A NEW NITROGEN-FIXING NON-LEGUME: CHAMAEBATIA FOLIOLOSA (ROSACEAE)

Specimens of Chamaebatia foliolosa Benth. with nodule structures on their roots fix atmospheric nitrogen. The nodules are similar to those of other non-legumes in gross morphology and structure, containing hyphal strands, some with club-shaped vesicles at their ends. A fixation rate of 130 nmoles N₂ per g fresh weight per hr is reported by using ¹⁵N₂ as a tracer. Equivalent rates of acetylene reduction were observed.     

地木耳显微及亚显微结构的研究

利用光学显微镜、相差显微镜、扫描和透射电镜等观察蓝藻类的地木耳,看到了一些特殊结构:1.藻体内部结构如海绵状,表面凸凹不平;2.由念珠状细胞组成的藻丝长短不一,弯曲折迥,有的堆积成团,有的分枝,有的排成环状;3.念珠状细胞壁分5层,最表层细波纹状,与相邻壁镶嵌连接;4.念珠状细胞为典型原核细胞,四周散布着类囊体,中央是拟核区,细胞质中分布着结构颗粒,多角体等,类囊体表面附有核糖核蛋白体和胆藻体,有的有明显液泡和腔穴;5.异形胞有厚的外套,这是正常壁外附加的包被,可称之为“细胞套”,它包括一层电子密集层和电子疏层,在极端形成半球形的“节球”,其间有孔与相邻细胞相通,流通物质有孔塞控制流向、流量;6.缢裂式繁殖,缢裂方向及位置各不相同,故出现细胞堆积现象。     

A NUMERICAL TAXONOMIC STUDY OF NOSTOC AND ANABAENA1

Thirty characteristics of 14 Nostoc and 10 Anabaena species were analyzed from previously published data. Using standard numerical taxonomic methods, simple matching coefficients were calculated and a phenogram drawn. The analysis revealed that some of the central characteristics of Nostoc are: a punctiforme stage; motile reproductive stage; plant mass with a dull to shiny luster, non-veined surface, and nonfimbriate margin; some spherical vegetative cells; no cylindrical heterocysts; and some spherical, but no cylindrical akinetes. Some of the central characteristics of Anabaena that were revealed are: no punctiforme stage; a motile vegetative stage; plant mass with a shiny luster, veined surface, and fimbriate margin; no spherical vegetative cells; some cylindrical heterocysts; and some cylindrical, but no spherical, akinetes. In general, Anabaena has larger akinetes and vegetative cells than Nostoc. Based on 30 morphological characteristics and the clustering data of the phenogram, keys were constructed for the Nostoc and Anabaena species studied. The data clearly support two separate and distinct, though similar genera and, less sharply, the separation of the 24 species. The more useful characteristics for separation of the species are size and shape of akinetes, vegetative cells, and heterocysts; color and luster of plant mass; veined plant mass surface; margin fimbriate; and shape of plant mass in nature.     

固氮蓝藻培养和应用的结果与展望

固氮蓝藻是一类低等原核植物。它能进行固氮作用,固定空气中分子态氮成为氮素化合物;又能进行光合作用,将二氧化碳变为碳素化合物并放出氧气,为自身的固氮提供能源和还原剂。由于具有以上功能,它们适应性很强往往是贫瘠土壤的先驱植物,因此,很早就引起了人们的重视。       

普通念珠藻营养物质及其利用

本文测定了普通念珠藻的粗蛋白、粗脂肪、糖及矿物质营养元素的含量.并研究普通念珠藻的提取物作为植物生长促进剂. 普通念珠藻的提取物用于小白菜、萝卜、生菜、绿豆及水稻种子能提高发芽率.例如,提取物粉末1g溶于1升水中,这种溶液稀释到1.25—5ppm,并浸种,在发芽率方面可观测到提高.     

发菜的生物学特性及资源保护

本文论述了发菜的外部形态、内部结构及生长繁殖方式等生物学特性,并探讨了发菜的适应性。研究结果表明,发菜具有典型旱生植物的生理特性和结构特征,耐干旱、耐炙热、耐严寒、耐贫瘠、嗜阳光、嗜盐碱,而不耐强盐碱和长期湿期环境。另外还分析了发菜资源面临枯竭的原因,并对其保护提出了建议。     

发菜的生态条件及其规律分析

 本文研究了甘肃永登和内蒙阿拉善左旗的发菜生态条件,发现了发菜生长中的水分节律现象。 发菜生于干燥的高原荒漠草原地带,属大陆性气候。其年平均气温为4.5—8℃,≥10℃积温为2231—2800℃·年,年温差大,昼夜温差明显。年平均降水量为201—290mm,集中在6—8月。年平均相对湿度为46—58%,有露水的天气约80天。土壤主要是由第三纪红土母质发育而来的棕钙土,营养贫乏,石灰质沉积明显,呈强碱性反应。年日照时数3000±300小时,辐射强烈。发菜在结构和生理上表现出强烈的旱生生态适应性,包括它的耐旱,耐贫瘠,嗜阳、嗜碱以及对温度变化的适应性强。 发菜生长中具有明显的水分节律现象。在5—10月,在暂短的降雨和露水后,藻体迅速吸取水分而得以生长。尔后,水分又很快被蒸发,藻体变干,生长停滞。发菜在这种湿润⇌干燥的反复节律中得到不断的断续生长和积累,从而完成发菜在干燥条件下的年生长过程。     

发菜的显微及亚显微结构的观察

通过光学显微镜、扫描电镜和透射电镜的观察、了解到一条发菜原植体大约由数十万计的念珠状细胞所组成,其藻丝多为单链,但也发现有分枝现象。整个原植体包被着厚薄不均的胶质鞘,外观粗糙,沟稜状起伏,且多裂隙。念珠状细胞为典型的原核细胞。细胞壁有三层结构,中央为色浅的核质区,四周为细胞质区其中散布着大量膜层薄而散乱的类囊体,膜上附有大量 rRNA 和藻胆体颗粒。还发现有膜层密集形如指纹的小类囊体。在细胞质中还分布着结构颗粒,多角体、聚磷酸体等嗜锇物质结构.一般细胞都具有分裂能力,方式多为横缢,先是细胞壁逐渐向中央扩展,最后将母细胞分成两个子细胞.从异形胞的结构特征来看,主要功能是渡过恶劣环境以保存物种。     

SPHENOPTERIDIUM AND TELANGIOPSIS IN A DIPLOPTERIDIUM-LIKE ASSOCIATION FROM THE VIRGILIAN (UPPER PENNSYLVANIAN) OF NEW MEXICO

The highly fossiliferous Virgilian (Upper Pennsylvanian) shales of the Kinney Brick Company quarry near Albuquerque, New Mexico, contain a diversified flora dominated by walchian conifers and neuropterid pteridosperms. Its other components include a specimen of Telangiopsis sp. and abundant material of Sphenopteridium manzanitanum, n. sp., a highly variable foliar form. Both genera are characteristically restricted to the Upper Mississippian, with the exception of one basal Pennsylvanian occurrence. Their occurrence together in the Kinney sediments and their possession in common of distinctive surficial ornamentation suggest that they represent dissociated parts of Diplopteridium, a very rare European Lower Carboniferous taxon. Other associated plants show later Paleozoic or even Early Mesozoic characteristics, which, together with the Mississippian elements, distinguish the Kinney site as paleobotanically unique.