中国卧龙自然保护区不同海拔川滇高山栎(Quercus aquifolioides)群体的遗传变异

海拔梯度造成的环境异质性，如崎岖的地形、复杂的植被结构以及花期延迟等可能会极大地影响到物种的形态和遗传变异格局。理解物种形态和遗传变异的海拔格局对于物种多样性的管理和保护是非常重要的。尽管植物群体遗传学是一个飞速发展的研究领域，然而与海拔相关的形态变异、遗传变异及群体间遗传差异的研究却很少。到目前为止，还不清楚遗传变异与海拔之间是否必然的相关性。 川滇高山栎是一种重要的生态和经济型树种，广泛分布于中国西南的四川、西藏、贵州和云南省的高海拔地区，在保持水土、调节气候方面起着十分重要的作用。尽管主要受阳光限制而仅分布于阳坡，但其海拔梯度范围较大，表明川滇高山栎对不同的环境具有很强的适应性。本文通过叶型及生理响应、微卫星分子标记和扩增性片段长度多态性方法，试图探索川滇高山栎叶沿海拔梯度的形态和生理响应及其沿海拔梯度的遗传变异格局，为川滇高山栎的保护和利用提供进一步的遗传学理论依据和技术指导。 对叶形、含氮量及碳同位素的试验结果表明，平均比叶面积、气孔密度、气孔长度和气孔指数等气孔参数随海拔的升高呈非线性变化。在海拔大于2800 m时，川滇高山栎的比叶面积、气孔长度和气孔指数都随海拔升高而降低，但是在海拔小于2800 m时，这些指标都随海拔的升高而增大。相对而言，单位叶面积的含氮量和碳同位素则表现出相反的变化模式。另外，比叶面积是决定碳同位素沿海拔梯度变化的最重要参数。本研究结果表明，海拔2800 m附近是川滇高山栎生长和发育的最适地带，在这里生长的植物叶片厚度更薄、气孔更大、叶碳同位素值更小。 利用六对微卫星引物对五个不同海拔川滇高山栎群体遗传多样性进行研究，结果表明，群体内表现出较高的遗传多样性，平均每位点等位基因数11.33个，平均期望杂合度达0.820。群体间差异较小，分化仅为6.6％。聚类分析也并没有显示出明显的海拔格局。然而低频率等位基因却与海拔呈显著性正相关(R2=0.97, P < 0.01)，表明在高海拔处，川滇高山栎以更多的稀有基因来适应恶劣的环境条件。本试验结果表明由海拔梯度形成的选择性压力对川滇高山栎群体的遗传变异影响并不明显。 为了进一步探讨川滇高山栎群体遗传变异与海拔之间的相互关系，我们还对其进行了扩增性片段长度多态性分析。结果表明：(1)随海拔的升高(从群体WL2到群体WL5)，群体内遗传变异降低，而群体间遗传差异增加；(2)低海拔群体WL1表现出最低的遗传变异性(HE = 0.181)，同时与其余四个群体间呈现出最大的遗传差异性(平均FST = 0.0596)；(3)在除去低海拔群体WL1后，Mantel检测表明群体间遗传距离与海拔距离之间表现出正相关性。另外，研究结果还表明，遗传变异受生境条件(过度的湿热环境)及人为干扰(火烧、砍伐和放牧)的影响，这一点至少在低海拔群体WL1上发生了作用。 通过叶形态、生理及DNA分子水平的研究，结果表明叶形态特征和碳同位素与海拔紧密相关，与海拔之间呈非线性变化，海拔2,800 m附近是川滇高山栎生长和发育的最适地带。海拔梯度在一定程度上会影响到川滇高山栎群体的遗传变异结构，但在这样一个狭窄的地理分布区域里，这种影响并不足以导致群体间较大的遗传分化。同时生境条件及人为干扰也是影响遗传变异的限制性因子，不容忽视。 Altitudinal gradients impose heterogeneous environmental conditions, such as rugged topography, a complex pattern of vegetation and flowering delay, and they likely furthermore markedly affect the morphological and genetic variation pattern of a species. Understanding altitudinal pattern of morphological and genetic variation at a species is important for the management and conservation of species diversity. Although plant population genetics is a fast growing field of research, there are only few recent investigations, which analyzed the genetic differentiation and changes of intra-population variation along altitudinal gradients. At present, it is still unclear whether there are some common patterns of morphological and genetic variation with altitude. Quercus aquifolioides Rehder & E.H. Wilson, which is an important ecological and economical endemic woody plant species, is widely distributed in the Yunnan and Sichuan provinces, Southwest China. Its large range of habitat across different altitudes implies strong adaptation to different environments, although it is mainly restricted to sunny, south facing slopes. It plays a very important role in preventing soil erosion, soil water loss and regulating climate, as well as in retaining ecological stability. In this paper, we tried to understand the altitudinal pattern of morphological and genetic variation along altitudinal gradients through the experiments of leaf morphological and physiological responses, microsatellite analysis and AFLP markers. In leaf morphological and physiological responses experiment, we measured leaf morphology, nitrogen content and carbon isotope composition (as an indicator of water use efficiency) of Q. aquifolioides along an altitudinal gradient. We found that these leaf morphological and physiological responses to altitudinal gradients were non-linear with increasing altitude. Specific leaf area, stomatal length and index increased with increasing altitude below 2,800 m, but decreased with increasing altitude above 2,800 m. In contrast, leaf nitrogen content per unit area and carbon isotope composition showed opposite change patterns. Specific leaf area seemed to be the most important parameter that determined the carbon isotope composition along the altitudinal gradient. Our results suggest that near 2,800 m in altitude