Advance Search

2017  Vol. 35  No. 6

Abstract:
Calanthe sieboldii Decne. is included in the National Implementation Plan for Rescuing and Conserving China's Plant Species with Extremely Small Populations (PSESP), highlighting the urgent need for its rescue. To determine the habitat characteristics of C. sieboldii and the interspecific relationships among species within the C. sieboldii community, we conducted a comprehensive investigation of C. sieboldii distributed in Jingxian County of Anhui Province, China. Based on data from 22 quadrats in 18 sample plots, we analyzed the habitat conditions of the C. sieboldii community, and analyzed the niche characteristics of the main herbaceous species in the community using Levins' and Hurlbert's formulae for niche breadth and the similarity ratio of resources used for niche overlap. Results showed that:(1) C. sieboldii exhibited scattered distribution in Taoling village of Jingxian County, with most plants found in relatively open areas under steep cliffs near rivers with no direct sunlight; (2) C. sieboldii had an obvious advantage in the herb layer of the community. Niche overlaps existed among the main species in the herb layer, but the degree of overlap was low, interspecific competition was not intense, and environmental resources could be sufficiently shared by different species. The herb layer in the community was in a relatively stable condition.
Abstract:
Based on spatial replacing temporal series, we studied the diversity of the bryophytes in five different natural succession stages in the karst bauxite tailing piles of the Xiaoshanba Bauxite Deposit, Xiuwen County, Guizhou Province. Results showed that:(1) There were 31 taxa of bryophytes belonging to 18 genera and 11 families, of which there were 29 taxa of mosses belonging to 16 genera and 9 families, and 2 taxa of liverworts belonging to 2 genera and 2 families. In the succession stages, the bryophyte life forms were simple, with short turfs the dominant life form, accounting for 67.7%, and the wefts accounting for 32.3%. The bryophyte species composition was monotonous, with many single-species communities, though mixed-species communities gradually increased along the succession stages. (2) The bryophyte indices were different in different natural succession stages, with the Shannon-Wiener Index, Pielou Index, and Abundance Index all lowest (0.196, 0.283, and -1.930, respectively) in the bare rock stage, and the highest (3.470, 1.281, and 2.342, respectively) in the herbosa-boscage stage. The diversity indices then gradually declined (2.128, 0.88, and 1.267, respectively) in the arbor-shrub stage. The Cody Index and Sørensen Similarity Index showed the opposite tendencies. The faster the replacement rate of species, the smaller was the similarity in the two adjacent succession stages. In the five different natural succession stages, the change in bryophyte diversity demonstrated a regular tendency, whereby the level of diversity increased at first, then decreased gradually on the karst bauxite tailing piles. Generally, the level of bryophyte diversity improved. These findings provide basic information for the ecological restoration and biodiversity conservation of the karst bauxite mining area.
Abstract:
Bretschneidera sinensis Hemsl. is a rare plant species mainly distributed in China. In this study, amplified fragment length polymorphism (AFLP) data were used to analyze genetic diversity, genetic structure, and phylogeography of this species. A total of 192 individuals from 24 populations in 11 provinces were sampled. Results showed a relatively high level of genetic diversity for B. sinensis, with an expected heterozygosity (He) and Shannon's diversity index (Ⅰ) of 0.2728 and 0.4070, respectively. Relatively high genetic differentiation (GST=0.7138) and lower gene flow (Nm=0.2005) among B. sinensis populations were detected. The infra-population genetic variations were significantly greater than the inter-population variations. Four phylogeographic groups were discovered from cluster, STRUCTURE, and BAPS analyses. Populations in the East Yungui Plateau showed high levels of genetic diversity with unique hereditary constitution. This area is a possible diversity center and glacial refuge for B. sinensis in China, which expanded northward, eastward, and southeastward after the last ice age. Populations from the Nanling Mountains, with a close relationship to their neighbor population, had higher genetic diversity than other areas. The Nanling Mountains are another probable glacial refuge in the evolutionary history of B. sinensis.
