种子超干保存种质的研究

当今，生物资源——“物种”正在以地质史上前所未有的速度灭绝或走向濒危。保护生物多样性已是世界范围内环境保护和生物学研究的热点。基于种子具有完善的保护结构和内潜的隐蔽生命以适应逆境的微妙机制，种子库被认为是保护植物种质资源的主要措施。现阶段世界各国的种子库均为低温库或超低温库，可观的建库投资和运转费用的经济负担直接影响到贫困国家和地区植物种质资源及时有效的保护，寻求取代低温库的廉价贮藏种子的策略和技术已列为联合国FAO／IBPGR的全球战略措施。 此乃本文的工作背景和最终目标。早期的研究已查明，通过降低种子含水量可以在适当提高温度的条件下达到在较高含水量在低温下同样的贮藏效果，但是由于干燥技术以及5%为种子安全含水量下限这一经典概念的局限，种子贮藏的含水量一直没有突破5%下限。超干贮藏即以此为依据，摸索以适当的干燥技术将种子含水量降至这一经典下限以下，即采取超低含水量种子密封贮藏的方法，以达到部分或完全取代低温库的目的。 作为种子贮藏的方法首先要保证种子活力的保持。本文选用了不同化学组份以及不同粒度大小的种子为材料，涉及到40个不同的种和品种，针对不同类型的种子摸索了适宜的干燥方法及辅助措施，从种子生活力和活力、细胞形态结构、细胞器发育和功能以及若干生理活性指标等多元角度上确认种子含水量可以安全降至5%以下，除了个别敏感类型种子外，在常温条件下能大幅度增强种子的耐藏性。 本文对种子耐干性差异以及辅助干燥措施提高种子耐干性进行了水分热力学方面的分析，认为种子本身的特性决定了种子内部水分吸附位点对关键水分束缚力量的不同，导致在相同干燥过程中失去关键性水分程度的不同，从而造成种子在耐干程度上有所差异。干燥的辅助措施可以通过改变种子中的化学成份增强种子对关键性水分吸附的力量，继而使得关键性水分不会轻易丢失。超干延缓种子劣变的原因在于，MC不能真实反映种子水分水平，一定MC范围内的超干种子的关键性水分仍然存在，即使在极度干燥的种子中，虽然一部分束缚水已失去，但对导致和抑制脂质过氧化的正负效应折衷的结果使劣变反应从整体上还是受到抑制。内源抗氧剂的活性及含量以及劣变产物MDA的积累量表明种子在超干贮藏过程中脂质过氧化被部分抑制，酶类抗氧剂系统保存完好，非酶类抗氧剂被消耗的量减少，使得种子在结束贮藏进入萌发状态时仍具有较高水平的自由基清除系统的正常运转能力。无氧贮藏，和外源抗氧防护等预处理措施使种子在超干贮藏过程中能更好地清除活性氧的伤害，吸湿回干、PEG等处理使超于种子吸胀时膜系统功能及结构更具完整性。回水预处理诱导的生化修补效应可保留于种子内部，以便在种子再次吸水时及早发挥作用。本文已在干前及干后预处理辅助措施上找到了若干行之有效的方法，其中有些是首次应用于种子技术范畴。 本文在总结系列试验研究结果和纵观近年来国内外在此领域的动态后，认为一般常规型种子在适度超低水分状态下不仅自身不受脂质过氧化的危害，并能保持种子内外形态学和种质遗传性的完整性，而且可使种子内部代谢停顿，更有利于耐藏性的大幅度提高，加上超干技术上的不断完善，为今后建立节能种子库展示了希望。

盐胁迫对光合作用的影响

盐害对植物光合作用的影响机理的研究目前还仅仅处于初步阶段，对于许多关键性问题远没有达成共识。本论文研究了盐胁迫对光合作用的影响途径和原初作用部位，对光合作用的各个分过程影响的先后关系，盐胁迫与光胁迫的协同作用，植物光合作用对盐胁迫的适应等基础理论问题，为盐胁迫下提高植物光合作用速率，改良植物种质提供了一定的理论依据。 1．采用荧光动力学的方法区分盐胁迫中的渗透因素和离子因素。用五种等渗Hogland培养液(分别含NaCl，KCl，NaN03，KN03和PEG)对冬小麦进行处理。结果，与对照相比，NaCl处理引起PSII受体侧电子库含量(CA／Fm)、PSII活性(Fv／Fo)、原初光能转化效率(Fv／Fm)、量子产量(Yield)与荧光光化学猝灭系数(qP)下降;QB-非还原性PSII反应中心含量增加。然而，等渗的PEG处理并不产生类似的伤害。这表明渗透因素不是盐胁迫对光合作用造成伤害的主要原因。鉴于NaCl和NaNO3处理却使QA含量、PSII活性、原初光能转化效率下降和QB-非还原性PSII反应中心的增加，KN03处理对光合作用不产生伤害;而等渗的PEG和KCl处理并不产生类似的伤害，这暗示Na+可能是盐胁迫影响光合作用的主要毒害离子。 2．用荧光动力学的方法研究了不同浓度的NaCl处理对PSII光能利用和耗散的影响。结果表明，与对照、100mmol/L和200mmol/L NaCl处理相比，经300mmol/L和400mmol/L NaCl处理的小麦，其荧光光化学猝灭效率明显降低，荧光非光化学猝灭效率较高，Fo猝灭系数较大，QB-非还原性PSII反应中心含量较大，然而，其荧光非光化学猝灭效率，QB-非还原性PSII反应中心含量和Fo猝灭系数潜在增高能力较弱。随着NaCl处理浓度的增加，PSII吸收过多的光能可能首先通过热耗散和状态转换逸散，而后阻断PSII从QA到QB的电子传递，最后损伤PSII反应中心。 3．研究了轻度(200mmol/L)和重度(400mmol/L)NaCl胁迫对光抑制和光恢复进程的影响。结果表明：1)轻度盐胁迫对光合放氧和碳同化速率的影响相对较小，而重度盐胁迫大大降低了光合放氧和碳同化速率，同时明显降低光合放氧和碳同化的光饱和点。2)碳同化是盐胁迫对光合作用造成伤害的敏感位点。3)轻度盐胁迫对PSII的光抑制进程影响较小;而重度盐胁迫则促进光抑制的产生，同时抑制PSII的修复过程，从而使得PSII受到光抑制的伤害更大。 4 为探讨盐胁迫下植物减轻或避免光抑制的机制，研究了盐胁迫对光能在PSI和PSII之间的分配的影响。结果表明，盐胁迫提高了Chla/Chlb比值和单位鲜重叶片中Chla的含量，降低了单位鲜重叶片Chlb的含量;提高了PSI的电子传递速度，能量储存;同时降低了PSII的电子传递和能量储存。这表明盐胁迫提高了光能在PSI的分配分额和PSI的含量，降低PSII对光能的吸收和利用，这对于植物在盐胁迫下减轻或避免光抑制对PSII的破坏有重要意义。

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。

Site-directed PEGylation of trichosanthin retained its anti-HIV activity with reduced potency in vitro

Trichosanthin (TCS) was the first ribosome inactivating protein found to possess anti-HIV-1 activity. Phase I/II clinical trial of this compound had been done. Antigenicity and short plasma half-life were the major side effects preventing further clinical trial. Modification of TCS is therefore necessary to revive the interest to develop this compound as an anti-HIV agent. Three potential antigenic sites (Ser-7, Lys-173, and Gln-219) were identified by computer modeling. Through site-directed mutagenesis, these three antigenic amino acids were mutated to a cysteine residue resulting in 3 TCS mutants, namely S7C, K173C, and Q219C. These mutants were further coupled to polyethylene glycol with a molecular size of 20 kDa (PEG) via the cysteine residue. This produced another three TCS derivatives, namely PEG(20)k-S7C, PEG(20)k-K173C, and PEG(20)k-Q219C. PEGylation had been widely used recently to decrease immunogenicity by masking the antigenic sites and prolong plasma half-life by expanding the molecular size. The in vitro anti-HIV-1 activity of these mutants and derivatives was tested. Results showed that the anti-HIV-1 activity of S7C, K173C, and Q219C was decreased by about 1.5- to 5.5-fold with slightly lower cytotoxicity. On the other hand, PEGylation produced larger decrease (20- to 30-fold) in anti-HIV activity. Cytotoxicity was, however, weakened only slightly by about 3-fold. The in vitro study showed that the anti-HIV activity of PEGylated TCS was retained with reduced potency. The in vivo activity is expected to have only slightly changed due to other beneficial effects like prolonged half-life. (C) 2004 Elsevier Inc. All rights reserved.

A decline in fish catches and the size of Oreochromis niloticus in Lake Wamala (Uganda) following human exploitation

The fishery of Lake Wamala has declined since the lake was stocked in 1956 and opened to fishing during the 1960s. Surveys were conducted on the lake during 1975/78 and 1988/92 to investigate the causes of declining fish catches. The lake produced an average of 4000 - 6000 tonnes of fish annually from 1960s through 1970s. Total fish catches decreased from a maximum of 7100 tonnes in 1967 to less than 500 tonnes by 1990s. Catch rates decreased from about 8 kg in the 1960s to less than 1 kg per net per night by 1975. During the 1970s the catch was dominated by Oreochromis niloticus (67%) followed by Clarias gariepinus (17%), and Protopterus aethiopicus (15.1 %). By 1990s the proportion of O. niloticus had decreased to 45.1% while that of P. aethiopicus had increased to 37.6%. These changes seem to have been caused by overfishing resulting from increased fishing effort from the recommended 250 to about 1000 boats and the additional increase in effort through driving fish into the nets by beating water. The maximum size of O. niloticus in the fishery decreased from 32 cm total length in 1975/78 to 22 cm in 1988/92 while the size at first maturity decreased from about 21 cm to 14 cm during the period. This has been concurrent with a shift in the mesh size of gillnet used from 127 mm (5") in 1960s to 64 mm by 1990s. Environmental changes, especially in lake level in 1980, may also have affected the fishery.

Evaluation of multi-sensory feedback on the usability of a virtual assembly environment

Virtual assembly environment (VAE) technology has the great potential for benefiting the manufacturing applications in industry. Usability is an important aspect of the VAE. This paper presents the usability evaluation of a developed multi-sensory VAE. The evaluation is conducted by using its three attributes: (a) efficiency of use; (b) user satisfaction; and (c) reliability. These are addressed by using task completion times (TCTs), questionnaires, and human performance error rates (HPERs), respectively. A peg-in-a-hole and a Sener electronic box assembly task have been used to perform the experiments, using sixteen participants. The outcomes showed that the introduction of 3D auditory and/or visual feedback could improve the usability. They also indicated that the integrated feedback (visual plus auditory) offered better usability than either feedback used in isolation. Most participants preferred the integrated feedback to either feedback (visual or auditory) or no feedback. The participants' comments demonstrated that nonrealistic or inappropriate feedback had negative effects on the usability, and easily made them feel frustrated. The possible reasons behind the outcomes are also analysed. © 2007 ACADEMY PUBLISHER.

Electronic properties of GaAs, InAs and InP nanowires studied by terahertz spectroscopy.

We have performed a comparative study of ultrafast charge carrier dynamics in a range of III-V nanowires using optical pump-terahertz probe spectroscopy. This versatile technique allows measurement of important parameters for device applications, including carrier lifetimes, surface recombination velocities, carrier mobilities and donor doping levels. GaAs, InAs and InP nanowires of varying diameters were measured. For all samples, the electronic response was dominated by a pronounced surface plasmon mode. Of the three nanowire materials, InAs nanowires exhibited the highest electron mobilities of 6000 cm² V⁻¹ s⁻¹, which highlights their potential for high mobility applications, such as field effect transistors. InP nanowires exhibited the longest carrier lifetimes and the lowest surface recombination velocity of 170 cm s⁻¹. This very low surface recombination velocity makes InP nanowires suitable for applications where carrier lifetime is crucial, such as in photovoltaics. In contrast, the carrier lifetimes in GaAs nanowires were extremely short, of the order of picoseconds, due to the high surface recombination velocity, which was measured as 5.4 × 10⁵ cm s⁻¹. These findings will assist in the choice of nanowires for different applications, and identify the challenges in producing nanowires suitable for future electronic and optoelectronic devices.

鱼腥藻细胞外膜完整性与防氧的关系

暴露鱼腥藻7120(Anabaena 7120)细胞于膜扰乱剂EDTA或Tris(pH 8.0,37℃,5—10分钟),导致细胞释放外膜脂多糖和蛋白成分。Tris处理后,细胞对结晶紫和洗涤剂(SDS,Triton X-100)的敏感性增加,整细胞碱性磷酸酶活性增强,暗示外膜结构被修饰,透过性增大;与此同时,被处理细胞固氮酶活性在空气氧中大大降低,而在厌氧条件下活性不受影响。将细胞释放物质与处理后的细胞重组时,可明显恢复固氮活性,表明外膜结构与固氮防氧保护有密切关系。EDTA处理的细胞,虽然释放的脂多糖和蛋

鱼类细胞融合中助融剂效应和特异性

在鱼类细胞融合中,微量的甘油可使PEG作用显著下降。DMSO可以极大提高PEG诱导鱼类细胞融合的能力。在低分子量和较低浓度的PEG中,DMSO的作用更加突出。但PEG浓度不能低于40%的临界,否则,细胞融合就失去了DMSO浓度依赖效应。在三组鱼类细胞交叉融合中,我们发现同核体数目远远超过异核体数目(P<0.05)。这表明,PEG诱导的鱼类细胞融合具有物种和组织特异性。

我国昆虫寄生线虫研究进展

<正> 在生物进化史上,线虫和昆虫在古生代(距今5-6亿年)就先后出现,在漫长的演化过程中,二者中有一部份发生了寄生与被寄生的关系。据聂克尔(Nickle,1974)记述,从欧洲莱茵河始新世(距今3700-6000万年)的煤炭和波罗的海琥珀中,发现两种寄生于昆虫的线虫(Heydonius antiquus和H.matutinus)化石,证明线虫寄生于昆虫已有很长历史。彭世奖考据(1983)江苏《高邮州志》记载:“庆元一年(1196年)飞蝗抱草死,每一蝗有一蛆,食其脑”,据认为是索科线虫害生所致。说明我国至

Probing the critical electronic properties of III-V nanowires using optical pump-terahertz probe spectroscopy

Optical pump-terahertz probe spectroscopy was used to study the key electronic properties of GaAs, InAs and InP nanowires at room temperature. Of all nanowires studied, InAs nanowires exhibited the highest mobilities of 6000 cm2V-1s-1. InP nanowires featured the longest photoconductivity lifetimes and an exceptionally low surface recombination velocity of 170 cm/s. © 2013 IEEE.

How polluted is the Yangtze River? Water quality downstream from the Three Gorges Dam

The concentrations of major anions and cations, nitrogen and phosphorus, dissolved and particulate trace elements, and organic pollutants were determined for the middle and lower reaches of the Yangtze River (Changjiang) from below the Three Gorges Dam (TGD) to the mouth at Shanghai in November 2006. The concentration of dissolved inorganic phosphate (DIP) was constant at a low level of 6-8 mu gP/L, but the concentration of nitrate (NO3-) approximately doubled downstream and was closely correlated with K+. This translated to a daily load of well over 1000 It of dissolved inorganic nitrogen (DIN) at Datong. The average concentrations of dissolved Pb (0.078 +/- 0.023 mu g/L), Cd (0.024 +/- 0.009 mu g/L), Cr(0.57 +/- 0.09 mu g/L), Cu (1.9 +/- 0.7 mu g/L), and Ni (0.50 +/- 0.49 mu g/L) were comparable with those in other major world rivers, while As (3.3 +/- 1.3 mu g/L) and Zn (1.5 +/- 0.6 mu g/L) were higher by factors of 5.5 and 2.5, respectively. The trace element contents of suspended particles of As (31 +/- 28 mu g/g), Pb (83 +/- 34 mu g/g), and Ni (52 +/- 16 mu g/g) were close to maximum concentrations recommended for rivers by the European Community (EC). The average concentrations of Cd (2.6 +/- 1.6 mu g/g), Cr (185 +/- 102 mu g/g), Cu (115 +/- 106 mu g/g), and Zn (500 +/- 300 mu g/g) exceeded the EC standards by a factor of two, and Hg (4.4 +/- 4.7 mu g/g) by a factor of 4 to 5. Locally occurring peak concentrations exceed these values up to fourfold, among them the notorious elements As, Hg, and Tl. All dissolved and particulate trace element concentrations were higher than estimates made twenty years ago [Zhang, J., Geochemistry of trace metals from Chinese river/estuary systems: an overview. Estuar Coast Shelf Sci 1995; 41: 631-658.]. The enormous loads of anthropogenic pollutants disposed to the river were diluted by the large water discharge of the Yangtze even during the lowest flow resulting in the relatively low concentration levels of trace elements and organic pollutants observed. We estimated loads of e.g. As, Pb and Ni to the East China Sea to be about 4600 kg As d(-1), 3000 kg Pb d(-1), and 2000 kg Ni d(-1). About 6000 t d(-1) of dissolved organic carbon (DOC) was delivered into the sea at the time of our cruise. We tested for 236 organic pollutants, and only the most infamous were found to be barely above detection limits. We estimated that the load of chlorinated compounds, aromatic hydrocarbons, phenols, and PAHs were between 500 and 3500 kg d(-1). We also detected eight herbicides entering the estuary with loads of 5-350 kg d(-1). The pollutant load, even when at low concentrations, are considerable and pose an increasing threat to the health of the East China Sea ecosystem. (c) 2008 Elsevier B.V. All rights reserved.

New data on the morphology and systematic status of Spinitectus petrowi and Spinitectus gigi (Nematoda : Cystidicolidae) parasitic in catfishes in central China

Two little-known nematode species of the genus Spinitectus Fourment, 1883, S. petrowi Belous, 1965 (prevalence 25%, intensity 1-8) and S. gigi Fujita, 1927 (prevalence 10%, intensity 2-3), were collected from the gastrointestinal tract of the yellow catfish, Pelteobagrus fulvidraco (Richardson), from Liangzihu Lake, Hubei Province, central China, in September of 2002. The light and scanning electron microscopical examination of this material, supplemented by a few museum specimens of S. gigi collected from the catfish Clarias fuscus (Lacepede) in southern China, made it possible to study in detail the morphology of these parasite species and to redescribe them. The first species, whose correct name is S. petrowi Belous, 1965, exhibits some morphological features (e.g., unusually short vestibule, shape of pseudolabia and of the left spicule) not found in most other congeners; a unique feature is the presence of peculiar pairs of transversely oriented peg-like cuticular spines with rounded ends on the ventral surface of the female tail. Spinitectus gigi was found to have 28-31 cuticular spines in the first ring, relatively long distances between the 2nd-7th rings of spines, and anterior rings divided into 2 sectors; the excretory pore is located at the level of the 4th ring of cuticular spines; males posses 4 pairs of preanal- and 6 pairs of postanal caudal papillae and a pair of small phasmids. Spinitectus bagri Wang, Wu et Yu, 1993 and S. wulingensis Yu et Wang, 1997 are considered junior synonyms of S. petrowi, whereas S. clariasi Ky, 1971, S. ophicephali Ky, 1971 and S. yuanjiangensis Wang, Wit et Yu, 1997 are regarded to be junior synonyms of S. gigi. Spinitectus petrowi was not previously reported from China.

Effects of polarization field on formation of two-dimensional electron gas in (0001) and (11(2)over-bar0) plane AlGaN/GaN heterostructures

Photoluminescence (PL) and temperature-dependent Hall effect measurements were carried out in (0001) and (11 (2) over bar0) AlGaN/GaN heterostructures grown on sapphire substrates by metalorganic chemical vapor deposition. There are strong spontaneous and piezoelectric electric fields (SPF) along the growth orientation of the (0001) AlGaN/GaN heterostructures. At the same time there are no corresponding SPF along that of the (1120) AlGaN/GaN. A strong PL peak related to the recombination between two-dimensional electron gas (2DEG) and photoexcited holes was observed at 3.258 eV at room temperature in (0001) AlGaN/GaN heterointerfaces while no corresponding PL peak was observed in (11 (2) over bar0). The existence of a 2DEG was observed in (0001) AlGaN/GaN multi-layers with a mobility saturated at 6000 cm(2)/V s below 80 K, whereas a much lower mobility was measured in (11 (2) over bar0). These results indicated that the SPF was the main element to cause the high mobility and high sheet-electron-density 2DEG in AlGaN/GaN heterostructures. (C) 2004 Elsevier B.V. All rights reserved.

纤维素直接发酵乙醇微生物的选育──Ⅲ.里氏木霉与运动发酵单胞原生质体融合的研究

用聚乙二醇（PEG）作为诱导剂，可使钝化的里氏木霉（Tri－chodermareesei）QM9414的原生质体和运动发酵单胞（Zymomonasmobilis）ATCC29191的原生质球之间可以产生远缘的细胞融合子。融合率可达1.9×10－2融合子能利用羧甲基纤维素为唯一碳源而产生羧甲基纤维素酶和乙醇。羧甲基纤维素酶活性高和乙醇产量高的融合子不稳定。这些融合子的产酶能力很容易大部分丧失，而产乙醇的能力亦很低。而酶活及乙醇产量较低的融合子，可能才是真正的基因重组子。