付志鑫，李 雪，劉 妍，范亞文

(1：哈爾濱師范大學生命科學與技術學院，哈爾濱 150025)(2：茅臺學院，遵義 564500)

扎龍自然保護區(qū)寬帶鼓藻屬(鼓藻目)一新種

付志鑫1，李 雪2，劉 妍1，范亞文1

(1：哈爾濱師范大學生命科學與技術學院，哈爾濱 150025)(2：茅臺學院，遵義 564500)

2011-2012年間對扎龍國家級自然保護區(qū)的藻類標本進行采集及觀察鑒定. 研究發(fā)現，該區(qū)域鼓藻類植物生物多樣性較高，共觀察到90個分類單位. 研究過程中發(fā)現寬帶鼓藻屬的一個新種——PleurotaeniumparvulumLi, Fan & Wei. 該物種特征為植物體單細胞，細胞小型，長圓柱形；半細胞頂端平截，其緣邊橫斷面可見5個小結節(jié)；細胞壁平滑或具點紋；半細胞具兩個軸生星狀的色素體，每個色素體具1個蛋白核. 本文比較了該物種與其相近種類之間的差異.

鼓藻；寬帶鼓藻屬；新種；扎龍國家級自然保護區(qū)

藻類作為重要的初級生產者和化學調節(jié)劑，是水生生態(tài)系統的重要組成成分，為水生生態(tài)系統中的其他生物提供了良好的生存環(huán)境. 鼓藻是一類淡水藻類. 他們對水質有敏感的指示作用，并且在凈化水環(huán)境方面起著重要的作用[1]. 一般情況下，鼓藻目經常存在于低電導率和低鈣含量的貧營養(yǎng)水體中，例如湖泊、池塘和溪流中. 在沼澤以及沼澤中的水坑里也較為豐富[2-3]. 某些鼓藻即便是出現的個體數量較少，也可以指示出該水體為弱酸和貧營養(yǎng)條件，例如Staurodesmuscrassus(West & G. S. West) S. Lillieroth、尖頭叉星鼓藻(S.cuspidatus(Brébisson) Teiling)、S.sellatus(Teiling) Teiling、S.extensusvar.joshuae(Gutwinski) Teiling、S.triangularisvar.limneticusTeiling和長臂角星鼓藻(Staurastrumlongipes(Nordstedt) Teiling)[4-6]. 新月藻屬(ClosteriumNitzsch)、鼓藻屬(CosmariumRalfs)、角星鼓藻屬(StaurastrumRalfs)則通常出現在富營養(yǎng)湖泊中，它們對水體的富營養(yǎng)狀況具有指示作用[4]. 例如針狀新月藻(ClosteriumaciculareT. West)稀少地分布于發(fā)生藍藻水華的富營養(yǎng)湖泊中(pH為6.7～8.5).

藻類細胞的形態(tài)多樣性是顯而易見的，故鑒定鼓藻幾乎完全依據其表面形態(tài). 盡管在過去的20年里，分子生物學的發(fā)展越來越迅速，但是當鑒定到屬和種的時候，還是要依賴于分類學的方法[7-11]，保留傳統的形態(tài)學鑒別方法是非常必要和實用的[12-14].

寬帶鼓藻屬是鼓藻科中種類相對較少的一個屬. 不同于角星鼓藻屬(超過3000個分類單位)，寬帶鼓藻屬目前僅報道有202個分類單位[15]. 寬帶鼓藻屬通常為單細胞(少數為單列細胞的絲狀體)，長圓柱形，中部略縊縮. 半細胞頂端平截或具圓形或圓錐形的小結節(jié). 色素體周生，呈許多不規(guī)則縱長帶狀[1]，少數種類色素體軸生，長帶狀.

扎龍國家級自然保護區(qū)位于黑龍江省齊齊哈爾市，處在候鳥遷徙的主要路線上，是鸛、鷺、天鵝、水鳥和其他鳥類棲息繁衍的樂園；該地區(qū)同時也是丹頂鶴保護區(qū)，其內湖澤密布，葦草叢生，是動植物理想的棲息地，具有較高的生物多樣性[16].

保護這一地區(qū)的水質，一直被視為水生態(tài)及相關研究的關鍵任務. 藻類作為反映水質好壞的一個重要指標，在這一地區(qū)的調查依然較少. 本文報道了扎龍國家自然保護區(qū)內寬帶鼓藻屬的一個新種，并對其進行描述.

