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991.
Lin Shi Naiwei Li Shuqiong Wang Yubing Zhou Weijie Huang Yuchen Yang Yongpeng Ma Renchao Zhou 《PloS one》2016,11(1)
Ilex, the largest genus of dioecious woody plants, is a good study system to assess the role of hybridization in speciation and evolution. Ilex dabieshanensis, a tree endemic to Dabieshan Mountains region, was initially described as a new species. Based on morphological intermediacy and sympatric distribution with its putative parental species, I. cornuta and I. latifolia, we proposed it as a natural hybrid between them. In this study, we sequenced one chloroplast intergenic spacer (trnH-psbA) and two nuclear genes (gapC and nepGS) in I. dabieshanensis and its putative parental species to test the hybrid origin hypothesis. Our results showed that there were one to two differentially fixed sequence differences between I. cornuta and I. latifolia at the two nuclear genes. Twelve of the 14 individuals of I. dabieshanensis exhibited additivity in chromatograms on these differentially fixed sites at both nuclear genes, and the remaining two exhibited additivity in chromatograms on the fixed site at only the nepGS gene. Except one haplotype of I. cornuta at the nepGS gene, all of the haplotypes of I. cornuta at the two nuclear genes were well separated from those of I. latifolia, and most haplotypes of I. dabieshanensis were shared with those of I. cornuta and I. latifolia. Phylogenetic analysis of these haplotypes was largely consistent with haplotype network analysis. I. cornuta and I. latifolia differed by two nucleotide substitutions in the chloroplast intergenic spacer, and 12 individuals of I. dabieshanensis had the same sequences as I. latifolia, while the remaining two were identical with I. cornuta. The molecular data provide convincing evidence for the hybrid origin of I. dabieshanensis and asymmetrical direction of hybridization. One haplotype of I. cornuta at the nepGS gene was nested with those of I. latifolia, indicating introgression to I. cornuta. 相似文献
992.
【目的】采用免培养的方法研究新疆艾比湖湖底沉积物放线菌组成及多样性。【方法】采集并混合5份艾比湖湖底沉积物样本,并提取其总DNA,采用放线菌通用引物对其16S r RNA基因序列进行Touchdown PCR,构建放线菌16S r RNA基因文库。蓝白斑筛选后随机挑选白色克隆分析,利用限制性内切酶HhaⅠ进行酶切分型,挑选具有独特限制性片段差异的阳性克隆进行测序分析。序列经Chimera Check检测,BLAST同源比对及构建16S r RNA基因序列系统发育树。【结果】随机挑选192个白色克隆,其中166个为阳性克隆,选取51个具有独特限制性片段差异的克隆进行序列分析。测序结果进行比对以及Chimera Check检测后,共获得36个可操作单元(Operational Taxonomic Units,OTUs),Gen Bank注册号为KR182090-KR182131。文库覆盖度结果表明克隆文库涵盖了本环境中90.4%的放线菌类群。聚类结果显示,艾比湖湖底沉积物中放线菌分为2个类群,第1个类群属于放线菌门(Actinobacteria),放线菌纲(Actinobacteria)中的放线菌目(Actinomycetales)、丙酸杆菌目(Propionibacteriales)、微球菌目(Micrococcales)和棒杆菌目(Corynebacteriales)4个目,该类群占克隆文库18.1%;另外1个类群属于Unclassified Actinobacteria的类群,分为3个不同的group,占整个克隆文库的81.9%。【结论】新疆艾比湖湖底沉积物中存在多种未知的放线菌类群。 相似文献
993.
Yicong Ma Sajal?K. Ghosh David?A. DiLena Sambhunath Bera Laurence?B. Lurio Atul?N. Parikh Sunil?K. Sinha 《Biophysical journal》2016,110(6):1355-1366
The cholesterol partitioning and condensing effect in the liquid-ordered (Lo) and liquid-disordered (Ld) phases were systematically investigated for ternary mixture lipid multilayers consisting of 1:1 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphocholine with varying concentrations of cholesterol. X-ray lamellar diffraction was used to deduce the electron density profiles of each phase. The cholesterol concentration in each phase was quantified by fitting of the electron density profiles with a newly invented basic lipid profile scaling method that minimizes the number of fitting parameters. The obtained cholesterol concentration in each phase versus total cholesterol concentration in the sample increases linearly for both phases. The condensing effect of cholesterol in ternary lipid mixtures was evaluated in terms of phosphate-to-phosphate distances, which together with the estimated cholesterol concentration in each phase was converted into an average area per molecule. In addition, the cholesterol position was determined to a precision of (±0.7Å) and an increase of disorder in the lipid packing in the Lo phase was observed for total cholesterol concentration of 20∼30%. 相似文献
994.
Isotopic perspectives (δ13C, δ15N, δ34S) of diet,social complexity,and animal husbandry during the proto‐shang period (ca. 2000–1600 BC) of China
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995.
