Photoautotrophic growth in suspension culture of cells from the moss, Barbula unguiculata

Chlorophyllous cells in suspension culture from the moss, Barbula unguculata Hedw., grown under photoheterotrophic conditions were transferred to photoautotrophic conditions. The cells started to grow photoautotrophically without selection. Maximum growth was observed under irradiances of more than 5 W m² and in an atmosphere enriched with 1% (v/v) CO₂. Under optimum growth conditions, dry weight and chlorophyll content in the culture had increased 20-fold after 20 days of cell growth. High concentration of chlorophyll [10–20 μg (mg dry weight)⁻¹] and high photosynthetic actively [30–70 μmol O₂ evolved (mg chlorophyll)⁻¹ h⁻¹] were observed throughout the culture period. In sugar-free culture medium, cell growth did not occur in the dark or in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) under light, although cell growth was observed in glucose-containing medium under those conditions. When cells that were grown photoautotrophically for one year were transferred to glucose-containing medium under ordinary air, they started to grow heterotrophically both in the light and in the dark.     

中国丛藓科的新变种及新记录种

本文发表了中国丛藓科一新变种, 侧立藓粗台变种Pleuroweisias chliephackei Limpr. Var apophysis Gao et X. Y. Jia, var. nov. 和一新记录种, 芽胞扭口藓Barbula horrinervisSaito.     

On Barbula munyensis R.S.Williams (Pottiaceae), an overlooked species from the tropical montane forest of South America

Abstract

Barbula munyensis R.S.Williams, a neglected moss species known only from the type material collected in central Peru in 1923, is newly reported for the moss floras of Argentina and Bolivia. The species is described, illustrated, mapped, and its habitat preferences are provided. Diagnostic characters and differentiation from some closely related South American taxa, with which it may be confused, are discussed. Barbula orizabensis Müll.Hal., a similar taxon, is excluded from the South American moss flora.     

小扭口藓(Barbula indica)芽胞发育特征的实验研究

在光照培养箱中人工对照培养小扭口藓(Barbula indica(Hook.) Spreng)的芽胞,显微镜下观察并记录其发育成配子体的全过程。结果表明:小扭口藓芽胞在3~4 d即可萌发;10 d左右开始分化出绿丝体、轴丝体及假根;18 d,轴丝体上的侧枝顶端细胞以分生缢割的方式产生单细胞或多细胞芽胞;40 d,轴丝体上开始出现配子体原始细胞;之后,配子体原始细胞发育成桑椹状的幼小配子体。还对芽胞形态发育、生理生态及配子体发生过程的特点进行了分析和讨论。     

Southern hemisphere synonyms of Racomitrium sudeticum (Funck) Bruch et Schimp.

Abstract

Type material is studied for six names of southern hemisphere Racomitria, viz. R. dustro-georgicum Par., R. amoenum (Broth.) Par., R. substenocladum Card., R. skottsbergii Card. et Broth., R. substenocladum fo. *nigrescens Card. et Broth., and R. austro-georgicum var. kranckii Riov. They are all placed as synonyms of R. sudeticum (Funck) Bruch et Schimp., which accordingly is bipolar. Racomitrium austro-sudeticum Broth. in Herz. belongs to the genus Grimmia.     

生物结皮光合作用对光温水的响应及其对结皮空间分布格局的解译——以黄土丘陵区为例

生物结皮是具有生命活性的地表覆被物,在黄土丘陵半干旱区广泛发育。迄今有关该区不同类型生物结皮的光合、呼吸作用潜力及其影响因素还不清楚。通过野外调查采样,利用室内半开放光合测定系统,测定了黄土丘陵区典型的藻类(3年生)、藓类(土生扭口藓)生物结皮(13年生)光合及呼吸作用过程对水分、温度及光照等环境因子的响应,在此基础上,解释了不同类型生物结皮空间分布格局的内在原因。结果表明:(1)在适合的光温水条件下,生物结皮的光合及呼吸作用强度取决于生物组成,研究区藓结皮的光合及呼吸作用速率显著高于藻结皮;(2)水分是生物结皮光合、呼吸作用的关键影响因子,只有当水分含量达到一定水平,才有光合及呼吸的可能。黄土丘陵区藓类及藻类生物结皮光合作用最适水分条件分别为80%-100%和40%-80%田间持水量。(3)藓类及藻类生物结皮光合作用光补偿点PAR均低于10μmol.m-2.s-1,光饱和点PAR分别为1000和800μmol.m-2.s-1,研究中2类生物结皮均未出现光抑制现象。(4)温度显著影响生物结皮的光合及呼吸作用,研究区藓类及藻类生物结皮的最适光合温度分别为20-25℃和25-30℃。(5)生物结皮光合作用对含水量及温度的响应可以解释结皮的空间分布特征。藻类植物光合作用的最适含水量较低而最适温度较高,因此在失水较快的阳坡及开阔地面上依然可以大面积发育;而藓类植物光合作用对水分条件要求较高,因此在水分条件较好的阴坡、低洼地才易演替至藓结皮阶段。