小麦叶片胞间隙蛋白的提取与鉴定

采用真空渗入离心法,通过特定的装置并在不同的离心力和时间条件下分离小麦叶片胞间隙液,结合十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)技术,以胞内高含量的蛋白-Rubisco大亚基为胞内物污染的指示,利用高效价的兔抗Rubisco抗体进行Western-blotting检测分析。结果表明,在离心力为3 000g,离心时间为10,15和20 min所提的胞间隙液量最大,且均检测到Rubisco的污染。结合胞间隙液的产率确定小麦叶片胞间隙液提取最佳的离心条件应为离心力1 000~2 500 g,时间15~20 min。     

适度水分胁迫提高黄瓜幼苗光合作用弱光适应性

以黄瓜（Cucumis sativus L.）‘戴多星’品种为试材,在人工气候室内研究弱光（75 ~ 85 μmol · m-2 · s-1）下水分胁迫（40%基质最大持水量）对幼苗叶片光合、荧光特性及Rubisco含量的影响。结果表明,弱光逆境下,经20 d水分胁迫后的幼苗较正常水分条件下叶片光合色素（以单位面积计）含量提高,叶绿素a/b（Chl.a/b）下降,植株光饱和光合速率Asat、表观量子效率（AQY）、羧化效率（CE）、RuBP最大再生速率及光饱和点（LSP）均显著增加,CO2补偿点（CCP）显著下降,并且光系统Ⅱ（PSⅡ）最大光化学效率（Fv/Fm）、潜在光化学效率（Fv/Fo）、PSⅡ光化学量子效率（ΦPSⅡ）、光化学反应速率（Prate）、非环式电子传递速率（J）以及PSⅡ吸收光能向光化学反应分配比例P等叶绿素荧光参数呈增加趋势,PSⅠ和PSⅡ间激发能分配不平衡性（β / α–1）减小,叶片可溶性蛋白质含量和Rubisco大、小亚基含量上升,表明适度的水分胁迫有利于提高弱光下黄瓜幼苗的光合适应性;而正常光照下（500 ~ 600 μmol · m-2 · s-1）经水分胁迫后的黄瓜幼苗上述主要光合特性指标如Asat、RuBP最大再生速率、CE、ΦPSⅡ、Prate、J和P等有所下降,光系统间激发能分配不平衡性（β / α–1）增加,光合作用受到一定抑制。     

内源水杨酸参与黄瓜叶片光合系统对低温胁迫的响应

 为了探讨内源水杨酸（salicylic acid,SA）在黄瓜幼苗光合系统响应低温胁迫中的作用机制, 采用高效液相色谱法测定低温下黄瓜叶片中内源SA 含量的变化;通过SA 合成抑制剂Paclobutrazol（Pac, 100 μmol · L^-1）喷施和外源SA（50 μmol · L^-1）饲喂的方法调节内源SA 含量,并测定不同处理幼苗的叶 绿素荧光参数和光合碳同化关键酶基因的转录水平。结果显示：低温引起黄瓜幼苗内源SA 含量升高,Pac 预处理抑制SA 的积累。低温导致PSⅡ的最大光化学效率（F v/F m）、实际光化学效率（Φ PSII）、潜在光化 学活性（F v/F o）和光合电子传递效率（ETR）等降低,叶片光化学猝灭参数[（Y（NO）]升高;内源SA 含量降低使PSⅡ活性下降幅度增大,加重了叶片的光损伤程度。低温下PSⅡ吸收的光能分配于光反应的 部分减少,而以非光化学反应的过剩能量耗散Ex 为主要的光能分配途径,内源SA 含量降低会加剧光能 向Ex 的分配。低温时喷施Pac 的幼苗中Rubisco 小亚基基因（RbcS）和碳酸酐酶基因（CA）的表达水平 显著低于对照植株。对喷施Pac 的幼苗外源饲喂SA 后,内源SA 含量升高,低温下叶片光合活性得到有 效恢复,光损伤降低,光能分配趋于合理,RbcS 和CA 的表达水平升高。上述结果表明,低温下内源SA 的积累有助于维持黄瓜叶片中较高的光系统活性和碳同化能力,从而保护光合系统,降低低温胁迫对植 物的损伤。     

29种中药提取物抗结核药物敏感性研究

本研究选取29种对结核分支杆菌和其他呼吸疾病有治疗作用生长在中国的药用植物,通过MABA (Microdilution alamar blue assay) 药敏实验方法检测了这些药物的乙醇和水提取物对结核分支杆菌M. tuberculosis H37Rv的敏感性。筛选到金银花、大蓟、小蓟和水车前等有显著的抗结核活性,为进一步考查其单体化合物的作用机制和有新型作用机制的抗结核药物开发打下基础。     

