Isolation of protoplasts from Fucus serratus and F. vesiculosus(Fucales, Phaeophyceae): factors affecting protoplast yield

Protoplasts were isolated enzymatically from meristematic tissues of the brown algae, Fucus serratus, using a combination of 2% cellulase R-10 Onozuka, 0.5% macerozyme and 1% crude extract of gland gut of Aplysia vaccaria. The main factors affecting protoplast yield were identified. Protoplasts were produced in large quantities from apical region of thallus and from plantlets compared to mature explants. Yields were greatly improved by the addition of sodium citrate and bovine serum albumin in the enzymatic solution and could reach 5.8 × 10⁶ protoplasts per gram of fresh wt. The applicability of these optimal parameters to other species Fucus vesiculosus was shown.     

Temperature and NaCl- tolerance of rock-inhabiting meristematic fungi

Black meristematic fungi together with lichens and cyanobacteria dominate the micro-flora of rock surfaces in arid and semi-arid environments of hot and cold deserts. This study shows that rock inhabiting meristematic fungi are extremely tolerant against high temperatures, desiccation and osmotic stress. Their temperature tolerance increases with increasing dehydration of the fungal thallus. Air dried mycelia of black yeasts stand temperatures up to 120 °C for at least 0.5 hours. As response to high temperatures multilayered cell walls are developed and trehalose is accumulated whereas the intracellular glycerol regulates the osmotic potential under NaCl stress. Strains from rock in moderate climate (North Germany) show the same tolerance than those isolated from the Mediterranean area. Hortaea werneckii – hitherto only described as agent of human Tinea nigra – is shown to be the most tolerant rock inhabiting species tested. Meristematic fungi cannot be pre-adapted to higher growth temperatures by increased incubation temperatures. Considering the results of this study the justification of the term stress is discussed with regard to rock inhabiting fungi and their natural environment. Consequences for conservation treatments of monuments decayed by meristematic fungi are discussed on the basis of the ecophysiological properties of the fungi.     

Stationary phase development of Trimmatostroma abietis

Processes of anamorph cell replication in Trimmatostroma abietis are described. Growth and conidiation are delimited on the basis of morphological, ultrastructural and ecological criteria. Cellular expansion shifts from bidirectional intercalary in exponential phase cells to isodiametric in late stationary phase cells, in the latter case with endogenous asexual reproduction. Ultrastructural similarities to dothideaceous black yeasts are discussed.     

小麦类根瘤胞间根瘤菌对分生细胞核的影响

在小麦类根瘤中,分生细胞核很大,而且较圆整,一般为一个核仁,有的核仁还有核仁泡,但通常一个核仁只有一个核仁泡,染色质较少,呈团块状分布。若胞间根瘤菌离分生细胞核较远,分生细胞核变化不大,只是染色质开始由团块状变为长条形,但仍有核仁。当胞间根瘤菌靠近分生细胞核时,细胞核变小,染色质密度增加并形成网状,而且无核仁出现。在上述这些无核仁的分生细胞核内有一种特殊的管状内含体,它们位于网状染色质附近的核基质中。本文还讨论了分生细胞核的变化规律及其与胞间根瘤菌存在的关系。     

Comparison of triploid and diploid cucumber in long-term liquid cultures

Triploid suspensions generally grew more vigorously in modified MS medium with 2,4-D than those of diploids. The embryogenic potential of 26-month-old auxin-dependent suspension cultures depended on the line. Neither triploid nor diploid BOR (Borszczagowski line) were able to produce somatic embryos. Similarly, 12–20-month-old cytokinin-dependent suspensions from the same triploid line were not capable of regeneration. Only aggregates from 26-month-old auxin-dependent suspension of triploid line 603 differentiated into somatic embryos. In contrast, 18-month-old diploid and triploid liquid cultures of meristematic clumps (LMC) of BOR retained their regeneration potential. The ploidy level of triploid and diploid auxin-dependent suspension cultures was stable during the first 8 months. However, the ploidy level of triploids remained stable over 26 months of culture, whereas 66.7% of diploid cultures underwent chromosome doubling. No ploidy changes were observed among plants regenerated from 18-month-old LMC. Our data suggest that loss of embryogenic potential in suspension culture was independent of ploidy level.     

