Family selection and evaluation of Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger based on stem analysis data at multiple sites

Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.

Phenological observations on Larix principis-rupprechtii Mayr. in primary seed orchard

Through 5 years of phenological observations on Larix principis-rupprechtii Mayr. in primary seed orchard and studies on population and individuals of clones, the annual periodic phenological laws were revealed and the annual phe-nological periodic table was drawn up. The correlation between various phenophases, the air temperature and active accumu-lated temperature were analyzed and expounded. The authors also analyzed the similarities and differences of phenophases among clonal individuals as well as the blooming properties of male and female flowers at the same time. This study could pro-vide theoretical reference for working out the production plan of improved varieties and other management measures in seed orchard of Larix principis-rupprechtii.

More tree growth reduction due to consecutive drought and its legacy effect for a semiarid larch plantation in Northwest China

Extreme climate has increasingly led to negative impacts on forest ecosystems globally,especially in semiarid areas where forest ecosystems are more vulnerable.However,it is poorly understood how tree growth is affected by different drought events.In 2006–2009,the larch plantations in the semiarid areas of Northwest China were negatively affected by four consecutive dry years,which was a very rare phenomenon that may occur frequently under future climate warming.In this study,we analyzed the effect of these consecutive dry years on tree growth based on the data of the tree rings in the dominant layer of the forest canopy on a larch plantation.We found that the tree-ring width index(RWI)in dry years was lower than that in normal years,and it experienced a rapidly decreasing trend from 2006 to 2009(slope=-0.139 year^(-1),r=-0.94)due to water supply deficits in those dry years.Drought induced legacy effects of tree growth reduction,and consecutive dry years corresponded with greater growth reductions and legacy effects.Growth reductions and legacy effects were significantly stronger in the third and fourth consecutive dry years than that of single dry year(p<0.05),which might have been due to the cumulative stress caused by consecutive dry years.Our results showed that larch trees experienced greater tree growth reduction due to consecutive dry years and their legacy effect,and the trees had lower recovery rates after consecutive dry years.Our results highlight that consecutive dry years pose a new threat to plantations under climate warming,and thus,the effect of climate extremes on tree growth should be considered in growth models in semiarid areas.

Changing regularity of plant and insect community characteristics due to pest outbreaks in Larix principis- rupprechtii plantations

Research has indicated that simple forest eco-system composition,structure and diversity have uncompli-cated community relationships and insufficient pest control capabilities.To investigate changing characteristics of plant and insect communities in under pest outbreaks in Larix principis-rupprechtii plantations,the research areas were defined as mature(48–50 years)and young(24–29 years)infested stands along with healthy stands.The results show a reduction in the complexity and diversity of plant communi-ties and herbaceous plant guilds(polycultures of beneficial plants)and the complexity and dominance of insect com-munities,especially natural insect enemies.The results also show the relative simplicity of the main factors of commu-nity change and development that represent the characteris-tics of pest outbreaks in L.principis-rupprechtii plantations.The complexity and diversity of plant communities,particu-larly herbaceous plant guilds play a fundamental role in the regulation and development in forest ecosystems.

新《档案法》背景下完善与加强档案普法的新要求、新内涵与新方向

新《档案法》出台后的贯彻落实,需要通过档案普法去宣传、领会和执行。从《“七五”规划》到《“八五”规划》,其普法制度、内容、策略和形式的变化充分折射出我国档案普法在新《档案法》背景下,不仅对于“如何紧跟新时代、如何完善责任制”等有了新要求,而且对于档案普法主体、对象、内容和形式等方面都有了新内涵,主体责任愈加清晰且格局愈加广阔;普法对象既抓住关键少数,又强调融入性;普法内容既凸显新的大篇章,又注重新的小细节;普法形式既要借助各种媒体,又要融入专业平台。鉴于此,积极打造档案普法线上服务平台,有效开展档案普法线下交流活动成为完善和加强档案普法的应有之举。展望未来,应通过科技赋能与模式创新,更加有效地提升档案普法水平。

Age–age correlations and early selection for growth traits in 40 half-sib families of Larix principis-rupprechtii

