Alpine ecosystems are characterised by frequent fluctuations between high and low temperatures. The resistance of alpine plants to low temperatures has received considerable attention, but little is known about their adaptation to extremely high temperatures (>45℃). In this study, the alpine species Arabis paniculata was shown to display superior basal thermotolerance and acquired thermotolerance than its relative Arabidopsis thaliana. Our chlorophyll fluorescence data suggest that under heat shock conditions, Apaniculata has a thermostable photosystem II (PSII) and that efficient nonphotochemical quenching maintains a high level of photosynthetic efficiency. Assays of ion leakage and malondialdehyde (MDA) content revealed that membrane damage caused by high temperatures was less severe in Apaniculata than in Athaliana. The degree of unsaturation and fatty acid chain length was closely correlated with membrane fluidity. Compared with Athaliana, Apaniculata had a lower 16∶3 (roughanic acid) content, longer fatty acid chain length and no major alterations in the level of unsaturation of membrane fatty acids; this might enable the maintenance of stable membrane fluidity. Furthermore, more extensive accumulation of heat shock proteins (HSPs), such as HSP101 and HSP70 in Apaniculata compared with Athaliana, might correlate with better protection against high temperature in Apaniculata than in Athaliana. Our findings suggest that the alpine plant Apaniculata uses all of these physiological and biochemical adjustments to adapt to high temperature, and that similar to lowland tropical species, Apaniculata exhibits systemic thermotolerance. Accordingly, Apaniculata might be a useful model plant to study the molecular and physiological mechanisms that contribute to thermotolerance in plants.
Temperature is an important factor to impact seed germination. Under the background of climate warming and grassland degradation, it includes great value to understand temperature change on seed germination of Stipa purpurea. In the present study, six constant temperature conditions (5, 10, 15, 20, 25, and 30℃) and three variable temperature conditions (5/15, 10/20, and 15/25℃) were set to systematically detect the effects of temperatures on seed germination characteristics of Stipa purpurea from three different populations. The results showed that the more suitable seed germination temperature of Spurpurea ranged from 15 to 25℃, and temperatures lower than 10℃ or higher than 30℃ would not be conducive to seed germination. Compared to the corresponding constant temperatures, variable temperature conditions had no effects on promoting seed germination of Spurpurea. Seed germination characteristics of Spurpurea from different populations responded to temperature change with both same and different points. Correlation analysis revealed that altitude showed highly significant negative correlation with the germination rate, whereas soil temperature of seed germination seasons in the field had significant negative correlation with seed germination delay. This study will provide a scientific basis for reasonable protection and restoration of Spurpurea meadow.
The 10 bamboo species for cloning lea3 gene concern two superfamily, six families and three subtribes，they are Thyrsostachys siamensis,Bambusa multiplex, Bambusa textilis, Dendrocalamus farinosus, Neosinocalamus affinis, Dendrocalamus semiscandens, Phyllostachys heterocycla, Chimonocalamus delicates, Pleioblastus amarus, Sasa fortunei. In the branch model and branch site model test, found that different bamboo species containing lea3 gene under different selection pressure, purifying selection function is in dominant (omega<1). In the site model test, detected a total of 18 significant positive selection sites, account for 111% of the total amino acid number. Locating the 18 significant positive selection sites, found 15 sites located 11 amino acid tandem repeat sequences areas, this means that 11 amino acid tandem repeat sequences areas of lea3 gene than in other regions more easily affected by natural selection effect. At the same time, based on the results of the site model test, through located these intence purifying selected sites, found a long no purifying selection sites area in 11 amino acid tandem repeat sequences.
