张广才岭北部三大硬阔树木生长-气候关系的时空变异

树木年轮在时空尺度上的比较可以更好地反映环境变化对树木生长的影响,在认识气候变化对森林生态系统的影响上具有重要意义。采用树木年代学方法分析了张广才岭北部地区阔叶红松林中主要阔叶树种-水曲柳(Fraxinus mandshurica)、黄菠萝(Phellodendron amurense)和胡桃楸(Juglans mandshurica)径向生长与气候关系的时空变异。结果表明,在同一地点树种间气候响应差异明显,胡桃楸受降水和最低温度共同作用,而黄菠萝和水曲柳则主要受最低温度限制,这表明树木生长与气候因子的关系具有一定的物种特异性。随着温度和降水格局的改变,三大硬阔年轮与气候关系在空间水平上存在差异,方正和西大圈样点的胡桃楸与6—8月最低温度呈显著正相关(P0.05),而凤凰山样点与5、6月最低温度和降水呈正相关(P0.05);黄菠萝和水曲柳径向生长随着降水空间格局的变化,其生长季末期相关性程度逐渐减弱。1980年后张广才岭北部出现气温显著升高,在升温前三大硬阔的生长趋势相对一致,而在升温后黄菠萝和水曲柳树轮宽度随温度升高呈上升趋势,但胡桃楸却出现随温度升高而生长下降的"分异现象"。如果未来增温趋势持续发生或者加重,可以推断在张广才岭北部胡桃楸可能受干旱胁迫加剧,其可能出现生长衰退,但增温可能更有利于黄菠萝和水曲柳的生长。     

辽东山区不同树种幼苗根际土微生物性质及其对氮磷添加的响应

辽东山区是东北重要的生态屏障区，主要分布经干扰形成的次生林和人工林。与原始林相比，该区森林土壤有效氮、磷低。本研究比较了辽东山区主要树种幼苗的根际土微生物学性质及其对氮、磷添加的响应，以期为辽东山区树种优化提供依据。以该区6个主要树种幼苗(2年生):水曲柳(Fraxinus mandshurica)、胡桃楸(Juglans mandshurica)、色木槭(Acer mono)、蒙古栎(Quercus mongolica)、落叶松(Larix gmelinii)、红松(Pinus koraiensis)为对象，采用盆栽试验，比较不同树种幼苗根际土的微生物生物量碳、氮和酶活性。结果发现，不同树种幼苗根际土微生物生物量碳、氮差异显著，表现为：水曲柳>落叶松、胡桃楸、色木槭>蒙古栎、红松，水曲柳幼苗根际土微生物生物量碳、氮分别比其他树种高27.2%～482.9%、15.7%～333.1%;根际土酶活性因树种和酶类型而异，其中胡桃楸β-葡萄糖甘酶和落叶松N-乙酰-β-葡萄糖甘酶活性分别比其他树种高25.0%～72.4%、50.0%～200.0%。与不同树种对土壤微生物生物量碳、氮的...     

Shoot-Specific Down-Regulation of Protein Farnesyltransferase （α-Subunit） for Yield Protection against Drought in Canola

Canola （Brassica napus L.） is one of the most important oilseed crops in the world and its seed yield and quality are significantly affected by drought stress. As an innate and adaptive response to water deficit, land plants avoid potential damage by rapid biosynthesis of the phytohormone abscisic acid （ABA）, which triggers stomatal closure to reduce transpirational water loss. The ABA-mediated stomatal response is a dosage-dependent process; thus, one genetic engineering approach for achieving drought avoidance could be to sensitize the guard cell＇s responsiveness to this hormone. Recent genetic studies have pinpointed protein farnesyltransferase as a key negative regulator controlling ABA sensitivity in the guard cells. We have previously shown that down-regulation of the gene encoding Arabidopsis β-subunit of farnesyltransferase （ERA1） enhances the plant＇s sensitivity to ABA and drought tolerance. Although the β-subunit of famesyltransferase （AtFTA） is also implicated in ABA sensing, the effectiveness of using such a gene target for improving drought tolerance in a crop plant has not been validated. Here, we report the identification and characterization of the promoter of Arabidopsis hydroxypyruvate reductase （AtHPR1）, which expresses specifically in the shoot and not in non-photosynthetic tissues such as root. The promoter region of AtHPR1 contains the core motif of the well characterized dehydration-responsive cis-acting element and we have confirmed thatAtHPR1 expression is inducible by drought stress. Conditional and specific down-regulation of FTA in canola using the AtHPR1 promoter driving an RNAi construct resulted in yield protection against drought stress in the field. Using this molecular strategy, we have made significant progress in engineering drought tolerance in this important crop species.     

