斑叶蒲公英的核型分析和花粉母细胞的减数分裂观察

采用根尖压片法确定斑叶蒲公英的染色体数目,通过分析斑叶蒲公英核型及花粉母细胞减数分裂过程,以确定其倍性水平。结果表明:(1)斑叶蒲公英根尖细胞染色体数目为32条,核型公式为2n=3x+x′=32=(18m+6sm)+(3m+4sm+1T),属于2A型。(2)斑叶蒲公英花粉母细胞减数分裂为同时型胞质分裂,四分体的排列方式以正四面体型居多,十字交叉型偏少,偶见左右对称型。(3)前期Ι染色体的构型复杂,中期Ι和中期Ⅱ有赤道板外染色体;后期Ι和后期Ⅱ出现落后染色体、染色体桥及断片;后期Ⅱ和末期Ⅱ还出现染色体分离不同步及不均等分裂的现象;四分体时期出现二分体、三分体、含微核的异常四分体及多分体等异常现象。(4)对其花粉进行离体萌发试验,花粉萌发率只有26.3%,说明斑叶蒲公英是异源四倍体,32条染色体不均等的减数分裂异常,造成花粉活性较低。     

黑芥与花椰菜体细胞杂种花粉母细胞的减数分裂不同步及染色体行为异常

本研究对黑芥与花椰菜体细胞杂种及其双亲的花粉母细胞减数分裂行为进行了观察和比较,结果表明黑芥与花椰菜的花粉母细胞减数分裂同步性很高,而其体细胞杂种表现出明显的减数分裂不同步,各杂种不同株系间减数分裂不同步的程度与跨度各异.减数分裂不同步发生是由于为部分花粉母细胞在减数分裂某一时期发生停滞或推迟,这一时期(或第一个停滞时期)主要发生在第一次减数分裂的前期.花粉母细胞发育虽不同步,但最后均完成减数分裂形成花粉粒,所形成的花粉粒的活性相差甚远.此外,研究结果还显示,体细胞杂种有着较高的减数分裂染色体行为异常频率,尤其是在中期Ⅰ后.主要表现为减数分裂中期Ⅰ的染色体的早迁、后期Ⅰ和后期Ⅱ的染色体滞后及染色体不均等分离、四分体时期的异常等现象.花粉粒的活性与减数分裂时期染色体行为异常程度有关,染色体行为异常及微核现象出现的频率越高,相对的花粉粒活力也越低.     

Cohesion介导的减数分裂异常与卵子老化发生的关系

社会发展及计划生育政策的顺势改变,使得高龄女性的生育需求不断扩大,但与年龄相关的卵子老化是高龄女性急需解决的生育难题,而造成卵子老化的主因确是卵母细胞非整倍体发生率的增加.粘连蛋白(cohesin)能够介导姐妹染色单体之间的着丝粒凝聚力从而稳定二价染色体结构,cohesin介导的减数分裂异常与卵子老化的发生关系密切,以...     

松香草花粉母细胞减数分裂及雄性子体发育-兼对某些异常花粉的观察

松香草(Silphium perfoliatum L.)为原产北美洲的多年生宿根草本植物,由于其地上部分有较高的蛋白质含量,近年来被引入我国作为一种有发展前途的饲料作物进行栽培,除了报道过体细胞染色体研究结果,该物种尚缺少系统的细胞学研究。最近,我们对其小孢子母细胞减数分裂和雄配子体发育过程进行了细胞学观察,并发现了一些异常形态的花粉,现将初步观察结果报道如下。1.材料与方法松香草不同的植株间开花期相差很大。用于观察的花序取自三年生植株。根据花序外部大小,上午11时同时取一系列大小不等的花序固定,重复取材3次。材料以卡诺液(冰醋酸:纯酒精=1:3)固定过夜,次日转于70%酒精中置冰箱内保存备用。细胞学制片用常规压片法。丙酸-水合氯醛-铁矾苏木精染色,临时制片以凡士林封     