could be the optimum zone for growth and development of Q. aquifolioides, and highlight the importance of the influence of altitude in research on plant physiological ecology. Genetic variation and differentiation were investigated among five natural populations of Q. aquifolioides occurring along an altitudinal gradient that varied from 2,000 to 3,600 m above sea level in the Wolong Natural Reserve of China, by analyzing variation at six microsatellite loci. The results showed that the populations were characterized by relatively high intra-population variation with the average number of alleles equaling 11.33 per locus and the average expected heterozygosity (HE) being 0.779. The amount of genetic variation varied only little among populations, which suggests that the influence of altitude factors on microsatellite variation is limited. However, there is a significantly positive correlation between altitude and the number of low-frequency alleles (R2=0.97, P < 0.01), which indicates that Q. aquifolioides from high altitudes has more unique variation, possibly enabling adaptation to severe conditions. F statistics showed the presence of a slight deficiency of heterozygosity (FIS=0.136) and a low level of differentiation among populations (FST=0.066). The result of the cluster analysis demonstrates that the grouping of populations does not correspond to the altitude of the populations. Based on the available data, it is likely that the selective forces related to altitude are not strong enough to significantly differentiate the populations of Q. aquifolioides in terms of microsatellite variation. To further elucidate genetic variation pattern of Q. aquifolioides populations under sub-alpine environments, genetic variation and differentiation were investigated along altitudinal gradients using AFLP markers. The altitudinal populations with an average altitude interval of 400 m, i.e. WL1, WL2, WL3, WL4 and WL5, correspond to the altitudes 2,000, 2,400, 2,800, 3,200 and 3,600 m, respectively. Our results were as follows: (i) decreasing genetic variation (ranging from 0.253 to 0.210) and increasing genetic differentiation with altitude were obtained from the WL2 to the WL5 population; (ii) the WL1 population showed the lowest genetic variation (HE = 0.181) and the highest genetic differentiation (average FST = 0.0596) with the other four populations; (iii) the positive correlation was obtained using Mantel tests between genetic and altitude distances except for the WL1 population. Our results suggest that altitudinal gradients may have influenced the genetic variation pattern of Q. aquifolioides populations to some extent. In addition, habitat environments (unfavorable wet and hot conditions) and human disturbances (burning, grazing and felling) were possible influencing factors, especially to the low-altitude WL1 population. The present study shows that there were close correlations between morphological features and carbon isotope composition in our data. This indicates that a coordinated plant response modified these parameters simultaneously across different altitudes. Around 2,800 m altitude there seems to be an optimum zone for growth and development of Q. aquifolioides, as indicated by thinner leaves, larger stomata and more negative d13C values. All available evidence indicates altitudinal gradients may have influenced the genetic variation pattern of Q. aquifolioides to some extent. Decreasing genetic variation and increasing genetic differentiation with altitude was obtained except for the WL1 population. And the environment of habitats and human disturbances were also contributing factors, which impact genetic variation pattern, especially to the low-altitude WL1 population.

