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Growth and Reproduction Characteristics of Plant's Kin Recognition in Two Different Lifestyle Species
No full textSome plant species grow with closely genetically related individuals, and may benefit from an ability to recognize kin and show cooperative behavior towards neighbors. Kin recognition has been demonstrated in few plant species till now and thus constrained the understanding of significance of kin recognition. We investigated different growth and reproduction characteristics of kin recognition in two lifestyle species, the annual plant Lolium multiflorum Lam. and the perennial plant Elymus sibiricus Linn., which the main differences between are in their root system types and nutrition demand. We observed less root biomass distribution in kin groups than stranger groups for L. multiflorum Lam., but no indication in shoot characteristics at either the individual level or group level. For E. sibiricus, there were no significant differences in any measured characteristic index between kin and stranger groups at any level. Our results suggest that kin selection or plant responses to kin may depend on plant features and life-form; the most sensitive traits to competition are more likely to respond to kin selection. In addition, we considered that kin selection was tensely associated with degree of competition. It could be that the moderate competition level in our experiment could not stimulate kin cooperation activity of E. sibiricus c 2018 Friends Science Publisher
Effects of 7-year enclosure on an alpine meadow at the south-eastern margin of Tibetan Plateau based on community structure and soil physico-chemical properties
No full text过度放牧作为青藏高原长期存在的人为干扰方式,严重地破坏了高山草地生态系统的结构及其功能。简便有效的围栏封育方式广泛应用于退化草地的修复过程中,但其修复效果存在两面性,因此系统科学地评估草地围封后的质量状况至关重要。本研究针对围封7年的青藏高原东南缘退化高山草地,基于围栏与放牧处理之间的草地群落生物量、物种多样性及土壤理化性质的差异对比,对草地质量进行了综合评估。结果表明:1)通过围栏修复7年后,围栏内大部分土壤理化指标有所改善,但仅有硝态氮含量差异达到显著水平;2)围栏内地上生物量和凋落物量均显著高于放牧区,分别增加了35.73%和65.75%,而围栏内外的物种多样性无显著性变化;3)采用主成分分析法对土壤质量进行评估,发现围栏内土壤质量有所改善,其综合得分(0.1)高于放牧区(-0.02),同时利用草地各项指标的变化与其权重值之间的关系对草地进行综合质量评估,发现围封7年后草地综合质量得到一定程度的恢复(相对得分为0.209),更多归因于土壤理化性质的改善。研究表明,围栏7年后退化高山草地质量有所提高。针对其修复作用的时效性,需实际应用中定期评估草地的修复状况,以达到围栏的最优实施效果
Genetic diversity of Sichuan Basin populations of Microhyla fissipes inferred from mt-COI gene sequences
No full text饰纹姬蛙(Microhyla fissipes)在中国广泛分布于秦岭以南地区,在四川盆地是常见的两栖动物之一,研究其种群遗传多样性可为当地两栖动物的保护与管理提供重要的遗传基础资料和理论依据.采用线粒体COI基因为分子标记,探讨四川盆地饰纹姬蛙种群遗传多样性及其分化程度、种群历史动态.共采集饰纹姬蛙28个种群354只,成功获得其COI基因618 bps片段序列.分析结果发现17种单倍型,总体单倍型多样性(H_d)为0.166,核苷酸多样性(P_i)为0.00075,基因流(N_m)为1.60.各种群间固定系数(F_(st))和遗传分化系数(G_(st))分别为0.270、0.140.中性检验中,Tajimas D =-2.380,P<0.001;Fus Fs =-22.169,P<0.02,均具有显著性差异;错配分布图呈泊松状的单峰.通过计算得出种群扩张时间约在更新世晚期0.235 Ma BP.上述结果表明,四川盆地饰纹姬蛙种群遗传多样性较低,种群间基因交流水平高,不同种群间遗传分化不明显,并且在历史上有过扩张的现象
