云南中新世和山西上新世果实和种子的研究

研究化石果实和种子的古果实学在欧洲和北美开展较早，近年来发展迅速，我国在这个领域的研究相对薄弱，迄今为止尚没有专项的研究工作。本论文首次对我国云南和山西晚第三纪的果实和种子进行专门研究，并根据它们对应的现存最近亲缘植物的分布及生态特征分析和重建了当时当地的吉植被、古环境和古气候。 1．云南省西部陇川盆地芒旦地区早一中中新世被子植物果实和种子植物群，包括果实和种子29种，详细研究了14种，隶属于ll科12属：壳斗科的石栎属、金缕梅科的蜡瓣花属、金丝桃科的金丝桃属、樟科的木姜子属、木兰科的木兰属和鹅掌楸属、桑科的榕属、杨梅科的杨梅属、蓝果树科的蓝果树属、芸香科的花椒属、清风藤科的清风藤属以及山矾科的山矾属。所有这些果实和种子的化石在中国均为首次报道，其中蜡瓣花属、鹅掌楸属、蓝果树属、清风藤属和山矾属还是该属在中国的首次大化石记录。在植物群组成中，石栎属占绝对优势，其他主要类群有蜡瓣花属、木姜子属、木兰属、花椒属和山矾属等。芒旦果实和种子植物群反映当时当地为亚热带常绿阔叶林的森林面貌和温暖湿润的亚热带气候条件。 2．山西省榆社盆地张村地区晚上新世( 2.3 Ma-3.5 Ma)水生植物川蔓藻属(Ruppia)果实和种子的大量发现及其与川蔓藻属2个化石种和5个现代种的比较表明，这些果实和种子属于一个新种—榆社川蔓藻Ruppia yushensis sp. nov。该新种的主要特征为内果皮卵形、表面光滑、侧面具两个显著的窄椭圆形凹陷、顶端具一个明显的小尖突，以及种子顶端具显著的球形膨大的种脐。榆社川蔓藻将川蔓藻属的第三纪地理分布范围从欧洲延伸到了东亚，并且填补了它在上新世地层的空缺。榆社川蔓藻作为榆社盆地晚新生代水生植物的发现，指示了当时当地的咸水环境。根据川蔓藻属植物的现代生态资料并结合其它矿物学和生物学指标，可以推测晚上新世张村地区为一个浅而平静的微咸水湖。榆社川蔓藻果实和种子的大量出现说明该植物可能在该水域形成了单一的优势类群，其光滑的内果皮表面指示当时当地为暖温带或温带气候。

四种国产野生无髯鸢尾种子休眠与萌发的研究

玉蝉花（Iris ensata）、山鸢尾（Iris setosa）、金脉鸢尾（Iris chrysographes）和西南鸢尾（Iris bulleyana）这四种国产野生无髯鸢尾的种子均存在休眠现象，然而萌发情况各异。通过大田实验、层积处理、离体胚培养、切割胚乳、剥离种皮、切割胚乳不同部位、对种子的珠孔端胚乳进行扫描电子显微镜观察和用Instron 5848微力材料实验机测量刺穿珠孔端结构所需要力，以及把离体胚放在PEG-6000的渗透液中来测试四种鸢尾种子胚的生长势等实验，发现：玉蝉花、山鸢尾、金脉鸢尾和西南鸢尾这四种鸢尾种子存在不同程度的休眠;胚不含萌发抑制剂，已经完成了生理成熟，不是这几种鸢尾休眠的障碍;鸢尾的种皮透水性良好，虽然种皮对萌发有一定的机械抑制作用，然而相对于珠孔端胚乳而言，对胚根伸长的阻力不大，因此不是种子休眠的主要因素。根据实验结果推测，鸢尾种子的胚乳含有萌发抑制剂，然而，珠孔端胚乳的机械束缚可能是鸢尾种子萌发延迟的主要原因。通过进一步的实验发现，玉蝉花和山鸢尾这两种鸢尾胚的生长势高于后两种鸢尾种子，然而，它们的珠孔端结构（胚乳和种皮）对胚伸长的束缚还不及后两者的一半，也就是说，鸢尾种子萌发与否主要取决于珠孔端胚乳对胚根伸长的机械束缚与胚根的生长势的力量的对比，当前者大于后者时，种子不能萌发，当珠孔端胚乳细胞的细胞壁解体或者这一部分被切割之后，珠孔端机械束缚等于或者小于胚的生长势时，种子萌发。

