On New York University Week: How do vines climb so quickly?
Joyce Onyenedum, assistant professor of environmental studies, looks inside the plant to find an answer.
Faculty Bio:
Joyce G. Onyenedum is an Assistant Professor in the Department of Environmental Studies at New York University. She holds a B.S. in Plant Sciences from Cornell University and received her Ph.D. in Integrative Biology from the University of California, Berkeley. The Onyenedum lab studies the evolution and development of plant biodiversity with a particular interest in addressing the age old question: How do plants climb?
Transcript:
While most plants are relatively stationary, only climbing vines have the capacity to move rapidly coiling themselves around host trees as a shortcut to access light at the top of the forest canopy. While beneficial to vines, this competitive edge can come at a cost to forest ecosystem because vines are growing quicker and larger in response to increasing temperatures and forest fragmentation. In the tropics, vines are proliferating often outcompeting and killing forest trees, while in highly developed urban centers, we also find vines proliferating. A notable example is the invasive Kudzu vine aka the “plant that ate the south”. Despite the ecological success of vines, we still lack a fundamental understanding of how they move.
My lab sought to investigate this problem. Using the common bean vine, we began by breaking down this complex form into phases: common bean begins a truncated shrub, then the main stem suddenly elongates and begins to rapidly whip around in a tightly controlled circular motion to attach to a host. Upon attachment, a critical change occurs within the stem: specialize contractile cells, called G-fibers, form enabling these plants to securely attach to a support to avoid slipping down.
But what do G-fibers do? We can answer this question by tweaking the development of G-fibers, which we achieved through enhancing and repressing the plant hormone, Brassinosteroid. Our findings were striking. Vines with excess hormones were lazy they failed to attach to support structures corresponding to a repression of G-fibers. By probing the genetics of this phenotype, we learned that cell wall enzyme gene expression was significantly altered in lazy plants, hence the underdeveloped G-fibers. Together, this study linked cell wall modifying genes to overall plant form and function, revealing a critical role of specialized cells in the success of climbing vines.
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