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梵净山稀果杜鹃群落结构及物种多样性初步研究
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作者 韦海霞 袁丛军 +4 位作者 李鹤 龙海燕 杨冰 冯邦贤 戴晓勇 《四川林业科技》 2020年第4期38-43,共6页
稀果杜鹃是贵州梵净山山顶杜鹃灌丛群丛特色物种之一,是构成梵净山杜鹃长廊景点的关键物种。采用常规群落生态学调查,对梵净山稀果杜鹃群落的种类组成、物种多样性及群落结构进行了研究,结果表明:在600 m2的样地中,共有维管植物15科25... 稀果杜鹃是贵州梵净山山顶杜鹃灌丛群丛特色物种之一,是构成梵净山杜鹃长廊景点的关键物种。采用常规群落生态学调查,对梵净山稀果杜鹃群落的种类组成、物种多样性及群落结构进行了研究,结果表明:在600 m2的样地中,共有维管植物15科25属27种,灌木层中稀果杜鹃重要值最高;物种多样性特征分析显示该群落多样性指数偏低,灌木层中优势种明显,物种分布随机性大,草本层物种较少,分布较均匀;群落垂直结构简单,高度集中在3~3.5 m,群落垂直结构稳定。 展开更多
关键词 稀果杜鹃 群落结构 物种多样性 梵净山
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苹果树稀果的好处及方法
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作者 红旭 《新农业》 1994年第6期29-29,共1页
苹果树稀果的好处及方法苹果树坐果过多,超过树体负担量,不仅影响当年果品质量和商品价值,而且会影响下一年的产量,出现大小年结果现象。合理稀果不仅能够节省树体养分消耗,还能调节花序内部营养物质的分配,使其集中供应,有利于... 苹果树稀果的好处及方法苹果树坐果过多,超过树体负担量,不仅影响当年果品质量和商品价值,而且会影响下一年的产量,出现大小年结果现象。合理稀果不仅能够节省树体养分消耗,还能调节花序内部营养物质的分配,使其集中供应,有利于增大果个,促进花芽分化,减轻"大小... 展开更多
关键词 稀果 效益
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外源GA3对两种杜鹃种子萌发特性的影响
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作者 罗婵 邓毅晖 +2 位作者 王熙富 刘宏 卢宗军 《南方林业科学》 2023年第4期27-30,共4页
以广西壮族自治区元宝山地区的稀果杜鹃、心基杜鹃种子为试验材料,研究不同浓度外源激素GA_(3)浸种处理对两种杜鹃种子萌发特性的影响。结果表明,经过不同浓度外源激素GA_(3)浸种处理后,两种供试杜鹃种子的萌发特性较未经外源激素浸种... 以广西壮族自治区元宝山地区的稀果杜鹃、心基杜鹃种子为试验材料,研究不同浓度外源激素GA_(3)浸种处理对两种杜鹃种子萌发特性的影响。结果表明,经过不同浓度外源激素GA_(3)浸种处理后,两种供试杜鹃种子的萌发特性较未经外源激素浸种的对照组有明显变化,萌发时滞和发芽持续时间缩短且萌发高峰期提前,发芽率、发芽势和发芽指数均有不同程度提高。稀果杜鹃种子以800 mg·L^(-1)的GA_(3)浸种效果最好。心基杜鹃种子以800 mg·L^(-1)的GA_(3)浸种时,发芽率和发芽指数最高,以400 mg·L^(-1)的GA_(3)浸种时,发芽势最高。因此,采用GA_(3)浸种处理可有效改善两种杜鹃种子在自然条件下萌发效果不理想的情况。 展开更多
关键词 稀果杜鹃 心基杜鹃 GA3 萌发特性 发芽时间
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Competition-density effect in plant populations 被引量:2
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作者 薛立 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第1期48-50,83,共3页
The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the compet... The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the competition-density effect in nonself-thinning populations and self-thinning populations were analyzed theoretically. This supplies a theoretical basis for analyzing the dynamics of forest populations and evaluating the effect of forest management. 展开更多
关键词 Competition-density effect Self-thinning population Nonself-thinning population
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银杏人工授粉技术
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作者 林隆锋 《福建农业》 1996年第8期10-10,共1页
银杏是我国特有的珍稀果树,属于双倍体裸子植物,多为雌雄异株,经过授粉可提高座果率。自然授粉的花粉主要靠风力和昆虫传播,一般有效传播距离在1公里以内。零星分散的银杏常因附近缺乏授粉树而不能自然授粉或授粉不足,导致低产甚至绝收... 银杏是我国特有的珍稀果树,属于双倍体裸子植物,多为雌雄异株,经过授粉可提高座果率。自然授粉的花粉主要靠风力和昆虫传播,一般有效传播距离在1公里以内。零星分散的银杏常因附近缺乏授粉树而不能自然授粉或授粉不足,导致低产甚至绝收。为了解决这个问题。 展开更多
关键词 人工授粉技术 银杏 花粉 授粉树 自然授粉 仙乡 有效传播距离 雄花期 稀果 雌树
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Effects of Periodic Boundary Condition on Traffic Waves
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作者 唐铁桥 黄海军 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期983-986,共4页
In this paper, we use the speed-gradient model proposed by Jiang et al. [Transp. Res. B 36 (2002) 405] to study the effect of boundary condition on shock and rarefaction wave. Our numerical results show that this mo... In this paper, we use the speed-gradient model proposed by Jiang et al. [Transp. Res. B 36 (2002) 405] to study the effect of boundary condition on shock and rarefaction wave. Our numerical results show that this model can reproduce the evolution of the two traffic waves, which further proves that this model can be used to perfectly explore the consequences caused by various boundary conditions. 展开更多
关键词 traffic flow shock rarefaction wave periodic boundary condition
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Influence of Tb substitution on low-field magnetocaloric effect in Gd_5Si_(1.72)Ge_(2.28) alloy
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作者 邓健秋 庄应烘 +2 位作者 王日初 阳震 徐斌 《Journal of Central South University of Technology》 2008年第4期429-433,共5页