Larix principis-rupprechtii Mayr is a dominant species in coniferous forests of North China.However,early selection of L.principis-rupprechtii for growth traits is poorly characterised.To explore the optimal selection age for this species,heights(HT)and diameters at breast(DBH)of 40 half-sib families were measured at ages 3,12,22,and 28 years in a progeny test population established in the town of Kangjiahui,Shanxi Province.Age trends in heritability,age–age genetic correlations,and early selection efficiency for height and DBH were analysed.The individual heritability of these growth traits varied over time,and maximized at different ages(0.55 at age 12 for HT and 0.48 at age 28 for DBH).The age–age genetic correlations were always positive,and the majority were high(0.790–0.953)between the juvenile and mature ages for HT and DBH.For the same pairs of measurements,HT demonstrated higher age–age genetic correlations than DBH,and both age–age genetic correlation data sets were described well by the linear relationship with the logarithm of the age ratio(r2[0.90).The regression slope for DBH was lower than that for HT.Based on the early selection efficiency estimates,the optimal selection age could be as early as age 6 for DBH and 8–9 years for HT.The results of this study provide information that can be used to assist early selection practices in L.principis-rupprechtii improvement programs in Shanxi Province.

Variations in stem radii of Larix principis-rupprechtii to environmental factors at two slope locations in the Liupan Mountains,northwest China

Relationships between stem growth and climatic and edaphic factors,notably air temperatures and soil moisture for different slopes,are not completely understood.Stem radial variations were monitored at the bottom and top slope positions in a Larix principis-rupprechtii plantation during the 2017 and 2018 growing seasons.Total precipitation during the growing season in 2017 and 2018 was 566 mm and 728 mm,respectively.Stem contractions typically occurred after mid-morning followed by swelling in the late afternoon in both plots,reflecting the diurnal cycle of water uptake and loss.Trees at the two locations showed the same growth initiation(mid-May)because of the small differences in air and soil temperatures.There were no significant differences in cumulative stem radial growth between the bottom plot(1.57±0.34 mm)and the top plot(1.55±0.26 mm)in 2018.However,in 2017,the main growth period of the bottom plot ceased 17 days earlier than in the top plot,while cumulative seasonal growth of the bottom plot(1.08±0.25 mm)was significantly less than the top plot(1.54±0.43 mm).Maximum daily stem shrinkage was positively correlated with air and soil temperatures,solar radiation,vapor pressure deficits,and negatively correlated with volumetric soil moisture content.The maximum daily shrinkage reflected transpiration rates as affected by environmental factors.Daily radial stem increment was correlated with precipitation and volumetric soil moisture in both years,but with air temperatures only in 2017.The seasonal growth of L.principis-rupprechtii Mayr thus shows interannual dynamics,while precipitation constitutes a key driving factor.

Estimation of leaf area index from high resolution ZY-3 satellite imagery in a catchment dominated by Larix principis-rupprechtii,northern China

Leaf area index(LAI) is a key factor that determines a forest ecosystem's net primary production and energy exchange between the atmosphere and land surfaces.LAI can be measured in many ways, but there has been little research to compare LAI estimated by different methods. In this study, we compared the LAI results from two different approaches, i.e., the dimidiate pixel model(DPM) and an empirical statistic model(ESM) using ZY-3 high-accuracy satellite images validated by field data. We explored the relationship of LAI of Larix principis-rupprechtii Mayr plantations with topographic conditions. The results show that DPM improves the simulation of LAI(r = 0.86,RMSE = 0.57) compared with ESM(r = 0.62, RMSE =0.79). We further concluded that elevation and slope significantly affect the distribution of LAI. The maximum peak of LAI appeared at an aspect of east and southeast at an elevation of 1700–2000 m. Our results suggest that ZY-3 can satisfy the needs of quantitative monitoring of leaf area indices in small-scale catchment areas. DPM provides a simple and accurate method to obtain forest vegetation parameters in the case of non-ground measurement points.

Rules of Changes in Soil Nutrients and Enzyme Activities of Larix principis-rupprechtii in Different Forest Ages

In this study,three different ages of Larix principis-rupprechtii forests in 5,10 and 20 years were selected as the research objects,and the changes in soil nutrient and soil enzyme activities in different growth stages were analyzed. The results showed that the contents of organic matter and available phosphorus in the soil of different growth stages showed a significant downward trend with the increase of soil depth.For different forest ages in the same soil layer,the soil available phosphorus content declined with the increase of the forest age. The organic matter content of 40-60 cm in 20 years of forest age was the lowest in July,which was 4. 17 g/kg,significantly lower than that in other soil layers. Besides,the soil available phosphorus content of 5 years of forest age reached the maximum in July,with an average of 4. 44 mg/kg,which was higher than the available phosphorus content in soil in May and September,but the difference between the three months was not significant. The changes in ammonium nitrogen and nitrate nitrogen content in soil with different forest ages were consistent with the changes in the soil depth,showing a downward trend. In the new leaf stage,the ammonium nitrogen content of the L. principis-rupprechtii forest land in5 years of age at 20-40 and 40-60 cm of the soil depth was 13. 47 and 9. 09 mg/kg,respectively,which was 46. 9% and 64. 2% lower than that at 0-20 cm( 25. 36 mg/kg) of the soil depth. The soil nitrate nitrogen content of 20 years of forest age was 19. 24 mg/kg,which was25. 8% lower than that of 10 years of forest age,showing significant difference( P < 0. 05). In addition,with the increase of the age of L. principis-rupprechtii,soil catalase( CAT),alkaline phosphatase( ALP) and urease( Ure) decreased,and the decline of ALP was slow,while CAT and Ure decreased significantly. In summary,it is concluded that the soil fertility of forest land declined with the increase of forest age on the basis of change trend of soil nutrient and soil enzyme activity in the surveyed forest age.

Range-wide genetic diversity in natural populations of Larix principis-rupprechtii Mayr.

Prince Rupprecht’s larch(Larix principis-rupprechtii Mayr.),a deciduous conifer,widely grows in middle and high elevations of Northern China.Its natural distribution has sharply decreased and has become fragmented,which may have resulted in the loss of genetic variation.In this study,ten natural populations across the entire range of this species were analyzed using amplifi ed fragment length polymorphism markers.A total of 309 loci were detected from 225 individuals of these populations,of which 261(84.5%)were polymorphic.At the species level,the genetic diversity was high(average of the Nei’s genetic diversity H e=0.2602,and Shannon’s information index I=0.3967).The results of molecular variance analysis showed that 90.71%of the genetic diversity occurred within populations.The genetic diff erentiation among populations was moderate as a whole(F ST=0.0929,G ST=0.1510),which is consistent with the moderate level of gene fl ow among populations(N m=2.8116).Based on the unweighted pair group method with arithmetic mean and STRU CTU RE analysis,these populations were grouped into three genetically distinct clusters.The degree of inter-population diff erentiation(G ST=0.1338)for the south group was larger than that for the north group(G ST=0.0915).There was a signifi cant correlation between genetic distance and geographic distance across the species range(r=0.316,P<0.05).Genetic diversity was signifi-cantly associated with longitude but not elevation or climatic factors.The populations with high genetic diversity from each cluster are therefore recommended for future conservation and management of this species.

Effect of thinning intensity on the stem CO_(2) efflux of Larix principis-rupprechtii Mayr

Background:Stem CO_(2) efflux(E_(S))plays a critical role in the carbon budget of forest ecosystems.Thinning is a core practice for sustainable management of plantations.It is therefore necessary and urgent to study the effect and mechanism of thinning intensity(TI)on E_(S).Methods:In this study,five TIs were applied in Larix principis-rupprechtii Mayr 21-,25-,and 41-year-old stands in North China in 2010.Portable infrared gas analyzer(Li-8100 A)was used to measure ES and its association with environmental factors at monthly intervals from May to October in 2013 to 2015.In addition,nutrients,wood structure and nonstructural carbon(NSC)data were measured in August 2016.Results:The results show that ES increased with increasing TI.The maximum ES values occurred at a TI of 35%(3.29,4.57 and 2.98μmol·m^(-2)·s^(-1))and were 1.54-,1.94-and 2.89-fold greater than the minimum E_(S) value in the CK stands(2.14,2.35 and 1.03μmol·m^(-2)·s^(-1))in July for the 21-,25-and 41-year-old forests,respectively.The E_(S) of the trees in low-density stands was more sensitive to temperature than that of the trees in high-density stands.Soluble sugars(SS)and temperature are the main factors affecting ES.When the stand density is low enough as 41-year-old L.principis-rupprechtii forests with TI 35%,bark thickness(BT)and humidity should be considered in addition to air temperature(T_(a)),wood temperature(T_(w)),sapwood width(SW),nitrogen concentration(N)and SS in the evaluation of ES.If a change in stand density is ignored,the CO_(2) released from individual 21-,25-and 41-year-old trees could be underestimated by 168.89%,101.94% and 200.49%,respectively.CO_(2) release was estimated based on the stem equation in combination with the factors influencing ES for reference.Conclusions:We suggest that it is not sufficient to conventional models which quantify ES only by temperature and that incorporating the associated drivers(e.g.density,SS,SW and N)based on stand density into conventional models can improve the accuracy of ES estimates.