DEADbox RNA helicases play an important role in multiple biological processes, including growth, development, stress response and metabolism of cell. A fulllength cDNA of DEADbox RNA helicase, named EaRH1, has been cloned from Equisetum arvense in this study (GenBank accession number: KJ734026). Sequence analysis indicates that the cDNA of EaRH1 is 3230bp in full length, and contains an ORF region from 487bp to 2799bp, encoding 770 amino acids. The corresponding protein includes 9 conserved mode structures. Comparison with the sequence of the DEADbox RNA helicase of other species, it is showed that the sequence of Motif Ⅰa, Motif Ⅱ and Motif Ⅲ are almost completely same while there are certain differences in sequence of Q motif, Motif Ⅰand Motif Ⅳ. The similarity of the EaRH1 sequence with the hypothetical DEADbox RNA helicase protein of Selaginella moellendorffii reaches 69%. And the highest sequence similarity is concentrated in the domain that includes 9 conserved motifs. Phylogenetic analysis of DEADbox RNA helicases sequences from different plants indicates that Equisetum arvense is more closely related to a DEADbox gene of Arabidopsis thaliana (At3g22320). It can be inferred from sequence comparison and phylogenetic analysis that EaRH1 might be involved in growth and development, miRNA biogenesis, interaction with RNA binding protein and abiotic stress responses. Our study provides references for further functional researches on DEADbox RNA helicases of Equisetum arvense.
Microsatellites remain the most popular markers in the studies of population genetics, conservation biology and molecular ecology because of its ease to development, high mutation rate and lowcost. Nowadays, the improvement of new technologies, such as NextGeneration Sequencing (NGS), multiplexPCR and capillary electrophoresis system have greatly promoted the development and using of microsatellite markers. However, null alleles, one of the most primary defects of microsatellite markers, widely presented in the studies using microsatellite markers, may lead to biased results. Unfortunately, the detection of null alleles has not been paid enough attention. In this review, we attempted to construct an indepth and comprehensive understanding on null alleles detection, and then, applied a detailed comparison for the different methods used to detect the occurrence of null alleles. Finally, we propose a meaningful suggestion for null allele’s detection in plant.
Viburnum species are widely used as ornamental shrubs in gardens and their hybrids with brilliant horticultural traits are increasingly popular worldwide. In this study, genome sizes of fourteen Viburnum species were estimated by using flow cytometry. Genome size for diploids ranged from 255pg in Vschensianum to 426pg in Vmacrocephalum form. keteleeri. And Vmacrocephalum form. keteleeri also had a more asymmetrical karyotype which may reflect its breeding history. The genome size of tetraploid species Vodoratissimum (762pg) was unusually more than twice as big as those of other diploid species, which revealed that polyploidization in this genus may be not remote in its evolution. These results lay a foundation for further research in the cytogenetics and taxonomy of Viburnum and provide useful insight into future hybridization efforts for this genus.
The karyotypes of the tribe Lilieae are rather constant bimodal, which is composed of 4 longer and 20 shorter chromosomes. However，it remains unclear which mechanisms (centric fission or polyploidisation) might contribute to the origin of biomodality in this tribe. Here, we collected the published data for all genera of the Li-lioideae and Medeoloideae, and re-analyzed the karyotype data. The evidence of individual chromosome features, fundamental number (FN), karyotype asymmetry and chromosome relative length indicated that centric fission is the main mechanism underlying karyotypic evolution in the Lilieae. However, centric fission is not expected to occur in isolation, and different mechanisms of karyotype change, such as pericentric inversion and segment translocation, are not mutually exclusive. Pericentric inversion and segment translocation may have played major roles in the karyotype evolution of the Tulipeae. Additionally, the karyotype analyses are carried out for the first time in three taxa: Fritillaria crassicaulis, Tulipa suaveolens, and Gagea oxycarpa.
