CloneIRD:面向代码溯源的克隆代码继承关系判定方法

随着开源软件的广泛使用,代码溯源成为管理软件源代码、降低潜在风险的重要技术手段。基于代码克隆检测的大规模代码溯源分析,从其检测结果中鉴别代码克隆对之间的继承关系,对代码来源追踪、组件依赖关系分析、软件脆弱性分析以及代码缺陷修复等具有重要意义。目前,已有方法在原始代码片段存在微小修改的情况下,会产生许多误判,并且检测克隆对的效率也有待提高。针对上述问题,提出了代码溯源中克隆代码继承关系的判定方法CloneIRD,包括一个基于自研快速分布式克隆检测工具FastDCF的代码溯源分析框架,以及该框架的核心算法——基于代码演化信息的克隆代码继承关系判定算法EIHR。为验证框架和算法的有效性,首先设计并实现了CloneIRD方法,并在Linux内核V4.9和V4.12的开源代码上进行了实验。实验结果表明,CloneIRD方法能够有效判定代码溯源结果中克隆对的继承关系,且基于FastDCF的溯源分析框架能够胜任大规模代码的溯源分析任务。

数字克隆人:“跨媒介—交互”中的数字沉浸性研究——基于容积视频捕获技术的探讨

容积视频捕获(Volumetric Video)是通过光学扫描来捕捉拍摄对象并生成动静两态4D数字影像模型的前沿机器视觉技术之一。与现有的虚拟数字人不同,它生成的数字克隆人是对真人一比一的真实呈现,故而数字克隆人所具有的视觉情感与叙事场景于受众而言具有更深刻的沉浸性。本文从数字克隆人的生成逻辑、技术特性出发,深挖其背后生发的感知体验与情感投射,通过跨媒介叙事分析,结合实验室成果探索其沉浸意境与实践意义,揭示数字克隆人在经历“生产—创造”的过程后将客观形态和主观感性融合在一起,冲破了人与技术、人与审美、人与群体的边界,在虚拟世界中转化为现实的仿真。

Selection of Media for Hardwood Cuttings Container Seedling-raising of Triploid Clones of Populus tomentosa

[Objective] The experiment was aimed to select effective and economical media for container seedling of triploid clones of Populus tomentosa that was carried out. [Method] The sandy loam, peat, perlite, vermiculite, riversand, sludge were taken as media of hardwood cutting and survival rate, seedling height were taken as indexes to select media for container seedling of triploid clones of Populus tomentosa. [Result] Different mixedmedia had great influence on survival rates of container seedlings. Taking peat and vermiculite with the proportion of 5∶2 (M10) or peat ,vermiculite with the proportion of 7∶2 (M11) or sandy loam (M1) as media would generate higher cutting survival rate that was higher than 90.0%. There were significant differece in height increments of container seedlings. Taking sandy loam, peat and vermiculite with the proportion of 6∶2∶2(M5)or sandy loam (M1), seedling height of 60-days the seedling was over 37.0 cm. [Conclusion] According to cost analysis of nursery medium, the optimum medium for hardwood cuttings container seedling-raising of triploid clones of Populus tomentosa was sandy loam.

戊地昔布抑制clone 26肿瘤细胞增生及机制

目的探讨戊地昔布对小鼠肠癌clone26细胞的生长抑制作用及机制。方法用噻唑蓝（MTT）法检测戊地昔布对clone26细胞生长的作用。用流氏细胞仪检测clone26细胞凋亡率和细胞周期分布。用Western blot检测clone26细胞caspase-3，PCNA和COX-2的表达．结果①戊地昔布可抑制clone26细胞生长并呈时间和浓度依赖性。②50-400μmol·L^-1戊地昔布可明显提高clone26细胞的凋亡率，从对照的3．1％提高到4．4％～11．0％。给予戊地昔布后，细胞的增殖指数，S期的细胞比例和G2／M期细胞有下降趋势，但只有在400μmol·L^-1戊地昔布组时才有统计学意义。③给予戊地昔布后，细胞PCNA的表达降低，caspase-3的表达升高，COX-2的表达没有变化。结论戊地昔布通过诱导凋亡和细胞周期停滞而抑制clone26细胞生长，小剂量时主要与凋亡有关，大剂量时与诱导凋亡和细胞周期停滞有关、Caspase-3参与戊地昔布诱导的凋亡。