Abstract:
Bryophyte communities and correlated urban environments in Wuhan were investigated from September to November in 2016. A total of 431 bryophyte specimens were collected from 73 plots in 26 sampling sites along seven central urban areas and suburban areas. We recorded 91 bryophyte species, belonging to 35 genera and 20 families, in the study area. According to the importance values, Haplocladium angustifolium and Entodon obtusatus were the dominant species, and were widely distributed in 24 sites. The species richness and Shannon-Wiener index of bryophytes in Qinglongshan national forest park were the highest, suggesting that the bryophyte community was highly complex in this site. According to the Pearson correlation analysis, the environmental factors that affected the diversity of ground bryophytes were soil water content and distance to main roads, with distance to main roads also related to the diversity of epiphytic bryophytes. Canonical correspondence analysis (CCA) was used to evaluate the relationships between the various bryophyte species and environmental factors in the 26 sample sites. Results indicated that human disturbance, herb coverage, and distance to main roads had significant impacts on the distribution of ground and epiphytic bryophytes in Wuhan. The effects of human disturbance and herb coverage on the distribution of ground bryophytes were the most significant, whereas tree trunk diameter at breast height and distance to main roads in the city had the most significant effects on the distribution of epiphytic bryophytes. This study illustrated that bryophyte diversity and distribution are impacted by human disturbance in Wuhan, and epiphytic bryophytes are more sensitive to automobile exhaust.
Abstract:
To study the floristic and origin characteristics of seed plants from the Shennongjia World Natural Heritage Site (SNJWNH), a time tree was established based on Phylomatic. Furthermore, the temporal characteristics of the origin of the genera in this area were discussed based on multidisciplinary evidence. Results showed rich gymnosperm diversity in SNJWNH, accounting for 67% and 74% of the total genera and species from the diverse mountainous regions in Central China. The proportion of basal families of angiosperms in SNJWNH was also high, reaching 85% of the total basal families in China. Monotypic families (containing only one genus and one species) in SNJWNH accounted for 42% of the total monotypic families in China. Furthermore, SNJWNH also possessed 56 genera endemic to China, accounting for 23% of the total endemic genera in China. The genera belonging to the East Asian and North American disjunctive distribution pattern in SNJWNH accounted for more than 50% of the total number of that floristic type in China. These results show that the seed plants of SNJWNH exhibit characteristics of ancient origin, and have continuous lineages lasting for a long evolutionary history. In conclusion, the seed plants of SNJWNH are critical to its value, and are of considerable importance to plant systematic and phylogenetic studies.
Abstract:
The habitat conditions, species composition, floral components and characteristics of two communities of Paphiopedilum purpuratum (Lindl.) Stein were analyzed based on field work in the Baixi Nature Reserve of Zijin County, Heyuan City, Guangdong Province, China. A total of 94 vascular species were recorded, belonging to 79 genera and 47 families in plots. At the generic level, pantropical and tropical Asian genera were the dominant components, contributing 84.3% of the total genera, excluding cosmopolitan genera. The floristic composition of the community showed tropical and subtropical transition. In Community 1, Adiantum flabellulatum Linn. and Carex chinensis Retz. were dominant, with P. purpuratum as a companion species. In Community 2, however, P. purpuratum was the dominant species. Life form distribution was dominated by microphanerophytes, with limited macrophanerophytes, hemicryptophytes, and therophytes. Vine richness further increased under dense forest canopies. Comparing the two community habitats, P. purpuratum had a strong dependence on the environment, particularly on slope aspect and environmental humidity. There was no obvious selectivity for the associated plants of P. purpuratum. Based on these results, we suggest that the conservation of P. purpuratum is of considerable value, with the application of in-situ protection and reproduction techniques critical.
