Characteristics and Species Diversity of Semi-Natural Plant Communities on Langqi Island.

(1) Background: Islands are relatively independent and fragile ecosystems with unique habitats. Studying the relatively stable semi-natural plant communities on islands can enrich island vegetation data and provide an understanding of the factors affecting species diversity and distribution. (2) Methods: The semi-natural plant communities on Langqi Island (LI) in Fujian Province were sampled, and the redundancy method was used to analyze the correlation between species diversity, community distribution, and environmental factors. (3) Results: (i) There were 432 species of vascular plants, with 306 genera and 110 families; (ii) the semi-natural plant communities consisted of three vegetation types, 10 formations, and 10 clusters; (iii) the species diversity indices of the semi-natural plant communities presented a trend of gradually decreasing along the shrub, tree, and herb layers. Different formations varied in terms of the species diversity index; and (iv) the soil total potassium and nitrogen contents significantly affected the species diversity of the LI semi-natural plant communities, whereas the pH, soil TN content, organic matter content, AK content, and altitude significantly affected the community distribution. (4) Conclusions: Selecting appropriate tree species for mixed forests based on plant characteristics and regional conditions, together with regulating the soil nutrient content, can improve the species diversity of semi-natural plant communities.

The complete chloroplast genome sequence of Michelia amoena Q.F.Zheng et M.M.Lin.

Michelia amoena Q.F.Zheng et M.M.Lin is classified in Magnoliaceae and has a high economic value. Herein, we report the complete chloroplast genome of M. amoena using Illumina sequence data. The chloroplast genome is 160,088 bp in length and contains a large single copy (LSC) region of 88,118 bp and a small single-copy (SSC) region of 18,798 bp separated by two inverted repeat (IR) regions of 26,586 bp each. It contained a total of 131 genes, with an overall GC content of 39.26%. The phylogenetic analysis showed that M. amoena is closely related to Michelia figo. This study provides important sequence information for species identification and its phylogenetic relationship in the Magnoliaceae.

The complete chloroplast genome of Callicarpa siongsaiensis Metcalf (Lamiaceae) from Fujian Province, China: genome structure and phylogenetic analysis.

Callicarpa siongsaiensis Metcalf is a drought resistance shrub with ornamental potential. In this study, Illumina sequencing data were used to assemble the complete chloroplast genome of Callicarpa siongsaiensis. The length of the circular genome is 154,144 bp. It contains a total of 130 genes, including 87 protein-coding, 36 tRNA, and seven rRNA genes. The GC content of the chloroplast genome of C. siongsaiensis is 38.09%. The phylogenetic analysis fully resolved C. siongsaiensis in a clade with C. formosana.

The complete chloroplast genome sequence of Casearia glomerata Roxb. (Malpighiales; Salicaceae) from Fujian, China.

Casearia glomerata Roxb. is classified in Salicaceae and has a high economic value. Herein, we report the complete chloroplast (cp) genome of C. glomerata using Illumina sequence data. The cp genome is 156,809 bp in length and contains a large single-copy (LSC) region of 84,888 bp and a small single-copy (SSC) region of 17,039 bp separated by two inverted repeat (IR) regions of 27,441 bp each. It contained a total of 123 genes, with an overall GC content of 36.81%. The phylogenetic analysis showed that C. glomerata is closely related to Casearia velutina. This study provides important sequence information for species identification and its phylogenetic relationship in the Salicaceae.

Anatomical explanations for acute depressions in radial pattern of axial sap flow in two diffuse-porous mangrove species: implications for water use.

Mangrove species have developed uniquely efficient water-use strategies in order to survive in highly saline and anaerobic environments. Herein, we estimated the stand water use of two diffuse-porous mangrove species of the same age, Sonneratia apetala Buch. Ham and Sonneratia caseolaris (L.) Engl., growing in a similar intertidal environment. Specifically, to investigate the radial patterns of axial sap flow density (Js) and understand the anatomical traits associated with them, we measured axial sap flow density in situ together with micromorphological observations. A significant decrease of Js was observed for both species. This result was accompanied by the corresponding observations of wood structure and blockages in xylem sapwood, which appeared to influence and, hence, explained the acute radial reductions of axial sap flow in the stems of both species. However, higher radial resistance in sapwood of S. caseolaris caused a steeper decline of Js radially when compared with S. apetala, thus explaining the latter's more efficient use of water. Without first considering acute reductions in Js into the sapwood from the outer bark, a total of ~55% and 51% of water use would have been overestimated, corresponding to average discrepancies in stand water use of 5.6 mm day-1 for S. apetala trees and 2.5 mm day-1 for S. caseolaris trees. This suggests that measuring radial pattern of Js is a critical factor in determining whole-tree or stand water use.

[Negative air ions generated by plants upon pulsed electric field stimulation applied to soil].

This paper investigated the capacity of plants (Schlumbergera truncata, Aloe vera var. chinensis, Chlorophytum comosum, Schlumbergera bridgesii, Gymnocalycium mihanovichii var. friedrichii, Aspidistra elatior, Cymbidium kanran, Echinocactus grusonii, Agave americana var. marginata, Asparagus setaceus) to generate negative air ions (NAI) under pulsed electric field stimulation. The results showed that single plant generated low amounts of NAI in natural condition. The capacity of C. comosum and G. mihanovichii var. friedrichii generated most NAI among the above ten species, with a daily average of 43 ion · cm(-3). The least one was A. americana var. marginata with the value of 19 ion · cm(-3). When proper pulsed electric field stimulation was applied to soil, the NAI of ten plant species were greatly improved. The effect of pulsed electric field u3 (average voltage over the pulse period was 2.0 x 10(4) V, pulse frequency was 1 Hz, and pulse duration was 50 ms) was the greatest. The mean NAI concentration of C. kanran was the highest 1454967 ion · cm(-3), which was 48498.9 times as much as that in natural condition. The lowest one was S. truncata with the value of 34567 ion · cm(-3), which was 843.1 times as much as that in natural condition. The capacity of the same plants to generate negative air ion varied extremely under different intensity pulsed electric fields.