phloem fingers degenerate first, followed by parenchyma further into the nectary, and finally the epidermal cells. All of these cells produce material in their vacuoles. The material consists of both a non-staining substrate and ribosome-like particles. As the vacuoles enlarge to near the periphery of the cells, several unique cytoplasmic structures appear: bundles of tubules pressed to the outside of the vacuole and in the cytoplasm away from vacuoles; single straight tubes containing ribosome-like particles in the cytoplasm and extending through plasmodesmata; and bridges of cytoplasm that extend into vacuoles like pockets. The functional significance of these structures is unknown. Following engorgement, vacuoles disintegrate and the cytoplasm and vacuole contents mix. This holocrine process terminates in collapse of cell walls and secretion of cellular contents. The entire nectary collapses leaving a shriveled mound and residue after the flower has opened. This manner of secretion is different than that reported for all other legume floral nectaries studied so far, and may be significant in the potential to attract insects.