Confocal Microscopy Image Gallery
Plant Tissue Autofluorescence Gallery
The ginkgo is a dioecious gymnosperm that produces microstrobili and ovules on separate trees in the spring after maturity is reached. The male reproductive structures are similar in shape to small catkins and the female structures are naked, possess a fleshy integument, and occur in pairs. They both can be found on short spur shoots located at the bases of leaves.
A tiny opening in the integument of each ovule enables pollen shed from microstrobili into the air to penetrate the ovule. Following pollination, the ovule expands significantly in size and the integument differentiates into a number of different layers. The outermost fleshy layer can cause nausea if eaten and has a rancid smell, which generally makes male ginkgos more popular as ornamentals. Usually fertilization occurs after ovules have dropped from the tree, a few months after they were pollinated. The embryo that develops is dicotyledonous.
Ginkgos are often very long-lived trees, with many living specimens having been cultivated more than 1,000 years ago. In China, there are individual trees that are believed to be as many as 3,500 years old. Contributing to the longevity of the ginkgo is the tree’s remarkable resistance to pests, diseases, and pollution. The growth and maturation of the ginkgo is a relatively slow process; more than a decade usually passes before it reaches a height of 20 feet, and ovule and microsporangia development require about two to three times that amount of time to occur. The unusual beauty of the ginkgo, however, generally makes growing the tree, which is sometimes utilized in the art of bonsai, well worth the wait.
Nathan S. Claxton, Shannon H. Neaves, and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.