Abstract:
We employed both nuclear and chloroplast DNA sequences to analyze the genetic diversity and structure of 20 individuals from two separate populations of Isoetes taiwanensis, with some suggestions for the conservation of this species also proposed. In the nuclear DNA data set, 18 haplotypes were discovered, with a haplotype diversity of 0.9842 and nucleotide diversity of 0.00215. In the chloroplast DNA data set, six haplotypes were detected, with a haplotype diversity of 0.6211 and nucleotide diversity of 0.00326. AMOVA results indicated that genetic variations within populations were larger than those among populations. Based on nucleotide DNA sequences, gene flow was 4.26 and Gst was 0.05543. Compared with other Isoetes species, the nucleotide diversity of I. taiwanensis was relatively low, possibly related to the ploidy level and narrow distribution. The genetic structure is likely related to strong gene flow and foundation effects. Both in situ and ex situ conservation is recommended.
Abstract:
Based on whole genome data of tartary buckwheat (Fagopyrum tataricum (L.) Gaertn), we used bioinformatics to exploit nine 11S seed storage protein genes, and analyzed their identification, location, protein structure, phylogenetic relationship, and expression. Results showed that the encoded protein lengths of these nine genes ranged from 189 to 914 aa, the isoelectric points ranged from 5.18 to 9.82, and the molecular weights ranged from 21.27 to 103.33 kD. Sequence alignment showed that one 11S seed storage protein (sample1_00009513-RA) contained only one cupin conservative domain, with the other eight members all containing two cupin conservative domains. In addition, there were 14 conservative amino acid residues in the cupin domain between tartary buckwheat and Arabidopsis. Location analysis demonstrated that these genes were mapped on six linkage groups of the tartary buckwheat genome (Megascaffold2/5 and scaffold77/344/395/861). Prediction analysis suggested that the tartary buckwheat 11S seed storage proteins exhibited two types of protein structure. The phylogenetic relationship of the 11S seed storage proteins from tartary buckwheat and six other species (Arabidopsis, peanut, soybean, almond, walnut, and sesame) indicated that these proteins could be classified into three groups, containing four pairs of paralogous and three pairs of orthologous. Compared with the reported allergic storage proteins in tartary buckwheat and 11S allergens from five other species (peanut, soybean, almond, walnut, and sesame), five 11S seed storage proteins demonstrated high similarity, with the highest similarity found with walnut; however, further experiments are needed to clarify whether these five members are food allergens or not. RNA-Seq analysis revealed that only four members (sample1_00018411-RA,sample1_00026786-RA,sample1_00021674-R,sample1_00022718-RA) had high expression levels in milk stage seeds of two kinds of buckwheat, and were more highly expressed in ‘Daku 1’ than in ‘Datian 1’.
Abstract:
Saline-alkali stress is a significant abiotic stress affecting plant growth worldwide. However, the hydraulic characteristics and carbon metabolism features of plants responding to saline-alkali stress remain poorly understood. Two saline-alkali tolerant plants, wolfberry (Lycium chinense Miller) and Chinese tamarisk (Tamarix chinensis Lour.), were examined to explore their water-carbon responses to saline-alkali stress under different salinity-alkalinity levels. Branch water potential, percentage loss of conductivity (PLC), stomatal conductance, net photosynthetic rate, nonstructural carbohydrate (NSC) concentration, and growth status of the plants were measured. Results showed that severe saline-alkali stress significantly reduced the predawn and midday water potential, photosynthetic rate, and PLC of both species, with T. chinensis exhibiting a more severe reduction in photosynthetic rate, stomatal conductance, and branch PLC than L. chinense. Strong saline-alkali stress also significantly reduced NSC concentration of all tissues in L. chinense; however, the NSC concentration in the aerial parts in T. chinensis was significantly increased, whereas the root NSC concentration was significantly decreased. Both species coped with saline-alkali stress using different strategies. Strong stomatal regulation of L. chinense was beneficial for the maintenance of hydraulic architecture, but constrained carbon uptake. Weak stomatal regulation of T. chinensis affected hydraulic architecture, but was advantageous for the maintenance of the carbon balance.
