Although trees all have the same shape, vines are everywhere, says Stefan Schnitzer, a botanist at Marquette University, who did not participate in the study.
These strange stem variations give the vines an advantage. “Being asymmetrical helps you anchor yourself in the trees you grow,” said Marcelo Rodrigo Pace, a botanist at the Universidad Nacional Autónoma de México and co-author of the study. “These vines also have loops that allow them to take pieces of stems and leaves and start growing.”
This adaptation is “purely mechanical, architectural,” he said. “It̵
The study looked at two time scales: the life of an individual plant and a longer evolutionary breadth. Dr. Chery and her colleagues found that in the early development of a single plant, when the liana is leafy, green and small, woody vines already have an unusual tissue formation. The stem is star-shaped rather than circular; the vascular bundles are scattered in the lobe of the star-shaped body and are missing in the arcs. In later stages, this lobed structure may lead to more unusual growth patterns.
During evolutionary time, vines from different groups developed different mechanisms to twist their stems. The authors’ authors found that the five different atypical forms found in mature liana strains trace their evolutionary history back to a common disorder of young plant development: the lobed stem.
“This is exciting because it is a step away from saying that this leads perfectly to understanding how vines do what they do,” said Dr. Schnitzer. While vines share most of the properties of trees, such as producing wood and thriving in similar environmental conditions, the two plant types invest differently in certain parts of their composition. Lianas have more cells related to being flexible, while trees prioritize being stiff and tough. Both have cells that are responsible for stiffness and flexibility in different conditions.
“They have the same ingredients, but the proportion of these ingredients is distributed differently,” said Dr. Chery.
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