Subjects: Biology >> Botany >> Applied botany submitted time 2023-07-26 Cooperative journals: 《广西植物》
Abstract： The genetic diversity of species was a key factor in their adaptability and survival capabilities. Habitat fragmentation was recognized as one of the key factors leading to biodiversity loss, and it had significant impacts on the genetic diversity of plant populations. Hydrocera triflora was in a regional extinction state, and the status of its genetic diversity and endangered mechanisms had not been reported. In this study, 34 samples of H. triflora from 7 populations were used to obtain single nucleotide variation sites by restriction site-associated DNA sequencing (RAD-seq). We discussed the mechanisms of endangerment of H. triflora by analyzing population genetic diversity and structure. Additionally, we combined these findings with historical population dynamics analysis and predictions of potential species distribution in different climate scenarios. The results were as follows: (1) H. triflora had low genetic diversity (Ho=0.1569, He=0.1654, Pi=0.1865) and low genetic differentiation; AMOVA analysis showed that genetic variation mainly occurred within populations; (2) The Mantel test indicated that there was a significant positive correlation between environmental distance and genetic distance, as well as geographical distance, with respective p-values of 0.0447 and 0.0082; (3) The effective population size of H. triflora had been continuously declining since the mid-Holocene. The eruption of the Qiongbei volcanic group and human activities played a significant role; (4) Compared to the modern climate, the total potential distribution area of H. triflora changed little in the future. However, in scenarios of high CO2 emissions, the highly suitable area decreased significantly, especially in the Malay Islands where the suitable habitat virtually disappeared. The results indicated that habitat fragmentation led to a continuous decline in the genetic diversity and effective population size of the H. triflora. Therefore, the low self-renewal capacity, as well as detrimental environmental conditions such as human disturbance and urbanization, were the primary factors contributing to its endangered status. On the one hand, it was recommended to strengthen the in-situ protection of the H. triflora, employing techniques such as artificial pollination to enhance gene flow among populations and thereby increase genetic diversity. On the other hand, we should focus on protecting wetlands from destruction.
Subjects: Biology >> Botany >> Applied botany submitted time 2023-06-05 Cooperative journals: 《广西植物》
Abstract： Except for Cymbidium lancifolium, all the Cymbidium species have been listed as national key protected wild plants, and the research of its future distribution patterns under the future climate would provide a reference and basis to protect this genus effectively. This paper gathered the distribution information of Cymbidium and 19 climatic factors, and used the Maximum Entropy Model (MaxEnt) and Geographic Information System (ArcGIS) to predict the future distribution patterns of the Cymbidium in China and its 20 species. The future distribution patterns were predicted under nine different climate scenarios, including the current climate and eight future climate scenarios. We also analyzed the dominant climate factors affecting the distribution. The results were as follows: (1) The precipitation of the driest quarter (Bio17), annual precipitation (Bio12) and temperature seasonality (Bio04) are the dominant climate factors affecting the future distribution of Cymbidium. (2) The analysis of species-level shows that the suitable areas of different Cymbidium species have different change trends in the future scenario, and the dominant climate factors affecting them are also different. The suitable habitat area of eight Cymbidium species such as C. dayanum trends gradually increases, while the suitable habitat area of 12 Cymbidium species such as C. tracyanum decreases. In conclusion, this study can provide an important reference for in-situ and ex-situ conservation of Cymbidium, and has positive significance to the protection of Cymbidium and other endangered wild plants.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-03-30 Cooperative journals: 《广西植物》
Abstract： Two new tetraploids quillworts species, Iso雝es longpingii and I. xiangfei, from China are described and illustrated. I. longpingii is a fully submerged plant found in a small pond of Hunan Province. It is morphologically similar to I. sinensis, but differs in its small and tuberculate-cristate megaspores and soft slender leaves that grow up to 60 cm. It is also similar to hexaploid I. orientalis, but differs in its 44 chromosomes and tuberculate-cristate megaspores. I. xiangfei is most similar to diploid I. yunguiensis in megaspore ornamentation, but differs in its microspore ornamentation, oblong sporangium, and 44 chromosomes. There are a few individuals of I. longpingii found in Ningxiang County of Hunan Province, and I. xiangfei is distributed in the wetlands of Tongdao and Huitong counties of Hunan Province. Because of their limited geographic range, small populations, fewer individuals and disturbed habitats, I. longpingii and I. xiangfei are ecaluated as critically endangered (CR) and vulnerable (VU) category, respectively, according to the IUCN Red List criteria. A key to all the current known Chinese quillworts is also provided for further taxonomic identification and conservation of these rare and endangered plants in China.
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