Study on Tissue Culture and Effective Clone Establishment of Hemistepta lyrata Bunge

[Objective] The research aimed to study the rapid propagation technology and establish effective clone of Hemistepta lyrata Bunge. [Method] With tender stem of Hemistepta lyrata Bunge as material, the conditions needed in calluses induction and differentiation, adventitious bud differentiation and radication, test tube seedling cutting and transplantation were studied. [ Result] The results showed that the optimum medium for granulated calluses induction from tender stem was MS ＋ BA 0.3 mg/L ＋2,4-D 1 -1.5 mg/L, for granulated calluses and adventitious bud differentiation was MS ＋ AgNO31.5 mg/L ＋ BA 0.4 mg/L ＋ NAA 0.1 mg/L. 1/2 MS ＋ IAA 0.6 mg/L was suitable for test tube seedling rooting and regeneration, and cinder was used as transplantation and cutting substrate. [ Conclusion]This study will provide the scientific reference for choosing the feasible medium in tissue culture of Hemistepta lyrata Bunge.

Effects of Drought Stress on Osmotic Regulation Substances of Five Catalpa bungei Clones

[Objective] This study aimed to investigate the effects of drought stress on osmotic regulation substances of Catalpa bungei clones. [Method] Potting experimental was carried out with plastic film sealing method, to differentiate the degrees of drought stress based on changes in soil water content and leaf water potential and investigate variations in contents of osmotic regulation substances（free proline,soluble sugar and soluble protein） in leaves of five Catalpa bungei clones under different degrees of drought stresses. [Result] According to changes in soil water content and leaf water potential, the whole process of drought stress was divided into normal level（CK, with soil water content of 97.49% and leaf water potential of-0.54MPa）, light drought（LD with soil water content of 59.96% and leaf water potential of-1.28 MPa）, mediate drought（MD with soil water content of 34.19% and leaf water potential of-2.32 MPa） and severe drought（SD with soil water content of 14.52%and leaf water potential of-2.99 MPa）. The soil water content and leaf water potential of five Catalpa bungei clones reached the highest correlation in exponential fitting, with an average R2of 0.989 3（P0.001）. The free proline content in leaves of five Catalpa bungei clones increased rapidly with the increasing degree of drought stress（P 0.001）. To be specific, free proline contents of Catalpa bungei clones015-1 and 7080 were 34.39 and 33.41 times of the normal level under severe drought conditions, which reached an extremely significant level（P0.001）; the free proline content of Catalpa bungei clone 1-3 rapidly increased to（855.46±227.52） μg/g Fw under light drought conditions. The soluble protein content in leaves showed different variation trends. To be specific, the soluble protein content of Catalpa bungei clone 7080 was the lowest at various drought stages and reached（1.644 ±0.137）mg/g Fw under normal conditions; the soluble protein content of Catalpa bungei clone 1-3 was relatively high under normal conditions and was reduced rapidly under light drought conditions, showing different response patterns. [Conclusion] Osmotic regulation substances in leaves of five Catalpa bungei clones all have certain response to drought stress. Free proline is the most important osmotic regulation substance, followed by soluble protein, while soluble sugar makes no significant contribution. According to changes in content of osmotic regulation substances, Catalpa bungei clone 7080 has relatively high capacity and good drought resistance, while Catalpa bungei clone 1-3 has the rapidest response to drought stress.

Study on Phenological Character in Seedling Period of Introduced Populus deltoids Clones

In order to provide directionally genetically improved breeding materials of poplar by exploring the phenological traits genetic variation level and its develop- ment potential of Populus deltoides and the resource evaluation was carried out; 8 phenological phases in seedling period were observed and analyzed of 60 Populus deltoids clones introduced from America. The results showed that： （1） there was obvious difference in phonological character among clones, especially in leaf-spread- ing peak stage and the end term of leaf-falling stage, with the largest variation co- efficient of 14.97% and the minimum of 3.83% respectively. （2） Leaf-spreading peak stage scattered but the end term of leaf-falling stage concentrated the most. The phonological character in early stage of seedling growth was the main factor influ- encing the length of growing season. （3） By principal component analysis, pheno- logical phases were classified into 3 typical periods, including germination stage, leaf-spreading peak stage and leaf-falling stage. （4） Totaling 60 clones were classi- fied into 4 types by using clustering analysis in phenological time variables of clones.