分子运动性预测顽拗性种子麻栎离体胚轴适宜贮藏条件初探

顽拗性种子在分类上分布广泛。由于顽拗性种子贮藏特性极为特殊，对脱水和低温均十分敏感，易受损伤，所以种子寿命很短，因此在植物种质资源保存领域，顽拗性种子的保存一直被列为重点研究课题，至今仍难以找到顽拗性种子的适宜贮藏条件，或该类种子保存通行的方法，仅推测长期保存顽拗性种子种质资源最有前途的方式是超低温保存，顽拗性种子资源保存是一个世界性难题。 本文试图使用分子运动性预测顽拗性种子离体胚轴的适宜贮藏条件。选用壳斗科植物麻栎种子为实验材料。应用电子顺磁共振波谱仪和自旋标记技术，以硝基氧探针CP为标记物，检测到室温下麻栎种子离体胚轴脱水过程中分子运动性的变化。含水量0.7 g H2O/g DW至0.64 g H2O/g DW范围是细胞质粘度的转折区域，低于这个含水量区域，细胞质粘度骤然上升，推测这个区域是室温下保存离体胚轴的适宜含水量下限。 通过变温电子顺磁测定，找到离体胚轴含水量在0.43 g H2O/g DW至1.02 g H2O/g DW范围内，分子运动性的临界温度和玻璃态相变温度所在区间。根据分子运动性随温度变化规律，预测含水量为0.69 g H2O/g DW的麻栎种子离体胚轴适宜贮藏温度约为-50 ℃。 根据EPR实验结果，将胚轴脱水，并根据实验条件选择不同温度进行低温贮藏验证实验，应用颜色观测法和TTC存活力鉴定法，初步验证分子运动性理论可以应用在顽拗性种子离体胚轴的低温贮藏研究中。 本研究说明顽拗性种子资源的保存有可能通过离体胚轴的低温贮藏实现，用分子运动性预测低温贮藏的适宜条件，很可能为上述问题的解决提供了有效的技术参数。

利用DSC和EPR技术研究杜仲种子的贮藏条件

种子贮藏稳定性对于种质资源的长期保存具有重要意义，目前关于种子贮藏的最新理论为玻璃态理论，该理论认为种子的玻璃化有利于种子的长期贮藏。当种子处于玻璃态时，玻璃化物质的高度粘滞性降低了种子细胞内分子流动性，阻止了细胞质中分子的扩散，从而减少老化过程中细胞结构的损伤和化学组分的变化，延缓种子老化劣变反应速率，延长贮藏寿命。评价玻璃态的一个重要指标是玻璃化转变温度，当种子贮藏于玻璃化温度或以下10℃～30℃范围内时，种子具有最佳的贮藏稳定性。因此，检测种子的玻璃化转变温度对于种子的长期有效贮藏具有重要指导意义。 本研究将差示量热扫描技术（DSC）与电子顺磁共振波谱仪技术（EPR）应用于杜仲种子玻璃化转变温度方面的研究。在DSC方法中，选用4.4%～31.6%含水量范围的杜仲种胚分别进行了DSC图谱扫描。EPR方法选用3-羧基-2,2,5,5-四甲基吡咯烷-1-氧（3-carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl，CP）和2,2,6,6-四甲基哌啶（4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy，TEMPO）作为探针标记杜仲种胚， 利用EPR技术测定不同含水量杜仲种胚的分子运动，通过对EPR图谱参数的分析计算，最终确定不同含水量杜仲种胚的玻璃化转变温度。 DSC实验结果显示，含水量为22.3%、28.0%、31.6%的杜仲种胚在0℃ 左右出现了一个水的熔融峰。该熔融峰的面积代表了自由水含量的多少，随着种胚含水量的降低该熔融峰面积减小。4.4%～31.6%含水量范围的杜仲种胚在-28℃左右还出现了一个熔融峰，推测此峰为杜仲种胚中某类物质熔融所形成的熔融峰。然而在此曲线上我们未观察到标志玻璃化转变的“台阶”出现。 CP-EPR实验的结果表明，利用EPR测定得到含水量为4.4%～11.6%的杜仲种胚在-110℃～20℃温度范围内，同一含水量的杜仲种胚随着温度的升高，分子运动速率加快;在同一温度条件下，高含水量的种胚比低含水量种胚的分子运动速率快。通过CP-EPR波谱两外缘峰最大距离（2Azz）的测定和数据统计分析，得到含水量为4.4%、5.7%、8.6%、10.3%、11.6%杜仲种胚的玻璃化转变温度分别约为44℃、25℃、4℃、-31℃、-43℃。可以把测定的杜仲种胚的这几个含水量的玻璃化转变温度与杜仲种子贮藏相结合，用于指导杜仲种子的贮藏。 TEMPO-EPR实验测定分析得到含水量为2.1%、3.4%、4.8%、8.3%、11.2% 的杜仲种胚的玻璃化转变温度分别为-21℃、-18℃、-24℃、-20℃、-27℃，玻璃化转变温度随含水量升高其变化的规律不明显，这与CP-EPR实验测得的结果有着较明显的差别。通过分析，认为对于脂质含量较高的杜仲种胚，随着含水量的降低，作为标记化合物的TEMPO随着脱水进入脂相，从而不能真实反映出不同含水量种胚的分子运动情况。与TEMPO标记相比，CP标记可能能够更真实地反映不同含水量杜仲种胚细胞质分子运动的情况，根据其分子运动情况得到的玻璃化转变温度更准确。

