Tree Cloning

In 1902, German botanist Gottlieb Haberlandt proposed that it was feasible to create artificial embryos from cultured vegetative cells. Although Haberlandt did not successfully develop a technique to do so, his landmark paper sparked decades of research into plant cloning. In 1938-39, three biologists independently reported successful plant tissue cultures. All three researchers had developed a totipotent mass of undifferentiated plant cells, now known as a callus, and sustained it for several months. The culture is still maintained. However, plant tissue culture did not become a viable commercial industry until 1957-8, when researchers discovered the growth regulators of plants and used them to direct the growth of different plant morphologies and to regulate the growth rate in vitro. In 1983, Belgian scientists created the first transgenic plant, a tobacco plant resistant to the antibiotic kanamycin. In 1994, Calgene became the first company to market a transgenic plant. The Flavr Savr tomato was genetically modified to increase its shelf life. However, the tomato exhibited increased disease sensitivity and decreased productivity, and was soon removed from the market. Despite this setback, genetically modified foods are now prevalent in the food industry.

Plant tissue culture makes it possible to quickly grow large amounts of uniform, disease-free plant tissue. G.M. Morel rapidly propagated orchids in 1960, creating a multi-million dollar market for micropropagated ornamental plants. Tissue culture also makes possible the commercial production of plant-derived pharmaceuticals, flavorings, and colorants. The most widely recognized benefit of tissue culture is the perceived uniformity of the resultant clones. Thus, tissue culture is recommended as a method for increasing the stock of elite clones-a clone can be micropropagated to produce over a million genetically identical plants.

As of 1991, laboratories around the world were culturing over 1,000 different plant species. However, plant tissue culture is still not a perfect science. Microbial contamination is a common problem in commercial laboratories today. Furthermore, while many plant biotechnologists tout the myriad commercial applications of plant tissue culture, it is still significantly more expensive to micropropagate clones than to grow seedlings. Furthermore, the capacity for a cloned plant line to successfully produce new clonal embryos decreases with each successive generation.

One of the clearest commercial advantages of plant tissue culture is the production of uniform plants in a species that has not been bred to uniformity. While the main industrial application of tissue culture is the elimination of variation, any home tissue culturist possessing a keen eye will notice how different each plant is from its fellow clones. Scientists have noted that despite the fact that micropropagated plants should produce clones, 'genetic instability' often leads to new morphological variations in resultant plants (Litz et al, 1993).

Biotech Hobbyist Micropropagation Kit

1. A sterile still air cabinet (fish tank on its side works well)
2. A pressure cooker, for sterilizing tools and materials
3. Glass jars with lids (such as baby food jars)
4. Scalpel and forceps
5. Paper towels
6. Disinfectant, preferably 70% alcohol solution in a spray bottle
7. Bleach, diluted to 25%
8. Skin disinfectant (such as hibitane)
9. pH indicator strips
10. Basic media
o 2 c. rain water
o ¼ c. sugar
o 1 c. fertilizer stock (1/2 T 10:10:10 (NPK) water soluble fertilizer in 1 L water)
o ½ inositol tablet (500 mg)
o ½ multivitamin tablet (must contain thiamine)
o 4 T agar flakes
(Recipe adapted from "Plant Tissue Culture for Home Gardeners", by Dr. Acram Taji)

The media can be easily modified for different purposes. To make multiplication and rooting media, add ½ tsp. malt and ½ c. of either coconut milk, orange juice, or green tomato puree. Media should always be between pH 5 and 6.

The Biotech Hobbyist Micropropagation Kit will contain everything needed (including further instructions!) except the still air cabinet, pressure cooker, and glass jars. The cabinet may be purchased at a pet store. Pressure cookers are available commercially through cooking supply stores, as are glass jars. The biotech hobbyist can also buy baby food at her supermarket and save the jars, or ask her reproductively-minded friends for leftover jars.