Comparative Study on Photosynthetic Characteristics of Different Catalpa bungei Clones

[Objective] This study aimed to provide scientific basis for the early selec-tion and breeding of excellent Catalpa bungei clones. [Method] The Li-6400 portable photosynthesis system was used to analyze the photosynthetic characteristics of five Catalpa bungei clones （1-3, 1-4, 004-1, 015-1 and 7080）. [Result] Al five Catalpa bungei clones had similar change trends of light response curves, but their maxi-mum net photosynthetic rates （Pmax） were in the order of 1-3＆gt;7080＆gt;015-1＆gt;004-1＆gt;1-4, showing that clone 1-3 and clone 7080 had strong light environmental adapt-ability with the light saturation points （LSP） of 1 147.97 μmol/m2＆#183;s and 1 196.31μmol/m2＆#183;s, respectively, while clone 1-4 had the narrowest range of adaptation to light. There were differences in the total photosynthetic amount per area among the five clones that clone 1-4 was the best of 433 974.24 μmol/m2, fol owed by clone 1-3 of 401 290.20 μmol/m2. The transpiration rates （Tr） and stomatal conductances （Cond） of the five clones presented the same change trend. And the diurnal varia-tion curves of net photosynthetic rate （Pn） of clone 1-3, 1-4 and 015-1 showed two typical peaks with obvious midday depression, while clone 004-1 and 7080 didn’t. [Concluson] Considering a variety of photosynthetic characteristics of indica-tors, photosynthetic capacity of clone 1-3 was the best among the five Catalpa bungei clones.

Study on Cutting Propagation of Toona ciliata Clones

Cutting propagation rhizogenesis of Toona ciliata clone cutting orchard were studied, and the results were as fol ows： Rooting type included both cal us rooting and cortex rooting. About 17 in 22 of clones were dominated by cortex rooting, accounting for the 77% of clones. There were 5 clones which occurred with both cal us rooting and cortex rooting during rooting process. The rooting efficiency index （REI） showed a positive correlation with the rooting rate. Under natural tem-perature condition, keeping moisture and shading, we found that the highest survival rate occurred in early June, September, and October.

纤维素降解菌I2的分离及相关降解基因功能验证

纤维素是地球上数量最大的可再生能源物质,利用微生物或其产生的酶可将纤维素水解成葡萄糖。筛选高效纤维素降解菌和纤维素酶一直是生物能源等领域研究的热点。该研究筛选分离了1株具有降解纤维素能力的短小芽孢杆菌I2,通过基因组测序,分析其参与纤维素降解的基因,并对纤维素酶的功能进行验证。I2分离自河南南阳宝天曼自然保护区落叶及长期堆积小麦秸秆的堆体等样本富集后的混合菌系,具有降解滤纸的能力,48 h内可以降解大部分滤纸。基因组组装分析显示,I2的基因组大小为4.2 Mbp,含有4635个基因。利用CAZy碳水化合物数据库注释和酶活性测定实验,对数据库检测到的182个基因进行分析,明确I2中4个基因在大肠杆菌表达后具有纤维素酶活性。其中,G2269纤维素内切酶活性最高,在pH 5.0,温度55℃条件下,酶活力可达49.02 U/mL。金属离子Ca^(2+)、Zn^(2+)对于G2269的活性有明显提高作用,Mn^(2+)和Cu^(2+)对G2269活性抑制比较明显,Mg^(2+)、Co^(2+)、K^(+)、Ni^(2+)、NH_(4)^(+)对于G2269的活性无显著影响。此外,G2269还具有良好热稳定性和酸碱稳定性,在65℃保持30 min后仍保留70%的活力,在食品加工和饲料生产等领域显示出较好的应用潜力。