Fourier Moment Method with Regularization for the Cauchy Problem of Helmholtz Equation

In this paper, we consider the reconstruction of the wave field in a bounded domain. By choosing a special family of functions, the Cauchy problem can be transformed into a Fourier moment problem. This problem is ill-posed. We propose a regularization method for obtaining an approximate solution to the wave field on the unspecified boundary. We also give the convergence analysis and error estimate of the numerical algorithm. Finally, we present some numerical examples to show the effectiveness of this method.

贫困山区民众生态知识科普需求调查研究

国家公园内的居民作为当地经济、教育及文化发展的主力军及受益者,对新农村建设、乡村振兴的推进和自然资源的保护以及国家公园的建设起着至关重要的作用。为了解当地居民对海南热带雨林国家公园的知情情况及其对相关生态知识科普的需求,从而为国家公园在林业管理、科普活动方面政策的制定及实施提供依据和参考。该研究采用问卷、走访及座谈的方式开展实地调研。研究结果表明:被调查群体中初中及以下学历占比达到86.04%,基础教育水平比全国教育落后地区的平均水平(81.93%)还要低;国家公园宣传力度不足,宣传效果不佳;当地居民在生态科普需求上存在较大的差异,对自然环境知识、种养技术知识的关注度较高,对科学文化知识学习和民族民俗文化传承意识较为淡薄。当地政府应重视基础教育,加强通识教育,提高民众文化水平;应加大国家公园建设内容和政策法规的宣传力度;应开展更多种植技术培训、职业技能培训和加强科学文化、特色民俗文化的宣传教育。

不同林龄华北落叶松人工林叶凋落物分解及养分动态比较

采用网袋法,对0～540 d内不同林龄华北落叶松(Larix principis-rupprechtii)人工林叶凋落物的分解特征及营养元素质量分数变化动态进行了比较分析。结果表明:经过540 d的分解,幼、中、近、成熟林4个龄组的叶质量损失率为48.47%～61.72%,并呈极显著差异,不同林龄的叶凋落物分解速率呈现出成熟林>近熟林>中龄林>幼龄林。用含哑变量的Olson指数衰减模型对叶凋落物的分解动态进行拟合,结果显示,幼龄林、中龄林、近熟林和成熟林叶凋落物的分解系数为0.028 30～0.036 19;半衰期和周转期分别为1.59～2.04 a和6.90～8.82 a。在整个分解过程中,4个龄组的养分质量分数变化一致,随着时间的延长,N质量分数不断升高;P质量分数呈现出先降低后上升的趋势;K、C质量分数和C/N呈下降的趋势。在分解过程中,4个龄组的N、P、K、C的释放率在总体上变化一致,C和K不断释放,且为净释放状态,呈现直接释放模式;N的释放率为富集-释放模式;P的释放率表现为淋溶-富集-释放模式。结果表明,成熟林和近熟林的叶凋落物比幼龄林和中龄林的叶凋落物易分解,且成熟林和近熟林中的营养元素也较易释放。

葛根素注射液对大鼠脑缺血/再灌注损伤的保护作用

脑梗死是中老年高发病,脑梗死后缺血区微血管受损,缺失[1]。葛根素注射液临床上广泛用于脑缺血,疗效明显。对血管内皮细胞有促增殖,抑钙超载,抗氧化等作用[2],对脑缺血有明显的保护作用。本实验用大鼠脑缺血/再灌注（is-chemia-reperfusion,CIR）模型,从促血管新生角度探讨葛根素治疗脑缺血的机制,观察其时效、量效关系。

