Subjects: Biology >> Botany >> Applied botany submitted time 2022-08-05 Cooperative journals: 《广西植物》
Abstract： Excentrodendron tonkinensis is a constructive species of karst seasonal rainforest and an obligate karst plant, which is also one of the national secondary key protected wild plant and an IUCN endangered plant, with high economic and ecological value. However, there is still a lack of understanding of how the potential suitable areas of Excentrodendron tonkinensis change in the context of global change and its key driving factors, which affect the scientific protection and utilization of Excentrodendron tonkinensis.To assess the impacts of climate change on the extents of the habitat of Excentrodendron tonkinensis, we used the Maximum-entropy model to analyze the potential changes in the geographical distribution in China of future climate scenarios SSP1-2.6 and SSP5-8.5), and tested the influence of the karst geological background distribution on predicting the suitable areas of karst obligate plants. The results show that: (1) in the case of adding karst geological background data, the average AUC of the prediction model for the suitable area is 0.997, which has a good prediction effect. And the model prediction results are strictly limited to the karst region, consistent with the characteristics of Excentrodendron tonkinensis which is karst obligate plant; (2) According to the fitting results of the model, the karst geological background, precipitation of warmest quarter(800-950 mm), and the min temperature of coldest month(7-11 ℃) are the key factors limiting the distribution of Excentrodendron tonkinensis; (3) with the increase of temperature in the future, the area of potential suitable areas for Excentrodendron tonkinensis would expand to higher latitudes karst areas. Large numbers of areas of stable habitats exist in parts of southwest Guangxi and southeastern Yunnan. These results suggest that the karst geological distribution is essential as predicting the potential geographic distribution of karst obligate plants such as Excentrodendron tonkinensis; if the temperature continues to rise in the future, its potential suitable areas will expand to high latitudes, and the degree of endangerment may be affected by climate, which means it is not obvious under the influence of climate changes; parts of southwestern Guangxi and southeastern Yunnan are suitable areas for the conservation and utilization of Excentrodendron tonkinensis under the climate changes in the future.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-07-05 Cooperative journals: 《广西植物》
Abstract： Liquidambar formosana is one of the important native tree species in Guangxi, which has high timber, ornamental and medicinal value. This study designs and develops EST-SSR markers of L. formosana based on data from the transcriptome sequencing. The purpose is to provide an effective and reliable molecular marker tool for studies of population genetics of this species, it is of great significance to the protection and utilization of all kinds of material resources of the tree. Simple sequence repeats were selected from the transcriptome data in L. formosana, and then primers were developed, and screened out by PCR amplification and polyacrylamide gel electrophoresis for high polymorphism, and the efficiency was tested by using 30 individuals from of a wild L. formosana population. The results were as follows: (1) A total 23 777 SSRs were obtained by searching SSR unigenes from transcriptome data. The repeat type of the SSR loci in L. formosana was dominated by mononucleotide repeats (46.54%). The highest proportion of SSR loci (72.36%) was between 5 and 12 times. (2) A total of 262 pairs of SSR primers were developed, and among them, 139 pairs amplified the target bands with a success rate of 53.1%, and 18 pairs of them that can be used to steadily obtain clear bands were finally identified. (3) The polymorphism detection showed that all sites had a high degree of polymorphism. The number of alleles, effective alleles, Shannon diversity index, observed heterozygosity and fixed index of the L. formosana populations ranged in 2-4, 1.112 8-2.609 6, 0.208 9-1.112 7 and 0.275 9-1.000 0, the average values were 2.333 3, 1.957 4, 0.708 5 and 0.722 6, respectively. In conclusion, the dominant SSR repeat type and repeat motif in L. formosama are basically the same as those in other species, the developed EST-SSR markers can meet the needs of population genetic studies of L. formosana, which provides abundant primers for the study of genetic diversity of L. formosana.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-06-07 Cooperative journals: 《广西植物》
