Abstract:Cathaya argyrophylla is one of the endemic rare and endangered wild plant with extremely small population in China, and is also the key protected object and flagship species in Guizhou Dashahe National Nature Reserve. Based on survey data of wild C. argyrophylla in the reserve in 2022, the quantitative dynamic index was calculated, static life table was compiled, survival curve was drawn, and survival function and spectral analysis were introduced to describe its structural dynamics. The results showed that the age structure of wild C. argyrophylla population was inverted J-type, and the dynamic change index of population (V_pi) was 39.43%, which was greater than V_pi' and both of them were greater than 0, indicating that the C. argyrophylla population was a growth type, but the growth was slow, and it was sensitive to external disturbance. The survival curve of the population belonged to Deevey-II type, and the survival rate, cumulative mortality rate, mortality density and risk rate changed greatly in age class from I to III stage, and then tended to be stable. The life spectral analysis showed that the III age class was the main stage affecting C. argyrophylla population. Therefore, the large number of young individuals and high mortality rates of C. argyrophylla in the reserve was the main reason leading to the difficulties of regeneration. It was suggested that the reserve should strengthen the care of C. argyrophylla seedlings and improve the living environment, so as to promote the natural regeneration and recovery of C. argyrophylla population.

Abstract:Paphiopedilum appletonianum is an endangered and class I protected orchid. In order to understand the status of its wild population and promote the protection of wild population, two large populations distributed in Nangaoling and Bawangling in Hainan were investigated in the field. The population distribution pattern was analyzed by point pattern method, and the population dynamic characteristics was analyzed through static life table, survival curve analysis, survival analysis, population reproduction strategy analysis and fertility table. The results showed that the distribution pattern of the two populations changed from aggregation to random and uniform distribution as the scale increased. The Bawangling population was mainly clustered at different scales, while the Nangaoling population was mainly random and even distributed. The age structure of the two populations was pyramid shape, and the survival curve was Deevey-II type, showing a decline trend with the increase of age class. There were two reproductive strategies: sexual reproduction and clone reproduction, and the asexual reproduction of Bawangling population was stronger, and the sexual reproduction of Nangaoling population was stronger. Therefore, Bawangling population was a growing population, while Nangaoling population was a slow negative increasing population.

Abstract:As one of the plant components of wetland park, the study of bryophyte community construction can provide important theoretical basis for wetland ecosystem management and biodiversity maintenance mechanism. Guiyang is rich in wetland and bryophyte resources. Based on three typical wetland parks in Guiyang, the species distribution of bryophytes and its relationship with environmental factors were studied. TWINSPAN analysis and canonical correspondence analysis (CCA) were used to quantitatively classify and rank the bryophytes community. The results showed that there were 17 families, 28 genera and 66 species of bryophytes in three typical wetland parks, among which Pottiaceae, Hypnaceae and Brachytheciaceae were dominant families. There was little difference in β diversity of bryophytes among the three wetland parks, with high species similarity and low richness. The habitats of bryophytes were mainly lithophyte and arboreal. The life forms were mainly interleaved and clustered. Bryophyte community could be divided into 13 types, all of which had their own characteristics, and their species composition and community characteristics could better reflect the relationship between the bryophyte type and environment factors. The habitats of the three wetland parks were similar. The results of CCA analysis showed that the primary environmental factor affecting the distribution of moss clusters in wetland park was altitude, followed by air humidity, canopy density, and light also had a certain effect. These provide a scientific basis for the conservation of bryophyte diversity in wetland park.

Abstract:In order to explore the changes of natural forest community structure in the national nature reserve, fourty-five 20 m×20 m plots were set up in three restoration stages, including original old forest (restored for 100 years or more), secondary forest restored for 40 and 25 years after clear-cutting. The interspecific association and community stability of dominant woody plants were studied by using Variance ratio (VR), χ² test, Pearson correlation test, Spearman rank correlation test and M-Godron stability test. The results showed that there was no significant positive association on the whole of dominant woody species in secondary forest restored for 25 and 40 years, but the significant positive association appeared in original aged forest restored for 100 years. The χ² test showed that the interspecific associations were not significant in 25 and 40 years plant communities, and only 2 species pairs in 100 years plant communities were significantly associated, and the interspecific associations were loose. The Pearson’s correlation coefficient test and Spearman’s rank correlation coefficient test also showed that the correlations among species pairs of most species were not significant, and displayed an independent distribution pattern. The M-Godron stability analysis showed that the plant community was in an unstable state at different stages, but the stability of the community gradually increased with restoration time. Therefore, interspecific correlation in the natural forest communities was weak at different restoration stages, and the species distributed independently and changed frequently, indicating that the community was still in the process of succession and was developing towards a stable stage.

