竹柏2种颜色叶片的光合特性研究

为了解竹柏(Podocarpus nagi)的光合特性,以3 a生全绿叶和花叶竹柏为材料,测定其光合色素含量和气体交换参数。结果表明,全绿叶竹柏叶片的叶绿素a、叶绿素b、类胡萝卜素、叶绿素a+b、叶绿素a/b和叶绿素a+b/类胡萝卜素均显著高于花叶竹柏;全绿叶竹柏叶片的初始量子效率、最大光合速率和暗呼吸速率均显著高于花叶,而光饱和点和光补偿点均显著低于花叶;全绿叶竹柏叶片的初始羧化效率、光合速率、CO2饱和点和光呼吸速率均高于花叶,而CO2补偿点低于花叶。2种颜色叶片的气孔导度、蒸腾速率和水分利用效率均随着光合有效辐射的增大而增大,且均表现为全绿叶花叶,而胞间CO2浓度则相反,表现为花叶全绿叶。因此,全绿叶竹柏利用弱光的能力强于花叶竹柏,而花叶竹柏利用强光的能力更强,在园林绿化配置中,可根据2种颜色叶片的光合特性合理配置。     

细菌的光合器与光合色素

大部分细菌无叶绿素,不能进行光合作用,但也有相当一部分细菌能够利用光作为能源、利用CO2作为碳源、以无机物作为供红体还原CO2合成生活所需的有机物质,这些细菌称之为光合细菌。光合细菌又根据它们在光合作用过程中的供氢体是无机物还是有机物而分为两类光合营养型。以无机物为供氢体的光合细菌称为光能自养型;以有机物为供氢体的光合细菌称为光合异养型。属于光能自养型的细菌例如绿硫细菌,其光合作用过程同高等绿色植物的光合作用过程相似,所不同的是高等绿色植物光合作用是以水作为CO。的还原剂,同时放出O。;而在绿硫细菌光…     

蓝藻的光合器与光合色素

蓝藻是地球上一类非常古老的生物,距今已有2．5XIc’a以上的历史。它们也是地球上最早以水和CO。为原料进行光合作用,合成有机物并释放（）z的生物。那么,蓝藻光合器的结构和化学组成是怎样的？它们是如何进行光合作用的？正蓝藻光合器的结构蓝藻细胞的结构和细菌非常相似,它们都属于原核生物,无核膜,也无叶绿体。在光学显微镜下,可观察到蓝藻细胞的原生质内有无色的中心质（entr。…。sin）和着色的色素质t仇。－mafoplastn）部分,其中色素质因含有色素能进行光合作用。在电镜下能够观察到色素质中有许多囊状的扁平结构,被称为…     

光合单位的周转率与叶片光合速率的关系

利用闪光技术,测得若干高等植物叶片的光合单位为 1450～2050 Chl/CO_2。在含O_2 2％及CO_2浓度和光通量密度都饱和的条件下,测得叶片的连续光合速率为25～70μmol CO_2 m~(-2) s~(-1)。从上述数据及叶片叶绿素含量计算,得叶片光合单位的周转率已达80～160次/s。这样的周转速率与Emerson当初用改变闪光间暗间隔而测到的光合单位周转时间相似(即<10 ms/次,或>100次/s),从而证实了光合单位的周转与光合速率直接有关。这样的速率可称之为叶片光合的理论速率。     

铁和镍对光合细菌生长和产氢的影响

基于金属元素在生物体功能发挥中的作用以及它们参与光合细菌光合放氢的重要性,着重进行了铁和镍对沼泽红假单胞菌（Rhodopseudomonas palustris）Z菌株和一株红杆菌（Rhodobactersp.）细胞生长、光合放氢和光合色素合成影响的研究。结果表明,高浓度Fe3+可显著提高两菌株光放氢能力和生物合成能力,最适浓度的Fe3+可使其产氢能力分别达对照组的1.32倍和2.8倍,产氢得率分别为360.6mL/g和385.9 mL/g,生物量分别为对照组的1.42倍和1.54倍。9μmol/L Ni2+的添加可使两菌株产氢能力分别达对照组的1.48倍和1.96倍,产氢得率分别为429.7mL/g和456.3 mL/g。而当Ni2+浓度为12μmol/L时,两菌株的产氢活性受到不同程度的抑制,产氢得率分别降低46.7%和19.4%。在铁浓度相同时,添加6μmol/L Ni2+能明显促进两菌株的生长。而当Ni2+浓度大于6μmol/L时,细胞生长受到抑制。Fe3+和Ni2+对Rhodobactersp.菌株类胡萝卜色素有显著影响。研究结果显示, 426nm色素峰随铁浓度的增加和镍的添加而消失,同时,产氢活性提高。     