药蒲公英再生体系的建立和优化

通过愈伤组织诱导和直接不定芽再生途径 ,建立了药蒲公英的快速高效再生系统。叶片外植体在含0.2mg LIAA和1mg LTDZ的MS培养基中培养 2周后便产生大量的丛生芽 ,在含有 0.5mg/L 2 ,4D和2mg/L 6BA的MS培养基中培养 30d后 ,形成明显的愈伤组织 ,愈伤组织块在含10mg/L 6BA的MS培养基中成功再生。对 9株再生植株进行RAPD检测表明 ,部分植株在DNA水平上发生了变异。与对照相比 ,再生植株的主要抗氧化成分无明显变化 ,保证了有效成分的稳定。     

药食佳品—蒲公英

随着人们对健康的日益关注 ,越来越重视天然无污染的野生植物资源 ,蒲公英既是常用的中药材 ,又是一种天然营养型保健型绿色食品 ,已逐渐进入餐桌 ,倍受人们的青睐。近年来 ,日本、法国、美国和我国已陆续兴起了“蒲公英”热。蒲公英 (ＴａｒａｘａｃｕｍｍｏｎｇｏｌｉｃｕｍＨａｎｄ .-Ｍａｚｚ .)为菊科蒲公英属多年生草本植物 ,别名黄花地丁、婆婆草 (丁 )、奶汁草、黄花三七、蒲公草等 ,全株含白色乳汁 ,根直生 ,肥厚 ,圆锥形 ;叶莲座状丛生 ,倒披针形 ,大头羽浅或深裂 ,全缘或有数齿 ,基部渐狭成柄 ,不同生长期 ,不同环境中叶形变化较…     

黄瓜花粉母细胞减数分裂行为的研究

研究了华北型、华南型和西南型黄瓜花粉母细胞的减数分裂行为,发现黄瓜细胞核减数分裂的同步性较高,细胞质是同时型分裂。在细胞核分裂的过程中,核仁在前期Ⅰ到中期Ⅰ逐渐消失,在前期Ⅰ再次出现,随后消失;染色体在前期Ⅰ到中期Ⅰ逐渐收缩,变得清晰,至末期Ⅰ解螺旋,变得模糊,在前期I再次清晰。不同生态型黄瓜终变期的染色体构型均以环状二价体为主。在前期Ⅰ和前期Ⅰ,西双版纳黄瓜的核仁都相应地比另外两种生态型黄瓜品种的多,在后期Ⅰ还偶尔出现染色体桥,显示了西双版纳黄瓜变种的特殊性。研究还发现寒冷的气候条件下栽培黄瓜都能够形成高频率的多分体,推测其形成很可能与低温逆境有关。     

小胡杨花粉母细胞减数分裂染色体行为研究

采用常规压片法对小胡杨花粉母细胞减数分裂过程染色体行为及花粉特性进行了研究.结果表明:小胡杨花粉母细胞减数分裂过程中表现出极强的异质性,减数分裂各时期异常细胞出现率均超过70%.其中,终变期存在大量单价体、后期观察到落后染色体,证明小胡杨的两个亲本亲缘关系较远.小胡杨花粉母细胞减数分裂过程高频率异常现象(后期I落后染色体71.87%,染色体桥8.13%;末期Ⅰ有77.18%的微核细胞;后期Ⅱ有85.60%的异常细胞等)的发生直接导致其大部分花粉发育异常(99.48%),表现出远缘杂种的败育特性.     