番茄种子萌发的高温耐性诱导及其生理效应

番茄（Lycopersicon esculentum Miller）原产于南美西部高原地带，适应原产地赤道附近高地干燥冷凉的气候特点，不耐高温多湿，种子萌发期间对高温非常敏感。本研究以佳粉17番茄种子为材料，试图寻找诱导番茄种子萌发期间高温耐性的方法，并通过研究高温耐性被诱导前后种子内部发生的生理生化变化，探索番茄种子萌发期间不耐高温以及高温耐性诱导的机理。试验结果显示： 25 ℃是种子萌发的最适温度，种子发芽率为97.5%。高温抑制种子的萌发，33 ℃和35 ℃条件下萌发率分别为58.5%和8.5%。 萌发适宜温度预吸胀、低温预吸胀、吸湿-回干预处理可提高番茄种子萌发期间的高温耐性，而水杨酸处理则没有明显效果。种子经25 ℃预吸胀30 h、0 ℃预吸胀10 h、吸湿-回干预处理后在33 ℃条件下的萌发率分别为81.5%、78.0%、90%，在35 ℃下的萌发率分别达到33.5%、42%、48.5%。经以上处理后，种子萌发速率提高，萌发高峰期提前，幼苗生长健壮，根干重增加，活力指数变大。 番茄种子萌发期间遭受高温危害时，电解质渗漏增加，相对电导率升高；脂膜过氧化作用加剧，其产物MDA的含量增加。经萌发适宜温度预吸胀、低温预吸胀、吸湿-回干等方法预处理后，高温伤害减轻，膜的完整性增强，电解质渗漏减缓，膜脂过氧化作用减弱，因而相对电导率降低，MDA含量减少。 高温抑制了抗氧化酶的活性，种子内部SOD、APX、CAT、GR等抗氧化酶活性降低。经萌发适宜温度预吸胀、低温预吸胀、吸湿-回干等方法预处理以后，抗氧化酶活性有不同程度的提高，清除细胞内超氧阴离子自由基的能力增强，因而使过氧化伤害减弱， 适宜温度预吸胀、低温预吸胀、吸湿-回干等预处理方法在保护生物膜的同时，增强抗氧化作用，抑制过氧化伤害，从而提高了番茄种子萌发的高温耐性，这是番茄种子高温耐性提高的生理机制之一。

