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Neomicrocalamus and Temochloa are closely related to bamboo genera. However, when considered with newly discovered and morphologically similar material from China and Vietnam, the phylogenetic relationship among these three groups was ambiguous in the analyses based on DNA regions. Here, as a means of investigating the relationships among the three bamboo groups and exploring potential sources of genomic conflicts, we present a phylogenomic examination based on the whole plastome, single-nucleotide polymorphism (SNP), and single-copy nuclear (SCN) gene datasets. Three different phylogenetic hypotheses were found. The inconsistency is attributed to the combination of incomplete lineage sorting and introgression. The origin of newly discovered bamboos is from introgressive hybridization between Temochloa liliana (which contributed 80.7% of the genome) and Neomicrocalamus prainii (19.3%), indicating that the newly discovered bamboos are closer to T. liliana in genetics. The more similar morphology and closer distribution elevation also imply a closer relationship between Temochloa and newly discovered bamboos. [ABSTRACT FROM AUTHOR]

Bamboo is a non-timber forest product and one of the most important grass plants of industrial and domestic use. It is widely distributed in tropical countries including India, China and Southeast Asian countries with wide genetic diversity. The diversity in the available genotypes becomes an important resource for the selection and improvement of the plants for ecological and commercial use. This study investigates eight commercially and ecologically important bamboo species of six genera (Bambusa, Dendrocalamus, Thyrsostachys, Vietnamosasa, Cephalostachyum and Indocalamus) from India, Thailand and Laos. These were evaluated for genetic differences by molecular makers, chemo-morphological variation and ability of silicon accumulation. The genetic cluster analyses of eight RAPD primers revealed genetic similarities in the ranges of 24–55%. The total silica content varied from 18.34 to 40.08 ppm in leaves of different bamboo species. Chemical analysis of the silicon content by ICP-OES and secondary metabolite profiling on TLC depicted the prominent distinction among the species. The PCA analysis of quantitative morphological data grouped the species in two major clusters and found to correlate with chemical pattern and genetic similarity to some extent. This is the first report that summarizes species-specific variability of leaf silica content, secondary metabolites, and quantitative morphological data towards delineation of genetic phylogeny of bamboo species. [ABSTRACT FROM AUTHOR]

Bamboo holocellulose was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) in water at pH 10 with an addition of 7.5 mmol g-1 of NaClO for 2 h. After oxidation, the weight recovery ratio of TEMPOoxidized bamboo holocellulose (TOBH) was 73% with a carboxylate content of 0.65 mmol g-1. The water-insoluble TOBH was converted to an aqueous dispersion of bamboo TEMPO-oxidized cellulose nanofibrils (TOBCN) through mechanical defibrillation and centrifugation, with the nanofibrillation yield of around 90%. Transmission electron microscopy (TEM) indicated that the widths of TOBCN were estimated to be between 3 and 4 nm and lengths of several micrometers. The TOBCN dispersions had high light-transparencies of 99% at a wavelength of 600 nm. These nanofibrils were used as reinforcing nanoparticles in thermoplastic starch (TPS) films. The TOBCN dispersions were added in dosages of 0, 0.3, 0.6, 0.9, 1.2, and 1.5 wt%. Glycerol was used as a plasticizer. Nanocomposite films were prepared through a solution casting process. The TOBCN/TPS nanocomposite films exhibited high optical transparencies and their tensile strength, Young's modulus, elongation around failure, and work to cause a fracture increased, compared to the TPS films without TOBCN. The presence of TOBCNs, at 1.5 wt%, improved moisture resistance. [ABSTRACT FROM AUTHOR]

A taxonomic review of the genus Pseudostachyum Munro in Thailand is presented including a description of its morphology, geographic distribution and habitat. An illustrated description of the newly recorded species P. polymorphum Munro, discovered in Thailand, is provided and a doubtful species, P. wakha Brandis ex Camus, is reduced to a synonym of P. polymorphum. [ABSTRACT FROM AUTHOR]