Exploring silica accumulation in bamboo leaves: a study on phytolith morphology and epidermal patterning in the tropical giant bamboo Dendrocalamus copelandii.

BACKGROUND AND AIMS

Bamboo is a grass in the Poaceae family with various applications. Bamboo leaves can accumulate high silica. However, silica deposition in bamboo has received limited study. Therefore, this research investigated silica accumulation in Dendrocalamus copelandii leaves. The study includes the localization of silica through phytolith morphology, examination of the distribution patterns of phytoliths in epidermal tissues, analysis of silica accumulation within specialized silica cells (short cells) and analysis of silicon concentration across various leaf developmental stages.

METHODS

We used imaging techniques, including differential interference contrast and a scanning electron microscope incorporating an energy-dispersive X-ray spectrometer, to investigate silica accumulation in bamboo leaves. We also analysed the silicon concentration using inductively coupled plasma-optical emission spectroscopy.

KEY RESULTS

Leaves of D. copelandii exhibited 11 phytolith morphotypes, namely Bilobate, Polylobate, Saddle, Acute, Acute bulbosus, Microhair, Stomata, Bulliform flabellate, Elongate sinuate, Elongate entire and Tracheary. Most of these phytoliths were found in short cells (Bilobate, Polylobate and Saddle) of epidermal tissues. The short cells were arranged transversely along the leaf length. Bilobate phytoliths were found in both the abaxial and adaxial epidermis, whereas the Saddle morphotype was found only in the abaxial epidermis. Silica accumulation in the short cells of unexpanded leaves begins at the leaf apex, spreads to the middle and base positions, and accumulates initially in the abaxial epidermis, then the adaxial epidermis. Moreover, bamboo leaves accumulate a higher silicon concentration as they age.

CONCLUSIONS

Phytolith morphotypes and silica accumulation in epidermal short cells are key factors in understanding silica deposition. Leaf age and climate significantly impact the silicon concentration in bamboo leaves. Our findings are informative for archaeological studies and for plant taxonomical classification. The results are also applicable for biotechnological applications.