Thigmomorphogenesis
Tyler Baras
If you have not seen the Thigmomorphogenesis video above, give it a look-see then check out the blog post below to learn more!
Not only does plant stimulation lead to increased chlorophyll content, increased stem diameter and reduced stem elongation; it also increases leaf density!
Dr. Joyce Latimer, while working in the Department of Horticulture at University of Georgia, wrote a great article for Hort Science Journal summarizing many of the thigmomorphogenic responses seen in wide variety of vegetable transplants, including tomatoes, lettuce, celery, eggplant, peas and soybeans!
Specific chlorophyll content (chlorophyll content per unit dry weight of tissue) increased in shaken tomato, brushed lettuce and celery, and rubbed or shaken eggplant. Specific leaf weight (SLW, leaf dry weight : leaf area), an estimate of leaf density, also increased in tomato, eggplant and soybean, pea, soybean, and in lettuce, celery, and cauliflower in response to various mechanical conditioning treatments. Increased SLW and chlorophyll content may enhance photosynthetic rate. Because early stages of leaf development influence SLW, mechanical conditioning of greenhouse-grown seedlings or transplants may improve their adaptation to field conditions, in part by increasing SLW
Source: http://hortsci.ashspublications.org/content/26/12/1456.full.pdf
Thigmomorphogenic responses increase with increasing wind velocity and are temperature sensitive!
Laboratory experiments show that as wind velocity increases, thigmomorphogenesis increases in an approximate linear fashion. Furthermore, it was found that low temperatures interact with mechanical perturbation to reduce the amount of thigmomorphogenesis, both in the field due to wind and in the laboratory due to rubbing. Other environmental factors do not seem to interact with the wind to modulate thigmomorphogenesis even though these factors affect plant growth.
Source: http://aob.oxfordjournals.org/content/45/6/665#cited-by
Thigmomorphogenic responses are greater under low photon flux levels or, in lay-gardener terms, low light. Indoor grows often have low light levels and therefore benefit tremendously from the addition of fans!
Seasonal variation in environmental conditions also can affect plant response to mechanical conditioning. Growth of tomato is reduced more by shaking during the winter than during the summer), and pea was more responsive during winter than during spring or fall. In general, plant response to mechanical conditioning is greater under moderate temperatures and low photon flux levels than under higher levels. Source: http://hortsci.ashspublications.org/content/26/12/1456.full.pdf
Mechanical stimulation also reduces and may eliminate the need to apply growth retardants, including plant growth hormones!
Mechanical conditioning results in plants that appear very similar to those treated with growth retardants like daminozide or chlormequat. Although chemical growth retardants are readily available for production of greenhouse-grown ornamental bedding plants, none is labeled for use on vegetable species. Source: http://hortsci.ashspublications.org/content/26/12/1456.full.pdf
Want more thigmo? Check out these articles:
Thigmomorphogenesis: a complex plant response to mechano-stimulation
Mechanical Conditioning for Control of Growth and Quality of Vegetable Transplants
PRODUCTS USED TO MAKE THIS VIDEO
My partnership with Hydrofarm does not force me to show specific products, I only choose my favorites to feature. Here are some of the products I used to make this video:
