Northeast China Transect (NECT), one of the fifteen International Biosphere-Geosphere Programme (IGBP) terrestrial transects, has been established for 10 years by Prof. Zhang Xin-Shi, through a core project of the IGBP — the Global Change and Terrestrial Ecosystems (GCTE). This transect is located in the mid-latitude semi-arid region, ranging 42-46°N latitude and 110-132癊 longitude. The primary driving force for global change is precipitation and the secondary one is land use intensity. Research progresses have been performed during the past decade in the following aspects: ecological database development, climate and its variability, ecophysiological response of plants to environments, vegetation and landscape changes, biodiversity patterns and their changes, plant functional types and traits with relation to climatic gradient, productivity and carbon dynamics, pollen-vegetation relationship, trace gas emissions, land use and land cover changes, as well as biogeographical and biogeochemical modelling. In order to achieve the higher level of integrated research, the NECT needs the consistent basic data sets within the same framework, further field experiments and observations, integrated simulations of vegetation structure, process and function from patch, landscape to biome scales, intercomparisons of results and simulations within the transect and to other IGBP transects, multidisciplinary research, national and international co-ordinates, and full scientific plan and implementation strategy.
The function of biomacromolecule is dependent on its space structure. X-ray diffraction analysis is generally an important way to obtain structural information of biomacromolecules. Here, the main advances in the growth and X-ray diffraction analysis of nitrogenase crystals are briefly introduced and reviewed. At last, the challenge and prospect of nitrogenase crystallography are discussed.
The infrared spectroscopic study of leaves of nine sections, 43 species, one subspecies and one variety in Hypericum L. and two species in Triadenum Raf. were conducted directly and rapidly with FTIR and OMNI-sampler accessory. The results showed that the infrared spectra of Hypericum and Triadenum were fingerprint-like patterns which were highly typical for different taxa. Significant differences in the infrared spectra were found between these two genera and among the nine sections of Hypericum. And certain differences exist in the spectra among species in the same section of Hypericum or in the Triadenum. Furthermore, no significant difference was found in the infrared spectral patterns in the leaves at various developmental stages and in leaves of the same species collected from different geographic regions, although occasionally geographic difference did exist in the same species. The results indicated that the infrared spectra of leaves are of taxonomic value at the level of species and sections in these two genera, and this technique can be widely used for identification and classification of other taxa when standard spectra are available.
In this paper a new species of anatomically-preserved lepidodendralean stem is described from coal balls in the No.16 coal seam of the Taiyuan Formation in Shanjialin Coal Mine, Tao-Zao Coal Field, southern Shandong Province. The stem has a well preserved stele, outer cortex, periderm and leaf cushions preserved. Its organization is protostelic and it lacks secondary xylem. Outer cortex consists of alternatively arranged radial thick-walled cell bands and damaged thin-walled cell areas. Periderm is well developed, 4-5 mm wide, and is divided into phellem and phelloderm. Phelloderm is wider than the phellem and is generally uniform but in some places is differentiated into alternatively arranged zones of tangentially thicker- and thinner-walled cell bands. Leaf cushions are approximately equidimensional or rhomboidal in tangential section, whereas leaf scars are slightly elevated and are probably lenticular or helmet-like in shape, located at the upper part of the leaf cushion. Leaf cushions are flat and lack a well developed keel or plications. Leaf traces extend through a horizontal course in the cushion and turn upwards slightly and then horizontally into the leaf scars, resulting in the outermost parts of the course being somewhat “S” shaped. In radial section ligule pits are obliquely orientated with a broad basic part and its aperture is directly located at the top of the leaf scar. The ligule is large, ovoid in shape, and approximately 1.2 mm long and 1.0 mm wide. Compared with the stems of other genera in Lepidodendrales, the stem under discussion is most comparable to the stems of Diaphorodendron to which it is here assigned. Each of the three previously known species of Diaphorodendron occur in the middle Late Carboniferous of the Euramerican Flora and are distinct from the stem under discussion in the form of the leaf cushions. These differences support the erection of a new species, D. rhombicum, representing the first discovery of the genus from late Late Carboniferous and Permian ages worldwide, and also representing the first occurrence of the genus within the Late Palaeozoic Cathaysian Flora. It is very interesting that the new species bears equidimensional leaf cushions with that probably represents a derived feature within the genus, while the leaf cushions with greater vertical than horizontal dimension occupied by the Euramerican species of Diaphorodendron are here considered ancestral in morphology. This hypothesis is supported by the younger geological age (late Late Carboniferous or early Early Permian) of the new species than that (middle Late Carboniferous) of the previously known Euramerican species of Diaphorodendron.