不同品质类型小麦非叶光合器官光合荧光特性研究

以强筋(郑麦9023)、中筋(新麦13)和弱筋(豫麦50)型小麦品种为试材,测定了它们非叶光合器官的叶绿素含量、荧光动力学参数、净光合速率及对籽粒的贡献率.结果显示,不同品质类型小麦非叶光合器官叶绿素含量表现为旗叶鞘>穗下节间>芒>穗部颖片,各非叶光合器官开花18d后叶绿素含量均表现为弱筋小麦>中筋小麦>强筋小麦;弱筋小麦的非叶光合器官在灌浆前期具有较高的Fv/Fm、ΦPSⅡ值,在灌浆后期其Fv/Fm和ΦPSⅡ值下降幅度显著小于强筋小麦并有较高的净光合速率;非叶光合器官对籽粒的相对贡献率依次为穗部>旗叶>节鞘,且对弱筋小麦籽粒的贡献率高于中筋和强筋小麦,其中节鞘和穗对弱筋小麦粒重的相对贡献率分别为15.7%和35.4%.研究表明,弱筋小麦豫麦50的非叶光合器官能维持较较强的光合能力,生产更多的光合产物,花后形成的光合产物对其粒重的增加起重要作用.     

过量施氮对冬小麦生产力的影响

设置0、70、140、210和280 kg N·hm ^-2 5个施N梯度, 对冬小麦(Triticum aestivum)旗叶光合速率(A_leaf)、群体冠层光合速率(A_canopy)、作物生长速率(CGR)和籽粒产量(GY) 4个生产力水平进行综合观测研究, 结果发现: 在0-210 kg N·hm ^-2区间, A_leaf、A_canopy、CGR和GY都随施N量的增大而增大; 在施N量由210增加到280 kg N·hm ^-2时, GY没有显著变化, 而灌浆期A_leaf、开花期和灌浆期A_canopy、开花-成熟阶段CGR有显著减小。综合分析认为: 1)过量施N (280 kg N·hm ^-2)能显著降低灌浆期冬小麦A_leaf、A_canopy和CGR, 进而抑制GY; 2)过量施N对冬小麦光合生产力的抑制作用主要发生在灌浆期; 3)在A_leaf、A_canopy、CGR和GY 4个生产力指标中, A_canopy对过量施N的反应最敏感。     

光合细菌对小麦生长和光合功能的影响

【目的】探明光合细菌对小麦生长、产量及光合功能的影响。【方法】以尧麦16为材料,在不同生长时期施用光合细菌,研究光合细菌对小麦生长、产量及光合功能的影响。【结果】光合细菌培养液的不同成分可提高小麦旗叶SPAD值、光合速率及干物质积累。拔节期施用后,混合菌液对叶片SPAD含量促进作用最大,较不施用对照提高33.6%,小麦干物质积累较对照增加25.7%,单株籽粒重量增效为14.3%。单菌株实验处理中沼泽红假单胞菌促进作用最强,干物质积累和单株籽粒重量较培养基稀释液对照增效均为13.1%。不同施用时期的结果表明沼泽红假单胞菌对灌浆期和拔节期小麦促进效应最强,其中静息细胞可延长叶片功能期,使光合产物持续增加;无细胞培养液通过促进小麦营养生长,进而提高小麦产量。【结论】光合细菌可促进小麦生长,有效提高小麦生育过程中相关光合功能;施用时期应为小麦拔节期和灌浆期;光合细菌对小麦生长和产量促进作用是静息细胞和代谢活性物质综合作用的结果。     

