不同固定条件下细胞与活细胞的原子力显微镜实时观察

用原子力显微镜（atom force microscope,AFM）观察固定细胞的最佳条件并在生理溶液中对活细胞实时观察.用不同固定剂和同一固定剂的不同浓度处理细胞;不加任何固定剂而直接在生理溶液中对细胞进行AFM成像.以戊二醛为固定剂并使用0.5%～1%的浓度固定细胞,后用缓冲溶液漂洗,再对细胞进行成像时可获得质量良好的图像.直接在生理溶液中进行观察,成像质量低于使用固定剂的细胞,但保持了细胞的生活原貌.在用原子力显微镜高分辨率观察生理条件下细胞的特点时,需要在制样与观测系统两方面进行改进.     

巴西甘薯叶亲脂性成分研究

巴西甘薯叶[Ipomoea batatas Lam.(cv.Simon)]的氯仿成分经反复硅胶柱层析分离得到了8个化合物,通过理化性质和波谱方法分别鉴定为：乙酰-β香树醇(1)、木栓酮(2)、表木栓醇(3)、三十烷醇(4)、β-谷甾醇(5)、咖啡酸乙酯(6)、东莨菪素(7)和胡萝卜苷(8)。其中3、4、6、7和8为首次从该植物中分得。     

茶叶多糖的抗氧化活性研究

从婺源粗老绿茶叶中提取纯化出了茶叶多糖,研究了它对超氧自由基、DPPH自由基的清除作用,以及对β-胡萝卜素-亚油酸氧化体系的抑制作用,以此来评价该多糖的抗氧化活性.结果表明,茶叶多糖对超氧自由基、DPPH自由基有较好的清除作用,而对β-胡萝卜素-亚油酸氧化体系也有较明显的抑制作用.     

水分胁迫对入侵植物薇甘菊幼苗生长的影响

水分是影响薇甘菊(Mikania micrantha)生长的重要环境因子,但通过调控生长环境包括土壤水分和空气湿度来探讨这一入侵植物的适应能力的报道较少.本文通过设置2个水分梯度:处理Ⅰ土壤含水量30%～60%和空气相对湿度80%～90%,处理Ⅱ土壤含水量10%～20%和空气相对湿度20%～30%进行试验.结果发现土壤含水量在10%～20%且空气相对湿度在20%～30%时,水分胁迫能显著影响薇甘菊的幼苗生长和光合特性.胁迫条件下植株生长速率明显降低,最大净光合速率和最大量子效率分别是1.94 μmol·m-2·s-1和64.91 mmol·mol-1,比对照8.63 μmol·m-2·s-1和211.34 mmol·mol-1明显偏低.本文将空气相对湿度作为水分胁迫条件之一,阐述了空气相对湿度的增加能扩大薇甘菊的适生范围,并分析得出气孔限制可能是水分胁迫下薇甘菊生长受抑制的主要原因.     

微生物法生产γ-癸内酯的初步研究

研究了耶罗威亚酵母(Yarrowia sp.)转化蓖麻油生成γ-癸内酯的过程.根据菌株的生长特性,确定底物蓖麻油的最适加入时间;分批培养菌体转化,γ-癸内酯产量为2.4 g/L;采用转化液接种进行二次转化,γ-癸内酯产量可提高到4.0 g/L;考察了溶氧条件变化对γ-癸内酯积累的影响.     

纯氧对采后杨梅果实腐烂的抑制与抗病相关酶的诱导

为研究高氧对抑制果实腐烂的作用及其与抗病相关酶活性诱导的关系,将杨梅果实采后在5℃用纯氧或空气(对照)处理12 d.结果表明,纯氧处理可显著抑制果实腐烂发生,贮藏12 d后对照果实的腐烂指数达到54%,而处理果实仅为17%.纯氧处理在贮藏前期可诱导杨梅果实几丁质酶和β-1,3-葡聚糖酶活性的升高,并在第6天时达到高峰.另外,纯氧处理增加了苯丙氨酸解氨酶和过氧化物酶的活性及总酚含量,并在整个贮藏期间一直高于对照水平.这些结果表明,高氧抑制杨梅果实腐烂的作用与诱导与抗病相关的酶的活性升高密切相关,抗病性诱导是高氧抑制杨梅果实腐烂的重要原因.     

