7 days old	16 days old

The purple color in the stems of certain stocks of Fast Plant is known as anthocyanin. Anthocyanin is a common pigment found in all Brassicas. The purple color is often used for aesthetic purposes in ornamental species like red cabbage. In Fast Plants it is observable in variable levels of expression in various sites on the plants, though it is almost never expressed in the petals or roots. Hairs known as trichomes are also expressed in this stock.

Tips for the Grower
This stock can be used by Fast Plants beginners, recognizing the effects of the stock's specific traits on growth and development. Hairiness delays flowering by approximately 1 day.

Expression of anthocyanin is environmentally conditioned: nutritional, temperature, and light stresses increase the amount and intensity of the purple in the plants. If you do not intend to investigate the environment's effects on purple expression, be sure to maintain the optimum growing conditions. Hairiness does not appear to be influenced by environmental conditions.

Notes on Genetics
Much research has been done on the anthocyanin pigment; it has been intensively studied in maize and other plants. A large portion of the fundamental genetics of anthocyanin expression is understood, except in Fast Plants! As quantitative traits, both the purple expression and hairiness are conditioned by many genes of small effect. The hairy trait is believed to be entirely genetically-based, as opposed to the influence of the environment on the expression of anthocyanin.

Quantitative - Investigate the quantitative nature of both the purple and hairy traits. The two systems together allow for the study of linkage of traits. This stock can be used in dihybrid genetic experiments in conjunction with the non-purple stem, yellow-green leaf stock.

Single-gene - Purple is the dominant allele for single-gene crosses with plants of the non-purple stem stock. Do any of the offspring express the non-purple stem phenotype?

Statistics - Use data from counts of hairs on the first true leaf to understand the statistical tools used to investigate a quantitative trait (mean, frequency, standard deviation, etc.).

Ecology - Explore the positive and/or negative adaptive attributes associated with this genotype. Do the plant's hairs have any impact on its defense against herbivory? Cross the hairiest of parents and observe the offspring: create a wooly plant! Does light quality have different effects on the purple expression? Try growing the plants under light filters of different colors.

Noninheritance of acquired characteristics - Use environmental stresses to increase the intensity of anthocyanin expression, then cross the plants and raise the offspring. Are the parent's acquired characteristics inherited across generations?

Comparative morphology - Use this stock as a basis for comparison with the anthocyaninless, hairless stock. Understand that there can be plants within this stock that do not have any hairs, yet do not have the hairless mutant trait. Can scales be developed to quantify the range of purple color or number of hairs per plant across a population?

C. O. Chichester, The Chemistry of Plant Pigments, Academic Press (New York), 1972.

T. W. Goodwin, ed., Chemistry and Biochemistry of Plant Pigments, Academic Press (New York), 1976.

G. Mazza, Anthocyanins in Fruits Vegetables and Grains, CRC Press (Boca Raton).