A new species of Anabaena (Cyanophyta, Nostocaceae) from a Minnesota lake. III
A new species of Anabaena (Cyanophyta, Nostocaceae) from a Minnesota lake. III
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来自明尼苏达州湖泊的鱼腥藻新种（蓝藻门，发菜科）。
DOI：
10.2216/i0031-8884-15-1-69.1
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
H. Hill
中科院分区：
文献类型：
--
作者：
H. Hill
安纳贝娜被发现的圣诞湖位于明尼苏达州明尼阿波利斯市以西约30公里处。湖的直径约为1.2 km，最大深度为30 m，温跃层约为6 m，在1974年5 - 11月取样期间，塞奇盘读数为3′5 ~ 5.5 m。因此，湖水总是清澈的。那里从来没有出现过任何藻类的繁盛。样本是通过长拖曳的浮游生物网获得的。圣诞湖的岸阶地一般较窄，向深水的斜坡较陡。一条水生植物带环绕着湖伸展开来。它主要包括水仙、美洲水仙、狐尾藻、狐尾藻、狐尾藻，特别是角藻。深水中的湖床是粘土。植物生长区床层松软易碎，植物生长区浅水区床层砂质多。1974年8月20日，在浮游生物中首次发现水藻。到9月8日，它产生了不成熟的细胞。在10月1日至12日期间，它有许多运动菌，在这一时期结束时，藻类表现出解体的迹象。在1974年10月23日和11月8日最后一次取样的样本中发现了一些没有动胞菌的藻类残留物。图1是a . [usca]菌落在玻璃罩下。图3和图4是开放水域的毛状体，没有覆盖玻璃。图3的毛状体为螺旋状，但在毛状体中心附近，螺旋由左向右变化。图4显示了更常见的群体排列，即许多圆形部分，不规则排列，间距很宽。圆形零件的直径为50-75 /-Lm。图2是一个毛状体，包含两个未成熟的动子和一个异囊，在油墨溶液中，显示粘液。狭窄的粘液是典型的。金银花的细胞呈柠檬形，细胞之间的连接非常狭窄（图5和图6）。细胞在生长的所有阶段都是棕色的。紫菜的细胞中有气体液泡。它们在每个细胞中也有一些细丝，这些细丝贯穿细胞的长度，看起来像液泡。A. [usca]细胞宽为5'5-6'5/- lm，长为(6'0)-7'0-8'5-(10,0)/- lm。异囊呈球形或接近球形（图5、6和7）。它们有一个宽的透明壁。异囊成熟时呈不均匀的浅绿色。它们未成熟时呈颗粒状。异囊沿毛状体间隔100-450 /-Lm。异囊尺寸为（6′0）-6′5-8′0-(8′5)/- lm宽，（6′5）-7′0-8′5(9′0)/- lm长。a . [usca]的基因子从一个异囊中形成一个、两个或很少的三个细胞，通常在异囊的两侧（图1、5、6和7）。在生长早期，它的形状是一个短圆柱体（图5和6），但在生长后期，它的形状是香肠状的（图1和7）。在几乎所有的异囊中都有动子形成。它们在未成熟的时候有液泡，包括qg，如在细胞中，有几根长在肌肌上的细丝，看起来像液泡。当叶片成熟时，液泡消失，表面出现颗粒。不成熟时，卵细胞呈蓝绿色，成熟时呈黄绿色。偶有在异囊的一侧或两侧串联的两个基因子。胞体在任何时候都不会在群体中形成中心团块，就像Anabaena lemer - mannii的胞体那样。akinete尺寸为(7'5)- 8010·0-(12·0)/- lm宽，(16)-26-42-(52)/- lm长。以下文献已被检查，并没有发现类似的Anabaena sp. [usca]
Christmas Lake, in which Anabaena [usca was found, is about 30 km west of Minneapolis, Minne sota. The lake is roughly 1·2 k m in diameter, has a maximum depth of 30 m, a thermocline at about 6 m, and, during the period of sampling in 1974, May-November, secchi disk readings of 3'5 to 5·5 m. The lake water was thus always clear. At no time was there a bloom of any alga. Samples were obtained by long tows of the plankton net. The shore terrace of Christmas Lake is generally narrow, and the slope to deep water is steep. A belt of aquatic plants extends all around the lake. It contains principally Potomogeton spp., Vallisneria americana, Myriophyllum exalbescens, Chara vulgaris and especially Ceratophyllum demersum. The lake bed in deep water is clay. The bed is soft and friable in the area of plant growth, and sandy in the shallow water shoreward of the plant growth. Anabaena [usca was first seen in the plankton 20 August 1974. It developed immature akinetes by 8 September. It had many akinetes in the period 1-12 October, and at the end of this period the alga showed signs of disintegration. A few remnants of the alga, without akinetes, were seen in the samples of 23 October and in the last sample taken on 8 November 1974. Figure 1 is a colony of A. [usca spread under a cover glass. Figures 3 and 4 are trichomes in open water, without a cover glass. The trichome of Fig. 3 is helical, but the helix changes from left hand to right hand near the centre of the trichome. Figure 4 shows the more usual colonial arrangement, i.e. many circular parts, irregularly arranged, with wide spacing. The circular parts have diameters of 50-75 /-Lm. Figure 2 is a trichome, containing two immature akinetes and a heterocyst, in an ink solution, to show the mucilage. The narrow mucilage shown is typical. The cells of A. [usca are lemon shaped, with a very narrow connection between cells (Figs 5 and 6). The cells are a brown colour at all stages of growth. The cells of A. [usca have gas vacuoles. They also have several filaments in each cell which run the length of the cell and which appear to be gas vacuoles. The cells of A. [usca are 5'5-6'5/-Lm wide and (6'0)-7'0-8'5-(10,0) /-Lm long. The heterocysts of A.f usca are spherical, or nearly so (Figs 5, 6 and 7). They have a wide hyaline wall. The heterocysts have a ho mogeneous light green colour when mature. They are granulated when immature. The heterocysts are spaced 100-450 /-Lm apart along the trichome. The heterocyst dimensions are (6'0)-6'5-8'0-(8'5) /-Lm wide and (6'5)-7'0-8'5(9'0) /-Lm long. The akinetes of A. [usca form one, two or rarely three, cells from a heterocyst, and usually on both sides of the heterocyst (Figs 1, 5, 6 and 7). The shape of the akinetes is that of a short cylinder early in growth ( Figs 5 and 6), but in later growth the akinetes are sausage shaped ( Figs 1 and 7). The akinetes form at nearly all heterocysts. They have gas vacuoles when immature, includiQg, as in the cells, several filaments which run the length of the akinete and which appear to be gas vacuoles. The gas vacuoles disappear as the akinete ripens, and surface granules then appear. The akinetes are blue-green in colour when imnlature, yellowish-green when ripe. Two akinetes in series on one side or on both sides of the heterocyst occur occasionally. The akinetes do not at any time form central masses in the colony, as the akinetes of Anabaena lemmer mannii do. The akinete dimensions are (7'5)-8,010·0-(12·0) /-Lm wide and (16)-26-42-(52) /-Lm long. The following literature has been examined and no Anabaena sp. similar to A. [usca was found in