TURNOVER OF PHOSPHATIDYLCHOLINE IN MICROSOMES AND MYELIN IN BRAINS OF YOUNG AND ADULT RATS

We have tested the hypothesis that the turnover of phosphatidylcholine in subcellular fractions of rat brain is a function of the age at which this lipid is deposited. Rats, 60 days of age, were injected intracranially with [2-³H]glycerol and either [methyl-¹⁴C]choline (to label the base moiety) or [U-¹⁴C]glucose (to label acyl moieties). Littermates were killed up to 90 days after injection and brain microsomes and myelin isolated. Lipids were extracted and the phosphatidylcholine was isolated by 2-dimensional TLC and hydrolyzed to its constituent moieties. The ³H in the glycerol backbone and ¹⁴C in the choline or acyl residues was quantitated. The microsomal and myelin ³H/¹⁴C ratios decreased with time with either set of precursors, indicating that labeled choline and acyl moieties were reutilized more efficiently than the glycerol backbone. The various precursors exhibited first order decay curves with half-lives for the glycerol backbone of 6 and 11 days for the microsomal and myelin fractions respectively. These results contrast with those previously obtained with identical experimental procedures when 17-day-old animals were injected. In that study, although much of the phosphatidylcholine turned over rapidly as for the older animals, by 2 weeks after injection most of the remaining phosphatidylcholine was turning over more slowly with a half-life of 13 and 25 days for microsomes and myelin respectively (Miller et al., 1977). The base and acyl moieties also had a corresponding shorter half-life in older animals relative to the slow turnover phase in younger rats.     

合成洗涤剂对人和哺乳动物细胞的诱变性研究

各种合成洗涤剂(洗衣粉,洗发膏,餐具洗涤剂等)产量日增。在日常生活中使用越来越普遍。洗涤剂直接或间接通过环境污染对人类健康产生影响,特别是潜在的致突变性引起公众的普遍注意。而现有的研究结果并不一致。本研究选用三种型号的合成洗涤剂,以小鼠生殖细胞染色体畸变和骨髓细胞微核率及离体的人类细胞和中国仓鼠细胞的染色体畸变和姐妹染色单体交换(SCE)为测定指标,系统地对合成洗涤剂的诱变活     

大鼠颌下腺促性腺激素释放激素及其mRNA的免疫组织化学与原位杂交研究

用免疫组织化学及原位杂交法,研究了促性腺激素释放激素及其ｍＲＮＡ在大鼠颌下腺的分布。结果显示,大鼠颌下腺的浆液性腺泡的上皮细胞,各级导管的上皮细胞及副交感神经节细胞均呈促性腺激素释放激素免疫反应阳性,阳性反应物质分布在胞质,胞核呈阴性反应。颌下腺的浆液性腺泡上皮细胞,各级导管上皮细胞同样被检测到很强的促性腺激素释放激素ｍＲＮＡ杂交信号。以上结果提示,大鼠颌下腺能自身合成促性腺激素释放激素,促性腺激素释放激素对消化功能可能有重要调节作用。     

武汉东湖沉积物和沉积物间隙水中氮和磷的含量及其分布

武汉东湖的沉积物中氮(N)的平均含量上层(0—10厘米)为14．2毫克／克(干重,下同),下层(10-40厘米)为12．0毫克／克。磷(P)的平均含量上层为0．87毫克／克,下层为0.62毫克／克。沉积物中氮和磷的含量均有明显的垂直和平面分布上的差异,上层高于下层,水果湖区高于其它湖区。沉积物间隙水中总溶解氮的浓度高,平均为儿．52毫克／升,主要以氨氮的形态存在,占总溶解氮的61．3％。总溶解磷的浓度较低,平均为0．113毫克／升,其中正磷酸盐占55.8％。间隙水中氮和磷的浓度均有明显的季节变动,夏季和秋季的浓度高,冬季和春季浓度低。除氨氮外,间隙水中氮和磷的浓度比底层湖水中氮和磷的浓度高,但一般不超过5倍,表明沉积物和湖水之间溶解的营养物质交换十分强烈。     