The lattice parameters, magnetic phase transition, Curie temperature and magnetocaloric properties for (Gd1-xTbx)5Si1.72- Ge2.28 alloys with x = 0, 0.15, 0.20 and 0.25 were investigated by X-ray powder diffractometry ... The lattice parameters, magnetic phase transition, Curie temperature and magnetocaloric properties for (Gd1-xTbx)5Si1.72- Ge2.28 alloys with x = 0, 0.15, 0.20 and 0.25 were investigated by X-ray powder diffractometry and magnetization measurements. The results show that suitable partial substitution of Tb in Gd5Si1.72Ge2.28 compound remains the first-order magnetic-crystallographic transition and enhances the magnetic entropy change, although Tb substitution decreases the Curie temperature (TC) of the compounds. The magnetic entropy change of (Gd1-xTbx)5Si1.72Ge2.28 alloys retains a large value in the low magnetic field of 1.0 T. The maximum magnetic entropy change for (Gd0.80Tb0.20)5Si1.72Ge2.28 alloy in the magnetic field from 0 to 1.0 T reaches 8.7 J/(kg·K), which is nearly 4 times as large as that of (Gd0.3Dy0.7)5Si4 compound (|-Smax| = 2.24 J/(kg·K), T_C = 198 K). 展开更多
关键词 rare earth alloy magnetic entropy change magnetic phase transition magnetocaloric effect (MCE) entropy
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Uplink user allocation scheme in cognitive coexistent cellular network
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作者 刘婷婷 Wang Mao +2 位作者 Shu Feng Wang Jianxin Pan Ziyu 《High Technology Letters》 EI CAS 2014年第4期376-382,共7页
In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This... In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This paper describes a cognitive cellular network which allocates low geometry users to the TV white space based on a proportional fair criterion.An uplink user allocation scheme is proposed and the validity of the proposed scheme is established by simulation of the cellular network usage in conjunction with the TV white space.The simulation results show clear improvements in both the user and the system performance with the cognitive coexistent cellular network compared with the traditional cellular network,and that the performance of the proposed user allocation scheme is superior to other user allocation schemes. 展开更多
关键词 cognitive radio TV white space spectrum efficiency system throughput fractional frequency reuse
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SKP2 attenuates NF-κB signaling by mediating IKKβ degradation through autophagy 被引量:5
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作者 Kunpeng Liu Lei Zhang +4 位作者 Qiang Zhao Zhiyao Zhao Feng Zhi Yunfei Qin Jun Cui 《Journal of Molecular Cell Biology》 SCIE CAS CSCD 2018年第3期205-215,共11页
NF-κB signaling controls a large set of physiological processes ranging from inflammatory responses to cell death. Its activation is tightly regulated through controlling the activity and stability of multiple signal... NF-κB signaling controls a large set of physiological processes ranging from inflammatory responses to cell death. Its activation is tightly regulated through controlling the activity and stability of multiple signaling components. Here, we identify that NF-κB activation is suppressed by an F-box protein, S-phase kinase associated protein 2 (SKP2). SKP2 deficiency enhanced NF-κB activation as well as the production of inflammatory cytokines. In addition, SKP2 potently blocked the NF-κB activation at the κB kinase (IKIO level. Mechanistic study further revealed that SKP2 functions as an adaptor to promote an interaction between active IKKβ and the autophagic cargo receptor p62 to mediate IKKβ degradation via selective autophasy. These findings identify a previously unrecognized role of SKP2 in NF-κB activation by which SKP2 acts as a secondary receptor to assist IKKβ delivery to autophagosomes for degradation in a p62-dependent manner. 展开更多
关键词 SKP2 IKKΒ NF-κB activation AUTOPHAGY INFLAMMATION
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