Assessment of I-129 measurement at low MV tandem voltages

IEECAS SKLLQG

低山丘陵半干旱区小流域综合治理初报

低山丘陵半干旱区气候干旱、土地贫瘠、水土流失严重 ,加上人类活动的长期负面影响 ,使得该地区生态环境不断恶化。而以小流域为单元的综合治理是改善本地区生态环境、促进农业和农村经济持续发展的有效途径。该文结合低山丘陵半干旱区的自然和社会经济条件 ,论述了进行小流域综合治理的重要性 ,并总结了该地区治理的具体措施和取得的经济、生态和社会效益 ,可以为同类地区生态环境建设提供参考。

几种酸性土壤供氮力测定方法的综合评价

模拟旱地条件进行黑麦草盆栽试验,对不同供氮力指标与黑麦草吸氮量相关性进行研究,结果表明,短期好气培养法测定的可矿化氮与吸氮量相关系数为0.820;氯化钾与氯化钙浸提的硝态氮与黑麦草吸氮量的相关系数分别为0.892和0.916,表明硝态氮含量作为土壤供氮能力指标具有一定的稳定性;微生物量氮的测定结果不够稳定且与黑麦草吸氮量相关性不高(r=0.751)。分析表明,氯仿熏蒸-浸提全氮与吸氮量的相关性最好,相关系数可达0.941,是一个较好的供氮力指标。

E_0值对潜水蒸发计算精度影响分析

目前常用潜水蒸发经验公式中,都包含了埋深为零时的潜水蒸发强度,并认为可用水面蒸发强度代替。但对不同土质,由于土壤含水孔隙大小及与大气直接交换的空间不同,必然造成不同土壤质地埋深为零时的蒸发量差异。选用阿维里扬诺夫公式、清华公式和叶氏公式,利用新疆渭干河灌区地下水均衡试验场实测潜水蒸发数据、就E0分别为水面蒸发强度和埋深为零时潜水蒸发强度两种情况进行计算与对比分析。结果表明:除细砂和砾石外,若用水面蒸发强度代替埋深为零时的潜水蒸发强度,计算结果会产生一定误差,应选用埋深为零时的潜水蒸发强度进行计算。提出了清华公式中参数η新的求解方法,建立了η与地下水埋深的指数函数关系。研究结果对潜水蒸发经验公式求解不同土质潜水蒸发量时E0的选用及清华公式中参数η的计算提供参考。

21世纪中国水资源危机警钟急鸣

水资源危机是全球关心的重大环境问题之一，引起世界众多的国家的不安和关注。根据中国属于世界上贫水的国家之一、人均拥有低于世界平均水平、在６８８个城市中有４００余座缺水的实际，针对建国５０周年多次出现“节约用水”的告诫，人们总是不以为然而认为水资源是“取之不尽，用之不竭”的资源、对水资源毫不珍惜的情况，文章分析了国内外水资源的现状和中国水资源危机及走向２１世纪存在的主要问题，为决策部门制订计划提供可靠的科学依据。

浅析红松人工果材林生长和结实的外部影响因素

国家天然林保护工程的全面实施大大限制了红松林的木材采伐量,使林业部门及人员不能再单纯追求木材收获所带来的利益,而趋向于追求木材和种籽的双重效益。充分了解红松果材林生长和结实的影响因素是实现种材兼收的重要前提。本文对红松生长和结实的各种外部影响因素进行了归纳综述,分析了地理位置、立地条件、主要气象因素、自然灾害以及人为经营管理等各种外部影响因素与红松生长和结实的因果关系,对正确拟定经营方案,实现红松果、材丰产,提高林业部门的经济收入以及满足社会需求具有一定的理论和现实指导意义。

隋唐时期东中部地区温度变化的重建(601～920年)