Abstract:
Pollen and stigma morphologies, floral characteristics, and flowering phenologies of introduced and cultivated Plumbago auriculata Lam. in Sichuan were systematically observed, with the collection period and storage temperature of pollen also examined. Results showed:(1) There were obvious differences between pollen and stigma morphology; P (polar axis length) and E (equatorial axis length) values of S-morph pollen were significantly higher than that of L-morph pollen; the stigma of the L-morph pollen was significantly longer than that of the S-morph pollen; and the exine ornamentation and stigma stromae of the two morphs of pollen were significantly different. (2) P. auriculata had a high flowering synchrony index of 0.89, but its relative flowering intensity was at a mid-level. (3) When the two morphs of pollen were harvested during the half-flowering period, viability reached the highest levels. The L-morph pollen viability reached 85.24% ±4.22% and S-morph pollen viability reached 87.74% ±2.95%. (4) L-morph and S-morph pollen maintained better viability when stored at low temperatures after drying at a constant temperature of 25℃ for 0.5 h and 1 h, respectively. (5) Dried pollen was best stored at -86℃, and after 30 d of storage the L-morph pollen viability was 66.51% ±0.85% and S-morph pollen viability was 69.07% ±1.57%. In summary, there were significant differences in the reproductive resource allocation between the two morph plants of P. auriculata, with differences in the size, morphology, and drying time of pollen, and significantly different characteristics in the stigma. Whether these different structures participate in the self-incompatibility reaction of P. auriculata remains to be further studied. In addition, low flowering intensity can cause insect pollination difficulties, which may be an important factor in the extremely low natural seed setting rate.
Abstract:
The study of biomass accumulation and distribution is of great significance to understand the mechanisms of crop yield formation. ‘Fengdan’ is a new woody oilseed crop originated from Paeonia ostii T.Hong et J.X.Zhang, though its production mechanism remains unclear. In the study, destructive sampling was applied to test the seasonal variations in biomass accumulation and allocation of different organs of ‘Fengdan’ plant in an annual cycle between different aged populations and under different shading treatments. Plant biomass of each age and each organ varied in different seasons and reached the highest levels during the mature fruit stage. Total biomass increased with tree age, whereas the relative growth rate displayed the reverse tendency. Biomass allocation of plant parts changed in different stages; the roots and stem exhibited the highest values during bud dormancy, whereas the highest value in the leaf occurred at the mature fruit stage. The reproductive allocation was only 3.24%-6.85% of total biomass, but this increased with age (fruit biomass was (7.74 ±0.31)g/plant for a 4-year-old fruit, but (26.81 ±0.44)g/plant for an 8-year-old fruit). Total assimilation in the annual cycle ranged from 161.21 g to 232.34 g and the seed harvest index was 2.71%-6.87%, which was positively correlated with tree age (R2=0.8178). Under shading treatments, the biomass of the root, stem, leaf, or whole plant decreased slightly, but the reproductive biomass and harvest index increased significantly to 3.66 g per plant and 389.36%, respectively, under 30% shading treatment. These findings demonstrate that the source-sink relationship in the ‘Fengdan’ plant changed dynamically over the annual cycle, tree age had a significant effect on biomass allocation and yield, and moderate shading may be more suitable for growth.
Abstract:
Species delimitation is an important part of plant research, but difficult for identification of closely related species. In field investigation and sampling, species are usually delimitated by direct observation of morphological characteristics, but often with bias, leading to delimitation errors. Currently, there is no accurate method for plant delimitation. In this paper, we analyzed two sympatrically distributed oak species, Quercus dentata Thunb. and Q. aliena Blume, using a landmark method, and summarized the species delimitation ability. This method is not only easy but also accurate when compared to the traditional morphologic method. Application of this approach can greatly improve plant species delimitation.