视网膜激光光凝对增殖性糖尿病视网膜病变患者视网膜前膜新生血管生成的作用

目的探讨增殖性糖尿病视网膜病变(PDR)患者视网膜激光治疗对视网膜前膜新生血管的作用。方法收集PDR患者20例20眼,按照玻璃体手术前是否接受过视网膜激光光凝治疗分为光凝组和非光凝组。收集术中剥离的视网膜前膜行苏木精-伊红染色,观察组织病理学改变。应用免疫组织化学染色法检测CD34在新生血管内皮细胞中的表达,比较两组患者视网膜前膜新生血管的密度及单细胞新生血管密度。结果两组患者的人口基线特征和眼部特征比较,差异无统计学意义(P>0.05),非光凝组患者视网膜+++级新生血管8眼,光凝组患者为1眼,二者比较差异有统计学意义(P<0.01)。组织病理学结果表明,非光凝组增生膜内可见较多散在的毛细血管型新生血管,多数由单个血管内皮细胞构成管腔,部分区域可见较多出血;光凝组增生膜组织变薄,玻璃样变成分较多,新生毛细血管明显减少。免疫组织化学检测证实,新生血管内皮细胞中CD34均呈强阳性表达,光凝组400倍镜下观察,每个视野新生血管密度为(2.18±1.26)个,非光凝组为(10.00±6.15)个,差异有统计学意义(Z=-2.994,P<0.05)。结论视网膜激光光凝可抑制PDR患者视网膜前膜新生血管的形成,从而降低玻璃体手术治疗PDR的难度。

路面用PZT/沥青压电复合材料的制备及性能

以锆钛酸铅PZT-5H为压电相,沥青为基体,采用热压成型法制备0-3型PZT/沥青压电复合材料.分析了此复合材料的制备工艺、极化条件及PZT的体积分数对压电应变常数d33的影响,测试了其介电性能,并完成了动态荷载作用下压电响应的测试.结果表明:优化的制备工艺为成型压应力10MPa,成型时间3min;最佳的极化条件是极化电场强度为3kV/mm,极化时间为10min,极化温度为50℃;PZT的最佳体积分数为75%;沥青基压电复合材料的相对介电常数εr及压电应变常数d33分别为32.95和53.7pC/N,荷载响应稳态输出电压为7.2V,其储存的能量为259.2μJ.

VEGF家族及其受体与视网膜新生血管形成

视网膜新生血管形成是眼部多种疾病共有的病理改变,其造成的眼部广泛损害已成为致盲的重要原因。VEGF家族(包括VEGF-A,VEGF-B,VEGF-C,VEGF-D,VEGF-E和胎盘生长因子)作为新生血管生成中必不可少的关键因子,通过刺激血管内皮细胞的有丝分裂、迁徙、增加血管的通透性、诱导毛细血管腔的形成。本文对VEGF家族理化特性及受体、在视网膜新生血管形成中的作用和针对其作用机制采取相应防治措施进行综述。

接触分析的光滑模型及迭代算法

利用变分不等式和基于信息熵的凝聚函数把有摩擦接触问题模型化为一个标准的凸二次规划问题，极大地简化了这一复杂的问题，同时引入摩擦方向约束并构造了以无摩擦解为初值的迭代算法，在较大摩擦系数时计算也能保证收敛，算例表明算法高效可靠．

腹腔镜脾切除联合贲门周围血管离断术18例体会

目的 探讨完全腹腔镜脾切除、贲门周围血管离断术（laparoscopic splenectomy plus pericardial devascularization,LSPD）的技术改进.方法 采用预先结扎脾动脉,建立脾门后隧道,根据脾门具体形态使用Endo-GIA分次离断脾蒂、应用直线切割闭合器离断胃冠状曲张静脉丛（胃蒂）的方法优化LSPD来治疗门静脉高压症及脾功能亢进.结果 18例病人均顺利完成手术,手术时间130～350min,术中出血120～900ml.其中11例病人行选择性贲门周围血管离断术,6例病人行非选择性贲门周围血管离断术,1例病人胃短静脉撕裂出血术中转为开腹手术.术后引流4～5 d,12例病人拔除引流管;术后6～8 d,6例病人拔除引流管.术后病人禁食及胃肠减压24～48 h,26～72 h肛门排气,引流4～8 d,住院及随访期间无死亡病例.术后2例病人出现血小板计数突然升高[（670～820）＆#215;109/L],7例病人出现腹水（550～800ml）,均对症治疗后好转,术后无感染性并发症、结肠损伤等严重并发症,切口愈合良好.18例术后住院时间8～20 d,术后1个月,上消化道钡餐或胃镜复查,8例病人改善为轻度胃底食管静脉曲张,5例病人改善为中度胃底食管静脉曲张,改善效果较为理想;其余5例也较术前减轻.随访8～24个月内,均未见死亡病例,无复发者.结论 改良的LSPD可显著提高全腹腔镜手术成功率,减少术中出血量和缩短手术时间.