黑龙江省次生林主要组成树种光合能力与叶片含氮量研究

以黑龙江省次生林主要组成树种蒙古栎、白桦、水曲柳、山杨、胡桃楸、黄波罗为研究对象,测定自然状态下这6个树种的光合能力,并分析光合能力与叶片含氮量之间的关系.研究结果表明,树种的光合能力存在明显的季节变化,不同树种间的光合能力、光合潜力存在差异.生长季中,胡桃楸具有最高的光合能力最大值,白桦具有最高的年平均光合能力,蒙古栎具有最大的光合潜力.蒙古栎叶片含氮量与光合能力线性正相关(r=0.97),白桦、水曲柳叶片含氮量与光合能力呈二次曲线相关(r=0.61,r=0.51).     

Expression of the Grifola frondosa Trehalose Synthase Gene and Improvement of Drought-Tolerance in Sugarcane （Saccharum officinarum L.）

Trehalose Is a nonreduclng dlsaccharlde of glucose that functions as a protectant In the stabilization of blologlcal structures and enhances stress tolerance to abiotic stresses in organisms. We report here the expression of a Grlfola frondosa trehalose synthase （TSase） gene for Improving drought tolerance In sugarcane （Saccharum offlclnarum L.）. The expression of the transgene was under the control of two tandem copies of the CaMV35S promoter and transferred Into sugarcane by Agrobacterium tumefaciens EHA105. The transgenlc plants accumulated high levels of trehalose, up to 8.805-12.863 mg/g fresh weight, whereas It was present at undetectable level in nontransgenlc plants. It has been reported that transgenlc plants transformed with Escherlchla coil TPS （trehalose-6-phosphatesynthase） and/or TPP （trehalose-6-phosphate phosphatase） are severely stunted and have root morphologlc alterations. Interestingly, our transgenlc sugarcane plants had no obvious morphological changes and no growth Inhibition in the field. Trehalose accumulation in 35S-35S：TSase plants resulted In In- creased drought tolerance, as shown by the drought and the drought physiological Indexes, such as the rate of bound water/free water, plasma membrane permeability, malondlaldehyde content, chlorophyll a and b contents, and activity of SOD and POD of the excised leaves. These results suggest that transgenlc plants transformed with the TSase gene can accumulate high levels of trehalose and have enhanced tolerance to drought.     

辽东山区主要树种叶片氮、磷、钾再吸收

养分再吸收作为植物保存养分的重要机制之一,在凋落物分解和养分循环中起着重要作用。为明确辽东山区主要树种养分再吸收状况,选择4种次生林树种:蒙古栎(Quercus mongolica)、色木槭(Acer mono)、胡桃楸(Juglans mandshurica)、花曲柳(Fraxinus rhynchophylla)和人工林落叶松(Larix spp.)为对象,测定了各树种叶片凋落前(成熟叶)后(凋落叶)全氮(N)、全磷(P)、全钾(K)浓度,并分析了养分再吸收特征。结果表明:所测树种凋落叶N、P、K浓度均显著低于成熟叶(落叶松K不显著);胡桃楸N再吸收率与蒙古栎、色木槭、花曲柳差异显著,花曲柳与蒙古栎、色木槭P再吸收率差异显著,色木槭K再吸收率与蒙古栎、胡桃楸、花曲柳差异显著(P0.05);总体上,落叶松N、P、K再吸收率低于次生林树种,尤其是P再吸收率显著低于花曲柳、K再吸收率显著低于胡桃楸和花曲柳(P0.05)。上述结果表明,落叶松通过降低养分再吸收率,提高凋落物养分输入量,对土壤养分有效性做出正反馈。     

东北地区5种阔叶树苗木对火烧的生理响应

以3年生水曲柳、胡桃楸、蒙古栎、黄菠萝、白桦为研究对象,研究3种火烧处理(T1处理:对叶片火烧;T2处理:对枝火烧;T3处理:对茎火烧)对幼树丙二醛(MDA)含量、叶绿素含量和净光合速率的影响。结果显示:5种幼树火害叶(T1处理)丙二醛含量与对照相比都显著提高,说明幼树叶片细胞都受到了火的影响,发生了膜脂过氧化作用。水曲柳、胡桃楸、白桦火害叶(T1处理)叶绿素含量与对照相比显著提高;水曲柳、胡桃楸火害叶(T1处理)叶绿素a/b与对照相比显著降低。火烧处理后幼树新生叶丙二醛含量的变化因物种而异。5种幼树3种火烧处理后新生叶叶绿素含量除蒙古栎的茎处理和胡桃楸的枝处理显著降低外,大多表现为升高的趋势;新生叶叶绿素a/b的变化因物种而异。5种幼树3种火烧处理后新生叶净光合速率除蒙古栎的茎处理显著降低外,其他都有不同程度的提高。表明火烧提高了幼树的光合作用能力。     

