TAXONOMIC STUDY OF CHLOROPHYTA, CHAROPHYTA AND VAUCHERIOPHYTA FROM NORTH-EASTERN AREAS OF PAKISTAN

Abstract

One hundred and thirty-nine species of planktonic, edaphic, epioikotic, epiphytic and epilithic green algae belonging to 3 phyla, 5 classes, 13 orders, 14 families and 26 genera have been collected from various freshwater habitats in the north-eastern areas of Pakistan. For this purpose several districts of the Punjab e.g. Gujranwala, Jauharabad, Jhang, Kasur, Lahore, Sargodha, Shiekhupura and Sialkot, certain areas of Attock and Swat in N.W.F.P. like Bahrain and Kalam as well as Chenari, Muzaffarabad and Neelum Valley in Azad Kashmir were surveyed during December 2003 and July 2005. They have been morphologically and cytologically investigated, taxonomically determined and described on the basis of such characters. Although all of them appeared to be taxonomically known species, but most of them were described for the first time from their area of collection. As a result of taxonomic studies members of the phylum Chlorophyta with 22 genera and 127 species were found to be more prevalent than other two phyla of green algae, while Vaucheriophyta included 3 genera and 10 species and Charophyta contained only 1 genus with 2 species and thus appeared to be the smallest phylum in diversity. Zygnemales was the most commonly distributed order with 5 genera and 63 species (45.3 %). It was followed by the order Oedogoniales with 2 genera and 28 species (20.1 %), while Prasiolales, Sphaeropleales and Botrydiales were poorly distributed orders with only 1 genus and 1 species each (0.7 %). As a result of that Zygnemophyceae appeared to be the most highly distributed class with 7 genera and 91 species (65.5 %) as compared to others. It was followed by the class Ulvophyceae with 11 genera and 25 species (20.1 %). The class Siphonocladophyceae appeared to be the least distributed class of the phylum Chlorophyta having 4 genera and 8 species (5 %). Spirogyra with its 42 species was the most commonly occurring genus. It was followed by the genera Oedogonium with 26 species and Zygnema with 10 species. Next common were the genera Ulothrix with 8 species and Zygnemopsis with 6 species. Except Ulothrix all these genera belong to the class Zygnemophyceae. Poorly distributed genera were Binuclearia, Chaetophora, Cylindrocapsa, Geminella and Heterothrichopsis among class Ulvophyceae, Hallasia among Zygnemophyceae, Sphaeroplea among Siphonocladophyceae and Botrydium among class Vaucheriophyceae, which were represented by a single species each. Aphanochaete, Bulbochaete, Chara, Cladophora, Coleochaete, Pithophora, Tribonema and Uronema were slightly better in their diversity, as each of them was represented by two species each. An overwhelming amount of the collected species was found in the free-floating or planktonic condition (75. 5 %). Next category of habitats, in which they were collected, is epiphytic condition (15. 8 %). Only a few species occurred in the edaphic and epilithic conditions (3.6 %), and epioikotic condition was the least occurring habitat (1.4 %). No epipsammic or epipelic alga was collected. These conditions were mainly represented by species of the phylum Chlorophyta. In the phylum Vaucheriophyta no species was found in the epioikotic or epilithic condition. Among Charophyta, apart from epilithic and epiphytic habitats all the other categories were missing. Largest number of species was found in the Lahore District (17. 3 %), which was followed by the collections made from Sheikhupura District (14 %). This was further followed by Kasur and Sialkot districts (12.1 % each). The cold areas of Swat and Azad Kashmir also displayed an appreciable number of species (9.3 & 9.8 % respectively). The areas of Attock and Pasroor were quite poor in the distribution of algae (3.3 %). Smallest number of species was observed in Sargodha and Jauharabad districts (1.9 & 2.3 %) respectively). The class Zygnemophyceae was well represented at all the 12 localities, but the class Ulvophyceae was not found at Sargodha District. The class Siphonocladophyceae was not present at several localities. The phyla Vaucheriophyta and Charophyta were found to be poorly represented at several localities, due to small number of species collected. Spirogyra was the most commonly collected genus, found at all the investigated localities except Sargodha District. Next to it was Zygnema, which was further absent at Jauharabad District. Further next were Ulothrix and Oedogonium, which were collected from different localities. Binuclearia, Botrydium, Geminella, Hallasia, Heterothrichopsis and Sphaeroplea were the least occurring genera, they were collected from one locality only. While Aphanochaete, Bulbochaete, Chaetophora, Chara, Coleochaete, Cylindrocapsa, Tribonema and Uronema were slightly better, as they occurred at two different localities. The largest number of collected species was found in spring (31.6 %), their frequency of occurrence remained almost the same during summer and winter (24.6 & 26. 3 % respectively), and they were collected in smallest number in autumn (17.5 %). It appeared that they started growing in winter, reached to a maximum growth during spring and began to disappear in autumn. The seasonally resistant most common genera were Oedognium, Pithophora, Spirogyra, Stigeoclonium, Ulothrix and Zygnema, which were found to grow in all the four seasons. Binuclearia, Cylindrocapsa, Geminella and Hallasia were only collected during spring, Heterothrichopsis was only found in summer, Chaetophora and Chara occurred only during autumn, while Aphanochaete, Botrydium and Sphaeroplea thrived only in winter. Species of these genera could not be collected during other seasons. The remaining genera were found in certain seasons of the year but remained absent during others.