大豆种子低温吸胀相关基因的分离与蛋白变化的研究

大豆 (Glycine max (L.) Meer.)是人们日常生活中不可缺少的食品，也是一种非常重要的油质、蛋白资源。目前根据大豆种子吸胀阶段对低温敏感性的不同，可将其划分成3种生态型：低温非敏感型、低温敏感型及中间型。对于低温非敏感型的种子来讲，4℃下吸胀24小时对其发芽率影响很小，而敏感型种子萌发率不超过5%。我国属于温带大陆性气候，大豆播种后由于温度波动而造成一部分种子不能萌发，最终导致减产甚至绝产的现象普遍存在。高产是育种工作的主要目标，提高逆境胁迫的适应能力是高产的前提和基础，所以从分子角度研究种子吸胀非常必要，一方面能够挖掘新的基因资源，另一方面为今后育种工作提供必要的理论依据。 本试验以此为立足点，低温吸胀非敏感型大豆品种 (Z22)为材料，利用cDNA-AFLP方法及蛋白质技术分离与低温吸胀相关的基因及蛋白，得到结果如下： 第一，本试验成功的分离出4个受低温诱导的基因，半定量RT-PCR方法进一步验证了这4个基因在种子吸胀24小时内受低温诱导。 第二，利用RACE方法成功的得到2个完整的全长基因，在NCBI数据库中查找后发现其中1个基因为新基因，命名为SCHI基因 (SCHI：Soybean chilling-induced gene)。SCHI全长为390bp，编码分子量大约为14.2KD的蛋白；另外一个基因是已知基因，其同源序列已经在其他的物种中得到分离。由于此基因与核糖体蛋白L34高度同源，所以把把这个基因命名为SOL34 (Soybean L34)。 第三，利用半定量RT-PCR方法对基因表达模型进行分析，结果表明：SCHI在种子低温吸胀18～24小时期间诱导表达量最高，而当种子低温吸胀24小时后转入常温下，其表达量在常温下18小时左右迅速下降；ABA (100μM)、PEG (30%，10000)及NaCl (250mM)能够诱导SCHI的表达，在诱导表达量上，ABA和PEG诱导效果最明显，而NaCl能够微弱的诱导此基因表达；对不同生态型的大豆品种而言，低温吸胀过程中，SCHI在非敏感型种子中的表达量高于敏感型种子，但非敏感型和中间型之间没有差别；另外，SCHI在大豆胚轴中是诱导型表达，在叶片和根尖中则是组成型表达。SOL34的表达在萌发前24小时内被低温诱导，但在不同生态型之间没有差别。SOL34在胚轴和根尖中受低温诱导，在叶片中是组成型表达。 第四，SCHI能够在原核生物中表达出相应蛋白，诱导表达蛋白的分子量在26-29KD，大约为理论值的2倍，说明在大肠杆菌中被表达的蛋白以2聚体形式存在。另外低温试验结果表明SCHI能够提高菌落忍耐短时间-20℃低温的能力。 第五，利用双元表达载体把SCHI转入拟南芥植株，经过低温、干旱和盐胁迫后，转基因植株的成活率均高于野生型植株。超表达SOL34的拟南芥植株降低了对低温的耐性；而抑制拟南芥中L34的表达反而提高了植株对低温的抗性。 第六，本试验利用蛋白质等有关试验检测了大豆种子低温吸胀时蛋白质发生的变化。从吸胀 (4℃和22℃下24h)后的大豆胚轴中成功鉴定出上调蛋白点25个，下调蛋白点15个。其中有参与能量代谢反应 (占10%，例如柠檬酸脱氢酶和苹果酸脱氢酶等)、细胞生长与分裂相关反应 (20%，例如LEA蛋白和种子成熟蛋白PM26)、胁迫反应 (10%，如乙醇脱氢酶)、种子宿命和贮藏蛋白 (20%，大豆球蛋白)等蛋白在此过程中发生了变化，暗示种子萌发前期低温吸胀过程中多种代谢发生变化。细胞生长变缓、能量代谢增强、胁迫代谢蛋白的高表达以及贮藏蛋白降解速度减慢等变化都有利于种子在吸胀过程中度过低温环境，为以后的生长作好准备。

Interference Competition and High Temperatures Reduce the Virulence of Fig Wasps and Stabilize a Fig-Wasp Mutualism

Fig trees are pollinated by fig wasps, which also oviposit in female flowers. The wasp larvae gall and eat developing seeds. Although fig trees benefit from allowing wasps to oviposit, because the wasp offspring disperse pollen, figs must prevent wasps fr

Fragmentation effects on diversity of wasp community and its impact on fig/fig wasp interaction in Ficus racemosa L.

