|Keywords (Extracted from title, table of contents and abstract of thesis)
cyanophyta, chroocophyceae, nostocales, chroococcales, chamaesiphonales, stigonematales, oscillatoria, anabaina, lyngbya, phormidium, monera, northern areas, pakistan
One hundred and eighty-three species of planktonic, edaphic, epipsammic,epioikotic and epilithic blue-green algae belonging to 2 classes, 4 orders, 9 families and 34 genera have been collected from various freshwater habitats of Pakistan in the Districts of Attock, Gujranwala, Jauharabad, .Jhang, Kasur, Lahore, Sargodha,Sheikhupura and Sialkot in the province or the Punjab, from Bahrain and Kalam (Swat)in the province of NWFP as well as from Chenari, Muzaffarbad and Neelum Valley in Azad Kashmir during March 1996 and August 2000. They have been morphologically and cytologically investigated, taxonomically determined and described on the basis of such characters.
As a result of taxonomic studies members of the class Nostocophyceae with 137 species were found to be more prevalent than those of the class Chroocophyceae with 46 species. Nostocales was the most commonly distributed order with 22 genera and 136 species. It was followed by the order Chroococcales with 10 genera and 45 species, while Chamaesiphonales and Stigonematales were poorly distributed orders, each with only 1 genus and 1 species. Oscillatoria with its 45 species was the most commonly occurring genus. It was followed by the genera Anabaina with 17 species, Lyngbya with 16 species and Phormidium with 14 species. Among unicellular genera from the class Chroocophyceae, Gloeocapsa was most common with 10 species. Poorly distributed genera were Johannespaptistia and Stichnsiphon among unicellular blue-green algae and Anabaenopsis, Aulosira, Microchaete, Noduleria, Pleclonema, Polyclamydum, Raphidiopsis, Rivularia, Scytonema, Scytonematopsis, Stigonema and Symploca among filamentous algae, which were represented by a single species each.
Greatest species diversity was exhibited by the collections made at Lahore and its neighboring areas, from where 124 different species have been identified. It was followed by the collections of Sheikhupura, from which 30 species could be identified. It was the only area from where representatives of all the four orders of blue-green algae have been collected. Species of the orders Chamaesiphonales and Stigonematales were not found in any other investigated area. The poorest diversity was shown in the collections obtained from the Districts of Attock, Jhang and Sargodha, in which only I or 2 species could be identified. The specific diversity of algal genera in other Districts of the Punjab ranged between 6 and 30 species, which can not at all be considered as good. Eve" the specific diversity of the areas of NWFP and Azad Kashmir was not comparatively good (22 and 16 species respectively). Heterotrichous species were only scarcely observed in the present collections.
The investigated blue-green algae were mostly found to grow in summer season, but some of them also occurred in winter. High temperature (up to 48°C) with rainfall, intense sunlight and st1gnant water with pH 7.5 appeared most suitable ecological conditions for their growth. Members of the same species growing in the summer and rainy season occurred in massive quantity, showing reproduction and possessed larger cells than those growing in the winter season. Their growth was most abundant in the aquatic environment especially in planktonic state than in the terrestrial environment in benthic condition, Out of 183 identified species, 141 were found to occur in planktonic condition, i e 77 % of them preferred this habitat. Among benthic condition (33 %), only 43 species (23 %) occurred in edaphic state either as soil binding or epipsammic algae. The remaining 10 % species were epioikotic and epilithic.