( A secret long held by plants has been r...)Researchers learn what sparks plant growth

The research, conducted by Sigal Savaldi-Goldstein and Howard Hughes Medical Institute investigator Joanne Chory at The Salk Institute for Biological Studies, puts to rest a century-old debate over which tissue system in plants drives and restricts cell growth.

"Our work exposes the presence of cell-cell communication during growth, from the epidermis to the inner layers. Such a mode of communication is important for plants to maintain a coherent and coordinated growth of the shoot," said Savaldi-Goldstein, a postdoctoral fellow in Chory’s lab.

Chory’s research group is interested in identifying the mechanisms by which plants alter their shape and size in response to changes in their environment. Chory studies Arabidopsis, a member of the mustard family that is to plant biologists what the mouse is to mammalian geneticists.

"How do organisms decide when to grow and when to stop growing? These questions are especially important in plants because they are rooted in the ground and must alter their shape and size in response to their local environment. Thus, it’s a question of survival," added Chory. "It took us 10 years to develop the tools to ask the question. It is very satisfying for me to see the results."

Roots and shoots are a plant’s two major organ systems. For this study, published in the March 8, 2007, issue of the journal Nature, the scientists examined shoots and the three layers of tissues that make up the shoot system: the epidermis, which is the waxy, protective skin; the mesophyl tissue, which contains the plant’s chloroplasts—cells that conduct photosynthesis; and the vascular tissue through which water
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Source:Howard Hughes Medical Institute