Habitat fragmentation usually results in alteration of species composition or biological communities. However, little is known about the effect of habitat fragmentation on the fig/fig wasp system. In this study, we compared the structure of a fig wasp community and the interaction between figs and fig wasps of Ficus racemosa L. in a primary forest, a locally fragmented forest and a highly fragmented forest. Our results show that, in the highly fragmented forest, the proportion of pollinator wasps is lower and the proportion of non-pollinator wasps is higher compared with the primary forest and locally fragmented forest. The proportion of fruits without pollinator wasps in mature fruits is also greatly increased in the highly fragmented forest. The proportion of galls in all female flowers increases in the highly fragmented forest, whereas the proportion of viable seeds does not change considerably. The disruption of groups of fig trees results in a decrease in pollinator wasps and even might result in the extinction of pollinator wasps in some extreme cases, which may transform the reciprocal interaction between figs and fig wasps into a parasite/host system. Such an effect may lead to the local extinction of this keystone plant resource of rain forests in the process of evolution, and thereby, may change the structure and function of the tropical rain forest.

蒲葵籽提取物体外抗HIV-1活性及机制的初步研究

下载PDF阅读器目的 研究蒲葵籽提取物的体外抗HIV-1活性,对有活性粗提物进行初步机制研究.方法 采用细胞毒性、合胞体抑制、HIV-1感染细胞保护实验和HIV-1 p24抗原测定等实验对蒲葵籽提取物体外抗HIV-1活性进行筛选和确认;采用重组HIV-1逆转录酶和蛋白酶活性抑制实验,融合阻断实验初步探讨活性粗提物的作用机制.结果 蒲葵籽的醋酸乙酯(P3)提取物具有较强的体外抗HIV-1活性,P3抑制HIV-1诱导C8166细胞形成合胞体的EC50为5.64 pg/mL,对C8166细胞的毒性较小,CC50大于200 μg/mL,治疗指数(T1)大于35.46;P3抑制HIV-1急性感染中p24抗原表达的EC50为23.04 μg/mL,抑制正常C8166细胞与慢性感染细胞Hg/HIV-1-B融合的EC50为8.00 μg/mL;P3在质量浓度为200μg/mL时,对HIV-1逆转录酶的抑制率为28.86%;P3抑制重组HIV-1蛋白酶活性的EC50为1.77μg/mL.结论 蒲葵籽的醋酸乙酯提取物(P3)具有较强的体外抗HIV-1活性,其作用机制可能主要为阻断病毒进入和抑制HIV-1蛋白酶活性.

Biotransfer of persistent organic pollutants from a large site in China used for the disassembly of electronic and electrical waste

Samples of groundwater, river water, river sediment, paddy soil, rice seeds, hen eggs, fish, umbilical cord blood, and newborn meconium were collected from October 2002 to October 2003 near a large site in China used for the disassembly of obsolete transformers and other electronic or electrical waste. Six indicator PCB congeners, three non-ortho dioxin-like PCB congeners, and six organochlorine pesticides were determined in the samples by GC with electron capture detector. The results demonstrated that the local environment and edible foods had been seriously polluted by toxic PCBs and organochlorine pesticides. The actual daily intakes (ADIs) of these pollutants were estimated for local residents living in the area. The intake data showed that the contents of PCBs in these local residents were substantial, as the ADI estimates greatly exceed the reference doses set by the World Health Organization and the United States Agency for Toxic Substances and Disease Registry. The presence of the indicator PCB congeners in the cord blood and the meconium samples, as well as significant correlations (r(2) > 0.80, p < 0.05) between these levels, suggests a potential biotransfer of these indicators from mothers to their newborns. This preliminary study showed that obsolete transformers and other electronic or electrical waste can be an important source for the emission of persistent organic pollutants into the local environment, such as through leakage, evaporation, runoff, and leaching. Contamination from this source appears to have reached the level considered to be a serious threat to environmental and human health around the disassembly site.

Selective control of toxic Microcystis water blooms using lysine and malonic acid: An enclosure experiment

