Sexual Plant Reproduction

, Volume 16, Issue 4, pp 179–190

Immunocytochemical distribution of polygalacturonase and pectins in styles of distylous and homostylous Turneraceae


  • Davood Khosravi
    • Department of BiologyYork University
  • Roshanak Joulaie
    • Department of BiologyYork University
    • Department of BiologyYork University
Original Article

DOI: 10.1007/s00497-003-0192-6

Cite this article as:
Khosravi, D., Joulaie, R. & Shore, J.S. Sex Plant Reprod (2003) 16: 179. doi:10.1007/s00497-003-0192-6


Distyly is a plant breeding system in which two self-incompatible, but cross-compatible, floral morphs occur within populations. The morphs differ in having a reciprocal arrangement of styles and anthers. Little or nothing is known of the proteins involved in self-incompatibility for any distylous species. Here we show that a 35 kDa putative polygalacturonase is specific to the transmitting tissue of short-styled plants of five species in series Turnera. The polygalacturonase was not detected in styles of long-styled plants, or in styles of five homostylous self-compatible species in this series of the genus. It is also absent from two X-ray generated mutants and a spontaneous somatic homostylous mutant that arose on a short-styled plant and whose style does possess this polygalacturonase. Three more distantly related species in the Turneraceae were investigated. Turnera weddelliana (series Salicifoliae) does possess the polygalacturonase; however, T. diffusa (series Microphyllae), and Piriqueta caroliniana, showed no evidence of possessing this polygalacturonase using immunocytochemistry. Polygalacturonase assays revealed activity in styles of long- and short-styled plants, but showed no activity of the 35 kDa style polygalacturonase. The distribution of pectins in styles and pollen tubes revealed no difference between the long- and short-styled morphs. Methyl-esterified pectins occur throughout the style tissues, except in the transmitting tissue. The transmitting tissue possesses unesterified pectins that could provide a substrate for polygalacturonase activity. We propose that the style polygalacturonase might act in a complementary manner, allowing pollen of long-styled plants to grow through short styles or, alternatively, oligogalacturonide products of polygalacturonase activity might play a role in signalling compatible responses.



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© Springer-Verlag 2003