云南松外生菌根真菌分离培养研究

就滇中一带云南松林进行了多次调查,共采集、鉴定标本130余号;从中选取13科, 19属, 33种真菌进行了菌种分离、培养的研究。选用并修改4种培养基进行了外生菌根真菌分离、培养的比较,结果共有11科, 17属, 25种真菌分离获得成功,成功率高达75.8%, 4种培养基的分离成功率依次为36.4%、63.6%、33.3%和57.6%。其中,修改PDA培养基和松针、玉米培养基较适宜于云南松外生菌根真菌的分离、纯化和培养。     

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.     

红茶菌抗菌蛋白产生方式的初步研究*

从红茶菌液中分离得到膜醋酸菌与裂殖酵母。采用单菌培养与混合菌培养,探讨了各菌对红茶菌抗菌蛋白的产生所起的作用。初步推断,裂殖酵母先合成相关蛋白,该蛋白经膜醋酸菌产生的酶修饰后,抗菌活力显著提高。不同属酵母与膜醋酸菌共培养,结果表明裂殖酵母优于其它酵母。     

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％。     

DISSECTING THE PHYSIOLOGICAL RESPONSE TO PHOSPHORUS STRESS IN MARINE SYNECHOCOCCUS ISOLATES (CYANOPHYCEAE)1

Marine Synechococcus is ubiquitous in aquatic environments. However, distinct phylogenetic lineages of this genus have a complex ecological distribution that is not fully explained. Here, we undertook a broad study of the phosphorus (P)–related behavior of marine Synechococcus isolates from all previously described ribotypes (sensu Fuller et al. 2003 ). A wide variability in P‐related physiology was noted among members of this genus, particularly in the utilization of organic P sources. However, some characteristics (e.g., cell size change during P limitation and the ability to accumulate polyphosphate) were largely consistent with their phylogenetic lineage and inferred ecology, with clear distinctions between oligotrophic, mesotrophic, and opportunistic lineages. Similarly, the ability to induce protein expression in response to P limitation was consistent with the presence/absence of phoB/R regulatory capacity of the corresponding strain. Taxonomic differences in P uptake, storage, and utilization strategies could explain the ubiquitous distribution of marine Synechococcus throughout the world’s oceans and explain the coexistence and/or ecological partitioning of multiple phototrophic taxa in the photic zone of tropical and subtropical oligotrophic oceans.     

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.     

AXENIC TISSUE CULTURE AND MORPHOGENESIS IN PORPHYRA YEZOENSIS (BANGIALES, RHODOPHYTA)

To better understand developmental phenomena in macroalgal tissue culture, we examined the morphogenesis of Porphyra yezoensis Ueda (strain TU-1) cultured aseptically in defined synthetic media . Generally, the filamentous thalli (sporophyte; conchocelis phase) of P. yezoensis were densely tufted with uniseriate filaments. The foliose thalli (gametophyte) were monolayered. In this study, axenic filamentous thalli retained their characteristic morphogenesis; there were no obvious differences between morphogenetic traits in unialgal and axenic conditions. However, conchospores, which might have developed into the foliose form under unialgal conditions, germinated into calluslike masses under axenic conditions. Most of the gametophytes gradually lost their typical morphogenesis after the first longitudinal cell division. Some of the calluslike masses developed rhizoidlike structures in several places or along the entire mass. Therefore, we concluded that P. yezoensis, in axenic cultures, loses its typical morphogenesis only during the gametophytic phase. The axenic tissue culture of Porphyra established in this study is a promising assay system for the identification of growth and morphogenetic factors.     

不同水分条件下两个树种木质部栓塞对P素添加的响应

 在两种水分供给(干旱胁迫和适宜水分,土壤含水量分别为田间持水量的30%～40%和70%～80%)下,研究了耐旱树种元宝枫(Acer truncatum)和 中生树种女贞(Ligustrum lucidum )木质部栓塞(以导水率(Percentage loss of hydraulic conductivity, PLC)损失程度衡量)对P素添加的 响应。结果发现,两个树种PLC的日变化均呈现出先上升后降低的规律,表明木质部栓塞的形成与恢复是植物体的一种平常事件;除适宜水分条 件的女贞外,P素可以显著提高元宝枫和遭受干旱胁迫时女贞的PLC;两种水分条件下,干旱胁迫时元宝枫木质部栓塞明显高于适宜水分供给时 。女贞的PLC在两种水分状况下无显著差异;树种间,干旱胁迫促进了元宝枫木质部的栓塞形成,明显高于同等水分条件下的女贞。该研究结果 证实了“木质部限流耐旱假设”。     

海河流域土壤中磷的库存量与通量研究

本通过对河流域土壤中磷及其形态含量的分析结果,计算出该流域土壤中磷的库存量为６．４２×１０＾１０ｋｇ。并以成土母质,人畜粪,化肥施入量和径流带入量,大气降尘及植物的残留量等因素为对土壤中磷的贡献,同时以径流的带出,大气的飘尘及植物体茎叶等因素为磷的迁出部分,计算出海流域土体中磷的进出量分别为４．２４×１０＾８ｋｇ／ａ和３．６６×１０＾８ｋｇ／ｄ,以此来研究其通量关系。     

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     

太湖不同解有机磷菌株胞外碱性磷酸酶活性对蓝藻碎屑的响应

浮游细菌胞外碱性磷酸酶在湖泊磷循环过程中具有关键作用, 但其与生物可利用性磷和颗粒态有机质之间的关系尚未得到充分的研究。研究以从太湖沉积物分离的3 株解有机磷细菌(OPB)和东湖水中OPB菌群为实验对象, 以蓝藻干物质为颗粒态有机质, 系统分析了模拟条件下OPB 的数量、不同大小颗粒所表现的胞外碱性磷酸酶活性(APA)与不同形态磷的浓度及其相互关系。从总体上讲, APA 与OPB 数量显著正相关, 且明显反比于溶解反应性磷(SRP)浓度, 在模拟实验过程中, 不同菌株(群)所对应的SRP 浓度均显著不同, 故其解磷能力各异。从绝对活性及其在总活性中所占的比例来看, 各处理间小颗粒(0.22—3.0 μm)APA亦明显不同, 而大颗粒(>3.0 μm)APA和溶解态(8 CFU/mL), SRP 浓度逐渐增加。实验后期(20—33 d)细菌数量大幅度减少, 且伴随SRP 和溶解态有机磷浓度的显著升高。因此, 在缺磷且富含颗粒态有机质的条件下, OPB 将产生胞外碱性磷酸酶, 分解有机磷, 进而满足其大量生长的需要, 同时有效改变溶解态磷的形态与生物可利用性。