DEVELOPMENTAL CHANGES IN LEVELS AND FORMS OF CHOLINESTERASES IN MUSCLES OF NORMAL AND DYSTROPHIC CHICKENS

Abstract— Acetylcholinesterase (AChE) and pseudocholinesterase (°ChE) were studied in vivo and during the first several months of development of pectoral and posterior latissimi dorsi (PLD) muscles in normal and dystrophic chickens. Muscle extracts were prepared in a high ionic strength-nonionic detergent medium in the presence of protease inhibitors, in order to obtain complete solubilization and to prevent degradation of intrinsic molecular forms of both enzymes. In both normal and dystrophic pectoral muscles levels of AChE and °ChE increase rapidly in vivo, °ChE accounting for 5–10% of total cholinesterase activity. In the normal pectoral muscle the concentration of both enzymes drops rapidly after hatching with increasing muscle mass; total AChE per muscle remains relatively constant for 30 days post-hatch. In the dystrophic pectoral muscle both AChE and °ChE accumulate after hatching, resulting in greatly elevated levels (approx 10–25-fold) of both enzymes throughout the period studied. Multiple molecular forms of AChE and °ChE are observed in the pectoral muscle by sucrose gradient centrifugation. Four principal forms are distinguished: two light (L₁, L₂), one medium (M), and one heavy (H₂). The °ChE forms are 0.5–1.0 S units lighter than the corresponding AChE forms. L₂ is the predominant light form of AChE, whereas L₁ is the major light °ChE form detected. The lighter forms of AChE predominate in normal and dystrophic embryonic pectoral muscle at day 14, being replaced by the H₂ form by day 19. H₂ is the major °ChE form detected at day 19. After hatching, H₂ AChE is the predominant form found in both of the normal muscles studied. In the dystrophic pectoral muscle, progressive accumulation of the L₂ form of AChE is detected as early as day 4 post-hatch; this form eventually becomes predominant, although the heavier forms are also elevated. In PLD muscle the same phenomenon occurs, but with a slower time course. In dystrophic pectoral muscle a similar rise in the L₁ form of °ChE is first observed by day 4, with heavier forms also elevated in the mature muscle. Thus the alteration in the control of these two enzymes in dystrophic fast-twitch muscles results in an accumulation of the light forms of AChE and °ChE.     

VASCULAR SUPPLY AND STRUCTURE OF THE OVULE AND ARIL IN PEONY AND OF THE ARIL IN NUTMEG

Camp , Wendell H., and Mary M. Hubbard . (U. Connecticut, Storrs.) Vascular supply and structure of the ovule and aril in peony and of the aril in nutmeg. Amer. Jour. Bot. 50(2): 174–178. Illus. 1963.—Examination of the placental region in the carpel of Paeonia indicates a complexity and super-abundance of vascular supply beyond that usually found in angiosperms and certainly more than is necessary for adequate nutrition and water supply of the ovules. From this it is concluded that the ovules once were borne on a larger and more complex structure than the present carpel. Vascular strands leading to the aril and the hypostase are interpreted as being relictual. The large multifid aril of Myristica has a well-developed vascular system composed of several sizes of branched bundles.     

CORRELATION OF OXIDATION AND PHOSPHORYLATION IN HEMOLYZED BLOOD IN PRESENCE OF METHYLENE BLUE AND PYOCYANINE

1. The system:hemolyzed blood + glucose never exhibits glycolysis or, in the air, oxidation of glucose. When glucose is replaced by hexosephosphate ester, addition of methylene blue causes oxidation in air. 2. When cozymase is added also, the oxidation is increased, and a synthesis of hexosephosphate esters takes place. 3. When pyocyanine is used instead of methylene blue, the rate of oxidation is the same as with methylene blue, but a synthesis of phosphate esters takes place without addition of cozymase. 4. There is never a phosphate ester synthesis without oxidation going on, but oxidation does not necessarily go hand in hand with phosphate synthesis. 5. In order to couple the oxidation process with phosphate synthesis, two methods are available: either to start oxidation by methylene blue and to add coenzyme from yeast cells; or to start oxidation by pyocyanine, in which case coenzyme is unnecessary, though it improves the effect. 6. Iodoacetate always suppresses synthesis, but only under certain conditions decreases oxidation. Cyanide has no effect upon either process.