Abstract： The distribution characteristics and internal links of soil enzyme activities, nutrient content and woody plant diversity in negative topographic habitats of Tiankeng were studied, which provided a theoretical basis for the protection and reconstruction of plant resources in karst areas. The Tiankeng forests of the Dashiwei Tiankeng group in Guangxi were selected as the object. Based on the community diversity survey and soil habitat survey from the inner and top area to the outer area of Tiankeng, the relationship between species diversity and soil factors of woody plants was explored by correlation analysis and redundancy analysis methods. The results were as follows: (1) There were 21 species, 31 genera and 20 families of woody plants in the inside area of Tiankeng, 91 species, 58 genera and 58 families of woody plants in the top area of Tiankeng, and 47 species, 30 genera and 30 families of woody plants in the outside area of Tiankeng. The Margalef index and Patrick index in the inside area of Tiankeng were significantly lower than those in the top and outside area of Tiankeng, indicating that the individuals of species increased, but the species distribution was steady; (2) The total soil nitrogen content in the outside area of Tiankeng was significantly higher than those in the top and outside area of Tiankeng. The soil total magnesium content, soil phosphorus content and soil available phosphorus content in the inside area of Tiankeng were significantly higher than those in the top and outside area of Tiankeng. The soil alkaline phosphatase content and soil urease activities in the outside area of Tiankeng were significantly higher than those in the top and inside area of Tiankeng. The soil phosphorus content in the Tiankeng was higher, but the soil enzyme activities were lower; (3) The results of Pearson correlation analysis and redundancy analysis showed that species diversity was strongly correlated with soil nutrients and soil enzyme activities. In conclusion, it can be seen that the habitats of the Tiankeng have a great influence on the species diversity, soil enzyme activity and soil nutrient content distribution characteristics. And the soil available phosphorus content, soil alkaline phosphatase activity, soil moisture content, soil urease activity, soil full magnesium content and soil total phosphorus content are the key factors affecting the species diversity of woody plants in the Tiankeng forest.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-04-29 Cooperative journals: 《广西植物》
Abstract： The Lijiang River Basin covers great variation in altitude, soil and vegetation types. In order to study its soil nutrients and extracellular enzymes activities, we determined soil nutrient contents and activities of several extracellular enzymes (amylase, sucrose, urease, protease and catalase) of the surface soils (0-20 cm) of typical vegetation types (natural forest, bamboo (Phyllostachys pubescens) forest, Pinus massoniana forest, orchard and rice paddy field) with calcareous soils and acid soils in the Lijiang River Basin). The results were as follows: (1) The soils at high altitude had greater total nitrogen (TN), total phosphorus (TP), available phosphorus (AP) contents as well as amylase, sucrose, urease and protease activities, whereas the catalase activity was to the contrary. (2) Compared to the acid soils, the calcareous soils had higher contents of total phosphorus (TP) and available phosphorus (AP). Among the acid soils, vegetation types had greater impact to soil nitrogen and phosphorus content. In general, anthropogenic vegetation resulted in decrease in nitrogen contents and increases in phosphorus content. The nutrients in the calcareous soils had relatively little variation among different vegetation covers. (3) Compared to the natural forest soils, soils from the anthropogenic vegetation had lower nitrogen related enzyme activities; whereas the carbon related enzyme activities was less impacted. The enzymatic stoichiometry revealed that soils of natural forests were nitrogen limited whereas those of anthropogenic vegetation was carbon limited. (4) The results of canonical correspondence analysis (CCA) showed that soil physiochemical properties in the first and second axes could explain 86.56% of the variation of soil enzyme activities with the contribution order of TN>pH>NH4+>AP>TP>NO3-, with the first three as the main impacts. All the above results indicate that acid soils in the Lijiang River Basin has great ecological sensitivity; vegetation changes easily resulted in nutrient imbalance, therefore, in order to improve the sustainable utility of landscape resources of the Lijiang River Basin, special attention should be paid to the conservation of soil nutrients and prevention of the loss of soil organic matter; and this study can provide theoretical base on the scientific conservation and development of local ecosystem.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-12-19 Cooperative journals: 《广西植物》
Abstract： Guangxi Zhuang Autonomous Region is located in South China, with humid climate, complex habitats and rich species diversity. Thirteen species of orchids are reported as new records from Guangxi Zhuang Autonomous Region, viz. Kuhlhasseltia yakushimensis (Yamamoto) Ormerod, Risleya atropurpurea King et Pantl., Stigmatodactylus sikokianus Maxim. ex Makino, Vrydagzynea nuda Bl., Apostasia shenzhenica Z. J. Liu & L. J. Chen, Bulbophyllum nipondhii Seidenf., Chamaegastrodia nanlingensis H. Z. Tian & F. W. Xing, Goodyera pendula Maxim., Hetaeria anomala Lindl., Liparis brunnea Ormerod, Luisia appressifolia Aver., Tropidia emeishanica K. Y. Lang, and Zeuxine nervosa (Lindl.) Trimen. Among them, Kuhlhasseltia J. J. Smith, Risleya King & Pantl., Stigmatodactylus Maxim. ex Makino, and Vrydagzynea Bl. are newly recorded genus in Guangxi. There are 128 genera and 469 species and 4 varieties of Guangxi Orchidaceae. Citation specimens, geographical distribution and pictures of the thirteen newly recorded species are provided．
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