根据史料对隋唐时期初终霜雪、春耕、山桃开花、秋收、海冰、柑橘种植北界等现象的记载,重建了公元601～920年的东中部地区温度变化.结果发现:隋唐时期,东中部地区的气候在总体上比较温暖,与1961～2000年相比,601～920年的冬半年平均温度高约0.22℃;其中,601～820年的冬半年平均气温比现在(1961～2000年,下同)高约0.52℃,821～920年时比现在低0.42℃左右;隋唐时期的冬半年温度存在显著波动,其在100,50,30和20年尺度上的最大变幅分别达到1.05,1.38,2.02和

1,1 '-di(tert-butyl)metallocenium cations. The x-ray crystal structures of [M((C5H4Bu)-Bu-t)(2)]PF6 (M = Fe, Co) and [Co((C5H4Bu)-Bu-t)(2)](2)CoCl4

The hexafluorophosphate salts [Fe((C5H4Bu)-Bu-t)(2)]PF6 (1) and [Co((C5H4Bu)-Bu-t)(2)]PF6 (2) crystallize in isotypic structures with centrosymmetric cations which have a staggered (transoid) conformation of the exactly parallel ring Ligands (conformational angle tau = 180 degrees). The tetrachlorocobaltate salt, [CO((C5H4Bu)-Bu-t)(2)](2)CoCl4 (3), contains one almost eclipsed (tau = 140.4 degrees) and one almost staggered (tau = 101.4 degrees) cobaltocenium cation; in both cases, the cyclopentadienyl ring planes are slightly inclined (by alpha = 5.4 degrees and 4.1 degrees, respectively) to give more room to the tert-butyl substituents which are bent away from the metal in all three complexes 1 - 3.

Polishable amperometric hydrogen peroxide sensor based on sol-gel-derived conductive composite containing vanadium-17-molybdodiphosphate

A new kind of conductive vanadium-17-molybdodiphosphate/graphite/methylsilicate composite was firstly prepared by the sol-gel technique and used as electrode material for the fabrication of amperometric hydrogen peroxide sensor. The remarkable advantage of the sensor is its excellent reproducibility of surface renewal by simple mechanical polishing.

Synthesis, structure characterization of the complexes of beta-alkoxycarbonylethyltin trichlorides with Schiff base ligands

Thirty - two title complexes (ROCOCHRCH2SnCl3)-C-1 . (2 - HOC6H4CH = NC6H4 - X) (R = Me, Et, n - Bu; R-1 = H, Me; X = H,4' - Cl, 3' - Pr, 3' - OH, 3', 4' - Cl-2, 4' - OMe) were synthesized and characterized by elemental analysis,UV - vis, IR, H-1 NMR. The crystal structure of n - BuOCOCH2CH2SnCl3 . (2 - HOC6H4CH - NC6H4OMe - 4') were determined by the X - ray diffraction analysis, The crystal belongs to monoclinic system, with a = 1.4661 (3)nm, b = 0.9307 (2)nm, c = 1.7888 (4)nm, beta = 94.04 (3)degrees, V = 2.4348nm(3), D-c = 1.581mg/m(3), Z = 4, F(000) = 1160, mu = 1.405mm(-1), R = 0.0354, R-w = 0,0486, space group: P2(1)/c. The complexes exist as a discrete monomer. The tin atom has a distorted octahedral geometry due to intramolecular coordination of the carbonyl oxygen and the phenolic oxygen of the Schiff base ligands, The coordination number of tin atom is 6.

β-烷氧羰乙基三氯化锡与Schiff碱配合物的合成、表征与结构

合成表征了32个标题化合物ROCOCHR~1CH_2SnCl_3·(2-HOC_6H_4CH=NC_6H_4-X)(R=Me,Et,n-Bu;R~1=H,Me;X=H,4’-Cl,3’-Br,3’-OH,3’,4’-Cl_2,4’-OMe),通过元素分析,UV-vis,IR和~1H NMR进行了表征n-BuOCOCH_2CH_2SnCl_3·(2-HOC_6H_4CH=NC_6H_4OMe-4’)的晶体结构分析表明,该晶体属单斜晶系,a=1.4661(3)nm,b=0.9307(2)nm,c=1.7888(4)nm,β=94.04(3)°;v=2.4348nm~3,Z=4;空间群P2_1/c.该化合物为含有分子内碳基氧配位,Schiff碱以酚羟基上的氧原子配位,中心锡原子为六配位,空间构型为畸变八面体构型的单分子有机锡化合物.