image: NTU scientists grew hydrogels to mimic the edge waving pattern found naturally in various leaves. view more
Credit: NTU Singapore
Scientists from Nanyang Technological University, Singapore (NTU Singapore) and Carnegie Mellon University in the U.S have discovered how mechanical forces can influence the shapes of plant leaves and flower petals.
While the genetic and biomolecular mechanisms that give rise to complex 3D shapes in plant organs have been widely studied, the role of biomechanical factors is unclear.
In their latest paper published in Proceedings of the National Academy of Sciences (PNAS), NTU President Prof Subra Suresh, Dean of NTU's Graduate College Professor K. Jimmy Hsia, NTU's Assistant Professor in MAE and SCBE Huang Changjin, and researchers at Carnegie Mellon University combined quantitative measurements of live plants with computational simulations to show how mechanical stress and deformation influence the shape of plant leaves.
Growth of a leaf is modulated by its growth factor, a natural substance capable of stimulating growth, proliferation, and differentiation in living cells. Where a leaf has higher growth factor concentration, (typically at the part near the leaf edge), it grows faster, resulting in additional stresses that eventually bend or deform a leaf into the different 3D shapes it can take.
The authors constructed a phase diagram illustrating how each of four common leaf geometries -- twisting, helical twisting, saddle bending, and edge waving -- are associated with specific combinations of the parameters.
By manipulation of the key parameters, which is the value of the power-law exponent that defines the strain profile and the maximum strain value, the authors reproduced the geometries in a hydrogel, the formation of which mimics plant growth.
These findings help to explain and give insights into how plant organs are shaped, providing the scientific understanding needed to generate bioinspired 3D structures in soft materials such as hydrogels.
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Note to editors:
The PNAS paper is titled "Differential growth and shape formation in plant organs" and was published yesterday, 19 Nov 2018.
See abstract and full paper here: https://doi.org/10.1073/pnas.1811296115
Media contact:
Lester Kok
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Corporate Communications Office
Nanyang Technological University
Email: lesterkok@ntu.edu.sg
About Nanyang Technological University, Singapore
A research-intensive public university, Nanyang Technological University, Singapore (NTU Singapore) has 33,000 undergraduate and postgraduate students in the Engineering, Business, Science, Humanities, Arts, & Social Sciences, and Graduate colleges. It also has a medical school, the Lee Kong Chian School of Medicine, set up jointly with Imperial College London.
NTU is also home to world-class autonomous institutes - the National Institute of Education, S Rajaratnam School of International Studies, Earth Observatory of Singapore, and Singapore Centre for Environmental Life Sciences Engineering - and various leading research centres such as the Nanyang Environment & Water Research Institute (NEWRI) and Energy Research Institute @ NTU (ERI@N).
Ranked 12th in the world, NTU has also been placed the world's top young university for the past five years. The University's main campus is frequently listed among the Top 15 most beautiful university campuses in the world and it has 57 Green Mark-certified (equivalent to LEED-certified) building projects comprising more than 230 buildings, of which 95% are certified Green Mark Platinum. Apart from its main campus, NTU also has a campus in Singapore's healthcare district.
For more information, visit http://www.ntu.edu.sg
Journal
Proceedings of the National Academy of Sciences