草菇减数分裂和担孢子形成细胞核行为

本文用苏木精染色和双苯并咪唑(Hoechst 33258)染色法,从草菇子实体“纽期”菌褶分化完开始,每3小时对同一个子实体连续切取菌褶进行染色观察。结果表明草菇子实体“纽期”菌褶形成时,约10％的担子发生了核配;在子实体发育过程中,尤其是子实体成熟期后,不断有少量新的双核担子产生,并发生核配,使草菇减数分裂的同步性不高;草菇从菌褶分化完成(此时已有10％担子发生核配)到子实体完全成熟,菌褶变成深粉红至褐色(此时约70％担子完成减数分裂)需要28—30小时;担子减数分裂的持续时间为18小时,其中细线期和偶线期5.9小时、粗线期6.2小时、双线期和终变期3.4小时、中期10.5小时、后期Ⅰ到四分体2小时;经过对粗线期、双线和终变期以及中期Ⅰ染色体条数的多次反复观察,认为草菇的染色体条数为11(n=11);减数分裂后,4个子核分别进入4个担孢子中,留下无核的担子;绝大部分担孢子是单核的,有约5％的担孢子是双核的。     

兰州百合小孢子母细胞减数分裂异常现象的观察

对兰州百合(Lilium davidii var.unicolor)小孢子母细胞减数分裂异常进行了研究,发现存在不等二价体、同源染色体早分离、染色体桥、不均等分离、滞后染色体、核外染色体、微核等。分析了这些异常形成的可能机制及对正常小孢子形成的影响。人工花粉萌发实验表明：小孢子母细胞减数分裂异常是导致花粉败育的主要原因。认为兰州百合长期行无性繁殖引起染色体结构变异,导致减数分裂异常。     

银缕梅茎皮的化学成分

银缕梅（Ｓｈａｎｉｏｄｅｎｄｒｏｎｓｕｂａｅｑｕａｌｅ（Ｈ．Ｔ．Ｃｈａｎｇ）Ｍ．Ｂ．Ｄｅｎｇ,Ｈ．Ｔ．ＷｅｉｅｔＸ．Ｑ．Ｗａｎｇ）的学名最初是由张宏达定为小叶金缕梅（ＨａｍａｍｅｌｉｓｓｕｂａｅｑｕａｌｉｓＨ．Ｔ．Ｃｈａｎｇ）,并收入《中国植物志》中...     

H. T. 奥德姆与中国的能值研究

简要论述了由霍华德.汤姆.奥德姆创立的能值理论与方法在中国的传播并综述了多年以来中国的能值研究进展。能值理论与方法在中国的传播始于1990年霍华德·汤姆·奥德姆第二次访华.在此期间,即1990年8月1日至1990年8月21日他访问了台北、广州、北京和沈阳,并作了多个学术报告,如“自组织与系统生态学”和“能值分析与环境评价”等。从此以后,我国的广州、北京、南京和沈阳、佛山等多座城市的大学和科研机构先后开展了10多年的能值研究,能值理论应用于多个领域,包括国家、省、市、自然保护区等生态经济系统的能值评估、农业生态系统、城市生态系统、环境与资源、废水处理、生态工程和工业的能值评价。用中文或英文发表关于能值的学术论文60多篇,由霍华德.汤姆.奥德姆所著的3本关于能值的书被翻译为中文,能值概念、理论和方法被10多部中文书刊引用,2本关于能值的中文专著已发表。能值分析的研究工作已得到国家自然科学基金资助,其中有些课题已结题,有些课题正在进行中。能值理论与方法已被许多中国生态学家所接受,但在应用过程中仍存在许多问题。     

Phosphorylation of histone H2A is associated with centromere function and maintenance in meiosis

Histone phosphorylation is dynamically regulated during cell division, for example phosphorylation of histone H3 (H3)-Ser10, H3-Thr11 and H3-Ser28. Here we analyzed maize (Zea mays L) for Thr133-phosphorylated histone H2A, which is important for spindle checkpoint control and localization of the centromere cohesion protector Shugoshin in mammals and yeast. Immunostaining results indicate that phosphorylated H2A-Thr133 signals bridged those of the centromeric H3 histone variant CENH3 by using a plant displaying yellow fluorescent protein-CENH3 signals and H2A-Thr133 is phosphorylated in different cell types. During mitosis, H2A-Thr133 phosphorylation becomes strong in metaphase and is specific to centromere regions but drops during later anaphase and telophase. Immunostaining for several maize dicentric chromosomes revealed that the inactive centromeres have lost phosphorylation of H2A-Thr133. During meiosis in maize meiocytes, H2A phosphorylation becomes strong in the early pachytene stage and increases to a maximum at metaphase I. In the maize meiotic mutant afd1 (absence of first division), sister chromatids show equational separation at metaphase I, but there are no changes in H2A-Thr-133 phosphorylation during meiosis compared with the wild type. In sgo1 mutants, sister chromatids segregate randomly during meiosis II, and phosphorylation of H2A-Thr-133 is observed on the centromere regions during meiosis II. The availability of such mutants in maize that lack sister cohesion and Shugoshin indicate that the signals for phosphorylation are not dependent on cohesion but on centromere activity.     