The objectives of this field experiment were to study the growth characteristics and yield potential of rice plants under non‐flooded irrigation in arid area. Non‐flooded treatments included drip irrigation with plastic mulching treatments (DIs), furrow irrigation with plastic mulching treatment (FIM) and furrow irrigation with non‐mulching treatment (FIN). Conventional flooded cultivation (F) was check treatment (CK). The four drip irrigation treatments differed in the amount of water applied before and after panicle initiation. Root length density, leaf dry weight, shoot dry weight and root activity were generally higher in the non‐flood‐irrigated treatments (especially the drip‐irrigated treatments) than in the flood‐irrigated treatment at mid‐tillering. However, the growth and development of rice plants were limited after jointing in the non‐flooded irrigation treatments. Increasing the root/shoot ratio and root length density in the 20–40 cm depth and decreasing specific root length at 0–20 cm soil layer were important mechanisms for helping the rice plants to adapt to the non‐flooded environmental stresses. Finally, the grain yield in the non‐flooded irrigation treatments was lower than that in the F treatment. These low yields were mainly attributed to the low root length density at 0–20 cm depth and root activity. Generally speaking, the restricted degrees in the DIs were smaller than that in the FIM and FIN treatments. Among the DIs, both the highest grain yield (8223–8900 kg ha?1) and the highest water use efficiency (WUE) (0.63) were observed when the soil water content was kept at ?30 kPa before panicle initiation and at ?15 kPa after panicle initiation (referred to as the DI2 treatment). The yield in the DI2 treatment was not significantly different than that in the flood‐irrigated treatment. However, WUE was 2.5 times higher in the DI2 treatment than in the F treatment. These results suggest that drip irrigation technology can be considered as a better water‐saving cultivation of rice plants in arid region. 相似文献
996.
997.
Y. Yang N. Yao Z. K. Jia J. Duan F. J. Chen Z. Y. Sang L. Y. Ma 《Biologia Plantarum》2016,60(3):555-562
In northern China, freezing injury is observed frequently in the rare species Magnolia wufengensis but not in the more common species Magnolia denudata. To investigate the role of the phytohormone abscisic acid (ABA) on frost tolerance in these two species, exogenous ABA was applied to the seedlings and then physiological and biochemical responses were measured during cold acclimation. Shoot growth cessation was stimulated by ABA in M. wufengensis but not in M. denudata. Abscisic acid inhibited shoot growth in M. wufengensis but not in M. denudata. Treatment with ABA stimulated leaf senescence in both species, and this effect was greater in M. denudata. For both species, ABA-treated plants exhibited bud dormancy sooner and had an increased tolerance to freezing, decreased water content and increased accumulation of proline, glucose, and fructose in shoots. These effects were generally greater for M. denudata. Freezing tolerance was significantly correlated with content of water, proline, glucose, and fructose for both species, but freezing tolerance was significantly correlated with raffinose content only in M. wufengensis. We conclude that exogenous ABA could increase cold acclimation and improve cold hardiness of both Magnolia species, although M. denudata was more responsive to ABA than M. wufengensis, which might result from a greater dehydration and accumulation of proline and certain soluble sugars. 相似文献
998.
Iron is required for the Fe-S cluster assembly which occurs in chloroplasts, mitochondria, and cytosol and here we characterized 44 Fe-S cluster biosynthesis genes and investigated their expression profiles during different peach flowering stages. Quantitative real-time PCR analysis shows that the highest expression of most peach Fe-S cluster biosynthesis genes appeared in the full bloom stage. Also, the highest Fe accumulation occurred in the full bloom stage followed by beginning bloom, petal fall, and bud swell stages. Activities of nitrite reductase (NiR) and succinate dehydrogenase (SDH) were closely correlated to the flower Fe content, whereas the aconitase (ACO) activity kept steady during the whole flowering process. Moreover, shading treatment significantly reduced Fe accumulation and NiR, SDH, and ACO activities of the full blooming flowers. Seventeen Fe-S cluster biosynthesis genes were down-regulated in response to a shading treatment. In particular, plastid sulfur mobilization genes were sensitive to the shading treatment. 相似文献
999.
J. Wang Y. Zhang Y. Li X. Wang Z. Liu W. Nan C. Zhao F. Wang J. Ma Y. Bi 《Biologia Plantarum》2016,60(2):299-310
A wide range of microorganisms found in the rhizhosphere are able to regulate plant growth and development, but little is known about the mechanism by which epiphytic microbes inhibit plant growth. Here, an epiphytic bacteria Stenotrophomonas maltophilia, named as LZMBW216, were isolated and identified from the potato (Solanum tuberosum L. cv. Da Xi Yang) leaf surface. They could decrease primary root elongation and lateral root numbers in Arabidopsis seedlings. The inhibitory effects of LZMBW216 on plant growth were not due to a reduced indole-3-acetic acid (IAA) content, as exogenously applied IAA did not recover the inhibition. Furthermore, LZMBW216 did not affect the expression of DR5::GUS and CycB1;1::GUS. However, we found that LZMBW216 exhibited little effect on the primary root elongation in the pin2 mutant and on the lateral root numbers in the aux1-7 mutant. Moreover, LZMBW216 decreased expressions of AUX1 and PIN2 proteins. Together, these results suggest that root system architecture alterations caused by LZMBW216 may involve polar auxin transport. 相似文献
1000.
Li Hongbo Wang Xin Rengel Zed Ma Qinghua Zhang Fusuo Shen Jianbo 《Plant and Soil》2016,409(1-2):405-417
Plant and Soil - Nutrient patches in soil have a limited life-span, but the long-term costs and benefits of root foraging in agro-ecological systems are poorly understood. Maize (Zea mays L) was... 相似文献