Schmalhausen, Zinger, and early Camelina research

Camelina is certainly a very interesting system for studying evolution, and much work has been done in it, although the majority of this work was done in the early 20th century in the U.S.S.R. and has yet to be rediscovered in the West.

Ivan Schmalhausen was a Ukrainian born, Soviet evolutionary biologist, whose work was largely disregarded in the U.S.S.R. due to the subduing of ideas that digressed from Lysenkoism. Schmalhausen used the term "norm of reaction", originally conceptualized by the German, Richard Wolterck, to explain how genotypes can react to the environment to vary phenotype. He used Camelina as an example of this, as C. glabrata (now recognized as C. sativa), shows a tall, slender morphology when planted in flax fields. He claimed that the tall structure, narrow leaves and long internodes of another "species", C. linicola (now C. alyssum), were stabilized through genetic fixation, while these are plastic characters in C. glabrata. Nikolai Wasiljevich Zinger, a Russian botanist, worked on Camelina in his little known paper "On the Species Camelina and Spergula Which Infest Flax Sowings and Their Origin". Zinger's figure, shown below, illustrates the norm of reaction in both of these Camelina varieties, where, when sown densely (or with flax) they adapt a tall, slender morphology, and when planted alone they branch and increase overall density of leaves and fruits. However, the stabilizing selection that acted on C. linicola as a flax weed can be noticed, as when grown alone it retains its narrow leaves and sparse habit compared to C. glabrata. Schmalhausen used this example as evidence that some physical forms can be under dynamic selection, as seen by Camelina changing morphology based on its environment (5a to 6a and 1a to 8a), while some traits become stabilized and are no longer subject to change by environment, like those in C. linicola of slender leaves and sparse growth when compared to C. glabrata under "wild" circumstances (6a to 8a). 

Zinger also noted that the selection of seed size in C. linicola was dynamic, meaning that the size were readily changed, although able to revert. The process of winnowing (separating the seeds from plant material) in flax, unintentionally selects for Camelina seeds which are larger in size so as to mimic flax seeds, and in doing so are planted with the next season's flax crop. Schmalhausen recognized this dynamic selection as labile, meaning that the variable trait is not fixed, and is phenotypically plastic depending on environmental factors.

Schmalhausen claimed that the propensity for Camelina to adapt rapidly to new environments was due to a "preceeding preparatory evolution". I would attribute this to C. sativa's polyploid status which gives it a large "tool set" for adaptation and rapid evolution, which has allowed the colonization of new geographies (temperate, mesic environments) and specific niches (flax fields). 

​Schmalhausen, I. I. 1949. Factors of Evolution. Blakiston, Philadelphia. (pp 1-95)