The emerging story of plant roots

July 2008 -- An international group of European and US scientists led by the Centre for Plant Integrative Biology at The University of Nottingham have uncovered a fascinating new insight into the unseen side of plant biology - the root.

Although less visible than shoots, leaves and flowers, plant roots are critical to our lives. They provide the crops we eat with water, nutrients, a firm anchor and a place to store food.

Roots are complex branching organs and show a wide variation in the way they grow through the soil to exploit the available resources. The way that new lateral roots are formed and grow is key to this process. Lateral roots originate deep within the parent root and must emerge through intervening layers of tissues before entering the soil. Despite its importance to the integrity and architecture of the root system, little is known about the regulation of lateral root emergence.This question has fascinated, yet frustrated, scientists since the nineteenth century. A paper appearing in Nature Cell Biology reveals for the very first time how lateral root emergence is achieved. It reports that new lateral roots reprogramme the cells that overlay them, causing them to separate and enabling the new root to emerge. In short, the scientists have discovered how new roots open the door to the world outside. Professor Malcolm Bennett, Biology Director for the Centre for Plant Integrative Biology and Head of Division of Plant and Crop Sciences, said: "In addition to providing new biological insight into lateral root emergence, we have identified a large number of genes that control this process."This is really important because this may enable us to breed crops with improved root architecture in the future." The Centre for Plant Integrative Biology (CPIB) is funded by the Systems Biology joint initiative of the Biotechnology and Biological Sciences Research Council (BBSRC) and the Engineering and Physical Sciences Research Council (EPSRC) which has provided £27m for six specialised centres across the UK. The Division of Plant and Crop Sciences is one of the largest communities of plant scientists in the UK. Around 160 people work in the division, which welcomes visiting scientists from all over the world, reinforcing its reputation as a world renowned centre. This international collaboration involved over 20 scientists from laboratories based in Belgium, France, Germany, Spain, Sweden, USA and UK.

Plants Recognize Their Siblings, Biologists Discover

June 2007 -- The next time you venture into your garden armed with plants, consider who you place next to whom. It turns out that the docile garden plant isn't as passive as widely assumed, at least not with strangers. Researchers at McMaster University have found that plants get fiercely competitive when forced to share their pot with strangers of the same species, but they're accommodating when potted with their siblings.

"The ability to recognize and favour kin is common in animals, but this is the first time it has been shown in plants" said Susan Dudley, associate professor of biology at McMaster University in Hamilton, Canada. "When plants share their pots, they get competitive and start growing more roots, which allows them to grab water and mineral nutrients before their neighbours get them. It appears, though, that they only do this when sharing a pot with unrelated plants; when they share a pot with family they don't increase their root growth. Because differences between groups of strangers and groups of siblings only occurred when they shared a pot, the root interactions may provide a cue for kin recognition."

Though they lack cognition and memory, the study shows plants are capable of complex social behaviours such as altruism towards relatives, says Dudley. Like humans, the most interesting behaviours occur beneath the surface.

Dudley and her student, Amanda File, observed the behavior in sea rocket (Cakile edentula), a member of the mustard family native to beaches throughout North America, including the Great Lakes. So should gardeners arrange their plants like they would plan the seating at a dinner party?

"Gardeners have known for a long time that some pairs of species get along better than others, and scientists are starting to catch up with why that happens," says Dudley. "What I've found is that plants from the same mother may be more compatible with each other than with plants of the same species that had different mothers. The more we know about plants, the more complex their interactions seem to be, so it may be as hard to predict the outcome as when you mix different people at a party." The study appears today in the Royal Society journal Biology Letters.

The study was made possible by a grant from the Natural Sciences and Engineering Research Council of Canada.