Research Progress of Conductive Self-healing Materials
No full text导电高分子材料因具备良好的导电性、质轻和易加工特性而被广泛应用于航空、生物医学设备、化学生物传感器和能源等领域。然而,导电高分子材料在使用过程中不可避免地会产生微裂纹,从而破坏导电通路并使整个电子设备瘫痪。受生物体启发,设计和构筑具备自修复功能的导电高分子材料是研究的热点。本文介绍了导电自修复材料的最新研究动态,综述了自修复机理和材料的制备方法及应用前景,最后简要分析导电自修复材料目前存在的主要问题并展望其发展方向
The Lycodon gongshan Found in Panzhihua City of Sichuan Province, China
No full text2014年9月至2017年9月,在四川省境内的攀枝花大黑山森林公园、攀枝花盐边县红宝苗族彝族乡共采集到贡山链蛇(Lycodon gongshan Vogel and Luo,2011)标本2号,为四川省首次发现该物种。2号标本(标本号R20140901和PZH20170901)保存在中国科学院成都生物研究所
Land Use Change in the Three-River Headwaters in Recent 40 Years
No full text针对三江源草地退化、水土流失及环境恶化等问题,根据三江源19802015年7期1∶ 100 000土地利用数据集,运用ArcGIS 10.0空间统计分析工具,定性与定量相结合的方法分析了该区土地利用时空动态变化及未来变化趋势,结果表明: ①研究期土地利用变化显著,分为3个时期:前15 a (19801995年)草地退化,中间5 a (19952000年)土地利用变化缓慢,后15 a(20002015年)退化草地恢复。②从土地利用结构看,19802015年,低、高覆盖度草地、水域、建设用地波动上升,未利用地明显减少,减少了17.61%,中覆盖度草地和林地基本不变,草地总面积增加了13.45%,主要由未利用土地转化而来。③从土地利用类型转化看,以低中高覆盖度草地、未利用土地与水域之间的转化为主。④据CA-Markov模型预测:水域基本保持不变,高、低覆盖度草地、未利用土地、耕地和建设用地面积不断增加,林地面积减少。⑤人口、经济结构变化及政策的实施是土地利用变化的主要原因,生态资产的供需平衡是驱动因子。因此提出加强基础文化建设、保护天然草地、优化土地利用生产模式,使土地得到合理利用,促进该区可持续发展
Spatial and temporal patterns of soil erosion in the Tibetan Plateau from 1984 to 2013
No full text土壤侵蚀严重威胁着区域生态安全与社会经济的发展乃至人类的共同福祉.采用土壤侵蚀模型(RUSLE)得到青藏高原1984-2013年的土壤侵蚀情况,并分析土壤侵蚀强度的时空变化特征,探讨不同生态系统土壤侵蚀的变化特征及原因.结果表明,1984-2013年青藏高原的土壤侵蚀量逐年波动变化,土壤侵蚀强度由南向北逐渐减弱,剧烈侵蚀主要分布在青藏高原南部(日喀则地区、拉萨市、昌都地区和山南北部地区).其中灌木、高寒草甸和稀疏植被生态系统侵蚀强度较大;土壤侵蚀量最大的是高寒草甸生态系统(2.17 * 10~(10) t),其次是高寒草原(1.59 * 10~(10) t)和稀疏植被生态系统(1.30 * 10~(10) t).海拔3 000-4 000 m的土壤侵蚀强度最大,但土壤侵蚀量最大的是海拔4 000-5 000 m的地区. 30年里,研究区主要生态系统土壤侵蚀量有所减少(-1.78 * 10~8 t/a).其中,土壤侵蚀增加的区域主要包括羌塘高原南部地区和柴达木盆地外围地区;明显减少区域则分布于横断山脉喜马拉雅山脉中部地区.研究区主要植被生态系统覆盖度的增加有利于减少土壤侵蚀,但降雨量的改变主导了土壤侵蚀的变化.降雨量增加导致低覆盖度且脆弱的高寒草原生态系统土壤侵蚀明显增强(增加量为1.19 * 10~8 t/a);森林和灌木生态系统由于稳定性较高且降雨量明显减少,土壤侵蚀减弱(减少量分别为-0.77 * 10~8 t/a和-1.65 * 10~8 t/a);稀疏植被系统土壤侵蚀量因降雨量的略微减少而少量减少(-0.44 * 10~8 t/a);虽然高寒草甸生态系统降雨量明显增加,但其较高的植被覆盖度在一定程度上削弱了降雨侵蚀力的变化,土壤侵蚀量有所减少(-0.11 * 10~8 t/a).本研究揭示了青藏高原土壤侵蚀较为严重的地区、海拔及生态系统,分析了不同生态系统土壤侵蚀量变化可能的原因,可为水土流失的科学治理提供基础数据和理论参考
A novel gene SI(stress insensitive) is involved in the response to abiotic stress in Arabidopsis
No full text非生物胁迫是影响农作物产量的主要因素,植物对非生物胁迫的应答机制一直是植物学研究的热点之一. 在拟南芥中克隆和鉴定了一个参与非生物胁应答的新基因SI(stress insensitive),该基因编码一个未知功能结构域的蛋白DUF1336,该家族蛋白结构域具有许多未知功能的假设植物蛋白C末端(约250个残基). 在单子叶植物和双子叶植物中,SI蛋白质是保守的. 通过瞬时转化实验证明,该蛋白定位于细胞质膜. 实时定量PCR分析结果显示,SI基因在各种组织中组成型表达. 在花、果荚和种子中表达量相对较高. 非生物胁迫和脱落酸(ABA)可以增加SI基因的表达,SI基因在ABA、NaCl和冷处理后分别上调3.5倍、2.1倍和4.7倍. SI基因的T-DNA插入突变体(SALK_021811C)植株表现出对冷胁迫和高盐胁迫的抗性. 种子的萌发实验也表明,突变体种子可以在高盐胁迫条件下萌发,对ABA的抑制作用也不敏感. 本研究表明SI基因是植物抗逆性的负调控因子,可为提高农作物的遗传改良提供新的候选基因
The complete mitochondrial genome of the toad species Oreolalax jingdongensis (Anura: Megophryidae) and related phylogenetic analyses