刺参TRAF7基因克隆及其响应高温胁迫下的表达特征分析

肿瘤坏死因子受体相关因子7 (tumor necrosis factor receptor associated factor 7, TRAF7)作为一种细胞内蛋白,参与信号转导,并介导宿主应激防御调控过程。为研究TRAF7在刺参(Apostichopus japonicus)高温胁迫中的作用,本研究利用c DNA末端快速扩增技术(RACE)和实时荧光定量PCR技术(RT-qPCR),克隆了刺参TRAF7(Aj TRAF7)全长c DNA序列,分析了其结构特征和在基因组中的分布,并检测了该基因在刺参不同组织和高温胁迫过程中体壁组织中的表达变化情况。结果显示,AjTRAF7全长2 576 bp,开放阅读框(ORF)长1 770 bp,5'UTR长345 bp,3'UTR长461 bp,编码589个氨基酸,预测蛋白分子量为65.6 kDa,理论等电点(p I)为7.52。蛋白序列包含1个RING finger结构域、1个Coiled coil结构域和6个WD40结构域,N端包含1个螺旋区域。该基因预测蛋白包含41个丝氨酸磷酸化位点、20个苏氨酸磷酸化位点和3个酪氨酸磷酸化位点,蛋白N端具有3个天冬酰胺糖基化位点。刺参基因组中比对到2个AjTRAF7基因拷贝,第一个拷贝包含18个外显子和15个内含子,第二个拷贝包含17个外显子和14个内含子。系统进化学分析表明,刺参TRAF7氨基酸序列与蝠海星(Patiria miniata)和紫色球海胆(Strongylocentrotus purpuratus)相似性较高,分别为40.58%和38.37%,刺参与蝠海星和紫色球海胆聚在一支。RT-qPCR结果显示,Aj TRAF7在健康刺参各组织中均有表达,其在雌性性腺中表达量最高,体腔细胞中表达量次之,在呼吸树、体壁、肠道、雄性性腺和纵肌中表达量依次降低,各组织间表达量差异显著(P<0.05)。在响应高温胁迫的过程中,与对照组相比,体壁组织中AjTRAF7基因表达量在第2天和第4天显著上升(P<0.05),第6天基因表达开始下降。综上,AjTRAF7基因可能参与刺参应对高温胁迫的表达调控过程,相关结果将为解析刺参应对高温胁迫的分子机制提供科学依据。

合作猪NTF3基因克隆、生物信息学分析及组织表达谱构建

克隆合作猪神经营养因子3基因(Neurotrophin3,NTF3)的编码区序列(Coding region sequence,CDS),预测分析其结构与功能,并检测基因在不同组织中的表达量,构建组织表达谱。通过PCR扩增、Sanger测序等方法获得合作猪NTF3基因CDS区序列,使用生物信息学方法分析其结构,并使用RT-qPCR技术检测其在不同组织中的表达水平。结果显示,合作猪NTF3基因CDS区长774 bp,编码257个氨基酸;等电点(pI)为9.46,属于碱性蛋白;合作猪与猪、牛亲缘关系较近;二级结构主要为α-螺旋和无规则卷曲,三级结构主要由β-折叠、α-螺旋等组成;整条链中亲水性氨基酸残基数量多于疏水性氨基酸残基数量,是亲水性蛋白;无跨膜区域,是非跨膜蛋白;在37~58位氨基酸残基有一个线圈结构域、64~79位有一个低复杂度结构域和144~249位有一个神经生长因子结构域;存在信号肽,推测是分泌蛋白;NTF3基因在合作猪脾脏的表达量最高,回肠表达量最低。

Field test of new poplar clone in Shangdong Province

Poplar is one of the dominant tree species for the establishment of fast growing plantations in Shandong Province. Eighteen poplar clones belonging to Populus aigeiros section were introduced from Italy, Turkey and domestic regions. Populus deltoides cv. 慙ux?I-69/55 (I-69), which was widely used in Shandong Province, China, was taken as control clone (I-69). Following a randomized complete block design, seedling test and controlled afforestation trials were carried out at Juxian County, Caoxian County and Laiyang City. The results showed that the poplar clone (Populus ?euramericana cv. ?02/74?, namely 102/74, performed well both in terms of adaptability and growth rate. The mean height of 13.9 m (H), diameter at breast height of 18.0 cm (DBH) and volume growth of 0.1445 m3 (V) were 2.2 %, 21.6% and 52.9 % higher than those of I-69 (CK), respectively, at the age of 5 years at three experimental sites. Moreover, the clone can be propagated easily and showed high resistance to poplar disease, pest as well as salinity and had longer growing period. Furthermore, wood basic density and fiber length of new poplar clone (102/74) were as same as I-69 (CK). It was concluded that the selected clone (102/74) was ideal for the estab-lishment of fast-growing poplar plantations, especially for the pulpwood plantations in Shandong Province.