Abstract:In order to understand the effect of warming on litter decomposition, the litter collected in subtropical evergreen broad-leaved forest was distributed in control and warming (+4 ℃) plots, respectively. The changes in the quantity and spectral characteristics of dissolved organic matter during litter decomposition under warming were studied. The results showed that the mass residual rate of litter decreased significantly with decomposition process, rapidly decreased by 20.08% to 23.32% in 0-60 days, and slowly decreased by 6.35% to 10.98% in 60-210 days. Along decomposition process, the dissolved organic carbon content of litter source showed a decreasing trend of first fast and then slow, and the overall decrease was 94.15%. The content of dissolved organic nitrogen fluctuating decreased by 81.82% overall. The spectral characteristics of dissolved organic matter (SUVA₂₅₄, SUVA₂₆₀, SUVA₂₈₀ and SUVA₃₇₀) showed an increase-decrease-increase tendency. The warming did not significantly affect the mass residual rate of litter and the spectral characteristics of dissolved organic matter, but the contents of dissolved organic carbon and organic nitrogen decreased by 16.72% and 25.10%. Therefore, the decomposition of litters decreased the mass residual rate of litters and the contents of dissolved organic carbon and organic nitrogen, and changed the spectral characteristics of dissolved organic matter. Although warming decreased the contents of dissolved organic carbon and organic nitrogen in litters, it did not significantly change the mass residual rate and spectral characteristics of dissolved organic matter in litters.

Abstract:Taking similar age arbuscular mycorrhiza (AM) species Cunninghamia lanceolata and ectotrophic mycorrhiza (EM) species Castanopsis carlesii in Sanming, Fujian Province as the research objects, the effects of nitrogen and phosphorus addition on morphological characteristics of fine roots of different mycorrhizal species were studied. The results showed that the diameter and root tissue density of fine roots of Cunninghamia lanceolata had significantly positive N and P plasticity response, and the specific root length and specific surface area had negative plasticity response, while the morphological traits of fine roots of Castanopsis carlesii showed opposite plasticity response. The P plasticity response of fine root morphological traits of Cunninghamia lanceolata was stronger than that of Castanopsis carlesii, but there was no significant difference between N and P plastic responses of fine root morphological traits of Castanopsis carlesii. The direction of plasticity response of the same morphological trait of fine root to N and P was the same, and there was a positive correlation. There was synergistic and tradeoff relationship between nutrient plasticity responses of different morphological characters in fine roots. Therefore, AM species Cunninghamia lanceolata adopted the resource conservation strategy to prolong the fine rootlife, while the EM species Castanopsis carlesii adopted the resource acquisition strategy to occupy resources quickly. In addition, the fine roots of AM species Cunninghamia lanceolata and the EM species Castanopsis carlesii might have the same foraging trend to N and P addition, and morphological traits of AM species Cunninghamia lanceolata fine roots were more sensitive to P addition than EM species Castanopsis carlesii.

Abstract:Primulina liangshengyui R. F. Li & L. Ding, a new species of Gesneriaceae from the limestone of Guangxi, China is described and illustrated. It resembles P. minutimaculata (D. Fang & W. T. Wang) Yin Z. Wang, but can be easily distinguished by a combination of characters, especially in its leaf blades both sides very short white strigillose; bracts adaxially glabrous, abaxially densely white strigillose; calyx lobes both sides densely glandular puberulent; corolla tube purple and gradually fading to white at the base; filaments glandular puberulent. There is only one population with less 500 mature individuals at the type locality. Thus, this species was provisionally assessed as Vulnerable Endangered [VU D2] by using IUCN criteria. Further, supplemented and described of floral morphology of P. minutimaculata is also appended, based on plenty of specimens with flowers and field works, and especially according to living plant in bloom.