Three enclosures (10 x 10 x 1.5-1.3 m in depth) were set beside Dianch Lake, Kunming, People's Republic of China, for the period from July 28 to August 26, 2002. The enclosures were filled with cyanobacterial (Microcystis aeruginosa) water bloom-containing lake water. Lake sediment that contained macrophytes and water chestnut seeds was spread over the entire bottom of each enclosure. Initially, 10 g/m(2) of lysine was sprayed in Enclosure B, and 10 g/m(2) each of lysine and malonic acid were sprayed together in Enclosure C. Enclosure A remained untreated and was used as a control. The concentrations of lysine, malonic acid, chlorophyll a, and microcystin as well as the cell numbers of phytoplankton such as cyanobacteria, diatom, and euglena were monitored. On day 1 of the treatment, formation of cyanobacterial blooms almost ceased in Enclosures B and C, although Microcystis cells in the control still formed blooms. On day 7 Microcystis cells in Enclosure B that had been treated with lysine started growing again, whereas growth was not observed in Microcystis cells in Enclosure C, which had been treated with lysine and malonic acid. On day 28 the surface of Enclosure B was covered with water chestnut (Trapa spp.) and the Microcystis blooms again increased. In contrast, growth of macrophytes (Myriophllum spicatum and Potamogeton crispus) was observed in Enclosure C; however, no cyanobacterial blooms were observed. Lysine and malonic acid had completely decomposed. The microcystin concentration on day 28 decreased to 25% of the initial value, and the pH shifted from the initial value of 9.2 to 7.8. We concluded that combined treatment with lysine and malonic acid selectively controlled toxic Microcystis water blooms and induced the growth of macrophytes. (c) 2005 Wiley Periodicals, Inc.

Effects of microcystins on the growth and the activity of superoxide dismutase and peroxidase of rape (Brassica napus L.) and rice (Oryza sativa L.)

Microcystins are naturally occurring hepatotoxic cyclic heptapeptides produced by some toxic freshwater cyanobacterial species. In this study, crude extract of toxic cyanobacterial blooms from Dianchi Lake in southwestern China was used to determine the effects of microcystins on rape (Brassica napus L.) and rice (Oryza sativa L.). Experiments were carried out on a range of doses of the extract (equivalent to 0, 0.024, 0.12, 0.6 and 3 mug MC-LR/ml). Investigations showed that exposure to microcystins inhibited the growth and development of both rice and rape seedlings, however, microcystins had more powerful inhibition effect on rape than rice in germination percentage of seeds and seedling height. Microcystins significantly inhibited the elongation of primary roots of rape and rice seedlings. Determination of the activities of peroxidase and superoxide dismutase demonstrated that microcystin stress was manifested as an oxidative stress. Using ELISA, microcystins were examined from the extract of exposed rape and rice seedlings, indicating that consumption of edible plants exposed to microcystins via irrigation route may have health risks. Significantly different levels of recovered microcystins between exposed rice and rape seedlings Suggested that there might be different tolerant mechanisms toward microcystins. (C) 2004 Elsevier Ltd. All rights reserved.

Agrobacterium-mediated transformation of Kentucky bluegrass

Embryogenic calli of Kentucky bluegrass, named Md, were induced from mature seeds and embryos, and proliferated on medium K3 containing 2,4-dichlorophenoxyacetic acid (2,4-D, 10.0 mumol/L), 6-benzylaminopurine (BAR, 0.5 mumol/L) and K5 which was the K3 medium supplemented with cupric sulfa (0.5 mumol/L) under dim-light condition (20-30 mumol.m(-2).s-1, 16 h light) at 24 degreesC. Embryogenic calli were transformed with plasmids pDM805 Carring bar and gus genes, Which was mediated by an Agrobacterium strain AGL1, four transgenic lines were obtained. The important factors that affect the transformation efficiency and obtain desirable number of transgenic plants included: (1) the quality of embryogenic calli; (2) light condition and time of co-cultivation; (3) concentration of antibiotics used for suppressing the overgrowth of Agrobacterium in the course of transformed plant regeneration; (4) selection pressure, etc. The micro nutrient of cupric had significant influence on the quality of embryogenic calli. This presentation is the first successful protocol of Kentucky bluegrass transformation mediated by Agrobacterium.

Growth of ZnO single crystal by chemical vapor transport method

ZnO crystals were grown by CVT method in closed quartz tube under seeded condition. Carbon was used as a transport agent to enhance the chemical transport of ZnO in the growth process. ZnO single crystals were grown by using GaN/sapphire and GaN/Si wafer as seeds. The property and crystal quality of the ZnO single crystals was studied by photoluminescence spectroscopy and X-ray diffraction technique.

Growth of ZnO single crystal by chemical vapor transport method

ZnO crystals were grown by CVT method in closed quartz tube under seeded condition. Carbon was used as a transport agent to enhance the chemical transport of ZnO in the growth process. ZnO single crystals were grown by using GaN/sapphire and GaN/Si wafer as seeds. The property and crystal quality of the ZnO single crystals was studied by photoluminescence spectroscopy and X-ray diffraction technique.