1 研究區(qū)域

扎龍國家級自然保護區(qū)位于黑龍江省西部的松嫩平原，由烏裕爾河下游流域一大片蘆葦濕地組成(圖1). 2011和2012年的春、夏、秋季分別對該區(qū)域內的扎龍湖進行藻類標本的采集，共設置了9個采樣點，在5個采樣點(SV～SIX)和12個采集樣品中發(fā)現該新種，采集時間、采樣點位置以及環(huán)境參數等詳細信息見表1.

圖1 扎龍國家級自然保護區(qū)采樣點分布Fig.1 Distribution of sampling sites in Zhalong National Nature Reserve

采樣點編號樣品編號生境地點溫度/℃pH電導率/(μS/cm)SV20111026附生扎龍湖南部8.88.2126120120714附生扎龍湖南部30.18.0029820120715浮游扎龍湖南部30.18.0029820120912浮游扎龍湖南部22.68.68274SVI20120709附生扎龍湖北部29.98.8829020120713浮游扎龍湖北部29.98.88290SVII20120718浮游扎龍湖西部29.29.62264SVIII20110720浮游扎龍湖中央21.56.7830220120707浮游扎龍湖中央29.310.27319SIX20110722浮游扎龍湖東部20.66.8830720120701附生扎龍湖東部29.39.5127320120910附生扎龍湖東部22.19.03290

2 材料與方法

浮游樣品用25#浮游生物網在水體表面以下 0.5 m處做“∞”字形往復撈取；固著樣品的采集主要使用鑷子、牙刷等工具刮取附著在水草、石頭等基質上的附著物. 采集樣品需要用甲醛固定液進行固定(甲醛∶甘油∶蒸餾水=4%∶10%∶86%). 利用光學顯微鏡(Olympus BH 2)對藻種進行鑒定和拍照；拍攝的圖片采用圖像處理軟件Photoshop 7.0處理. 藻類標本保存在哈爾濱師范大學藻類標本室. 描述術語遵循文獻[17-18].

3 結果與討論

小型寬帶鼓藻

PleurotaeniumparvulumLi, Fan & Wei sp. nov. (圖2)

圖2 小型寬帶鼓藻(1：手繪草圖；2～12：不同形態(tài)的藻類細胞；13～14：生殖狀態(tài)下的藻類細胞)Fig.2 Pleurotaenium parvulum Li, Fan & Wei sp. nov.

模式標本：圖2(1)，標本號20120701，保存于哈爾濱師范大學藻類標本室.

副模式標本：標本號20120701-2，保存于中國科學院水生生物研究所.

標本采集地：黑龍江省扎龍國家級自然保護區(qū)，劉妍、李雪采集于2011、2012年.

命名依據：依據物種的外形較小將其種名定為parvulum.

描述：植物體為單細胞，細胞小型，長圓柱形，長為寬的6.0～8.6倍，細胞中部略收縊；從半細胞的基部到頂部兩側近平行或從基部到頂部逐漸狹窄，半細胞頂端平截，其緣邊橫斷面可見5個小結節(jié)；細胞壁平滑或具點紋；半細胞具兩個軸生星狀的色素體，每個色素體具1個蛋白核. 細胞長71.0～96.7 μm，基部寬10.6～12.6 μm，縊部寬9.2～11.4 μm，頂部寬7.2～10.8 μm.

分布：扎龍湖5個采樣點中的夏季和秋季樣品中均能觀察到此新種. 湖水pH為7.50～8.45，溫度為15.7～26.5℃，電導率為248～337 μS/cm. 優(yōu)勢種為固氮魚腥藻(AnabaenaazoticaLey)、旋轉囊裸藻(Trachelomonasvolvocina(Ehrenberg) Ehrenberg)、極小橋彎藻(CymbellaperpusillaCleve-Euler)和湖生卵囊藻(OocystislacustrisChodat).

Haplotaeniumminutum(Ralfs) Bando(之前被命名為Pleurotaeniumminutum(Ralfs) Hilse)與我們觀察到的新種最為相似，這兩個物種之間最主要的區(qū)別是H.minutum(Ralfs) Bando的半細胞頂端無小結節(jié).Haplotaenium同Pleurotaenium的主要區(qū)別在于色素體的形態(tài)[19].Haplotaenium的色素體軸生，長帶狀，每個半細胞只有一個色素體；而Pleurotaenium的色素體為周生或軸生，長帶狀，每個半細胞有幾個色素體[1]. 盡管Pleurotaeniumminutum(Ralfs) Hilse這個名字現在仍在使用[20-22]，但是通過基因分析也表明Haplotaeniumminutum(Ralfs) Bando不屬于寬帶鼓藻屬，分子學層面上的研究支持了這個觀點[9].