No full textThe complete mitochondrial genome of Oreolalax jingdongensis occurring from the southwestern mountains of China was determined. The new complete mitochondrial genome is 17,864 bp in length and contain 13 protein-coding genes, 2 rRNA genes, 23 tRNA genes, and a control region. Different from the typical gene order in most of anuran species, structure of the mitochondrial genome of O. jingdongensis has a tandem duplication of two tRNA-Met genes and rearrangements of several tRNA genes. Phylogenetic relationships was reconstructed base on the sequences of 13 protein-coding genes from the complete mitochondrial genome of 18 representative Megophryidae species using Bayesian inferences and Maximum likelihood approaches, and the results supported the monophyly of this family. This study supplied basic genetic data for further genetic research and conservation of the toad group
Nitrogen addition reduces dissolved organic carbon leaching in a montane forest
No full textDissolved organic carbon (DOC) plays a significant role in the forest soil carbon cycle and can be regulated by nitrogen (N) addition. However, the regulatory direction, mechanism and seasonal pattern of DOC under N addition are less clear. Here, in a montane evergreen forest located at the eastern edge of the Tibetan Plateau, 2 levels of N were applied over 2 years to determine the effects of N addition on DOC release from organic (O layer) and mineral soil. Frequent sampling revealed that high levels of N addition could decrease the concentration of DOC and the flux from the O layer but not from mineral soil and that moderate N addition had no effect on DOC leaching from either the O or mineral layer. The effect of N addition on DOC leaching from the O layer was seasonally dependent, showing a significant reduction in DOC leaching during autumn/winter but no changes during summer and spring. This seasonally different response of DOC to N addition affected the seasonal pattern of DOC leaching. Soil and leachate pH were not influenced by N addition in the short term, indicating that there was not enough difference in DOC retention by mineral soil to significantly affect DOC leaching under N addition. In contrast, N addition-derived reduction in DOC leaching was likely to be due to suppressed fresh litterfall-derived DOC production during autumn/winter; this speculation was supported by lower values of O layer water-extractable organic carbon and microbial biomass carbon as well as lower saccharase and cellulose activities found with high N addition. These results suggested that the processes in control of DOC leaching and their responses to N addition were different for O and mineral soil and that short-term N addition could decrease O-layer DOC leaching, which is likely associated with decreased DOC production rather than greater DOC retention