Effects of exogenous sodium nitroprusside (SNP), a nitric oxide (NO) donor, on the salt tolerance of wheat (Triticum aestivum L.) seedlings indicated that NO donor significantly alleviated the growth inhibition, water loss and the decay of chlorophyll in wheat seedlings caused by 150 mmol/L NaCl salt stress, thus led to the promotion of salt tolerance against salt stress. Combined with 1 mg/mL hemoglobin treatment reverted the above SNP actions by restoring the growth of wheat seedlings and chlorophyll content to the level found in untreated wheat seedlings under salt stress. The specific role of NO in regulating the salt tolerance of wheat seedlings under salt stress was confirmed by using NaNO2 and K3[Fe(CN)6] as control. Further investigation showed that the effect of both which might be related to the induction of plasma membrane H+-ATPase and H+-PPase (H+-pyrophosphatase) activities by NO in the roots of wheat seedling under salt stress. NO obviously enhanced the hydrolylic activities of H+-ATPase and H+-PPase, but did not affect the H+ transport ability across plasma membrane in wheat seedling roots under salt stress. Treatment with exogenous CaSO4 and EGTA also showed that Ca2+ was vital to the NO induced activities of H+-ATPase and H+-PPase respectively in the roots of wheat seedling under salt stress. Investigation of NO on the content of Na+ and K+ in the roots of wheat seedlings illustrated that NO did not obviously affect the content of Na+, but significantly elevated the content of K+ as well as leading to the increase the ratio of K+ to Na+ in the roots of wheat seedling under salinity conditions. This was also important to believe that NO induced the adaptive abilities of wheat seedlings against NaCl salt stress.
Chlorophyll a fluorescence and circular dichroism (CD) spectra of photosystem Ⅱ (PSⅡ) membrane were measured after heat treatment. The chlorophyll fluorescence parameter Fo'' remained stable after treatment at the temperatures from 30 ℃ to 40 ℃ and then reached a maximum after treatment at 55 ℃. In PSⅡ membranes and LHCⅡ (light-harvesting chlorophyll a/b binding complex)-enriched complexes, anomalous CD signals with extremely large amplitudes occurred during the heat treatment. The temperature corresponding to the maximum anomalous CD intensity peaking at 677 nm was 40 ℃. The results indicate that the aggregation state of the LHCⅡ in PSⅡ is related to the anomalous CD signal, and can be an important factor influencing Fo'' in the heat treatment of PSⅡ membrane.
In the present study our investigation shows that phosphorylation of tonoplast proteins purified from maize (Zea mays L.) roots increases obviously V-type H+-ATPase (V-ATPase) activities of ATP hydrolysis and H+ transport. Further research indicates that some of the purified tonoplast proteins can be thiophosphorylated and one band about 69 kD is identified as subunit A with antibody against subunit A of V-ATPase. In order to determine the phosphorylation site(s) in subunit A of V-ATPase, the subunit A band at 69 kD was isolated from thiophosphorylated gel and then completely digested by trypsin. After purification of these enzymatic lysis fragments with RP-HPLC, the molecular weight of phosphorylated peptide fragment was determined as 573.83 Da with mass spectrometry. Data search indicates that subunit A can generate 61 peptide fragments after tryptic digestion, of which only F56 with molecular weight of 573.66 Da is close to that of the identified fragment, and F56 can only be phosphorylated at Ser525. Therefore our research suggests that Ser525 is the potential phosphorylation site of V-ATPase subunit A in maize roots. To our knowledge, this is the first time to determine the phosphorylation site of V-ATPase subunit A in plants.
A set of wheat germplasms with rye’s characters was obtained by crossing the Triticum aestivum L. cv. “Xiaoyan No.6” and Secale cereale L. cv. “German White”. Eight lines were found carrying rye chromosomes or segments by genomic in situ hybridization (GISH), including three addition lines, one substitution line and four translocation lines. Two-color fluorescent in situ hybridization (FISH) was used to identify the genome composition and individual chromosome of the hybrids using pSc119.2 labled with fluorogreen and pAs1 labled with fluorored as probes. The partial results showed that BC116-1 is a wheat-rye 1RS/1BL translocation line; BC152 is a monosomic 1RS/1BL translocation line; BC97-2 is a disomic substitution line with a pair of 2D chromosomes substituted by 2R; BC122-3 is a 6R monosomic addition line with one of the long arm of 6B deletion. The application of sequential GISH and two-color FISH in wheat breeding is discussed.
