MORPHOGENESIS OF MONOSTROMA OXYSPERMUM (KÜTZ.) DOTY (CHLOROPHYCEAE) IN AXENIC CULTURE,ESPECIALLY IN BIALGAL CULTURE1

The typical morphology of Monostroma oxyspermum (Kütz.) Doty is lost in axenic culture. In synthetic media of the ASP type, it grows as a colony-like mass composed of round cells with numerous rhizoids. Such a mass is a fragile structure which falls apart upon shaking, or slight touch, into small cell-groups and single cells or cells with a long rhizoid. Only temporary saccate or monostromatic fronds appear and reach 1–2 mm in length when grown in enriched seawater media, but disintegrate and become a colony-like mass. The typical morphology is easily restored by adding at specific intervals filtrates of bacterial cultures and supernatant medium from axenic brown and red algal cultures to the basal medium (ASP7), or by reinfecting the Monostroma with an appropriate bacterial flora. Furthermore, the typical morphology in also maintained by bialgal cultures between Monostroma and other axenic strains of various species of seaweeds except the species belonging to the Chlorophyceae. Monostroma thus appears to utilize some substances released by most species of brown and red algae for its typical growth. Active substances released by bacteria, brown and red algae have not yet been identified and purified. However, it is demonstrated that in axenic cultures many species of seaweeds produce active extracellular substances which play an important role in growth and Morphogenesis of other species of seaweeds.     

武汉东湖磷含量的变动及其分布

本文总结了武汉东湖水体中磷含量（均以PO4计算）的周年逐月季节和年际变动及其分布上的差异（1973－1985年）。按面积加权法计算总磷的平均含量为0．244毫克／升（1983－1985年）,总溶解磷和溶解活性磷的平均含量分别为0．121毫克／升和0．051毫克／升（1981－1984年）,总磷和总溶解磷周年中出现两次高峰含量,即春季（3－5月）和夏末秋初（8－9月）。低含量出现在水温最低的冬季（12－2月）,周年中溶解活性磷高峰含量出现在冬末春初（1－3月）,低含量多数出现在春天夏初（5－7月）。东湖水体中磷含量平面分布有明显的差异,而垂直分布表层和底层差异小,各种形态磷的组成中颗粒磷所占比较最大（1983－1984年平均值）,平均占总磷63．4％,溶解非活性磷所占比较最小,平均占总磷12．0％。     

ASCOPHYLLUM NODOSUM (PHAEOPHYTA) IN AXENIC CULTURE AND ITS RESPONSE TO THE ENDOPHYTIC FUNGUS MYCOSPHAERELLA ASCOPHYLLI AND EPIPHYTIC BACTERIA1

Ascophyllum nodosum (L.) Le Jol. was freed from bacteria and the endophytic fungus Mycosphaerella ascophylli Cotton by repeated treatment with chlorine solutions and grown in artificial seawater. Two types of axenic culture of different origin were obtained. Type 1 was developed from apices of A. nodosum collected in the sea. Type 2 was from plants which developed from adventitious embryos on rhizoids formed by type 1. This is the first time A. nodosum has been cultivated axenically. Growth of the axenic alga was increased by IAA, 21P and zeatin. Without external growth regulators some strains of the axenic alga deteriorated within a year; others developed a filamentous habit. Sulfur in a reduced state also stimulated growth. Addition of either glucose, mannose or mannitol to the medium caused the formation of calluslike layers of loosely packed colorless cells under the epidermis of the thalli and the epidermis was sloughed off. No increase in thallus length was noticed. Mycosphaerella ascophylli in axenic culture did not excude any substances stimulating growth of the alga, but that does not exclude an influence of the fungus on the alga in vivo. The fungus, when growing within the alga, seemed to have little influence on algal morphology. A bacterized but fungus-free A. nodosum was cultivated in an artificial seawater for 8 years. In the bacteria-free alga, the fungus protruded from the epidermis and evidently utilized the alga as a carbon source. The bacteria thus seem much more important than the fungus for normal growth of the Ascophyllum plant.     