因此，基于色素體的特點，認為該新種在分類學上屬于寬帶鼓藻屬. 其與Haplotaeniumminutum(Ralfs) Bando的區(qū)別是：新種較小，半細胞具2個色素體，色素體具1個蛋白核，半細胞頂端平截，且平截面有5個小結節(jié).

Holotype: Fig.2;Sampling No. 20120701, housed at Algae Herbarium, Harbin Normal University.

Isotype: Sampling No. 20120701-2, housed at Institute of Hydrobiology, Chinese Academy of Sciences.

Type Locality: Zhalong National Nature Reserve in Heilongjiang Province, China. By Liu Y & Li X at 2011 and 2012.

Etymology: The epithetparvulumis based on the outline of this species.

Description: The species is a unicellular plant. Cells are small and long cylindrical. Length is 6.0-8.6 times longer than the breadth without processes. Constriction is median to slight. Two sides of the semicell are nearly parallel from the base of the semicell, or converge gradually to the apex. Apices is truncate and provided with small nodules (5 visible in face view). Cell walls are smooth or with puncta. Chromatoplasts, two per semicell, shaped as axial longitudinal ridge. Each chromatoplasts has one pyrenoid. Cell length is 71.0-96.7 μm; basal breadth is 10.6-12.6 μm. Isthmus is 9.2-11.4 μm long, apex breadth is 7.2-10.8 μm.

Distribution: This species occurred in summer and autumn, and was observed from 5 sites in Zhalong Lake. Water pH was from 7.5 to 8.45; water temperature was during 15.7-26.5℃, conductivity was from 248 to 337 μS/cm. The dominant species wereAnabaenaazoticaLey,Trachelomonasvolvocina(Ehrenberg) Ehrenberg,CymbellaperpusillaCleve-Euler, andOocystislacustrisChodat.

The most similar taxon with the new species isHaplotaeniumminutum(Ralfs) Bando, which was named previously asPleurotaeniumminutum(Ralfs) Hilse. The most important difference between these two species is theH.minutum(Ralfs) Bando lack the small nodules at the end of the semicell. Bando (1988) separatedHaplotaeniumfromPleurotaeniumbased on the character of chloroplast[19]. The chloroplasts ofHaplotaeniumare axial and ribbon-like, only one chloroplast per semicell, while those ofPleurotaeniumare parietal and ribbon-like, several chloroplasts per semicell[1]. Although the namePleurotaeniumminutum(Ralfs) Hilse was still used[20-22], molecular analysis showed thatHaplotaeniumminutum(Ralfs) Bando does not group withPleurotaeniumspp. as shown in gene, supporting the separation of these two genera[9].

Therefore, based on the features of chloroplasts, we believe the taxon of the new species belongs to the genusPleurotaenium. Differences fromHaplotaeniumminutum(Ralfs) Bando are obvious: the new species is smaller, two chromatoplasts per semicell, one pyrenoid per chromatoplast, and each semicell has five small nodules transversely.

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A new species ofPleurotaeniumN?geli (Desmidiales) in Zhalong National Nature Reserve, NE China

FU Zhixin1, LI Xue2, LIU Yan1& FAN Yawen1**

(1:CollegeofLifeScienceandTechnology,HarbinNormalUniversity,Harbin150025,P.R.China)(2:MoutaiCollege,Zunyi564500,P.R.China)

A very abundant desmids biota was found in Zhalong National Nature Reserve in 2011-2012, including 90 taxa in total. Among them, aPleurotaeniumspecies is proposed as new to science,PleurotaeniumparvulumLi, Fan & Wei. The new species is characterized of small cells and a long cylinder without processes, a truncated apex, five small nodules on cross section, cell wall smooth or with puncta, semicells with two axial longitudinal ridge-shaped chromatoplasts, and each with two pyrenoids. Differences between the species and allied taxa are discussed.

Desmids;Pleurotaenium; new species; Zhalong National Nature Reserve

國家自然科學基金項目(31270250, 31470308)資助. 2017-02-10收稿；2017-05-07收修改稿. 付志鑫(1991～)，女，碩士; E-mail: fuzhixin1991@163.com.

; E-mail: fanyaw@163.com.

DOI 10.18307/2017.0526