Genetic Control of Air-Dried Wood Density, Mechanical Properties and Its Implication for Veneer Timber Breeding of New Triploid Clones in Populus tomentosa Carr

The wood samples of 9 triploid clones of Populus tomentosa Carr. taken from a 9 year old clonal test site were analyzed in order to investigate the genetic variation of wood properties, including air dried wood density and some mechanical properties. The results showed that significant or extremely significant difference in air dried wood density and the mechanical properties existed among the clones, this means these wood properties were under moderate or strong genetic controls and could be improved by genetic manipulations. The radial and vertical variation patterns of air dried wood density were also studied and the results were found to coordinate with other previous research results. The vertical variation patterns of most mechanical properties within the individual tree also conformed to the general wood theories except the modulus of elasticity and cross section hardness. Among the mechanical properties, modulus of elasticity (MOE) and tangent section hardness were under strong genetic control, with the clonal repeatabilities being 0 90 and 0 80, respectively. However, the clonal repeatabilities of other mechanical properties under study were a little lower than above two indexes. Genetic correlation analysis indicated that super clonal selection and breeding for veneer timber could be realized through indirect selection of wood density and form indexes.

ZjERF098鉴定及其提高冬枣黑斑病抗病性的效果研究

克隆并鉴定冬枣转录因子ZjERF098明确其分子特性,验证ZjERF098瞬时过表达对枣果实黑斑病的抑制效果,为枣果实抗病机制研究奠定基础。对ZjERF098进行系统发育树构建、同源序列比对、结构域分析、蛋白质结构预测、启动子顺式作用元件分析,克隆并构建了pEAQ-ZjERF098等多个重组载体,在烟草上进行亚细胞定位和转录激活活性分析,在冬枣果实上进行瞬时过表达。结果显示,ZjERF098的开放阅读框包含426个碱基对,编码141个氨基酸,与拟南芥中的AtERF098序列相似度最高,同属于ERF转录因子亚家族,只有1个AP2结构域,不含信号肽与跨膜结构域。启动子区域含有与植物防御反应相关的脱落酸响应元件、茉莉酸响应元件等响应元件。ZjERF098具有转录激活活性,主要定位在细胞核上,同时在细胞质膜也有GFP荧光信号。同时,ZjERF098瞬时过表达能够增强枣果实对黑斑病的抗病性,显著降低枣果实的发病率与病斑直径,表明ZjERF098是在枣果实对黑斑病抗病性中起到重要作用的转录因子。

六个繁育场异育银鲫的克隆系鉴定及特征分析

为了厘清湖北省异育银鲫(Carassius gibelio)繁殖群体的种质资源现状,研究以湖北省6个苗种繁殖场的异育银鲫亲本为研究对象,比较不同群体的生物学特征和品质性状的差异,利用基因组重测序进行品种与克隆系鉴定和遗传多样性分析。研究结果表明,根据180尾异育银鲫全基因组重测序的SNPs,共鉴定出10个异育银鲫克隆系,其中2个异育银鲫“中科3号”亚克隆系,5个异育银鲫“中科5号”亚克隆系和3个其他克隆系。遗传多样性分析表明,单核苷酸密度(SNP/kb)、单核苷酸多态性(p)、多态信息含量(PIC)和观测杂合度(H_(o))分别为11.17、0.0050、0.4332和0.5612。系统发育树和主成分分析结果显示,不同群体之间表现出中度到高度的遗传分化,同时也存在较为显著的交叉聚类现象,结合异育银鲫克隆系分布,表明除了梁子湖和正大群体外的繁殖亲本存在一定的种质混杂现象。不同克隆系之间的形态上存在差异,体高/体长和头长/体长可以作为初步判断异育银鲫形态的两个参考指标。异育银鲫“中科5号”和异育银鲫“中科3号”的肌肉营养成分中粗脂肪含量差异显著,而粗蛋白含量无明显差异。不同克隆系间的肌肉中17种脂肪酸含量均存在显著差异,DHA+EPA总量在不同克隆系之间也存在差异。研究不仅有利于异育银鲫种质资源的合理开发与保护,而且有助于异育银鲫新品种选育和养殖产业的可持续发展。

