Search

The pollen morphology of 63 species, one subspecies and six varieties of 11 genera in the family Liliaceae was studied in detail using light microscopy (LM) and scanning electron microscopy (SEM). Among them, 22 species and one variety are reported for the first time. Ten pollen characteristics (shape in polar view, ends in polar view, width of colpus, depth of colpus, length of colpus, colpus costa, colpus membranes, type of surface ornamentation, muri, lumina) were selected for cluster analysis of the genera Gagea and Lloydia and for cluster analysis and principal component analysis of the genera Lilium and Nomocharis. The results show that the polar view, colpus morphology and surface ornamentation of pollen grains have important systematic significance. The surface ornamentation of pollen grains in this study can be divided into five types, namely gemmate, reticulate, rugulate, rugulate-perforate and verrucate. In combination with the results of previous research, our results suggest that (i) Clintonia and Streptopus should be included in the family Liliaceae; (ii) Fritillaria and Lilium should be considered independent genera; (iii) Lloydia should belong to Gagea; and (iv) Nomocharis should be merged into Lilium. But our results do not support dividing Lilium into seven sections. [ABSTRACT FROM AUTHOR]

Pollen morphology of 79 species, one subspecies and eight varieties representing nine genera of tribe Alsineae and two of tribe Sperguleae was studied using light microscopy (LM) and scanning electron microscopy (SEM). Among them, 53 species and eight varieties (22 species of which are endemic to China) were reported for the first time. The results demonstrate that the number of pores, the pollen surface ornamentation and the density of microechini have important systematic significance. The surface ornamentation can be divided into three types, namely microechinate-perforate, microechinate-punctate, and microechinate-punctate-perforate. Pollen characteristics support: (i) isolation of Arenaria subgenus Odontostemma from Arenaria and reclassification of Arenaria subgenus Odontostemma to Odontostemma; (ii) isolation of Cerastium subgenus Dichodon from Cerastium and reclassification of Cerastium subgenus Dichodon to Dichodon; (iii) isolation of Minuartia subgenus Rhodalsine from Minuartia and reclassification of Minuartia subgenus Rhodalsine to Rhodalsine; (iv) isolation of Rhodalsine from tribe Alsineae and reclassification of Rhodalsine into tribe Sperguleae; and (v) isolation of Sagina from tribe Alsineae. In addition, the relationships of Arenaria subgenus Eremogone and Arenaria subgenus Eremogoneastrum to tribe Alsineae need to be further studied. Furthermore, pollen characteristics indicate that tribe Alsineae is more evolved than tribe Sperguleae. [ABSTRACT FROM AUTHOR]

Previous studies reported that intrageneric relationships of genus Veratrum of family Melanthiaceae are controversial and hard to delimit. Therefore, we observed the pollen morphological features of six species in the genus Veratrum in detail using both light microscopy and scanning electron microscopy and investigated their significance for Veratrum taxonomy. Among them, five were studied for the first time. The results demonstrated that pollen grains of Veratrum are medium in size with P/E being 0.31–0.60. Three types of shape in polar view have been observed elliptic, long‐elliptic, or wide‐elliptic with blunt or rounded at both ends. Two types of width of colpus reported narrow or wide, two types of depth of colpus reported deep or flat, and two types of length of colpus reported extend almost or do not extend to the ends, whereas two types of colpus membranes reported absent or obvious. One type of surface ornamentation was noted as reticulate. These results support species Veratrum album and Veratrum lobelianum as well as Veratrum grandiflorum and Veratrum oxysepalum as two independent species, respectively, rather than classifying Veratrum into two sections. Overall, we demonstrated that the ratio of polar axis length to equatorial axial length, pollen characteristics at the polar view, the colpus morphology, and the surface ornamentation of pollen grains of genus Veratrum have important systematic significance in identification and delimitation of species. To study palynomorphology of genus Veratrum in detail.Pollen characteristics support species Veratrum album and Veratrum lobelianum as well as Veratrum grandiflorum and Veratrum oxysepalum as two independent species, respectively.Pollen characteristics do not support classifying Veratrum into two sections. [ABSTRACT FROM AUTHOR]