Philosophical ideas and scientific practice: A note on the empiricism of T.H. Morgan

In a reply to Marga Vicedo the philosophical inconsistency of Morgan is emphasized. It is argued that even if a strict classification of scientists according to their philosophical position is not possible, their science may still be influenced by their philosophical ideas. Finally it is suggested that philosophical ideas influence science less by a direct effect on the scientists than indirectly through science policy and administration.     

Analysis of the meiosis in the F1 hybrids of Longiflorum x Asiatic(LA) of lilies (Lilium) using genomic in situ hybridization

Longiflorum and Asiatic lilies of the genus Lilium of the family Liliaeeae are two important groups of modern lily eultivars. One of the main trends of lily breeding is to realize introgression between these groups. With cut style pollination and embryo rescue, distant hybrids between the two groups have been obtained. However, the F1hybrids are highly sterile or some of them could produce a small number of 2n gametes, and their BC1 progenies are usually triploids. Dutch lily breeders have selected many cultivars from these BC1 progenies based on their variation. It is presumably suggested that such variation could be caused by intergenomic recombination and abnormal meiosis during gamete formation in F1 hybrids of Longiflorum x Asiatic (LA) hybrids in Lilium. Therefore, the meiotic process of ten F1 LA hybrids was cytologically investigated using genomic in situ hybridization and traditional cytological methods in the present research.The results showed that: at metaphase I, the homoeologous chromosome pairing among different F1hybrids ranged from 2.0 to 11.4 bi-valents formed by homoeologous chromosomes per pollen mother cell (PMC), and very few multivalents, and even very few bivalents were formed by two chromosomes within one genome rather than homoeologous chromosomes in some PMCs; at anaphase I, all biva-lents were disjoined and most univalents were divided. Both the disjoined bivalents (half-bivalents) and the divided univalents (sister chromatids) moved to the opposite poles, and then formed two groups of chromosomes; because the two resulting half-bivalents retained their axes in the cell undisturbed, many crossover types, including single crossovers, three strand double crossovers, four strand double crossovers, four strand triple crossovers, and four strand multiple crossovers between the non-sister chromatids in the tetrads of bivalents,were clearly inferred by analyzing the breakpoints on the disjoined bivalents. The present investigation not only explained the reason for sterility of the F1 LA hybrids and the variation of their BC1 progenies, but also provided a new method to analyze crossover types in other F1 interspecific hybrids as well.     

中国云南象牙参属(姜科)一新种——苍山象牙参

描述了中国云南姜科Zingiberaceae一新种——苍山象才参Roscoea cangshanensisM．H．LUO,X．F．Gao＆H．H．Lin。该种与大理象牙参R．forrestii Cowley在体态上相近,但唇瓣深裂成2裂片,每个裂片再2裂,基部收缩成具白色条纹的柄,叶片较狭窄,（2-）7-24×1．5-2．5cm,叶片基部狭缩成叶柄状而不同。该新种叶片基部狭缩成叶柄状,唇瓣倒卵状楔形,长2．5-3．5cm,宽2．5-3．0cm,基部收缩成具白色条纹的柄,与长柄象牙参R．debilis Gagnep．相似,但苞片非管状,较短,长5-15mm,隐藏于叶鞘内,花冠管较长,10-12.5cm,唇瓣深裂成2裂片,每个裂片再2裂,可与后者明显区别。     