Initiation and development of resin ducts were studied in cortex of stem of Pinus massoniana Lamb. by thin section. It is shown that the development of resin ducts can be divided into four stages: the initial stage, the intercellular space forming stage, the lumen expanding stage and the mature stage. To further investigate the original mode of resin ducts, cytochemical localization of pectinase with a transmission electron microscope (TEM) was conducted. Results showed that the pectinase was active during resin duct development. At the initial stage, reaction products of pectinase first appeared in the corner of swollen cell wall among the future epithelial cells and later along the walls. At the intercellular space forming stage, reaction products occurred in the cell wall/intercellular space interface and its density decreased while the intercellular space enlarged. At the mature stage, no reaction products were found in the walls of the epithelial cells. These results indicate that pectinase catalyzes the degradation of the middle lamella of the epithelial cells during the resin ducts development. The cytochemical evidence supports that the resin ducts are formed by schizogeny. This report represents the first direct evidence for the involvement of pectinase in resin ducts formation .
The long hull floral organ mutant in rice (Oryza sativa L.) was firstly discovered in the hybrid progeny of a wild rice (O. nivara Sharma et Shastry) and a cultivar rice (O. sativa subsp. indica Kato). The florets of the mutant plant show long, leafy paleas/lemmas that result in open hulls. A single floret consists of one to ten stamens, one to three pistils and one to five stigmas on the same ovary. Stamens/pistils-like structures and bulged tissues near ovaries were observed. Low seed setting rate was another obvious character of this mutant. According to statistical analysis, seed setting rate was 18.2%. The percentage of pollen fertility was 62.46%. The process of floral organ morphogenesis was also investigated using scanning electron microscopy (SEM), and genetic analysis indicated that mutant traits were controlled by single recessive gene (temporarily designated as lh). The possible relationships between this lh gene and other floral organ mutants reported earlier in rice are discussed. Furthermore, we deduced that this gene might represent an example of a gene required for generating proper floral organ number and also be similar to B-like genes in Arabidopsis and Antirrhinum.
In the present study the authors observed and reported the morphological characters and development process in all stages of the life history of Monostroma latissimum Wittrock for the first time in China. The process of parthenogenesis has also been observed in yearly culture. When the dioecious macrogametophytes mature, they liberate biflagellate gametes, and when the spherical microsporophytes mature, they produce quadriflagellate zoospores. Its life history is a periodical heteromorphic alternation of haploid gametophyte generation and diploid sporophyte generation. In addition, this study indicates the multiplication of zygotes and cysts by binary fission, two-year-old cysts compared with gametophytes living for one year in the life history of M. latissimum. The male and female gametes that do not conjugate also undergo parthenogenesis as they adhere to the substrates. They become unicellular bodies, spherical in shape, somewhat smaller than the zygotes. Then, the cysts of parthenogenesis mature and liberate a number of quadriflagellate swarm spores. These spores adhere to substrates and germinate directly into the leaf fronds. As for zygotes, parthenogenesis of the male and female gametes also can be used for artificial seeding of M. latissimum in culture.
Using degenerate oligonucleotide primers and genomic PCR reactions, the complete coding region sequences of two 1Ay high molecular weight (HMW) glutenin subunit genes were amplified from Triticum urartu accessions that showed differential expression of the 1Ay HMW glutenin subunits in their seeds. The coding sequence amplified from the accession that expressed the 1Ay gene (Tu1Ay-e) was highly homologous to that of known y type HMW glutenin subunit genes. Consequently, the primary structure of the protein translated from the coding sequence of Tu1Ay-e was identical to that of previously published y type subunits. Bacterial expression of the coding sequence of Tu1Ay-e produced a polypeptide identical to the 1Ay subunit extracted from seeds, indicating that the cloned sequence was an accurate representation of the original coding region of Tu1Ay-e. In contrast, the coding region sequence amplified from the accession that did not express 1Ay subunit contained three in-frame premature stop codons. Based on past findings on silenced HMW glutenin subunit genes, we conclude that the presence of in-frame premature stop codon(s) is an important feature of the silenced 1Ay gene (Tu1Ay-s) in T. urartu. The potential value of the active 1Ay gene in improving the end use quality of common wheat and the mechanism underlying 1Ay gene silencing are discussed.
