Throughout our class we have obviously been talking about phenotypic plasticity within the animal kingdom, but what about plants!? Plants are incredibly divers and have covered virtually every inch of the world's surface (with some really cold exceptions). I started to wonder about phenotypic plasticity in plants. I remembered back in my dendrology class how leaves at the base of a tree will be more etiolated (elongation of leaves / stems) than leaves in the canopy to better collect sunlight in a shaded environment. This caused me to dig into the literature of plant plasticity. Surprisingly, carnivorous plants of the North American genus Sarracenia is at the center of this research. Just like how amphibians are often used to describe plasticity because of their "two-life" strategy, so are carnivorous plants. Sarracenia compensates for living in N poor soils by trapping inverts, however these plants still need and use their modified leaves (hoods) for photosynthesis.
Ellison et al. 2004 found morphological differences in Sarracenia purpurea across their range, specifically hood thickness, wing size, size of pitcher opening, and hood length. This is obviously interpreted as adaptive responses to different environmental conditions across this species' range. These differences are largely explained by soil nutrient availability where nutrient rich sites create larger winged hoods better for photosynthesis and cooler temps have thicker walled hoods to prevent frost damage.
However, Bott et al. 2008 tested plasticity of this species by conducting a reciprocal transplant experiment where they moved species from more nutrient poor sites to nutrient rich and visa versa. This experiment lasted for two years, showing short term morphological changes. Leaf length, pitcher aperture (how narrow the hood is), and wing width changed in each plant to match the native conspecifics in the habitat they were transplanted to. These morphological changes are consistent with previous findings that larger pitcher aperture aids in prey capture within more nutrient poor sites and wider wings in nutrient rich environments aid in better photosynthesis. This offers evidence that a long lived perennial like the purple pitcher plant can adapt year to year by optimizing pitcher leaf structure to best take advantage of the environment it is in.
Plants are cool.
Bott, T., Meyer, G.A., Young, E.B., 2008. Nutrient limitation and morphological plasticity of the carnivorous pitcher plantSarracenia purpureain contrasting wetland environments. New Phytologist 180, 631–641.. doi:10.1111/j.1469-8137.2008.02575.x
Ellison AM, Buckley HL, Miller TE, Gotelli NJ. Morphological variation in Sarracenia purpurea (Sarraceniaceae): Geographic, environmental, and taxonomic correlates American Journal of Botany. 2004 Nov;91(11):1930-1935. DOI: 10.3732/ajb.91.11.193
Cool post. I never thought of plants in terms of plasticity. As I was reading I struggled to understand the pitcher aperture plasticity. If insects are a source of nutrients like nitrogen, wouldn't it make sense for them to always grow a large aperture regardless of environment? Or is there a tradeoff energetically/fitness-wise with having a large opening versus a small opening? If they invest more towards forming a large opening I could see how this type of change would be necessary to adapt to the environment. Enlighten me!
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