Understanding leaf growth could be key to creating resilient farming
BATON ROUGE — LSU biologists John Larkin and Maheshi Dassanayake have been awarded a three-year, $890,720 grant by the National Science Foundation to research the role of cell cycle regulation in leaf development.
“Leaves are crucial organs for plants, and for all life on earth,” said Larkin. “Their job is to balance many competing factors for optimal function in plant growth.”
“(With this project) we are asking a basic question: How do leaves develop?” Dassanayake added. “We know that everything we eat as humans and animals on this planet—more like 99 percent of the living organisms other than plants—depends on photosynthesis, so how the leaves develop is a fundamental question that relates this work to one of the key questions the NSF mission has in answering questions for food security and climate change.”
As the researchers explain, this sunlight is captured for photosynthesis by leaves that have shapes optimized for light harvesting while minimizing water loss. Leaves of some plants are also adapted for growth in extreme environments such as high salt or other stressful conditions, showing that there are genetic controls of growth responses to the environment.
The project will start by looking at the leaf growth of two plant models, the commonly used genetic model plant Arabidopsis thaliana and the salt-adapted Schrenkiella parvula.
Leaf growth can be roughly divided into two phase phases. Early in leaf development, growth occurs by rapid cell divisions, but later in leaf growth, cell division slows down and eventually stops, and growth is dominated by cell expansion. Kind of like water blowing up a water balloon, the plant is taking up water from the soil, driving expansion, while the cell wall gives an elastic resistance to expansion, Larkin explained.
“It turns out that switching from cell division to cell expansion, including both the timing of that switch and which cells make that switch, is really important to controlling the growth of a leaf,” he said.
The group’s findings will be applied to study how leaf growth is controlled in response to salt exposure in Schrenkiella parvula. Understanding how plants can grow in extreme salt-stressed conditions will provide basic information about how plants respond and adapt to the environment.
It’s more important than ever to study plant growth in extreme environments, Dassanayake said. Louisiana, alone, has seen farmers struggle with the effects of salt water intrusion, drought, and other environmental stressors.
In the short term, the project will give further insight into how leaves adapt to the environment through cell growth. Long-term, this foundational research will provide vital information for a resilient and sustainable agriculture in the face of changing environments.
Science Communications Team
LSU College of Science