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Abstract: The genetic diversity of the genus Dendrobium is not well known and the phylogenetic relationship of Dendrobium species are mainly determined by studies of the comparative vegetative anatomy and plant systematics. In the present study, we used the technique of inter-simple sequence repeats (ISSRs) to evaluate genetic diversity and phylogenetic relationship among 31 Dendrobium species from Yunnan region of China. In total, 2368 bands were amplified by 17 ISSR primers, resulting from 278 ISSR loci with 100% polymorphism at genus level. Thirty-one species were unequivocally distinguished based on ISSR fingerprinting. Species-specific ISSR markers were identified in nine of 31 tested Dendrobium species. Unweighted pair-group mean analysis (UPGMA) showed that 31 Dendrobium species were grouped into six clusters, indicating the genus was polyphyletic with several well-supported lineages. The high polymorphism and reliable amplification across species demonstrated the utility of ISSR marker for species diagnosis and genetic diversity study of the genus Dendrobium. [Copyright &y& Elsevier]

Chrysanthemum morifolium plants are important commercial herbs in China, widely used in ornamental horticulture and traditional medicine. In this study, start codon targeted (SCoT) polymorphic markers were applied to assess genetic relationships among 32 populations of C. morifolium . Thirty-two SCoT primers produced 872 loci, 90% (785) of which showed polymorphism. Average polymorphism information content of the SCoT primers was 0.987 (0.950–0.993), showing that plenty of genetic diversity exists among Chinese C. morifolium cultivars. Cluster analysis of SCoT markers (based on UPGMA and PCoA method) grouped all the cultivars of C. morifolium into two clusters. The partition of clusters in the dendrogram and PCoA plot was similar and large degree of grouping according to their origin and ecological distribution. Our results will provide much more useful information for C. morifolium germplasm resource protection and will also useful to improve the current plant breeding programs. Our results also indicated that SCoT markers are informative and could be used to evaluate genetic diversity of Chinese medicinal C. morifolium cultivars. [ABSTRACT FROM AUTHOR]

In this study, the individual and interactive effects of influent substrate concentration ( TN inf ), hydraulic retention time (HRT) and upflow velocity ( V up ) on the performance of anaerobic ammonium oxidation (anammox) in a granule-based upflow anaerobic sludge blanket (UASB) reactor were investigated by employing response surface methodology (RSM) with a central composite design. The purpose of this work was to identify the optimal combination of TN inf , HRT and V up with respect to the nitrogen removal efficiency (NRE) and nitrogen removal rate (NRR). The reduced cubic models developed for the responses indicated that the optimal conditions corresponded to a TN inf content of 644–728 mg N L −1 , an HRT of 0.90–1.25 h, and a V up of 0.60–1.79 m h −1 . The results of confirmation trials were similar to the predictions of the developed models. These results provide useful information for improving the nitrogen removal performance of the anammox process in a UASB reactor. [ABSTRACT FROM AUTHOR]

The floatation of flocculent and granular sludge was investigated in this study. An anaerobic ammonium oxidation (anammox) upflow anaerobic sludge blanket (UASB) reactor was operated for 665 days. During this time, the maximum nitrogen removal rate was 52.6 kgN m −3 d −1 . Floccule floatation occurred between days 100 and 140, which potentially resulted from the sudden increase in gas yield and the poor settling ability of the floccules. Increasing the shear rate from 0.084 to 0.135 s −1 was effective at eliminating floccule floatation. In addition, granule floatation occurred between days 572 and 665, which likely resulted from the formation of hollows within the granules. Floatation may be effectively prevented by maintaining a shear rate of more than 0.778 s −1 . Furthermore, the mechanisms of granule floatation and the floatation processes were proposed. Overall, controlling the shear force may effectively overcome sludge floatation. [ABSTRACT FROM AUTHOR]

Highlights: [•] The role of bio-augmentation in assisting recovery of ANAMMOX from OS was studied. [•] The bio-augmentation time (BAT) was optimized. [•] The bio-augmentation dosage (BAD) was optimized. [•] The changes in sludge characteristics were monitored. [•] The mechanisms of bio-augmentation were discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] A full-length D. nobile cDNA library was constructed and 1835 ESTs were obtained. [•] One hundred seventy novel EST-SSRs were developed in D. nobile. [•] A set of 142 EST-SSRs showed robust transferability among 31 Dendrobium species. [•] The genetic diversity showed wide genetic differentiation of section Dendrobium. [•] The phylogeny analysis revealed different genetic architecture among sections. [Copyright &y& Elsevier]

Abstract: The genome organization of Dendrobium species remains largely unexplored. An F1 family derived from the controlled interspecific hybridization between Dendrobium moniliforme and D. officinale were used to create genetic linkage maps of parental Dendrobiums using double pseudo-testcross strategy. A total of 422 markers, including 66 EST-SSR, 126 SRAP, 74 ISSR, and 156 RAPD markers, showed expected Mendelian segregation ratio and were used for genetic map construction. Genetic linkage groups with Kosambi genetic distances were constructed using a LOD score≥4 and a recombination threshold of 0.4. The map of D. moniliforme was 1127.9cM in total length with 165 marker loci distributed in 17 linkage groups; and the D. officinale map consisted of 19 genetic linkage groups with a total length of 1210.9cM positioned by 169 marker loci. The genetic maps constructed in this study can serve as a reference linkage map of Dendrobium species for efficient studies of comparative genetics, genetic mapping of traits with economic interest, and marker-assisted selection in horticultural breeding. [Copyright &y& Elsevier]