Predicting potential distribution of Ziziphus spinosa (Bunge) H.H. Hu ex F.H. Chen in China under climate change scenarios

Ziziphus spinosa (Bunge) H.H. Hu ex F.H. Chen is a woody plant species of the family Rhamnaceae (order Rhamnales) that possesses high nutritional and medicinal value. Predicting the effects of climate change on the distribution of Z. spinosa is of great significance for the investigation, protection, and exploitation of this germplasm resource. For this study, optimized maximum entropy models were employed to predict the distribution patterns and changes of its present (1970–2000) and future (2050s, 2070s, and 2090s) potential suitable regions in China under multiple climate scenarios (SSP1‐2.6, SSP2‐4.5, SSP3‐7.0 & SSP5‐8.5). The results revealed that the total area of the present potential suitable region for Z. spinosa is 162.60 × 10⁴ km², which accounts for 16.94% of China''s territory. Within this area, the regions having low, medium, and high suitability were 80.14 × 10⁴ km², 81.50 × 10⁴ km², and 0.96 × 10⁴ km², respectively, with the high suitability regions being distributed primarily in Shanxi, Hebei, and Beijing Provinces. Except for SSP‐1‐2.6‐2070s, SSP‐5‐8.5‐2070s, and SSP‐5‐8.5‐2090s, the suitable areas for Z. spinosa in the future increased to different degrees. Meanwhile, considering the distribution of Z. spinosa during different periods and under different climate scenarios, our study predicted that the low impact areas of Z. spinosa were mainly restricted to Shanxi, Shaanxi, Ningxia, Gansu, Liaoning, Inner Mongolia, and Jilin Provinces. The results of core distributional shifts showed that, except for SSP1‐2.6, the center of the potential suitable region of Z. spinosa exhibited a trend of gradually shifting to the northwest.     

Roscoea cangshanensis M. H. Luo,X. F. Gao & H. H. Lin,a new species of the Zingiberaceae from Yunnan,China

Roscoea cangshanensis M. H. Luo, X. F. Gao & H. H. Lin, a new species of the Zingiberaceae from Yunnan, China, is described and illustrated. The new species is related to R. forrestii Cowley in habit, but differs in having 2-lobed labellum, each lobe 2-lobulate, base narrowed to a stalk with white lines, and narrower leaf blade, (2–)7–24×1.5–2.5 cm, with base narrow to petiole-like. The new species is also similar to R. debilis Gagnep. in having leaf base narrow to petiole-like, labellum obovate-cuneate, 2.5–3.5×2.5–3.0 cm, with white lines at throat, but differs in having bracts non-tubular, shorter, 5–15 mm long, concealed in leaf sheaths, corolla tubes longer, 10–12.5 cm long, labellum 2-lobed with each lobe further 2-lobulate.     

东北地区蒲公英属瘦果微形态特征及其分类学意义

通过对东北地区10种蒲公英瘦果形态及微形态特征进行观察比较,为蒲公英属（Taraxacum F.H.Wigg.）分类研究提供瘦果形态学证据。利用体式数码光学解剖镜和电子探针显微镜,对蒲公英瘦果进行观察比较,并根据瘦果大小、形状、喙基比例、颜色及微形态表面纹饰特征进行聚类检索。结果表明,（1）瘦果微形态特征为全身具刺,具白色斑点,刺状突起成行且规则排列,但刺大小及密度存在显著差异;（2）检索结果表明,以蒲公英瘦果形态及微形态特征进行检索的结果与《中国植物志》中的分类结果一致。该实验通过对东北地区10种蒲公英瘦果形态及微形态特征进行描述,确定了蒲公英瘦果形态特征差异可作为分类学表征证据,并将喙基长度（B）与瘦果长度（A）（不包括喙基长）之比命名为喙基比（B/A）,该比值可增补为分类要点。研究结果支持《中国植物志》中对蒲公英属的分类结果。