Phaeotheca triangularis, a new meristematic black yeast from a humidifier

Two strains of a new species of meristematic fungi, described as Phaeotheca triangularis, were isolated from moisteners of air-conditioning systems. The species is believed to be related to dothideaceous black yeasts. Its morphology, ultrastructure and nutritional physiology are reported.     

早花百子莲叶片器官发生和胚胎发生再生体系的建立

以早花百子莲(Agapanthus praecox)叶片为外植体, 建立了器官发生和胚胎发生离体再生体系, 并对移栽驯化基质进行了初步筛选。结果表明, 毒莠定(PIC)对叶片愈伤组织诱导效果良好, 最适培养基为MS+2.0 mg·L ^-1 PIC; 叶片组织分生能力决定愈伤组织诱导效果, 1-2片新叶基部愈伤组织诱导率可达85.71%, 叶片分生区0-0.5 cm愈伤组织诱导率为66.48%, 叶片横切面中部诱导效果优于边缘。不定芽诱导最适培养基为MS+1.5 mg·L ^-1 PIC+0.3 mg·L ^-1 6-BA, 诱导率达80.27%。体细胞胚诱导培养基为MS, 0.05 mg·L ^-1多效唑或1.0 mg·L ^-1 ABA均对体胚诱导具有显著促进作用。1.0 mg·L ^-1 6-BA对幼苗增殖有利, 器官发生和胚胎发生途径幼苗增殖系数分别为2.23和2.93。草炭:珍珠岩:蛭石=1:1:1 (v/v/v)为早花百子莲移栽驯化的最佳基质, 成活率达100%。该研究建立了早花百子莲叶片外植体再生体系, 丰富了百子莲快繁技术体系, 可为其它单子叶植物离体再生体系建立提供参考。     

Shoot regeneration from nodules of <Emphasis Type="Italic">Charybdis</Emphasis> sp.: a comparison of semisolid,liquid and temporary immersion culture systems

Nodules of Charybdis numidica maintained in liquid Murashige and Skoog (MS) medium with 20 mol BA in the dark were subjected to different treatments under continuous light for shoot regeneration. A high regeneration rate without hyperhydration of the shoots was observed on semisolid basal MS medium with 1% sucrose. The use of liquid MS medium (1% sucrose, no growth regulators) resulted in a significantly lower amount of shoots per gramme of nodules under both submerged and temporary immersion (TI) conditions. Shoot hyperhydration was lowest in a TI system with one 5 min immersion every 24 h. When compared on a per container base, large amounts of shoots could be produced in the TI system with less labour input than in the system with semisolid medium.     

粗茎鳞毛蕨原叶体细胞有丝分裂过程中微管列阵的变化

应用Steedman‘s wax切片法,间接免疫荧光标记技术和激光共聚焦扫描显微镜技术研究了粗茎鳞毛蕨（Dryopteris crassirhizoma Nakai)原叶体大液泡化细胞和分生组织细胞有丝分裂过程中微管列阵的变化。结果显示：应用高浓度的多聚甲醛（8%）可以很好地保持大液泡化细胞的结构和微管的抗原性。结果也显示Steedman‘s wax切片法和间接免疫荧光标记技术的优点;（1）避免在微管标记过程中酶解细胞壁;（2）在乙醇脱水过程中样品中叶绿素的自发荧光被减到最小;（3）能够详细观察到有丝分裂过程中微管骨架的变化。因此,这种方法可以被广泛用来调查简单植物体和复杂植物体中细胞的有丝分裂过程以及发育过程中微管骨架的变化。     

小麦根端分生组织细胞核中核仁通道结构的电镜观察

用常规电镜和整体银染电镜观察技术对小麦根端分生组织细胞核进行了研究。发展核仁与其周边染色质之间存在通道结构。初步分析认为,染色体NORs中的rDNA是通过该通道进入到核仁的纤维中心的。