In this paper, we studied pollen morphologies of seven species in genus Aletris in detail by light microscopy and scanning electron microscopy. Of these, six species were reported for the first time. The palynological characteristics do not support the infrageneric classification into two clades. The results indicated that pollen grains of Aletris are small or medium with the P/E ratio of 0.36–0.59. They are elliptic or long‐elliptic in the polar view with blunt, round or acute ends and bilateral symmetric with a monosulcate, narrow or wide, deep colpus that has length extending to the ends of pollen grains, obvious or absent colpus membranes. The pollen ornamentation is gemmate, perforated, or reticulate. The sexine is slightly or quite thicker than the nexine. [ABSTRACT FROM AUTHOR]

Xylulose kinase is an important enzyme involved in xylose metabolism, which is considered as essential biocatalyst for sustainable lignocellulosic‐derived pentose utilization. Bacillus coagulans IPE22 is an ideal bacterium for refinery due to its strong ability to ferment xylose at high temperature. However, the B. coagulans xylose utilization mechanism remains unclear and the related promising enzymes need to be developed. In the present study, the gene coding for xylulose kinase from B. coagulans IPE22 (Bc‐XK) was expressed in Escherichia coli BL21 (DE3). Bc‐XK has a 1536 bp open reading frame, encoding a protein of 511 amino acids (56.15 kDa). Multiple sequence alignments were performed and a phylogenetic tree was built to evaluate differences among Bc‐XK and other bacteria homologs. Bc‐XK showed a broad adaptability to high temperature and the enzyme displayed its best performance at pH 8.0 and 60 °C. Bc‐XK was activated by Mg2+, Mn2+, and Co2+. Meanwhile, the enzyme could keep activity at 60 °C for at least 180 min. KM values of Bc‐XK for xylulose and ATP were 1.29 mM and 0.76 mM, respectively. The high temperature stability of Bc‐XK implied that it was an attractive candidate for industrial application. [ABSTRACT FROM AUTHOR]

The morphology of 75 different pollen grains from 67 species of genus Solanum L., two species of genus Cyphomandra Sendt., and six species of genus Lycianthes (Dunal) Hassl. was studied using light microscopy and scanning electron microscopy. Among them, the pollen of 66 species is described for the first time. Our results suggest that the sexine ornamention of Solanum, Cyphomandra and Lycianthes is extremely similar, but the apertures of genus Solanum and Cyphomandra are not syncolpate while those of genus Lycianthes are syncolpate. Overall, we argued that the Solanum species studied demonstrated sufficient pollinic heterogeneity in their shapes, aperture feature and sexine ornamentation to enable their palynological characterisation and support the point of view that the genus Cyphomandra should be merged into Solanum, but Lycianthes should be an independent genus from the aspect of palynology. [ABSTRACT FROM AUTHOR]

The pollen morphology of 54 species and one variety of seven genera in Polygonatae including Clintonia, Disporopsis, Disporum, Maianthemum, Polygonatum, Smilacina and Streptopus was observed and studied in detail; of these, nine species were reported for the first time. Our results showed that the surface ornamentation of pollen grains of the studied materials could be divided into seven types, namely gemmate, granulate-foveolate, perforate, reticulate, rugulate, rugulate-perforate and verrucate. In line with previous studies, we believe that (i) Smilacina ginfushanicum should be classified into the genus Heteropolygonatum rather than the genus Smilacina; (ii) Polygonatum should be divided into section Polygonatum and section Verticillata; (iii) Smilacina and Maianthemum should be combined as one genus, i.e. Maianthemum sensu lato; and (iv) Clintonia, Disporum and Streptopus should be separated from the tribe Polygonatae. [ABSTRACT FROM AUTHOR]