Abstract:
We investigated the dormancy mechanism of Gentiana crassicaulis Duthie ex Burk. seeds, as well as the applicable technology to break the seed dormancy and encourage rapid germination. The water absorption of seeds and activity of crude extracts were determined using dried G. macrophylla seeds, which were dry stored for after-ripening. We conducted the germination experiment by soaking seeds in priming solutions of gibberellic acid (GA3), potassium permanganate (KMnO4), polyethylene glycol(PEG6000) or hydrogen peroxide (H2O2), and then compared seed germination under the different treatments. Results showed that the G. crassicaulis seed capsules did not impede water absorption to any great extent. At the different concentrations, the crude extract showed inhibitory effects on the germination and growth of Chinese cabbage and wheat, and a certain inhibition effect on the germination of G. crassicaulis, which was the most significant (P < 0.05) when the concentration reached 0.1 g/mL. The KMnO4 treatment significantly improved the germination rate of G. crassicaulis seeds and was the most significant (P<0.05) at a concentration at 1.5%, whereas treatment with H2O2 had a much less significant effect. In addition, soaking with 500 mg/L of GA3 and priming with 300 mg/L of PEG6000 disturbed the seed dormancy of G. crassicaulis (P < 0.01). Our research showed that the seed endogenous inhibition of G. crassicaulis is one of the factors affecting dormancy, and that the seed mechanical barrier affects seed germination to a certain extent. The G. crassicaulis seeds showed comprehensive dormancy characteristics. Soaking the seeds with KMnO4 and GA3 and priming with PEG6000 interrupted seed dormancy, shortened germination time, and promoted germination.
Abstract:
In the present study, the effect of mannitol concentration, combination of different enzyme (cellulase and macerozyme) solutions, and enzymolysis time on the separation of mesophyll protoplasts and purification of protoplasts from two high density separating solutions were studied in the leaves of tea seedlings. The results demonstrated that high quality mesophyll protoplasts were obtained from tea leaves subjected to enzymatic digestion in a solution containing 0.6 mol/L mannitol, 1.5% cellulase, and 2.5% macerozyme for 16-18 h in the dark. In addition, protoplasts gathered into a band on the layer between 10% mannitol and 25% iodixanol.
Abstract:
Fruits are the reproductive organs of angiosperms and greatly influence the pattern, effectivity, and distance of seed dispersal. Fruit type diversity is partly responsible for the ecological variation among plant taxa and impacts the diversification rates and patterns of flowering plants. This review expounds several key pathways and the evolutionary mechanism of fruit type diversity, discusses the potential factors affecting the evolution of fruit types, and illustrates the evolutionary routes and patterns of fruit types to provide insight into angiosperm fruit diversity and evolution.
Abstract:
Cytoplasmic male sterility (CMS) is a maternal genetic trait widely found in higher plants. CMS is not only a favorable material for studying the interaction between mitochondrial and nuclear genes, but also an important basis for the utilization of plant heterosis, with its molecular mechanism the focus of current research. Evidence suggests that mitochondrial genes are closely related to CMS. With the continuous development of molecular biology and genetics, many plant fertility restoration (Rf) genes have been mapped and cloned, further elucidating the molecular mechanisms of plant CMS and Rf. This review summarizes the recent research advances in CMS and Rf-related genes in plants, and explores the application of the CMS/Rf system in breeding.
Abstract:
Carotenoids are important components responsible for the coloration of apples, with both the composition and content of carotenoids deciding fruit appearance and nutritional value. We reviewed the recent advances in the study of carotenoids in apples, including carotenoid content and composition, changes during fruit development and storage, genes and enzymes involved in the carotenoid biosynthetic pathway, and the relationship between environmental factors and accumulation of carotenoids. The regulatory mechanism of the carotenoid biosynthesis pathway in the apple remains to be further studied.
Abstract:
Plant leaves represent an important interface between a plant and the surrounding environment, and their functional traits are influenced by the external environment and phylogeny. Elucidating variations in leaf functional traits in different environments is crucial to understand plant adaptation. In this paper, the types and functional significance of the functional traits of leaves are summarized. Related studies on the two main factors affecting the functional traits of leaves (environmental factors and phylogenetic history), as well as involvement in plant adaptation, are also discussed. Finally, we propose prospective research directions based on the current situation and future tendency of leaf functional trait studies.