东北地区胡桃楸次生混交林乔木物种组成和多样性

为了解东北地区胡桃楸次生混交林乔木树种组成和多样性,在黑龙江、吉林和辽宁三省中东部23个胡桃楸典型分布区内,设置123块面积0.1 hm2圆形样地,对样地内DBH≥5 cm乔木树种的物种组成、区系特征、重要值、丰富度和多样性等进行调查与分析。结果表明:东北地区胡桃楸次生混交林内共调查到乔木物种48种,隶属于17科,31属,其中黑龙江省30种,隶属于14科,21属;吉林省37种,隶属于14科,25属;辽宁省35种,隶属于16科,25属。物种主要以北温带分布区类型为主,不同区域物种数量随纬度升高呈先增加后减少趋势,随海拔升高呈先增加后减少趋势,在海拔300～700 m物种数量最为丰富。3个地区调查样地内重要值排在前6的共有树种是胡桃楸(Juglans mandshurica)、春榆(Ulmus pumila)、色木槭(Acer mono)、蒙古栎(Quercus mongolica)和水曲柳(Fraxinus mandshurica),非共有树种为红松(Pinus koraiensis)(黑龙江)、紫椴(Tilia amurensis)(吉林)和花曲柳(Fraxinus rhynchophylla)(辽宁)。调查样地内多样性表现均较高,除Shannon多样性指数在吉林省显著高于黑龙江省和辽宁省外(P0.05),Simpson多样性指数和Pielou均匀度指数三省之间均无显著性差异,且三省群落之间均表现为中等相似。本研究可为深入了解东北中东部地区胡桃楸次生混交林物种多样性和森林经营提供基础。     

Patterns of tree phenological diversity in dry tropics

Recent phenological studies in tropical deciduous forests revealed a mosaic of vegetation composed of several pheno-phases that are evolved as an adaptation by the species to overcome seasonal drought in different ways. These pheno-phases represent extent of annual deciduousness (～leaflessness) and triggering factors for buds break (e.g. vegetative and flower). Thus, studying patterns of various pheno-phases (phonological diversity) in tropical forest have been thought to provide a potential tool to address critical questions related to climate change modeling and monitoring. In tropics, tree species represent a gradient of deciduousness (from leaf-exchanging species to >6 months deciduous species) and flowering initiation (breaking of flower buds in various part of annual cycle). Both processes are mostly triggered by variation in day length and/or temperature during late dry season/autumn, and/or first significant rain during rainy season. In addition, few factors like drought induced leaf fall and sporadic winter rains are supposed to affect these processes temporarily. Besides, the abundances of pheno-phases (i.e. leafing and flowering) also vary among tropical deciduous forest trees. Presence of such variations in tropical tree pheno-phases and their abundances are reported to vary due to micro-climatic variables and has specific implications in tropical forests. Present paper discusses the existing information on various pheno-phases and their abundances in tropical forests and role of climatic factors on tree phonological diversity. Further, we emphasized the need to develop predicting understanding of impending climatic change (i.e. precipitation and temperature) on diversity of pheno-phases by collecting long-term data on tree pheno-phases through a network of phonological stations in dry tropics.     

人工湿地植物种类和多样性对氧化亚氮释放及功能基因丰度的影响

为了解人工湿地处理中碳/氮水平的废水时植物种类及多样性对系统氧化亚氮释放及功能基因丰度的影响,本研究构建了实验尺度的垂直流人工湿地微宇宙实验系统.选取芦苇(Phragmites australis)、千屈菜(Lythrum salicaria)和海寿花(Pontederia cordata)3种人工湿地常用、景观效果好的植物,在系统中配置了3个单种处理和1个三物种混种处理.结果表明:芦苇、千屈菜与海寿花混种系统的氧化亚氮释放强度(24597.0 μg N2O·m-2·d^-1)高于三物种单种系统的平均值(11744.8 μg N2O·m^-2·d^-1)(P<0.001),同氧化亚氮释放一样,混种系统的amoA基因绝对丰度(6.33× 10^7 copies·g^-1 soil)和nirS基因绝对丰度(1.92× 106 copies·g^-1 soil)也高于三物种单种系统的平均值(5.70×10^7和1.58×10^6 copies·g^-1 soil).此外,混种系统的出水硝态氮浓度低于三物种单种系统的平均值(P<0.05),但出水硝态氮浓度、微生物量和植物生物量在单混种系统间无显著差异(P>0.05).3个单种系统间的氧化亚氮释放强度、amoA基因绝对丰度、nirS基因绝对丰度、出水铵态氮浓度、微生物量和植物生物量存在显著差异(P<0.01),但出水硝态氮无显著差异(P>0.05).通过植物种类和丰富度对各指标变异的解释度发现,植物种类和丰富度分别解释变异的比率存在一定差异,总体上,植物丰富度对氧化亚氮释放、amoA基因绝对丰度和nirS基因绝对丰度的影响大于植物种类,植物种类对出水硝态氮浓度的影响大于植物丰富度.     