湖羊PSMB9基因克隆、序列分析及对成肌细胞增殖的影响

[目的]探讨湖羊蛋白酶体亚基β9(proteasome 20S subunit beta 9,PSMB9)基因编码区、启动子区序列特征、转录调控机制及其对成肌细胞增殖的影响。[方法]采用克隆测序法获得湖羊PSMB9基因编码区序列,根据绵羊PSMB9基因组的定位确定其启动子区大小,并通过生物学软件分析PSMB9基因编码区和启动子区序列特性,采用Mega 5.0中的邻接法(Neighbor-Joining)构建基于PSMB9氨基酸序列的系统进化树;采用实时荧光定量PCR鉴定PSMB9基因在湖羊不同组织中的表达谱;利用双酶切法构建湖羊PSMB9基因过表达载体,采用CCK-8试剂盒检测细胞的增殖能力,通过实时荧光定量PCR检测PSMB9基因在C2C12细胞系中的过表达效果和增殖基因PCNA的表达水平。[结果]湖羊PSMB9基因编码区长660 bp,编码219个氨基酸残基,其核苷酸序列和氨基酸序列与哺乳动物(如人、牛、猪和小鼠)的相似性较高,PSMB9氨基酸中活性位点和β亚基相互作用位点均高度保守;系统进化树显示,湖羊与牛先聚在一起,再与猪、人和小鼠聚在一起,说明PSMB9在哺乳动物中相对保守。PSMB9基因启动子区含有1个CpG岛、2个GC-box(CCGCCC)和2个E-box(CANNTG),且存在SP1、KLF4、STAT3、YY1、CREB1等多种转录因子潜在结合位点。组织表达谱显示,PSMB9基因在湖羊各组织中广泛表达,其中在脾脏中表达量最高,肌肉次之。与对照组相比,在C2C12细胞系中过表达PSMB9基因后极显著提升了细胞的增殖能力(P<0.01),增殖标志基因PCNA表达水平极显著上调(P<0.01)。[结论]本研究成功克隆获得了湖羊PSMB9基因序列,该基因在哺乳动物中高度保守,启动子区含有重要调控元件、CpG岛和转录因子潜在结合位点。PSMB9基因在湖羊脾脏和肌肉组织中高表达,PSMB9基因过表达可促进成肌细胞的增殖。研究结果为进一步阐明PSMB9基因调控湖羊肌肉发育的分子机制提供依据。

‘新露’核桃内果皮发育相关基因JrMYB44和JrMYB13的克隆及表达分析

木质素合成是核桃内果皮硬化的必要条件,但其调控机制尚不清楚。克隆核桃木质素合成相关基因JrMYB44和JrMYB13的CDS全长,检测这两个基因在核桃不同组织器官以及内果皮不同发育时期硬化与非硬化部位的表达水平,调查这两个蛋白的亚细胞定位。结果表明:JrMYB44和JrMYB13分别编码319和317个氨基酸,两者同源性为39.5%;系统发育树分析发现,JrMYB44与Juglans regia×Juglans major杂交核桃和山核桃同源蛋白的亲缘关系较近,而JrMYB13与Juglans regia×Juglans major杂交核桃同源蛋白的亲缘关系较近。亚细胞定位结果显示,JrMYB44和JrMYB13均在细胞核内表达。基因表达检测发现,JrMYB44基因主要在核桃内果皮的非硬化区富集表达,且在内果皮不同发育时期的表达水平与木质素含量呈负相关,推测JrMYB44基因对木质素合成起负调控作用;JrMYB13基因主要在核桃内果皮硬化区富集表达,且表达水平随木质素含量增加而上升,推测JrMYB13基因对木质素合成起正调控作用。

Effects of Drought Stress on Contents of Endogenous Hormones in Leaves of Different Clones of Liriodendron chinense×L. tulipifera

[Objective] The aim was to study the effects of drought stress on contents of endogenous hormones in leaves of different clones of Liriodendron chinense×L. tulipifera. Drought-resistant Liriodendron chinense×L. tulipifera clones NE25,NE78 and drought-sensitive Liriodendron chinense×L. tulipifera clones NE04,NE23 were selected as experimental materials to study the content changes of four kinds of endogenous hormones such as abscisic acid （ABA）,indoleacetic acid （IAA）,ribosylzeatin （ZR） and jasmonic acid （JA） in leaves of different clones under drought stress. [Result] Under drought stress,ABA was accumulated I leaves of different clones,however,the content changes in drought-resistant clones were not obvious; IAA content showed a decreasing trend,and the content changes n drought-resistant clones during later period of drought stress was decreased; JA content showed an increasing trend in leaves of drought-sensitive clones,indicating that drought-sensitive clones had to maintain higher contents of JA to resist drought stress. [Conclusion] The result of this study had provided scientific basis for the screening,planting and application of drougt-resistant clones of Liriodendron chinense×L. tulipifera.