Abstract:The taxonomic status of Epipogium sessanum was discussed. By field observations and a critical survey of the literature and specimens in herbaria, it was found that E. sessanum and E. roseum had obvious differences in the flower. It is suggested E. sessanum to be reinstated as a distinct species, and a new Chinese name “zang nan hu she lan” is proposed.

Abstract:To understand the effect of phosphorus on the induction and growth of cluster buds in the proliferating seedlings of Acacia melanoxylon, the tissue-cultured seedlings of clone SR17 as materials was inoculated proliferation medium containing 0.9, 1.2, 1.6, 2.0, 2.4, and 2.7 mmol/L KH₂PO₄, respectively, and the growth and development indexes of cluster buds were investigated after for 1 and 2 cycles of subgeneration, respectively. The results showed that 2.0–2.7 mmol/L KH₂PO₄ promoted the rapid growth of height, number of cluster bud and base callus of proliferating seedlings, among which 2.4 mmol/L KH₂PO₄ had the best effect, and the accumulation of biomass and chlorophyll content was higher. With the enhance of phosphorus content in the medium, phosphorus and potassium contents in the cluster buds significantly increased, while nitrogen content had no significant change. Pearson correlation analysis revealed that the phosphorus level had significantly positive correlation with height, number, base callus, fresh weight, dry weight, tissue water content, and contents of total chlorophyll, chlorophyll a, chlorophyll b, phosphorus, potassium of bud in 1 and 2 cycles of subgeneration. Therefore, phosphorus plays an essential regulatory role in the growth and development of cluster buds of A. melanoxylon.

Abstract:In order to explore the effects of eutrophic waterlogging and post-waterlogging drought on the tolerance of terrestrial woody plants, the control (CK), nutrient (H), waterlogging (W) and eutrophication waterlogging (WH) treatments were set in the first stage. In the second stage, control-drought (CKD), nutrient- drought (HD), watering-drought (WD) and eutrophic watering-drought (WHD) treatments were set up to study the effects of different water and nutrient treatments on the growth and physiology of one-year-old Dalbergia odorifera seedlings. The results showed that D. odorifera had high survival under all treatments; the seedlings exhibited the highest biomass, net photosynthetic rate and total chlorophyll concentration under H treatment. In contrast, both W and WH treatments significantly reduced stem height increment, total biomass, net photo- synthetic rate, stomatal conductance, total chlorophyll content and leaf water potential, but significantly increased the activities of superoxide dismutase (SOD), peroxidase (POD), and contents of H₂O₂ and soluble protein. Notably, the impact of W stress was more pronounced than that of WH stress. Compared with the first stage, the biomass increment decreased significantly under both of CKD and HD treatments, but which showed the opposite trend under WD and WHD. Furthermore, compared with CKD and HD treatments, net photosynthetic rate significantly increased, while SOD activity and H₂O₂ content decreased under WD and WHD. Moreover, compared with WD, biomass increment, total chlorophyll content and POD activity increased under WHD, but Car content decreased. Therefore, it was demonstrated that nutrient supply could alleviate the negative effects of waterlogging on seedling growth of D. odorifera to a certain extent, and early waterlogging, especially eutro- phication waterlogging, was conducive to biomass accumulation of seedlings under later drought condition.

Abstract:In order to understand the chemical composition of Ainsliaea glabra, ten compounds were isolated from petroleum ether extraction fraction of 90% ethanol extract by silica gel, sephadex LH-20 gel column chromatography, semi-preparative high-performance liquid chromatography. Based on spectral data, their structures were identified as pinerenol diisovalerate (1), 3β-hydroxy-11α,13-dihydro-costunolide (2), matricarin (3), taraxasteryl acetate (4), betulyl alcohol (5), 27-hydroxyolean-12-en-28-oic acid (6), morolic acid acetate (7), (-)-loliolide (8), butyl benzoate (9), and E-phytenal (10). Compound 1 was a new structural compound. Compounds 3 and 7 were isolated from Ainsliaea genus for the first time. Compounds 2-7 and 9 were first reported in the A. glabra. The results of antibacterial activity test showed that compounds 1, 2 and 8 had certain inhibitory effects on Staphylococcus aureus with MIC values of 31.2, 25.0, and 21.8 μg/mL, and compounds 1 and 3 had potential inhibitory effect on Candida albicans with MIC values of 1.9 and 3.9 μg/mL, respectively.

