ARS | Publication request: Trichomes on the Gynoecium of Cultivar Clark (Glycine Max L.), Seven Near-Isogenic Lines, and a Tetraploid Clark: a Comparative Study of Their Relative Numbers and Types

Submitted to: Botanical Society Of America Abstracts
Publication Acceptance Date: August 4, 2004
Publication Date: August 4, 2004
Citation: Healy, R., Horner, H.T., Bailey, T.B., Palmer, R.G. 2004. Trichomes On The Gynoecium Of Cultivar Clark (Glycine Max L.), Seven Near-Isogenic Lines, And A Tetraploid Clark: A Comparative Study Of Their Relative Numbers And Types. Botanical Society Of America Abstracts. Abstract No. 198.

Technical Abstract: The identification of floral traits that will enhance the attraction of pollinators to Glycine max L., an autogamous species, is important to the concept of producing commercial hybrid soybean seed. The numbers and types of trichomes present on the gynoecium are of potential interest in this regard. Little attention has been focused on trichomes of the soy flower gynoecium. We studied the three types of trichomes present on the gynoecium of the normal cultivar Clark from one day prior to anthesis through anthesis. We were interested in comparing trichomes by type, number, form and location on the gynoecium of the normal Clark with seven near-isogenic lines, and the tetraploid Clark. These included the glabrous (P1), puberulent (p2), sparse (Ps), sharp hair tip (Pb), dense-1 (Pd1), dense-2 (Pd2) and extra dense (Pd1 Pd2) lines, as well as the normal diploid (2n) and tetraploid (4n). The normal line has long, thin-walled unicellular trichomes and short, 5- to 10-celled secretory trichomes mostly distributed along the ovary. Long, thick-walled trichomes are concentrated at the juncture of the ovary and style, and extend part way up the style. They are more abundant on the dorsal side of the gynoecium, but occur on the ventral side also. The three types are present in all lines except for the glabrous, which is missing thick-walled trichomes. Thick-walled trichomes have the most variable distribution among the different lines. They are greatest in number in the dense pubescence lines, and they are shortest in the puberulent line. Secretory trichomes vary least in their number and morphology, but are notably fewer in number on the extra dense line. Unicellular trichomes vary most in number, being greatest in the dense-2 and extra dense lines, and the tetraploid. The importance of these three types of trichomes to crosspollination and protection is being investigated.