Resistance of Maize Calli to Herbicide Basta and Its Relevant Effect by Some Amino Acids

Maize (Zea mays L. ) embryogenic calli were cultured on N6 medium and treated respectively with different concentrations of herbicide Basra and amino acids. The NH4+ concentrations and weight increase of maize calli were measured. Statistical analysis revealed that callus weight increased less when cultured on N6 medium with 4 mg/L of Basta while Nih+ concentration reached its peak when cultured on N6 with 8 mg/L of Basta. Therefore 6 mg/L of Basta was considered as the optional dosage for selection of transgenic calli L-arginine and L-glutamic acid significantly reduced the NH4+ concentration in maize calli while L-proline had little effects on NH4+ concentration even though it enhanced callus weight enormously.     

Differentiation and Ultrastructure of the Protophloem Sieve Elements of Minor Veins in the Maize Leaves: Changes in the Protoplast

Protophloem sieve element differentiation in the minor veins of the maize ( Zea mays L. ) leaves was first evidenced as an increase of the wall thickness, which began in the comers of the cell and then extended to other parts of the wall, and the appearance of long rough endoplasmic reticulum cistemae distributed throughout the cytoplasm, and then the presence of characteristic crystalloid inclusions within the plastids. As differentiation progressed, long cisternae of rough endoplasmic reticulum appeared to transform into shorter forms and eventually aggregated into small stacks, losing their ribosomes during the process. The nuclei degenerated, although frequently persisted until very late in differentiation the stages of maturation, as darkly stained amorphous aggregates surrounded by double nuclear envelope or only inner membrane of nuclear envelope. Subsequently, the nuclear envelope collapsed and became discontinuous. At the beginning of nuclear degeneration the perinuclear spaces were partly dilated and sometimes the outer nuclear envelope in the dilated portions then ruptured, and was accompanied by the disappearance of the cytoplasmic portion near it. During the peried of nuclear degeneration, in addition to the endoplasmic reticulum, plastids and mitochondria underwent structural modification, while components such as ribosomes, cytoplasmic ground substances, vacuoles and dictyosomes disintegrated and disappeared. At maturity, the surviving protoplasmic components, including plasmalemma, mitochondria, small stacked smooth endoplasmic reticulum and P-type plastids with crystalloids, became parietal in position. As differentiation of adjacent metaphloem sieve elements proceeded, the protoplasmic components of the mature protophloem sieve elements progresively degenerated and finally obliterated.     

中国珍稀特有植物永瓣藤生物学特性的研究

本文研究了我国珍稀特有植物永瓣藤(Monimopetalum chinense)的自然环境、地理分布、群落学特点、外部形态、内部结构特征、生长发育及其开花结实特性,为其种质保存和保护生物学研究提供基础资料。     

Yinpingmudan,the Wild Relative of the King of Flowers,Paeonia suffruticosa Andrews

Paeonia suffruticosa Andrews subsp. spontanea (Rehder) S. G. Haw et L. A. Lauener ( ＝P. spontanea ＝ P. jishanensis) has been considered as the wild form of widely cultivated P. suffruticosa. However, the subspecies differs from the cultivated one in shape, division and indumentum of leaves and reproductive biology. As a result of extensive field work, a form with two individuals in Yinping Shan, Caohu, Anhui, and Songxian, Henan, are found to be extremely similar to P. suffruticosa, but apparently different from P. jishanensis. The form is considered to be the wild one of P. suffruticosa and described as new: P. suffruticosa subsp, yinpingmudan Hong, K. Y. Pan et Z. W. Xie.     

金丝猴颅骨及牙齿的比较形态研究

金丝猴(Rhinopithecus roxellanae M.-E.)自从1870年订名以来,对它的研究多限于分类和个体生态习性的观察描述,至于它的形态解剖方面的论述国内几无报道。国外Hooizer(1950)和Swindler(1976)对其牙齿作了简单扼要的描述,前者并在11例川金丝猴头骨中发现一例左侧上颌骨具有P⁴。这次我们对金丝猴系统的研究过程中,在解剖方面,除了进行各器官系统解剖外,同时还与猕猴、黑叶猴相比较,并对其器官的形态变化和生态生理机能的结合上给以适当注意和解释。     

一种简便、快速的大肠杆菌质粒转化方法

将受体菌与质粒DNA混匀直接在Ca2+离子选择平板上进行转化和筛选,其转化过程仅需2 min左右,并能得到105以上的转化效率, 可满足一般克隆工作的需要。 Abstract：After mixing the recipient cells and plasmids DNA, directly spread the mixture on selective media containing Ca2+. The whole process of transformation just needs 2 min or so, and could acquire the transformation efficiency of more than 105, which is enough to common gene cloning.     

大理鸢尾和高原鸢尾的花粉形态

大理鸢尾（ＩｒｉｓｄａｌｉｅｎｓｉｓＸＤＤｏｎｇｅｔＹＴＺｈａｏ）是笔者发表的鸢尾植物分类群（董晓东等,１９９７）,因与高原鸢尾（ＩｒｉｓｃｏｌｅｔｉＨｏｋ．ｆ．）相似,国外有学者认为它是高原鸢尾的一个变种（Ｈｅｎｒｙ,１９９５）。为弄清它的...     

巨穗小麦种质C—分带特征分析

对５个不同类型巨穗小麦种质材料进行Ｃ－分带分析,发现均有一对特征染色体存在,初步确定这对染色体为小麦－黑麦１ＢＬ／１ＲＳ易位染色体。     

对大鲵自然种群在河北省(含京津)分布的质疑

在多年对野生动物种群调查的基础上, 通过检索河北省（含京津） 境内９２ 个市县, 自明清时代至今的近２００ 卷册地方志和走访有关学者, 分析并确定在河北省境内并无大鲵自然种群的分布。在部分地区偶见大鲵成体, 乃为幼鲵自繁殖地被偶然携带至该地而异地育肥的结果。     

芒果核仁的化学成分及其抑菌活性

从杧果(Mangifera indica L.)果实核仁中分离得到6种化合物。经光谱分析及与文献对照,分别鉴定为没食子酸(1)、没食子酸甲酯(2)、没食子酸乙酯(3)、间-二没食子酸甲酯(4)、对羟基苯甲酸(5)和丁二酸单甲酯(6),它们均为首次从芒果核中获得。用琼脂平板稀释法测定了化合物1~5对7种细菌和4种真菌生长的抑制活性。结果表明,化合物1对金黄色葡萄球菌(Staphylococcus aureus)、表皮葡萄球菌(S. epidermidis)、干燥棒状杆菌(Corynebacterium xerosis)和藤黄微球菌(Micrococcus luteus)的最小抑制浓度(MIC)为50~100 µg mL-1,化合物4对绿脓杆菌(Pseudomonas aeruginosa)有抑制活性。