Bamboos are one of the few monocot species that grow to a tall stature and play a vital role in tropical ecosystems. However, their water regulation strategies have remained poorly understood until recently.

In a study published in Physiologia Plantarum, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences revealed how specialized cells in bamboo leaves trigger curling to minimize water loss and regulate water potential during dry conditions. The research quantitatively linked leaf anatomy, particularly the role of bulliform cells, to water conservation mechanisms across multiple bamboo species.

The researchers studied studied nine coexisting bamboo species in the XTBG bamboo garden, measuring daily and seasonal variations in water potential. They examined the contributions of soil water uptake, leaf water storage, and leaf structural traits to the plants’ ability to maintain hydration.

The findings showed that bamboos primarily absorb water from soil within 32 cm of the surface. They exhibit low saturated moisture content and short to moderate leaf desiccation times. The leaf’s ability to retain water, indicated by a slow desiccation rate, was the strongest predictor of its midday water status in the dry season. Species that lost water more slowly maintained a healthier, less negative water potential.

Bulliform cells (large, thin-walled cells on the upper leaf surface) were found to be key in the water regulation of bamboo species. The researchers identified two complementary water regulation mechanisms driven by these cells. A higher density of bulliform cells allowed leaves to curl more rapidly in response to water deficit, helping conserve water overnight and resulting in higher predawn water potential.

Additionally, factors such as soil water-uptake depth, stomatal structure, and plant height were found to have no significant impact on midday water potential, underscoring the unique importance of leaf curling.

“Our study demonstrates that the synergy between bulliform cell structure and leaf curling plays a dominant role in bamboo water conservation, enabling diverse species to thrive in the challenging conditions of seasonal tropical forests,” said CHEN Yajun of XTBG.

Bamboo garden of XTBG. (Image by WANG Li)

First published: 19 August 2025