POLYMORPHIC BEHAVIOR OF ULVA LACTUCA (CHLOROPHYTA) IN AXENIC CULTURE. I. OCCURRENCE OF ENTEROMORPHA-LIKE PLANTS IN HAPLOID CLONES1

An isolate of Ulva lactuca L. was brought into axenic culture in both defined synthetic medium and enriched seawater. Haploid clones were established and followed through several generations in both media. Plants possessing distromatic, partially distromatic or completely tubular blades in cross sections, as well as individuals that were completely distromatic in one area of the blade and tubular in another all developed from the same swarmer population. Variations in basal area morphology also occurred. Progeny from swarmers of any of these morphological types showed a similar mixture of morphological variation, indicating non-mutational variability in phenotypic expression of the blade and basal areas. A mechanism by which such variation may occur without mutation is discussed.     

COMPETITION FOR PHOSPHORUS AMONG PLANKTONIC DESMID SPECIES IN CONTINUOUS-FLOW CULTURE1

When grown under stringent P limitation, affinity for P uptake and growth in Staurastrum pingue Teil. and Staurastrum chaetoceras (Schr.) G. M. Smith (both originating from eutrophic lakes) were of the same magnitude, whereas these parameters for Cosmarium abbreviatum Rac. var. planctonicum W. & G. S. West (isolated from a meso-oligotrophic lake) were significantly higher in value. On the other hand, at all growth rates tested, maximum P uptake rates were lower in C. abbreviatum than in the two Staurastrum species. The outcome of competition between either Staurastrum species and C. abbreviatum in mixed chemostats under different levels of continuous P limitation was in agreement with what could be predicted from the species-specific affinity parameters: Staurastrum was outcompeted at dilution rates lower than 0.012 h^?1, calculated to correspond with external inorganic P concentrations lower than 0.02 μM P, but won out at higher dilution rates. When P was added in two pulses of 2.5 μmol · L^?1 a week instead of continuously, S. chaetoceras outcompeted C. abbreviatum at a slow rate. When P was supplied as a daily pulse of 0.7 μmol · L^?1, a stable coexistence of S. chaetoceras and C. abbreviatum was established, Staurastrum predominating the culture in cell numbers at ca. 85%. The results show that P uptake and growth characteristics of the three species can predict the outcome of competition under various P-limited conditions. Specific growth kinetic parameters as found in this study may also explain distribution patterns of the species observed in the field.     

海马神经元乙酰胆碱激活通道在不同培养期的功能特性

用膜片箝技术对不同培养期的新生大鼠海马神经元上乙酰胆碱受体单通道特性进行了研究,结果表明不同培养期ＡＣｈ激活通道的电学特性不同。培养早期（１－２ｄ）,２０ｐｓ通道占优势,开放以单个短开放事件为主,平均开放时间小于２ｍｓ．培养后期（１８－２１ｄ）３１,ｐＳ通道为主,开放随膜片的不同可分成两类,即单个短开放（时间常数为０．３５ｍｓ和１．２９ｍｓ）和簇状开放（时间常数为１．１５ｍｓ和９．６ｍｓ）,同时也     

SOME ASPECTS OF THE DISTRIBUTION OF REACTIVE PHOSPHORUS IN LAKE McILWAINE,RHODESIA: PHOSPHORUS LOADING AND ABIOTIC RESPONSES

SUMMARY

This study was designed to investigate the apparent loss from the water column in Lake McIlwaine This study of significant quantities of reactive phosphorus. The Total Reactive Phosphorus mass-balance for the lake for 1977/78 was calculated, and both in situ and laboratory experiments were carried out to determine the effect of the lake sediments on the phosphorus loading of the lake. The experimental results showed that both uptake and release of phosphorus occurs in the lake, but that uptake of phosphorus by the sediments was by far the dominant process, thus accounting for the observed loss of phosphorus from the water column. The availability of the bound phosphorus for algal growth was also studied and it is suggested that algal uptake of bound phosphorus is possible. Various factors affecting phosphorus uptake by the sediments are discussed.     