Cotton (Gossypium hirsutum L.) fibers are derived from the outer integument of ovule, while little is known about cotton ovule development. In order to identify and analyze the expression of genes associated with cotton ovule development, a cDNA array approach was used to screen for genes with altered expression in cotton ovule before and after anthesis, and 25 differentially expressed genes were subsequently identified. Among them, GhIAA16 encodes a predicted polypeptide of 208 amino acids highly homologous to Arabidopsis IAA16. Molecular analysis revealed that it is a single-copy gene in cotton genome and specifically expressed in the ovule endothelium. To our knowledge, GhIAA16 is the first endothelium-specific gene isolated from cotton. Its possible function is discussed during cotton ovule formation.
Stylosanthes guianensis Swartz, one of the most important tropical forage legumes, is native to South and Central America and Africa. Anthracnose, caused by the fungus Colletotrichum gloeosporioides (Penz.) Sacc., is a major constraint to the extensive use of Stylosanthes as tropical forage. Forty-two accessions of S. guianensis were assessed by amplified fragment length polymorphism (AFLP) for genetic diversity and for resistance to anthracnose. In AFLP analysis, four selective primer combinations screened from 96 primer combinations were used to analyze these accessions, which showed a 95.5% level of polymorphism on average. Genetic similarity from 31.0% to 95.0% among the accessions was calculated with NTSYS-pc software. The dendrogram was constructed with unweighted pair group method of averages (UPGMA) based on the AFLP data, and five clusters were defined at 48% genetic similarity. Principal coordinates analysis showed that the contribution of the first principal coordinate and the second one to the genetic variation of 42 accessions is 56.04% and 6.40%, respectively. Two typical strains of C. gloeosporioides from Stylosanthes in China were used for anthracnose resistance screening. All plant accessions showed variation in the reaction to two strains, and the correlation of resistance had a value of 0.904 (P ＜0.01), suggesting the common resistance to the two strains. The resistant accessions were randomly distributed in the different groups of UPGMA clustering. Also, these results demonstrate that AFLP analysis is an efficient method for evaluating the genetic diversity among S. guianensis accessions.
Seven genes encoding glutenin subunits that present in Agropyron elongatum (Host) Nevski were cloned by PCR analysis and named AgeloG1 to AgeloG7. The complete open reading frames (ORFs) of the seven genes were amplified with primers special for high-molecular-weight (HMW) glutenin subunit genes and subsequently cloned and sequenced. Five of them were completely sequenced, and the other two (AgeloG1 and AgeloG4) were sequenced at the two ends only. Comparison of amino acid sequences suggested that the primary structure of the subunits encoded by the seven genes was very similar to that of y-type HMW glutenin subunits published from wheat, though four of them (AgeloG4, AgeloG5, AgeloG6 and AgeloG7) were shorter than 1.8 kb. Phylogenetic analysis of the five completely sequenced genes and those subunit genes of Triticum aestivum L. (AABBDD), Aegilops tauschii Coss. (DD), Aegilops caudata L. (CC), Secale cereale L. (RR) and Aegilops umbellulata Zhuk. (UU) indicated that the AgeloG2 was most closely related to 1Dy; the AgeloG3 was to 1By; the AgeloG5, AgeloG6 and AgeloG7 were to 1Ay.
In our previous study, a cDNA library to poly(A) RNA isolated from mature pollen of Zea mays L. was constructed. One cDNA fragment, designated ZM401 (Z. mays), was obtained from maize mature pollen cDNA library by differential screening and cold-plaque screening method. It was specifically or preferentially expressed in mature pollen. According to the ZM401 cDNA fragment sequence, full length of ZM401 cDNA was generated by 5'' and 3'' RACE methods. ZM401 cDNA was 1 149 bp in length. Within the full-length cDNA sequence, a clear open reading frame (ORF) was undectable by OMEGA 2.0 and DNAMAN softwares. The longest potential ORF was 269 nucleotides (791–1 060), coding 89 AA, had a poor consensus sequence for translation initiation. But it had a poly(A) tail. All these results suggested that ZM401 was one of a growing number of non-coding mRNA-like RNA transcripts that exerted their cellular functions directly as RNA. RT-PCR and Northern blotting analyses showed the ZM401 was transcribed from tetrad stage of microspore development and increased in concentration up to mature pollen, which suggested that ZM401 belongs to late gene in pollen development. Two transcripts of the ZM401 gene were detected by Northern blotting analysis (1.2 kb, 2.0 kb). Southern hybridisation showed that the ZM401 in corn was present in one or a very few copes in the maize genome.
For Upcoming Special lssue: