Developmental and Structural Section
Coté, Gary G. .
Microscopic Crystals in Aroid Flowers: A Role in Gamete Protection?
Many plants have idioblast cells which produce crystals of calcium oxalate. Crystal idioblasts are well known in the vegetative tissues of species in the Araceae. Many aroid species have a type of crystal idioblast, termed the biforine, which is able to forcibly expel the crystals. It has often been proposed that these crystals, particularly those in biforines, might play a role in defending against herbivory. If this is true we would hypothesize that crystals would be abundant in reproductive tissues, arrayed so as to protect the pollen and ovules without interfering with pollinators. To test this, we examined floral tissues from 21 aroid species in 12 tribes, collected from greenhouse material and from the wild in Connecticut and Virginia (USA) and French Guiana. These species represented a variety of pollination strategies, including bribing pollinators with edible sterile flowers (staminodia). Tepals, in those species which had them, always contained crystals. Crystals were common in gynoecial walls, but generally absent from the ovules themselves. Crystals were found the connectives and filaments of stamens, particularly in those species where stamens fuse into synandria. Dense strands of biforine-like cells were seen in synandria. However, crystals were rare to absent in anthers, except that species of Caladieae and Dieffenbachieae contain prismatic crystals among the pollen. The results are generally consistent with the hypothesis that aroids deploy crystals to protect gametes. Unexpectedly, however, staminodia were often well endowed with crystals, and there was evidence that the crystals could limit staminodia consumption in some species. This suggests a more complex role for crystals in these organs.
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1 - Radford University, Department of Biology, Box 6931, Radford, VA, 24142-6931, USA
Presentation Type: Poster:Posters for Sections
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM