Pollen germination and tube growth are a developmental stage in fertilization of flowering plants during which the complex interactions between female and male cells take place. In this process, extracellular signal molecules are the main regulating factors that can induce signal transduction cascade in the two sexual cells. The present review attempts to summarize the advances in this research field.
Stained with Fluo-3/AM and investigated under the laser scanning confocal microscope (LSCM), the spatial-temporal changes of ［Ca2+］cyt(the free Ca2+ concentration in the cytoplasm) in the protoplasts of mesophyll cells of wheat (Triticum aestivum L.) cultivars with different cold-hardiness under resting and temperature decreasing conditions were compared. The results showed that under the resting condition, the fluorescence intensities in the protoplasts of both cold-sensitive and cold-resistant wheat manifested no significant changes, implying that ［Ca2+］cyt could keep at a stable level under the resting condition although different wheat cultivars were different. However, different dynamics appeared with temperature decreasing from 15℃ to 2℃. In particular, for the cold-resistant wheat, ［Ca2+］cyt level at first increased, followed by drop to the resting level at 2℃, and then increased further when the temperature was below 2℃. On the contrary, the ［Ca2+］cyt level of the cold-sensitive spring wheat increased continuously to the maximal level within the whole range of temperature changes. Based on the above observations, it could be reasonably inferred that different dynamics of ［Ca2+］cyt determines decisively different cold acclimation abilities of plants. Furthermore, the results provide a new supporting evidence for the hypothesis that Ca2+ plays a key role as a primary physiological transducer upon chilling”.
刘炜1,3 孙德兰1* 王红1 简令成1 尚忠林2 王学臣2 赵可夫3
（1 中国科学院植物研究所，北京100093；2. 中国农业大学生物学院，农业部植物生理生化重点开放实验室，北京100094；3.山东师范大学逆境植物研究所，济南250014）
摘要：用Fluo-3/AM染色,通过激光扫描共聚焦显微镜(LSCM)方法,对静息态及连续降温条件下不同抗寒性小麦(Triticum aestivum L.)叶肉细胞原生质体[Ca2+]cyt (the free Ca2+ concentration in the cytoplasm)的时空变化进行了比较.结果表明,静息态下小麦原生质体整体荧光强度基本不变,暗示[Ca2+]cyt能维持在一稳定水平;同时,不同品种小麦间也显示了[Ca2+]cyt水平荧光强度的不同.温度由15 ℃连续降至约2 ℃时,抗寒冬小麦[Ca2+]cyt出现升高后的回复,2 ℃之后逐渐升高;冷敏感春小麦则无此回复过程,而是一直升高到最大值.推测这一不同的动态变化最终决定了植物在低温下产生冷适应的不同能力.这进一步为"Ca2+是低温下生理信号的传导者"这一假说提供了新的证据.
The typical eukaryote interphase nuclei were reconstructed in vitro following incubation of chromosomes of primitive eukaryote dinoflagellate Crypthecodinium cohnii E. in extracts of S phase eggs of Xenopus laevis L. Micrococcal nuclease digestion experiments indicated that the reconstructed nuclei contained typical nucleosomes. Since the chromosomes of C. cohnii do not contain histone and nucleosomes, these data suggest that nucleosome assembly is independent of specific DNA sequences, nuclear membranes and Lamin. Moreover, it has been demonstrated that Topoisomerase Ⅱ was partially involved in the process of nucleosome assembly. Taken together, these findings suggest that nuclear assembly is independent of formation of nucleosomes and that histone and non-histone may be the decisive factors in this process.
刘晓玲 陶伟 高云飞 卢智刚 翟中和*
摘要：利用纯化的原始真核生物寇氏隐甲藻（Crypthecodinium cohnii E.）染色体，使之与非洲爪蟾（Xenopus laevis L.）S期卵提取物温育，发现甲藻染色体经历了一系列去凝集、再凝集的形态变化，最后形成类似典型高等真核生物的间期核结构。小球菌核酸酶酶切分析表明，不具备组蛋白和核小体结构的甲藻染色体在非洲爪蟾卵提取物中进行了核小体装配，此过程与DNA序列本身、核膜以及核纤层蛋白（Lamin）是否存在无关，但部分拓扑异构酶Ⅱ（TopoⅡ）参与了这个过程，说明核小体的组装并非为核重建所必需，决定染色体高级结构的因素并不在DNA本身，而可能是非细胞体系中的组蛋白和非组蛋白。
Comparison of regional permeability and translocation across the node and the internode in the etiolated mesocotyl excised from corn ( Zea mays L.) seedling was made before and after treatment with different concentrations of acetylcholine (AChs). Regional permeability was determined by electrical resistance measurement; and translocation by detecting the distribution of the fluorescent probe (carboxyfluorescein, CF), fed at the cut end of the etiolated coleoptile. The cells constituting the internode were more or less cylindrical in size and arranged more or less parallel to the long axis, whereas those in the node were shorter in length and arranged irregularly. The results showed that the specific electrical resistance across the node was higher than that across the internode. Consequently, short nodal cells with lower intercellular permeability retained more CF than that in the cylindrical internodal cells. Treatment with 0.1 mmol/L ACh could increase the permeability of both node and internode, thus promoting higher rate of CF translocation than that of the control. Variation in material translocation across the node and the internode, as well as its modulation by ACh treatment, can be largely attributed to differences in their intercellular permeability.
摘要：对乙酰胆碱处理前后的黄化玉米 (ZeamaysL .)幼苗中胚轴切段节和节间的通透性和物质运转进行了比较。用电阻法测定通透性 ;通过加在胚芽鞘切口的经共质体转运的特异荧光物质羧基荧光素 (carboxyfluorescein ,CF)的分布检察物质运转。节间由柱状的、排列方向多少和长轴方向平行的细胞构成 ;而构成节的细胞短、排列不规则。结果表明跨节比电阻比节间的高 ,通透性低的短的节细胞比柱状节间细胞累积更多的CF。 0 .1mmol/L乙酰胆碱 (ACh)处理增加了节和节间的通透性 ,促进了CF的运转。物质在节和节间运转的不同 ,以及ACh对此的调控效应很大程度上可归结于细胞通透性的差异
The growth behavior, photosynthetic productivity and carbon utilizing characteristics of filamentous cyanobacterium Spirulina platensis Geitler were investigated in continuous cultures in a 10 L internalloop airlift photobioreactor. It was found that the cell density and the amount of carbon in the reactor increased and decreased with dilution rate respectively, and the relationships among them could well be expressed by the modified Monod equation. When dilution rate was 0.45/d, the rate of cell growth and that of carbon assumption reached their maximum points 0.362 g/(L·d) and 0.177 g/(L·d) respectively. The cell growth yield against carbon was 2.050 g/g. The proposed model of continuous growth fitted the experimental data quite well.
曾文炉* 李浩然 丛威 蔡昭铃 欧阳藩
Fluorescence properties of light-harvesting complex LHCⅡ） in photosystem Ⅱ isolated from spinach (Spinacia oleracea L.) was investigated with the time-resolved fluorescence spectroscopic technique. The sample was excited by double frequency Ti:Al203 laser with 400 nm wavelength and 120 fs width. Fluorescence signal was detected by Boxcar. Three life-time components （320 fs，4.0 ps and 20.0 ps） were obtained by multi-exponential curve model and nonlinear least-square fitting method. Three fluorescence peaks （652 nm, 672 nm, 691 nm） were obtained by Global analysis and Gauss curve fitting. These components were analyzed according to the structural and fluorescence spectroscopic property of LHCⅡ. The fluorescence ratio of each component to that of all the component was 3.4%, 50% and 46.6% respectively. The possible model of energy transfer in LHCⅡ was discussed.
任兆玉1,2,3 贺俊芳1,2 王水才1侯洵1,2 匡廷云4
2. 西北大学光子学与光子技术研究所，西安710068；3. 西北工业大学应用物理系，西安710072；
摘要：采用时间分辨荧光光谱技术研究了菠菜(Spinacia oleracea L.)叶绿体中捕光色素复合体 (LHCⅡ) 荧光的时间特性和光谱特性.用脉宽为120 fs、波长为400 nm的倍频钛宝石激光激发LHCⅡ样品;原始荧光信号由Boxcar采集,通过建立多指数模型,用非线性最小二乘法拟合,得到了激发能在LHCⅡ中传递的时间常数分别为:320 fs、4.0 ps和20.0 ps.相对应的各组分荧光占总荧光的百分比分别为:3.4％、50.0％和46.6％.经全局分析,解得荧光强度随波长变化曲线;用高斯3峰解叠得到荧光光谱的峰值波长分别为:652 nm、672 nm和691 nm.通过分析得出了时间常数与LHCⅡ中各色素成分之间的对应关系,并给出了可能的能量传递模型.
关键词： 捕光复合体（LHCII）；能量传递；时间常数；荧光特性；Chl a/b
The photodamage processes of PSⅠ particles isolated from two wheat cultivars “Jing 411” and “Xiaoyan 54” were studied by comparing the difference in spectroscopic properties. It was found that high light intensity caused the damage of pigments in PSⅠ, especially Chl a molecules with maximum absorption at 683 nm is very sensitive to high light. The change in fluorescence spectra revealed that photodamage also led to the damage of the process of energy transfer in PSⅠ. In the PSⅠ particles “Xiaoyan 54”, the absorption of Chl a molecules at 683 nm slightly decreased at the beginning of illumination and meanwhile the fluorescence become stronger, but the absorption become stable rather long, and declining after 40 min. On the other hand, PSⅠ particles of “Jing 411” showed no such changes during the process of photodamage. Presumably in PSⅠ of “Xiaoyan 54”, excessive energy was distributed to long wave chlorophyll molecules and the number of antenna pigment molecules was less, so that less energy was transferred to the reaction center P700 and thus it was protected. This is the possible reason why “Xiaoyan 54” was more resistant to photooxidation.
郁飞1 唐崇钦1* 辛越勇1 彭德川1 李良璧1 匡廷云1 李振声2
（1. 中国科学院植物研究所光合作用基础研究开放实验室，北京100093；2. 中国科学院遗传研究所，北京100101）
Effects of photoinhibition and its recovery on photosynthetic functions of winter wheat ( Triticum aestivum L.) under salt stress were studied. The results showed that several parameters associated with PSⅡ functions, e.g. Fv/Fo 、 Fv/Fm and qP were not influenced by lower salt concentration (200 mmol/L NaCl) while CO2 assimilation rate decreased significantly. When exposed to higher salt concentration (400 mmol/L NaCl), PSⅡ functions were significantly inhibited which led to the decrease of carbon assimilation. These results suggest that different concentrations of salt stress affected photosynthesis by different modes. Salt stress made photosynthesis more sensitive to strong light and led to more serious photoinhibition. Under lower concentration of salt stress, the QB-non-reductive PSⅡ reaction centers formed at the beginning of photoinhibition could be effectively used to compose active PSⅡ reaction center (RC) and repair the reversible inactivated PSⅡ RC. Under higher concentration of salt stress, PSⅡ reaction centers were seriously damaged during photoinhibition, the QB-non-reductive PSⅡ RC could only be partly effective at the early time of photoinhibition, thus led to the accumulation of QB-non-reductive PSⅡ RC in the course of restoration under dim light.
朱新广 王强 张其德* 卢从明 匡廷云
Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton (Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter Fv / Fm and ΦPSⅡ , which reflect the efficiency of PSⅡ, obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, Fo value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the Fv / Fm and the net photosynthetic rate ( Pn ) continued to decline, then began to increase gradually 6 d later and turned stable after 10-12 d, appearing as an acclimation phenomenon. However, the final value of Fv / Fm and Pn did not reach the level as in those leaves grown in the full sunlight ever before. The final Pn was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of Fv / Fm and Pn might associate with the damage of the PSⅡ reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.
杨兴洪1,2 邹琦1* 王玮1
The human epidermal growth factor （hEGF） is a small single-chain polypeptide of 53 amino acid residues. It can stimulate the proliferation of many cell types, mainly those of epidermal and epithelial tissues both in vivo and in vitro . A vector pRL-hEGF was constructed using plasmids pRL-489 and pUC-hEGF. The synthetic hEGF gene was recombined into the downstream of strong promoter psbA in plasmids pRL-489. Then, the vector was introduced into Synechococcus sp. PCC 7002 and Anabaena sp. PCC 7120 by triparental conjugative transfer. The transformation was confirmed by PCR amplification. The pRL-hEGF is thought to be retained as a plasmid form in the transgenic Anabaena sp. PCC 7120, since it can be recovered. However, it has been integrated into the chromosome of Synechococcus sp. PCC 7002 as there is no duplication origin in the pRL-hEGF in this cyanobacterium and plasmid cannot be isolated from the Synechococcus sp. PCC 7002 either. The radioimmunoassay (RIA) proved that the hEGF gene has been expressed as the protein existed in these two strains of transgenic cyanobacteria, and the hEGF protein in Anabaena sp. PCC 7002 could be secreted into the medium.
戴? 1,2 施定基1* 张卉1,2 钟晖3 冉亮1 彭国宏4 甘人宝5 陈素娟3 连慕兰2
（1. 中国科学院植物研究所，北京100093；2. 北京师范大学生命科学学院，北京100875；3. 解放军301 医院东亚免疫研究所，
北京100853；4. 中国科学院海洋研究所，青岛266071; 5. 中国科学院生物化学研究所，上海200031）
摘要：人表皮生长因子(hEGF)是由53个氨基酸组成的蛋白,在临床上内服与外敷可促进内外表皮细胞的生长.将人工合成的hEGF基因连接到质粒pRL-489上,位于启动子psbA下游.验证连接成功后,用三亲接合转移方法将载体pRL-hEGF导入聚球藻Synechococcus sp. PCC 7002和鱼腥藻Anabaena sp. PCC 7120.由于pRL-hEGF没有能在单细胞蓝藻中自主复制的复制子,通过筛选,hEGF在聚球藻7002中是整合到蓝藻染色体上进行表达的.用PCR扩增的方法在两种转基因藻中均检测到hEGF基因的存在.放射免疫分析证明,hEGF基因在两种转基因藻中均得到了表达.而且,在聚球藻7002中是采用分泌形式将表达产物分泌到培养液中.
关键词： 人表皮生长因子；鱼腥藻Anabaena sp.PCC7120；聚球藻Synechococcus.sp.PCC7002；载体；转基因蓝藻；三亲接合转移
A full-length cDNA for lycopene β-cyclase (LYC-b) was isolated from carrot ( Daucus carota L.) roots by 5′ and 3′ RACE. The cDNA is 2 089 bp long with an open reading frame of 1 515 bp, which encodes a polypeptide of 505 amino acids. The deduced amino acid sequence of the cDNA is significantly conserved as compared with those of LYC-b from tomato ( Lycopersicum esculentum Mill.), tobacco ( Nicotiana rustica L.) and pepper (Capsicum frutescens L.), but with difference from those of the bacteria such as Agrobacterium aurantiacum Conn and Erwinia uredovora (Pon et al .) Mergaert et al . In contrast to orange roots of the variety CA201 which contains rich α- and β-carotene, and shows rather high level of the level of LYC-b mRNA, expression of the LYC-b is suppressed severely in purple roots of the variety “Qitouhong" containing high level of lycopene and low level of α- and β-carotene, leading apparent accumulation of the lycopene in “Qitouhong" roots due to low transcriptional activity of the LYC-b gene.
陈大明* 薛颖 刘敬梅 王永健 陈杭
摘要：利用 5′和 3′RACE技术从胡萝卜 (DaucuscarotaL .)肉质根中分离了茄红素 β_环化酶基因的全长cDNA。该cDNA长 2 0 89bp ,包含一个 15 15bp的开放阅读框架 ,所编码的肽链长 5 0 5个氨基酸 ,其一级结构与番茄 (Lycoper sicumesculentum Mill.)、烟草 (Nicotianarustica L .)和辣椒 (Capsicumfrutescens L .)等植物的茄红素 β-环化酶高度同源。茄红素 β-环化酶在胡萝卜肉质根中的表达受品种特异性的调控 ,在CA2 0 1胡萝卜肉质根中表达十分活跃 ,而在“齐头红”胡萝卜肉质根中该基因的表达受到了强烈的抑制 ,导致茄红素在细胞中大量积累
Based on the biology peculiarity of Liriodendron L., the non-bagged pollination technique was used widely in cross breeding of the genus. Theoretical analysis and indirect detection indicated that the pollen contamination rate of this pollination technique was no higher than 1%. But there is no evidence from direct detection by now. The pollen contamination rate produced in this pollination technique, for the first time, was detected by means of RAPD markers in this study. The results revealed that all the 93 progenies detected, derived from the non-bagged pollination technique, were progenies of the purpose male tree of the cross. No pollen contamination was found. Because the frequency of the 4 paternal marker fragments selected for the detection were relatively low in the population, the reliability of the pollen contamination rate detected was very high (>99%). Therefore, the non-bagged pollination technique is viable in Liriodendron . The authors also considered that RAPD markers had higher potential of use in other fields of botanic study such as pollen competition, pollen flow, pollen contamination of forest seed orchard, etc.
（1. 西北农林科技大学林学院，陕西杨凌712100；2. 南京林业大学森林资源与环境学院，南京210037）
Cercis (L.) (Leguminosae) consists of approximately 8 species, disjunctly distributed in eastern and western Asia, southern Europe, and North America. Phylogenetic analysis was performed using sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA. The two North American and one Southern European and Western Asian species consistently form a clade, nesting within the eastern Asian species, suggesting a slightly closer relationship between the North American and Southern Europe-Western Asian species than each with the Eastern Asian species of Cercis . A close relationship between the eastern and western North American species is furthermore demonstrated, although with weaker support. The possibilities of migration via either the Bering land bridges or the North Atlantic land bridges could not be precluded; it suggests that the biogeographic patterns in the Northern Hemisphere are complex.
郝刚 张奠湘* 郭丽秀 张明永 邓云飞 文香英
摘要：紫荆属 (CercisL .)约含 8种 ,间断分布于亚洲东、西部 ,欧洲南部和北美。应用核糖体DNA的ITS基因序列研究紫荆属的系统发育关系。在最简约性分析中 ,北美的两个种和南欧、西亚的一个种构成一单系群而隐藏于东亚的种类中。这表明紫荆属北美的种类和南欧、西亚的种类之间的关系比它们各自与东亚的种类的关系要密切。研究还发现北美洲东、西部的种类可能具较近亲缘。紫荆属以白令陆桥或北大西洋陆桥为迁移途径的可能性似乎都不能排除 ;北半球的生物地理分布式样可能具有复杂的起源
Nearly Twenty years after the first large-scale field survey on wild rice in China during 1978-1982, we have recently made an extensive survey on Chinese Oryza granulata (Nees et Arn. Ex Watt.), including its current distribution, population characteristics and status of endangerment. Because of the change in the division of administrative areas, the number of counties or cities where the wild rice grows has reached up to 30. Oryza granulata grows normally under the coverage of 90%-210% in the tropical forest with resistance to drought and moderate disturbance. The measurement of aggregation showed that it maintains a colony pattern in the community. Oryza granulata scatters seeds mainly by gravity and animals, causing limited scale of gene flow between local populations and attaining a typical metapopulation structure of the distributional pattern. Our survey revealed that 12.9% of the populations had been extinct, and 83.9% were endangered. The extent of disturbance varied in different areas. Up to date, the majority of the populations grow in the mountainous areas of southwestern Hainan and drainage area of Nanding river, Lancang river of Yunnan, under the threat of human activity. A total DNA bank was established that consists of 1109 individuals from 49 populations. In the practice of conservation, difficulties such as lacking immediate utility and scattered distribution impeded the conservation efficient. However, owing to its characteristics of population genetics, sustainable and ex situ conservation strategies are appropriate in some places to salvage this important rice germplasm.
钱韦* 谢中稳 葛颂** 洪德元
摘要：继1978～1982年全国野生稻普查后,又一次对中国疣粒野生稻(Oryza granulata (Nees et Arn. Ex Watt.))主要分布点的居群特征、濒危现状和破坏情况进行了野外生态学研究.由于行政区划的改变,目前疣粒野生稻在中国分布的市(县)达30个.它在群落盖度为90%～210%下生长良好,具有抗旱和适应中度干扰的能力.聚集参数分析表明在群落中居群以集群分布为主.该物种主要通过重力和动物传播种子,居群间的基因流有限,形成了典型的集合种群 (metapopulation)结构.生境丧失对疣粒野生稻的生长造成非常严重的后果,已有12.9%的疣粒野生稻居群灭绝,83.9%的居群处于中度和重度的干扰之下.由于各地区的破坏程度不平衡,目前疣粒野生稻的分布被压缩到海南省的西南部山区和云南省的澜沧江中下游、南汀河流域,面临热区开发的巨大威胁.研究中建立了中国疣粒野生稻的总DNA库,作为易位保护的手段之一和开展保护遗传学研究的基础;并讨论了居群遗传结构与居群分布格局之间的相互关系和保护中需注意的问题.
Through a detailed field study on a 1.0 hm plot at 3 580 m a.s.l. in Hailuo clough of Gongga Mountain, the characteristics of individual growth, population structure and dynamics, natural disturbance and gap regeneration of the timberline population of Abies fabri Craib were analyzed. The results suggested that, while apparent stresses on the development of configuration, and growth of height and diameter were shown in A. fabri individuals, the effect on regeneration was undetected. An intensive environmental selection and competitive self-thinning were detected at the age of 0-20 a and 60-140 a respectively through the specific-time life table and the survivorship curves of the timberline population. The fluctuation of death rate in the later stage was also shown to be relative to environmental variation. The life limit of A. fabri is 400 a or so near the upper timberline. The A. fabri population near timberline is disturbed by the gaps in a high frequency and small scale. Although 86.4% of the gaps are induced by more than one gap-maker, most of them are small as the major gap-maker A. fabri died standing. Disease, ice and snow, and hitting by the dead trees are the main causes of gaps, whereas wind is not an important disturbance agent near the timberline. The seedling of A. fabri is fairly shade-tolerant, although the regeneration of the species shows dependence on the existence of gaps. More than one factor on different spatial scales should be responsible for the regeneration pattern of A. fabri.
沈泽昊1 方精云1 刘增力1 伍 杰2
（1. 北京大学城市与环境学系，北京100871；2. 四川省甘孜州林业科学研究所，四川姑咱626001）
摘要：通过对贡嘎山海螺沟海拔3 580 m处1.0 hm2峨眉冷杉(Abies fabri Craib)林的定位调查,分析了峨眉冷杉的个体生长、种群结构与动态、干扰及更新特征.结果表明:1)林线附近的环境胁迫影响了个体的形态发育和高、径生长,但对其更新繁殖无明显影响;2)静态生命表和种群生存曲线反映了20 a以前和60～140 a分别经历的强烈环境筛选和竞争自疏,以及后期与环境变化相关的死亡率波动,峨眉冷杉寿命极限为400 a左右.3)林线种群遭受高频率、小规模的林隙干扰.尽管86.4%的林隙由多木形成,但死亡的峨眉冷杉以枯立为主导致林隙较小;病害、冰雪和死树的打压是林隙形成的重要因素,而风不是这里林线环境的主要自然干扰.4)峨眉冷杉的幼苗表现了相当的耐荫性,尽管其更新依赖林隙的存在,但更新格局存在多尺度的成因.
The mountain-basin system(MBS) in the north of the Tianshan Mountains consists of mountain vegetation vertical belt system and concentric circular vegetation (geologic and geomorphic) system of desert basin. The MBS contains three “circles”: montane, piedmont fan and alluvial plain, including nine belts, viz. alpine belt, montane forest-grassland belt, low-mountain desert belt, gravel gobi desert belt, agricultural oasis, marginal belt of diluvial fan, alluvial desert plain, sandy desert belt, and lake. The above-mentioned zonation is the most essential existence and functional pattern of those precious natural resources. It is the representation of an irresistible rule of the nature and, also, the guidance system of ecological conservation and land use. Basing on this foundation, a “mountain-oasis-oasis/desert ecotone-desert eco-productive paradigm”is proposed. The MBS is its basic frame. Its driving forces are the biogeochemical cycles, biogeophysic process, and biogeosocial interaction, which run through the whole system. Thus, the establishment of a sustainable agricultural system and an optimized land use and land cover structure and pattern, which aimed at ecological conservation, may be possible.
The binary vectors which respectively contain chimeric genes ( SCaM1-GFP，SCaM4-GFP ) were constructed and used to transform tobacco ( Nicotiana tabacum L.), pGTV-GFP was used as control. The plasmolyzed cells of transgenic callus treated with CBW were investigated under the laser scanning confocal microscope. Green fluorescence was found in the cell wall of transgenic SCaM1-GFP callus. However there was no green fluorescence in the cell wall of SCaM4-GFP or GFP transgenic callus. These results indicate that SCaM1 can be secreted into the apoplast of plant cells, while SCaM4 does not exist in the apoplast of plant cells.
周华林 马力耕 刘曼 毛国红 孙大业*
With highly infective activity, and the production and role of reactive oxygen species (ROS) in Laminaria japonica Aresch against infection by five strains of alginic acid decomposing bacteria were investigated. The results were as follows: 1. The production of reactive oxygen species in L. japonica during infection of alginic acid decomposing bacteria was an universal response. 2. The massive production of reactive oxygen species occurred only at early stage of infection and decreased gradually accompaning with the decrease of photosynthesis. 3. The notable decline of ROS production occurred earlier than that of photosynthesis. 4. The rate of production of ROS at early infective stage was related to the resistance of L. japonica against infection.
唐学玺 王悠 黄健 杨震 宫相忠
Maowusu sandy grassland locating at an ecotone between typical desert and typical grassland contained several landscape ecotypes or elements where Caragana intermedia Kuang et H.C.Fu naturally distributed as a dominant species in shrub ecosystems. Based on a phenomenon of gene segregation of open-pollinated seeds within each plants similar to Mendel's segregation in F2, a study on testing the breeding systems of populations under 4 landscape ecotypes was conducted. Statistical data showed its availability in estimation of breeding system parameters when isozymes were used as genetic markers. Nei's genetic differentiation GST among 4 ecotypes in Maowusu was estimated at 0.07 from lap loci close to a GST =0.076 reported in the authors' laboratory. The results indicated that breeding systems of populations gradually changed from total outbreeding to partial inbreeding when water conditions worsened. Therefore, the former RAPD data, especially the cline of frequencies for a few polymorphic DNAs in different landscapes can be partially explained by gene fixation caused by selfing or inbreeding probably induced by drought. It was difficult to assess breeding system parameters by using one dimensional SDS polyacrylamide gel electrophoresis of seed proteins of C. intermedia simply due to a difficulty of genetic analysis of seed protein subunits.
周永刚 王洪新 胡志昂*
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