不同波长的光对佛甲草离体茎段培养过程中生长发育的影响

植物的正常个体发育过程中都存在着一个受光控制的光形态建成过程。光作为植物组织培养中的一个调控因子,已有报道。本实验通过对佛甲草的不同波长的光处理,比较其形态发生及生理生化指标。佛甲草为一种药用植物,本实验为建立佛甲草茎段培养的理想诱导模式提供了初步的资料。     

水华蓝藻噬藻体对不同条件培养的宿主细胞感染性分析

在从武汉东湖水样中培养分离水华蓝藻噬藻体(Planktothrix agardhii Virus from Lake Donghu,PaV-LD)的基础上,对在不同条件培养的宿主蓝藻细胞中,PaV-LD增殖效率及裂解作用进行了测定分析。分别将PaV-LD接种到生长期、半连续培养更新率或光照不同的宿主蓝藻液中,并采用稀释培养计数(Mostprobable number,MPN)方法与电镜观察,测定子代PaV-LD释放量及宿主细胞的裂解作用。结果显示:对数生长期宿主蓝藻单个细胞中子代PaV-LD的平均释放量为350感染单位(Infectious Units,IU/cell),显著高于稳定生长期的平均释放量110 IU/cell。在用新鲜培养基更新率为0%、35%、50%和65%的半连续培养宿主蓝藻中,接种PaV-LD 5d之后,噬藻体的释放量分别约为50 IU/cell、70 IU/cell、220 IU/cell或310 IU/cell,表明子代PaV-LD释放率随培养基更新率的增加而显著提高。在光照条件下感染3—4d后,宿主蓝藻细胞充分裂解,并释放大量子代PaV-LD,滴度可由初始7.00×103IU/mL快速增加到8.56×107IU/mL;但在遮光条件下,同样感染的蓝藻细胞未见裂解,也检测不到释放的子代噬藻体。电镜观察显示,在光照条件下感染的蓝藻细胞类囊体膜结构消失,而大量子代PaV-LD颗粒主要分布在原有类囊体的部位。显然,宿主蓝藻细胞的培养条件和状态可能对获得噬藻体纯培养有决定性影响。     

向日葵幼胚培养中体细胞胚胎发生的观察

1.向日葵不同品种体细胞胚胎发生的情况不同。2.较高浓度的蔗糖有利于向日葵幼胚的体细胞胚胎发生。3.在同样条件下,2mm长的幼胚较其它时期的幼胚体细胞胚胎发生的频率高。4.在蔗糖浓度为17.5％并分别加入0.5—10.0ppm玉米素的Nitsch培养基中,向日葵幼胚产生体细胞胚胎发生的频率随着玉米素浓度的增高而增加。5. 2,4-D能使体细胞胚胎发生,但不能分化器官。6.切片观察表明:在含玉米素的培养基上,幼胚产生了胚性细胞团和胚状体。并多数发生于子叶与下胚轴的深层。胚性细胞团周围细胞退化,使其与周围组织之间形成间隙。     

三分三悬浮培养细胞中苯丙氨酸、鸟氨酸和莨菪碱至东莨菪碱的生物转化

在三分三悬浮培养中分别补充前体苯丙氨酸、鸟氨酸和莨菪碱时,悬浮细胞的生长速率及东莨菪碱的转化率均以补充苯丙氨酸者为最高,分别比未加前体的对照增加50.2％和4.0％。 在上述处理培养两周后于培养液中分别加入70ppm的放线菌酮抑制蛋白质合成时,虽然细胞中东莨菪碱的转化按克干重计算均有明显增加,但是由于细胞生长受强烈抑制不利于东莨菪碱的总的转化,按每瓶总干重计算的转化率均比对照低。 在分别补充三种前体并培养两周后使营养缺乏时,细胞生长比对照稍有降低,但细胞中东莨菪碱的转化却显著增加。特别是补充莨菪碱并使营养缺乏时,大大利于莨菪碱转化为东莨菪碱,转化率高达27.4％。既降低了培养成本又提高了东莨菪碱产量,有利于未来的工业生产。     

植酸对红豆杉细胞悬浮培养影响作用的研究

针对红豆杉细胞培养中经常遇到的褐变问题,以植酸做抗氧化剂,添加到悬浮细胞培养基中,能提高细胞鲜重,明显抑制细胞多酚氧化酶和过氧化物酶活性,从而有效地控制细胞褐变,促进红豆杉悬浮细胞生长。以005%浓度的添加效果最好。