Screening of superior fiber-quality-traits among wild accessions of Bambusa balcooa: efficient and non-invasive evaluation of fiber developmental stages

The search for alternative fiber resources is receiving worldwide attention for the potential role of these fibers in climate and forest restoration. Among bamboos, Bambusa balcooa is generally preferred for industrial use due to its rapid growth, excellent flexibility and tensile strength. The aim of this study is to establish a non-invasive and efficient method of screening superior fiber quality from the wild gene pool of B. balcooa. Anatomical features of B. balcooa internodes were revealed by light microscopy. Confocal laser scanning microscopy (CLSM) was used to study fiber developmental stages in emerging branches using the intrinsic fluorescence properties of lignin and chlorophyll. Physical properties of B. balcooa fibers from different gene pools were studied, and biochemical estimations of lignin and cellulose contents were performed. CLSM-based semi-quantitative in situ estimations of cellulose and lignin contents in fiber bundles were performed using orthochromatic Congo red (CR) and acridine orange (AO) labeling, respectively. Fibers isolated from representative accessions of locations 3 and 4 showed the highest cellulose contents and superior physical properties. The results obtained from biochemical analyses of cellulose and lignin contents of fiber bundles among the accessions correlate significantly with CR and AO fluorescence values using non-invasive methods. A CLSM-based study demonstrated the possibility of differentiating stages of fiber development with autofluorescent markers of lignin and lignin precursors that would help to define stages of fiber development and maturation in bamboo effectively, which is a prerequisite for understanding the mechanism of fiber development at the molecular level in bamboo. A CLSM-based cellulose and lignin assay is a non-invasive method, exploited for the first time for genetic diversity screening in a wild gene pool. This protocol would also be useful for rapid resource screening for various commercial purposes.