光质对杉木种子萌发及幼苗生长的影响

光是影响森林早期天然更新(种子萌发和幼苗生长)的重要因子之一.但光质对杉木(Cunninghamia lanceolata(Lamb.) Hook)早期更新的影响尚不清楚.为探讨光质对杉木种子萌发及幼苗生长的影响机制,以杉木种子为研究对象,通过设置8h白光(W)、8h红光(R)、6h红光-2 h远红光(R-FR)、4h红光-2 h远红光-2 h红光(R-FR-R)、黑暗(D,对照)5种不同光质处理,观察种子萌发及幼苗生长特征.结果表明,不同光质处理对杉木种子萌发影响显著,D和R-FR-R处理促进杉木种子萌发,R处理抑制种子萌发.最后一次照光选择红光处理(R和R-FR-R)能够显著促进杉木幼苗根和子叶的伸长,促进生物量积累以及增加叶生物量分配比例,但抑制茎的伸长,远红光处理则促进茎的生长.杉木种子为光不敏感种子,黑暗处理下萌发率最高,且远红光间断处理能够相对促进其萌发,说明杉木种子可以较好地适应异质光环境.     

丹江口库区湖北水源区不同密度马尾松人工林水源涵养能力

为了研究南水北调中线水源区汛期森林的水源涵养功能,以丹江口库区龙口林场马尾松人工林为对象,于2018年6-9月采用野外观测与室内分析相结合的方法,对高、中、低3种密度马尾松人工林,从林冠层、枯枝落叶层和土壤层进行分析,探究其丰水期水源涵养功能的林分密度效应.结果表明:(1)3种密度马尾松人工林林冠截留量为56.13~77.68 mm,且随林分密度增加林冠截留量增大,林内穿透雨量则趋势相反;(2)3种密度马尾松人工林枯落物总生物量为12.76~19.56 t·hm^-2,随着林分密度增加枯落物总生物量增大,且半分解层枯落物生物量均大于未分解层枯落物生物量;高密度枯落物总厚度最大,中密度次之,低密度最小;枯落物最大持水量为21.32~28.24 mm,有效持水量为16.82~22.51mm,且均表现为中密度>高密度>低密度;枯落物持水量、吸水速率与浸泡时间分别呈对数函数和幂函数关系式;(3)3种密度马尾松人工林O~ 30 cm土层土壤容重为1.45~ 1.54g·cm^-3,总孔隙度均值为42.18%~45.71%,土壤有效持水量为2.94~4.81 mm,且土壤容重大小为低密度>高密度>中密度,土壤总孔隙度排序则与之相反,土壤有效持水量表现为中密度>低密度>高密度;(4)3种密度马尾松人工林综合水源涵养能力为204~237.55 mm,表现为中密度>高密度>低密度.综上,丹江口库区中密度马尾松人工林水源涵养服务能力最优,建议在今后库区森林抚育过程中,合理控制林分密度.     

卫星跟踪中蒙之间秃鹫春季迁徙路线及活动区域

秃鹫(Aegypius monachus)被世界自然保护联盟(IUCN)列为近危物种。每年冬季或者早春在渤海湾都会救护到因体质较弱而无法飞行的秃鹫,为了对秃鹫及其迁徙路线进行更有效的保护,于2016年春季对两只救护放飞秃鹫(ID1051和ID2016),利用卫星跟踪技术研究其迁徙路线和活动区,旨在为秃鹫的救护和保护提供基础资料。结果表明,ID1051和ID2016都迁徙到蒙古国的布尔干省和后杭爱省交界处,行程分别为2 200 km和2 400 km。ID2016在度夏初期、中期和后期的活动区面积(50%Fixed Kernel),分别为31 261.01km^2、1 492.96 km2和11 027.70 km^2。秃鹫在迁徙过程中主要时间在静息,其次是飞行和寻觅行为。在0至7时和19至24时,即晨昏和夜间秃鹫都处于静止状态。从8时开始,秃鹫开始活动,并在12和13时达到活动高峰,随后活动逐渐趋缓,直至18时趋于静止状态。本文提供了秃鹫的春季迁徙路线以及重要中途停歇地,为秃鹫的救护和保护提供了基础资料。