Plants are smarter than most people give them credit for. Darwin hypothesized that plants had cells dedicated to controlling root growth, like a brain. Darwin’s initial thoughts were published in 1880, but it took until the 1990’s for scientists to actually make headway in confirming that theory. Scientists first discovered that plants’ roots can determine whether roots are their own or not in a 1996 study using the desert shrub Ambrosia dumosa. They found that the roots would stop growing when they encountered the roots of other plants from the same population, but they wouldn’t stop growing then they encountered their own roots.

While researchers observed that plants could control their root growth based on whether they encountered foreign roots, they did not have an idea of what biological mechanism controlled that response. In 2010, a study observing Arabidopsis thaliana looked to test whether chemicals secreted by plant roots could be the signal controlling root growth. Roots secrete many different chemicals such as phenols, flavonoids, sugars, organic acids, amino acids and proteins. These compounds are collectively referred to as the root exudate. Researchers suspected that roots might be able to detect the presence of these compounds in the soil to figure out when they are near roots that aren’t their own.

To test this, the scientists grew the plants in a liquid media instead of soil. The liquid media was primed for the experiment by growing other specimens in it beforehand, and it retained the exudates from the previous occupant. The researchers used three testing groups: plants that were placed in media that they themselves had been in before, plants that were placed in media that was previously used to grow plants directly related to them (“kin”), and plants that were placed in media that was used to grow unrelated plants (“strangers”). The researchers found that plants grew longer roots when they were grown in the media from strangers compared to the root length when they were grown in the media from their kin.

Scientists know that root growth is largely a nutrient-dependent process; longer lateral roots lead to greater nutrient uptake by the plant. Since the plants are growing shorter roots when they are in contact with their kin, that implies that the plants can recognize their relatives and are actively avoiding competing with them for resources. When they are in contact with chemicals they identify as coming from strangers, the plants grow longer roots to out-compete their neighbors.

Powers Scientific offers several different equipment options for experimentation with plants. If your research focus is micropropagation of Arabidopsis or other plant species, the Plant Tissue Culture Chambers were designed for this application. They have four slide-out shelves (some are removable), with low velocity conditioned air delivered uniformly under each. Over each shelf are six fixed lamp positions, delivering high intensity visible light, visible/black light combinations, or other light combinations that can be stepped on/off.  The chambers can be run at temperatures as low as 7°C with lights on, for vernalization studies. They are also capable of functioning as an incubator, reaching temperatures of 40°C or higher, if needed.

If your research involves plant growth or seed germination studies, our Diurnal Plant Growth/Seed Germination Chambers are a great choice. These chambers offer digitally controlled temperature and lighting over a 2-50°C temperature range, with day/night cycles to simulate the nurturing environment seeds and plants need for successful growth. To meet additional study requirements, the models offered can be customized with additional lights (vertically, horizontally, or both), fresh air intake, additive humidity, or horizontal air flow ducts for temperature uniformity under higher intensity lights.

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