Promotive Effect of Low Concentrations of NaHSO3 on Photophosphorylation and Photosynthesis in Phosphoenolpyruvate Carboxylase Transgenic Rice Leaves

Spraying a 1-2 mmol/L solution of NaHSO3 on the leaves of wild-type rice (Oryza sativa L.)Kitaake (WT), phosphoenolpyruvate carboxylase (PEPC) transgenic (PC) rice and PEPC phosphate dikinase(PPDK) transgenic rice (PC PK), in which the germplasm was transformed with wild-type Kitaake as the gene receptor, resulted in an enhancement of the net photosynthetic rate by 23.0%, 28.8%, and 34.4%,respectively, for more than 3 d. It was also observed that NaHSO3 application caused an increase in the ATP content in leaves. Spraying PMS (a cofactor catalysing the photophosphorylation cycle) and NaHSO3 separately or together on leaves resulted in an increase in photosynthesis with all treatments. There was no additional effect on photosynthetic rate when the mixture was applied, suggesting that the mechanism by which NaHSO3 promotes photosynthesis is similar to the mechanism by which PMS acts and that both of compounds enhanced the supply of ATE After spraying a solution of NaHSO3 on leaves, compared with the WT Kitaake rice, a greater enhancement of net photosynthetic rate was observed in PEPC transgenic(PC) and PEPC PPDK transgenic (PC PK) rice, with the greatest increase being observed in the latter group. Therefore ATP supply may become the limiting factor that concentrates CO2 in rice leaves transformed with an exogenous PEPC gene and exogenous PEPC PPDK genes.     

根施甜菜碱对干旱胁迫下小麦幼苗类囊体膜组分和功能的影响

干旱胁迫造成两小麦品系类囊体膜上的单半乳糖脂甘油二酯(MGDG)、双半乳糖脂甘油二酯(DGDG)、磷脂酰胆碱(PG)以及叶绿素含量显著下降,甜菜碱预处理能缓解这些组分的下降.干旱胁迫下,抗旱型小麦品系HF9 70 3的硫代异鼠李糖甘油二酯(SQDG)、反式十六碳-烯酸[16:1(3t)]含量显著上升,MGDG中亚麻酸(18:3)相对含量显著下降;而干旱敏感型品系SN215953则表现为SQDG、16:1(3t)含量显著下降,MGDG中脂肪酸变化不明显,这可能是两个小麦品系抗旱性差异的重要原因之一;甜菜碱处理能显著减小干旱处理与对照之间的差异,且对SN215953的作用较HF9703大.另外,干旱胁迫引起类囊体膜上Ca2 -ATPase活性、Hill反应活性及叶片净光合速率下降,外源甜菜碱能缓解其下降趋势.     

铝胁迫下植物根系的有机酸分泌及其解毒机理

酸性土壤中的铝毒害问题,已成为限制植物生长发育的主要因素之一.耐铝植物通过根系分泌有机酸来解除或减轻铝的毒害是外部解铝毒的重要机制.文章对铝胁迫下植物根系分泌有机酸的种类,有机酸解铝毒机理、解铝毒能力,有机酸分泌方式及调控其分泌的主要因素等相关研究进行综述.     

Isolation and Characterization of a Novel Chitosan-Binding Protein from Non-Heading Chinese Cabbage Leaves

To know the mechanism of ammonia assimilation in non-heading Chinese cabbage (Brassica campestris L. ssp. chinensis (L.) Makino) leaves regulated by chitosan (CTS), a CTS-binding protein was isolated from non-heading Chinese cabbage leaves using the chitosan affinity chromatography approach and this CTS-binding protein was partially characterized. The profile of the 53.1 kDa purified protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was compared with the native molecular weight of 106.5 kDa, which indicated that the purified protein was a dimer with identical subunits. After isoelectric focusing, a band was obtained at pH 8.25. The agglutination test and periodic acid-Schiff staining further revealed that the protein was a glycoprotein with lectin activity. Moreover, the purified protein contained 17.4% (w/w) neutral carbohydrate and 82.56% (w/w) protein. The comparison of this protein and the 67 kDa CTS-binding protein isolated previously from Rubus culture tissue exhibited some differences in characterization. According to results of peptide mass fingerprinting analysis, the protein purified in the present study does not show any similarity with any protein in the protein data bank. Thus, it was deduced that the protein purified in the present study is a novel CTS-binding protein.