香菇菌株的脱毒研究

香菇具独特香味且有多种保健功能,是我国栽培的主要食用真菌之一。但近些年我国大陆部分产区出现了不同程度的香菇病毒病,使香菇的产量和质量受到明显影响,重者绝收,损失严重。通过试验发现病毒在香菇中是普遍存在的。本文选取3株带毒香菇菌株,采用菌丝尖端挑取法（挑取长度小于0.2mm的菌丝尖端）进行脱毒。结果显示：通过菌丝尖端挑取法,获得一株无毒菌株（不含dsRNA条带）,和一些未完全脱毒菌株（含1条11kb的dsRNA）。对脱毒不彻底菌株、脱毒彻底菌株以及带毒菌株分别进行了生物学特性,纤维素酶、木聚糖酶、漆酶和多酚氧化酶活性的测定,发现在pH值8时,脱毒菌株的生长速度比带毒菌株快,脱毒菌株的漆酶和多酚氧化酶活性明显大于带毒菌株,而纤维素酶和木聚糖酶则没有显著区别。通过栽培实验,发现：三个菌株的子实体产量没有显著差别。     

Chilling Stress Accelerates Degradation of Seed Storage Protein and Photosynthetic Protein during Cotton Seed Germination

Low temperature is one of the major abiotic stresses limiting the productivity and geographical distribution of many important crops. To gain a better understanding of chilling stress responses in cotton ( Gossypium hirsutum L . ), we carried out a comparative proteomic analysis. Cotyledon proteins of 1-week-old cotton seedlings treated with or without chilling treatment at 4 °C were extracted, separated by a two-dimensional gel electrophoresis and compared. Among 1500 protein spots reproducibly detected on each gel, 25 protein spots were down-regulated and 29 were up-regulated. Seven cotton proteins were identified by mass spectrometry analysis as beta-globulin A precursor fragments. One was identified as a Rubisco large subunit fragment, providing evidence of both seed storage protein and photosynthetic protein destruction by chilling stress. The related physiological and biochemical analysis showed that there was a significant increase in endopeptidase activity and activated oxygen generation rate, and an obvious decrease in carboxylation efficiency and maximum net photosynthetic rate of cotton seedlings under chilling stress. Based on the above results, the degradation mechanisms of beta-globulin and Rubisco under chilling stress were discussed. In conclusion, our study provides new insights into chilling-stress responses in cotton and demonstrates the advantages of proteomic analysis.     

超高产水稻生育后期剑叶光合生理特性变化的研究

笔者研究了黑龙江省第一积温带5个产量不同的主栽品种生育后期剑叶叶绿素含量、净光合速率和RuBP羧化酶活性变化规律。结果表明：超高产品种生育后期的剑叶叶绿素含量、光合速率和RuBP羧化酶活性均高于常规品种,品种间差异显著。因此,将剑叶生育后期叶绿素含量、净光合速率和RuBP羧化酶活性的变化研究,作为寒地粳稻高光效育种和超高产育种中的一项措施是可行的。     

超高产水稻生育后期剑叶光合生理特性变化的研究

笔者研究了黑龙江省第一积温带5个产量不同的主栽品种生育后期剑叶叶绿素含量、净光合速率和RuBP羧化酶活性变化规律.结果表明:超高产品种生育后期的剑叶叶绿素含量、光合速率和RuBP羧化酶活性均高于常规品种,品种间差异显著.因此,将剑叶生育后期叶绿素含量、净光合速率和RuBP羧化酶活性的变化研究,作为寒地粳稻高光效育种和超高产育种中的一项措施是可行的.     

盐胁迫对黄瓜幼苗光合作用及其关键酶基因表达特性的影响

以对盐胁迫敏感性不同的两个黄瓜品种中农大22号和戴多星为材料,研究了盐胁迫下黄瓜幼苗叶片光合特性、叶绿体超微结构以及光合作用关键酶1,5-二磷酸核酮糖羧化酶/加氧酶(Rubisco)和磷酸烯醇式丙酮酸羧化酶(PEPC)活性及其编码基因表达的变化。结果表明:盐胁迫(150 mmol·L~(-1)NaCl处理)下,黄瓜幼苗光合色素(叶绿素和类胡萝卜素)含量、净光合速率、暗呼吸速率和蒸腾速率显著降低;叶绿体类囊体片层结构垛叠程度下降,淀粉粒变小且数量减少;Rubisco大亚基编码基因rbc L、PEPC编码基因Csppc2的表达水平先响应性上调,随后下降;Rubisco和PEPC活性呈降低趋势。相对中农大22号,戴多星具有较强的盐胁迫耐受性。     

Root restriction-induced limitation to photosynthesis in tomato (Lycopersicon esculentum Mill.) leaves

Root restriction often depresses photosynthetic capacity and the mechanism for this reduction, however, remains unclear. To identify the mechanism by which root restriction affects the photosynthetic characteristics, tomato (Lycopersicon esculentum Mill.) seedlings were subjected to root restriction stress with or without supplemental aeration to the nutrient solution. With the development of the root restriction stress, CO₂ assimilation rate was decreased only in confined plants without supplemental aeration. There were also significant decreases in leaf water potential, stomatal conductance (g_s), intercellular CO₂ concentration (C_i), and increases in the stomatal limitation (l) and the xylem sap ABA concentration. Meanwhile, the maximum carboxylation rate of Rubisco (V_cmax) and the capacity for ribulose-1,5-bisphosphate regeneration (J_max) also decreased, followed by substantial reductions in the quantum yield of PSII electron transport (Φ_PSII). Additionally, root restriction resulted in accumulation of carbohydrates in various plant tissues irrespective of aeration conditions. It is likely that root restriction-induced depression of photosynthesis was mimicked by water stress.