Mate choice in plants( Plants are very selective when it come...)

Plants are very selective when it comes to choosing mates. Flowering plant pollination systems are clever devices for attracting pollinators like birds, ants, and insects, but there are also mechanisms for keeping out unwanted pollen. Some plants happily self-fertilize with their own pollen but others reject such pollen because of the deleterious effects of inbreeding. In these plants, their own pollen or that of close relatives is rejected if it lands on the female stigma. For all plants, the pollen of other species is undesirable, as it will result in aborted zygotes or infertile offspring. Plants have evolved various mechanisms for rejecting unwanted pollen. The self-incompatibility (SI) system, found in several plant families, including the Solanaceae, which includes tobacco, tomato, and eggplant, is the best studied. A number of components that function in the SI system have been identified, but the exact molecular mechanisms by which incompatible pollen is recognized and rejected and compatible pollen allowed to proceed to the ovary are still unknown. Understanding the molecular mechanisms of pollen recognition is important for designing novel plant breeding systems as well as ensuring safeguards against unwanted pollination by genetically modified crops.

Dr. Felipe Cruz Garca and his colleagues Karina Jimenez Duran, Grethel Busot, Claudia Ibarra Sanchez, and Bruce McClure have been investigating the components of the self-incompatibility system in tobacco. Dr. Cruz-Garcia, of the Departamento de Bioqumica, Facultad de Qumica, Universidad Nacional Autonoma de Mxico, will be presenting this work at a symposium on the Biology of Solanaceous Species at the annual meeting of the American Society of Plant Biologists in Mrida, Mexico (June 29, 11:00 AM).

In flowering plants, the female reproductive organ, the pistil, comprises the stigma, style, and ovary. The stigma catches pollen shed by the male anthers. If the pollen i
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