Gametophyte development and oogenesis of the fern Microlepia platyphylla were studied using microscopy and transmission electron microscopy. The present studies have significance in clarifying the cytology mechanism of oogenesis and reveal the evolution status of Mplatyphylla. The spores are brown, tetrahedral and trilete. The spores germinate about 5-10 days after sowed. They develop into cordate prothallus through filament and plate stages. The development of the prothallus is the Adiantumtype. The adult prothallus are usually diecious. Antheridia (an) us ually are produced on irregular prothallus and archegonium (ar) are produced near the apical notch of the heartshaped prothallus. Sex organs are Leptosporangiatetype. Studies on the oogenesis showed that the archegonium develops from a superfacial initial cell under the growth point. Two divisions of the initial cell result in a tier of three cells, ie the upper cell, primary cell and basal cell. The primary cell finally develops into a neck canal cell, a ventral canal cell and an egg by two unequal divisions. The three cells were associated closely with each other. Then the neck canal cell and the ventral canal cell degenerated gradually. A separation cavity was formed between the ventral canal cell and the egg cell, but plasmodesmata still connected the ventral canal cell and the egg in pore region. Egg envelope and fertilization pore were formed in the matured egg. Nuclear evaginations were produced from the nuclear surface. It was showed that oogenesis of the fern Mplatyphylla is similar to the fern Pteridium aquilinum.
In order to breed highyield and highoil species, associated with 28 agronomic traits, 7 Cornus wilsoniana clones were observed and analyzed by variance, principal component, cluster and correlation analysis methods. Variance analysis showed that the variation coefficients of 28 agronomic characters ranged from 804% to 9430%, and the biggest variation was leaf pattern, such as leaf shape, leaf color and leaf margin character. Phenotypic differentiation coefficients ranged from 4527% to 9640%, and it showed that the inheritances of various characters were relatively stable. Main of inheritances were presented by four principal components, which are inflorescence, fruit, oil content and fruit quantity per cluster. According to the factor scores resulted from principal component analysis, these 7 clones were clustered into 4 groups. The highyield and highoil target species can be hybridized by group Ⅱ and group Ⅲ.
Based on literatures of alien invasive plants in China, the scientific names of sixteen species are revised, since their records in the Chinese literatures are confused: the same species with different scientic names were used by different authors in different regions and in different times, even different species with similar Chinese names were treated as identical. The data from floras updated were emplyed to compile the scientific name of each species, along with vernacular name, synonym, their origin and distribution both in China and abroad.
Three species and one variety: Brotherella recurvans, Clastobryum cuculligerum, Taxithelium liukiuense and Trismegistia calderensis var. rigida are reported as new records to China, and their description and illustrations are provided. These new records are based on the specimens from Hainan, Hong Kong and Yunnan.
A revision of Canoparmelia from the Hengduan Mountains (Yunnan, China) revealed the occurrence of Cecaperata, based on specimens previously identified as Parmotrema conformatum. Cecaperata is hereby reported as new to the flora of China. The study also led to the identification of Ctexana as a component of the flora of Yunnan. In order to make sure the systematic position of these species, a phylogenetic analysis of rDNA ITS sequence was also carried out in this paper, indicating that Cecaperata is closely related to Ctexana and Cconcrescens. Detailed information and discussion of these two new records are provided, together with a key to all the known taxa of Canoparmelia recorded from China. Following our revision, Parmotrema conformatum should be excluded from the flora of China.
A species of the genus Delphinium (Ranunculaceae), Dbrachyurum, is described as new from Yunnan Province. The diagnostic differences between it and the other species, with which it belongs to the same subsection, are given.
A species of the genus Thalictrum (Ranunculaceae), Tcuonaense, is described as new from Xizang Autonomous Region, China. The diagnostic differences between the new species and its closest ally, Treniforme, are given.
From 1985 to 2013, there were only 9 literatures reports on alien invasive plants in Jiangsu, less than 025% of total 3665 similar reports during the same period in China, and it was much disproportionate with the development level of social, economic, cultural and other aspects of the province. Through field investigation, literature review and specimen inspection, the preliminary statistics, analysis and discussion of 47 families 128 genera and 209 species of alien invasive plants in Jiangsu have been made, including their composition, origin, and the life form. All alien invasive plants were ranked into 5 grades according to the damage to ecosystem and economy: twentytwo malignant invasive species; fortyone serious invasive species; thirtytwo local invasive species; fiftyone general invasive species; a left 63 species with unknown damage wait for further observation. The characteristics of alien invasive plants in Jiangsu have been discussed, and the proposals of suggestion have been made.
