ABSTRACT
Karst ecosystems are becoming increasingly problematic, and high calcium is one of the main characteristics of soils in rocky desertification areas. Chlorophyll fluorescence is one of the most important indicators of the extent to which plants are affected by their environment. There are few reports on the effects of changes in exogenous calcium levels on the chlorophyll fluorescence properties of Fraxinus malacophylla seedlings. In the present study, we investigated the growth, chlorophyll fluorescence properties and antioxidant system of Fraxinus malacophylla seedlings in response to exogenous calcium (as the concentrations of 0, 25, 50, 75 mmol L-1). The results showed that Ca2+ concentration (25-50 mmol L-1) treatment mainly promoted the growth, biomass accumulation, root activity, and chlorophyll synthesis and effect on chlorophyll fluorescence in Fraxinus malacophylla; the developed root system became a strong linking hub for calcium adaptation. In addition, the activities of the antioxidant enzymes peroxidase (POD) and catalase (CAT) are upregulated and play an important role in preventing excessive oxidative damage. OJIP test parameters changed significantly with the addition of exogenous calcium, and parameters related to each photosystem II (PSII) reaction centre, such as ABS/RC and DIo/RC, increased significantly in the OJIP test, with enhanced function of the PSII electron donor lateral oxygen evolution complex. In conclusion, the addition of exogenous calcium (25-50 mmol L-1) had an important protective effect on the photosynthetic mechanism of Fraxinus malacophylla, promoting photosynthesis, better growth and better adaptability.
Subject(s)
Antioxidants , Fraxinus , Antioxidants/metabolism , Chlorophyll , Calcium/pharmacology , Seedlings , Ecosystem , Fluorescence , PhotosynthesisABSTRACT
BACKGROUND: Grassland plays an important role in the ecosystem, but overgrazing harms the grassland system in many places. Grazing prohibition is an effective method to restore grassland ecosystems, and it plays a great role in realizing the sustainable development of grassland systems. Therefore, it is necessary to carry out research on the influence of regional grazing prohibition on the physical and chemical properties of different grassland systems. METHODS: In Potatso National Park, Southwest China, we selected experimental plots in the artificial grazing meadow area to study the effects of grazing prohibition on plant and soil indexes in subalpine meadows and swamp meadows. We investigated the biomass and species diversity of grazing prohibition treatment and grazing treatment plots and sampled and tested the soil index. The variation percentage was used to remove the original heterogeneity and yearly variation, allowing us to compare differences in plant index and soil index values between grazing prohibition and grazing treatments. RESULTS: Grazing prohibition increased the aboveground biomass, total biomass, total meadow coverage, average height, richness index, Shannon diversity index and evenness index and reduced the belowground biomass and root/shoot ratio in the subalpine meadow and swamp meadow. Additionally, grazing prohibition reduced the pH and soil bulk density and increased the soil total carbon, soil organic carbon, soil total nitrogen, soil hydrolyzable nitrogen, soil total phosphorus and soil available phosphorus in the subalpine meadow and swamp meadow. Nonmetric multidimensional scaling (NMDS) analysis showed that both plant indexes and soil indexes were significantly different between grazing and grazing prohibition treatments and between meadow types. Short-term grazing prohibition had a great impact on improving the fertility of meadow soil in the study area. We suggest that long-term and extensive research should be carried out to promote the restoration and sustainable development of regional grassland systems.
ABSTRACT
Solanum betacea is a sub-tropical tree, and the fruit has high nutritional value, unique flavor and color. It is used as a functional ingredient in health care, food, cosmetic and pharmaceutical applications. The complete chloroplast(Cp) genome of S. betacea has been assembled and annotated in this paper. Its length was 155,937 bp, containing a large single-copy region of 86,731 bp, a small single-copy region of 18,450 bp, and a pair of IR regions of 25,378 bp in each. The complete chloroplast genome of S. betacea contained 134 genes, including 90 protein-coding genes, 36 transfer RNA genes (tRNAs), and 8 ribosome RNA genes (rRNAs). The overall GC content was 37.7% and the GC contents of the LSC, SSC, and IR regions were 35.7%, 31.8%, and 43.1%, respectively. Phylogenetic analysis with the reported chloroplast genomes revealed that S. betacea has been most closely related to Solanum torvum. These findings will provide useful information for further investigation of chloroplast genome evolution in Solanum betacea.
ABSTRACT
Crateva unilocularis is naturally distributed in Southern China, which is an elite natural tree with high edible and medicinal value. In this study, whole chloroplast (cp) genome of Crateva unilocularis was assembled and characterized on the basis of Illumina pair-end sequencing data. The complete cp genome was 156,417 bp in length, containing a large single-copy region (LSC) of 85,607 bp and a small single-copy region (SSC) of 18,164 bp, which were separated by a pair of 26,323 bp inverted repeat regions (IRs). The genome contained 128 genes, including 85 protein-coding genes, 35 tRNA genes, and 8 rRNA genes. The overall GC content is 36.32%, while the corresponding values of the LSC, SSC, and IR regions were 33.98, 29.45, and 42.48%, respectively. The maximum-likelihood phylogenetic analysis showed a strong sister relationship with Crateva tapia. These findings provide a foundation for further investigation of cp genome evolution in Crateva unilocularis and other higher plants.
ABSTRACT
Fraxinus malacophylla is one of the commonly used ecological restoration tree species in rocky desertification areas. It has high medicinal and timber value. And has high marketization prospects. The complete chloroplast genome sequence of F. malacophylla was generated by de novo assembly using whole-genome next generation sequencing. The complete chloroplast genome of F. malacophylla was 155621 bp in total sequence length and divided into four distinct regions: large single copy region (86404 bp), small single copy region (17821 bp), and a pair of inverted repeat regions (25698 bp). The F. malacophylla chloroplast genome annotation predicted a total of 131 genes, consisting of 35 tRNA genes, 8 rRNA genes, and 88 protein-coding genes. Phylogenetic analysis with the reported chloroplast genomes revealed that F. malacophylla has most closely related to F. excelsior.
