Is No-Mow Grass in Our Future?

It's unlikely there will ever be a putting green that never needs mowing. But a team of scientists is working on technology that might someday result in lawns and golf course rough that never grows but is always green.

Their goal is to map the critical hormone-signaling pathway that regulates the stature of plants. In addition to lawns that rarely require mowing, the finding could also enable the development of sturdier, more fruitful crop plants such as rice, wheat, soybeans and corn. In a paper published in the May 4, 2006, issue of the journal “Nature,” Howard Hughes Medical Institute scientists report they have deciphered the signaling pathway for a key class of steroid hormones that regulates growth and development in plants.

"By manipulating the steroid pathway . . . we think we can regulate plant stature and yield," said Joanne Chory, a HHMI investigator at the Salk Institute for Biological Studies.

Manipulation of plant stature has been a longstanding goal in horticulture, agronomy and forestry. The ability to precisely control plant size would have broad implications for everything from urban forestry to crop and garden plant development. Beyond perpetually short grass, trees could be made more compact for better growth in crowded cities and berry bushes could be made taller for ease of harvesting.

To chart the pathway, Chory and colleague Grégory Vert examined the molecular influence of a family of plant hormones known as brassinosteroids. As critical chemical messengers of plant development, they are found in low levels in virtually all plant cells, including seeds, flowers, roots, leaves, stems, pollen and young vegetative tissue.

"Without them, plants are tiny dwarves, with reduced vasculature and roots and are infertile," Chory explained. "They also regulate senescence or aging. Since brassinosteroids mainly regulate cell expansion, though, they are one of the most important hormones that regulate stature.

"We might be able to dwarf grass and keep it green by limiting brassinosteroids or increase the yield of rice by having more brassinosteroids in seeds," she said.

Through traditional methods of plant breeding, humans have been manipulating plant stature for thousands of years. In recent years, through the methods of genetic engineering, more precise methods for altering industrial plant strains have come into play.

But access to a pathway used by plant hormones to dictate size promises broader influence over the many genes involved in the process of growth. Levers that could be used to alter a hormone pathway to influence plant development and stature, according to Chory, include modifying the levels of the hormone, manipulating the chemical structures of hormones and recoding the signals sent along the pathway.

This story originally appeared in the May 25, 2006, edition of Divot Mix, an e-publication of the Golf Course Superintendents Association of America (