Abstract:In order to understand the mineral element composition and active component, the contents of seven mineral elements (K, Mg, Ca, Na, Fe, Zn, Se), total phenol, total flavone, total ascorbic acid and soluble sugar, tea polyphenol, caffeine and amino acid in the leaves of six Camellia species, such as C. achrysantha, C. long- zhouensis, C. ptilosperma, C. limonia, C. chuongtsoensis and C. nitidissima, were determined. Based on the contents of active component, principal component analysis and cluster analysis were studied. The results showed that the contents of K, Mg, and Na in C. limonia were the highest, which were 18.70, 2.67, and 1.01 g/kg, respectively. The Ca content in C. achrysantha was the highest (42.99 g/kg), the Fe content in C. chuongtsoensis was the highest (334.14 mg/kg), the Zn content in C. ptilosperma was the highest with 22.46 mg/kg; the Se content in C. long-zhouensis was the highest with 0.47 mg/kg. There were significant differences in seven mineral elements in leaves among different species (P<0.05). A total of 15 amino acids were detected in 6 Camellia species, only asparagine, tryptophan, threonine, cysteine and glutamine were missing. The active ingredient contents in 6 Camellia species showed the trend of soluble sugar>total phenol>total flavone>total ascorbic acid, and those of C. ptilosperma were the highest. The content of tea polyphenol in C. achrysantha was the highest. The caffeine content in 6 Camellia species was low, but not detected in C. achrysantha and C. chuongtsoensis. The principal component analysis showed that the cumulative contribution rate of PC1, PC2 and PC3 reached 87.439%, and based on comprehensive score of component content, C. limonia was the best. The cluster analysis based on active component content showed that the difference between C. limonia and other species was large, and that between C. achrysantha and C. ptilosperma, C. chuongtsoensis and C. nitidissima was small. Therefore, these would provide theoretical basis for the development and utilization of Camellia sect. Chrysantha.

Abstract:Pogostemon Desf. consists of about 80 species and is the largest genus in the tribe Pogostemoneae, subfamily Lamioideae, family Lamiaceae. Pogostemon cablin, which belongs to the subgenus Pogostemon, is the representative species of the genus due to its secondary metabolite (patchouli oil) widely used in cosmetics and pharmaceutical industry. The presence of exserted stamens bearing moniliform hairs is an important character to distinguish the genus from all other members circumscribed in the same tribe. The circumscription of the genus has been changed in large extent based on the consideration of results from phylogenetic analyses, and a new infrageneric classification system of the genus was also provided recently based on evidence from molecular and morphological data. Here in, advances in phylogenetic and taxonomic studies of Pogostemon were given. Moreover, some useful recommendations for further phylogenetic and taxonomic studies on the genus were provided, which would be important for further investigation and evaluation of plant resources of the genus. Twenty-nine species and two varieties in the genus were recorded in China, and a key to these taxa was provided.

Abstract:Because of the narrow distribution range, few individuals, and imperfect endangered relief technology, the wild plants with extremely small populations (WPESP) are facing the risk of extinction at any time, and need to be saved. Due to the differences in biological characteristics and endangered mechanisms of wild plants with very small populations, basic research on specific species is helpful to provide scientific basis for their conservation and population rejuvenation. Hopea hainanensis used to be the key tree species and characteristic species in the tropical rain forest of Hainan, but under the influence of human activities and regeneration difficulties, the population of H. hainanensis has decreased sharply. Although more research work has been carried out, problems such as unclear resource status, lack of mechanism research, unclear future research priorities, and failure of scientific research to effectively guide conservation practice are still prominent, and long-term, in-depth and systematic research needs to be strengthened. Based on a comprehensive search of relevant literature, the research progress of H. hainanensis was reviewed from the aspects of biological characteristics, natural distribution area, wild population size, adaptability, in situ and ex situ conservation, artificial breeding techniques and potential endangered mechanisms, and discussed the existing problems and future research priorities in the conservation of wild plants with very small populations. Based on the current research status, specific suggestions are put forward to provide reference for the protection and rescue of slope barrier.