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The preliminary Phytochemical investigations and phytotoxic effects of aqueous leaf extracts of Albizia lebbeck on Sorghum bicolor was assessed. The result from phytochemical screening revealed that all the allelochemicals tested where found present except steroids and phlobatannins when petroleum ether, methanol and water extracts were used. Petroleum ether extract show the presence of amino acids, protein and glycosides while methanol and water extracts showed their absence. Alkaloids, anthraquinones and acids were found present when methanol was used and absent using petroleum ether and water extracts. These allelochemicals are all important allelopathic sources. The leaf extract slowed down the rate of growth of the radicle and plumule of Sorghum bicolor seeds when compared to control. But these inhibitions were not significantly different at 5% level. The degree of inhibition increased with increase of concentration of the extracts hence inhibitions were prominent at extract of higher concentrations.

Pinnunavis edkuensis is reported as a new diatom species from Egypt from brackish and marine habitats. Its description and diagnoses focus on 12 continuous morphological characters: valve breadth, valve mantle shape and surface area, axial-central area shape and surface area, axial area breadth, distal and proximal interstriae distances, striae slopes, magnitude and position of maximal slope along a semivalve transect, and inter-raphe distance. These characters are considered along their ontogenetic trajectories, using a size vector, by means of regression analyses. Shape was assessed using geometric morphometric methods. Diagnostic comparisons of P. edkuensis were made with P. yarrensis, for which a lectotype was chosen and Grunow’s unpublished description and drawings presented, and P. zalatii, a new name replacing the illegitimate name, Navicula aegyptiaca. P. edkuensis was demonstrated to be a distinct group compared to these two similar species using 11 of the 12 characters. The diagnoses emphasize species recognition by means of anova, regression and randomization analyses and specimen determination primarily by means of regression-based prediction intervals. Additional comments are made on the statistical nature of gaps associated with characters described by discrete or continuous variables, the importance of reporting sample sizes as part of diatom diagnoses and other comparisons, and the role of size in specimen comparability and taxon identification. The generic distinctness of Pinnunavis and Pinnularia is discussed based on a preliminary cladistic analysis of morphological characters.

T HE microalgal palynomorphs considered one of the main categories of non-pollen palynomorphs recognized in palynological slides which characterized by their potential paleoecological and stratigraphical values especially in the pre-Quaternary deposits. For this importance, four subsurface cutting samples recovered from two Cretaceous (Aptian/Albian and Turonian) geological units in Bougaz-1 well, northeast Sinai have been palynologically analyzed in order to study their algal content. Seven species of algae related to four genera from two divisions have been described and illustrated: Pediastrum boryanum, P. duplex, P. kawraiskyi, P. simplex, Scenedesmus acuminatus, and Chomotriletes minor (Chlorophyta); and Pterospermella sp. (Prasinophyta). Of these, two species (Pediastrum kawraiskyi and Scenedesmus acuminatus) are recorded for the first time from the Cretaceous of Egypt. Notes on the stratigraphic range and the geographical distribution of the most important recorded genera are given. The cell wall nature and its role in resistance to degradation are also discussed. The ecology of extant taxa has been used to determine the paleoenvironment and paleoecology prevailed in the studied area during the Cretaceous period.

Genetic variations and phytochemical constituents of Dictyota dichotoma and Sargassum dentifolium, collected from Hurghada and Abu-Qir bay, were investigated. Results revealed an increase in the concentrations of carotenoids, sugars and DPPH% in the samples of both algal species collected from Hurghada as compared with those collected from Abu-Qir. Regarding the samples collected from Hurghada, an increase in the concentrations of chlorophyll a, b and phenols was recorded in S. dentifolium; while a decrease in chlorophyll a, b only was observed in D. dichotoma. No significant difference was observed in phenol concentrations between D. dichotoma samples collected from the two studied localities. DNA was isolated and thirteen SCoT molecular markers were used to detect the genetic variations between the samples of the two localities. In D. dichotoma, the total average of polymorphism is 56.68%. SCoT-1 exhibited the highest polymorphism (80%), while SCoT-28 recorded the lowest polymorphism (35.71%). In S. dentifolium, the total average of polymorphism is 61.63%. SCoT-3 showed the highest polymorphism (90%), while SCoT-13 exhibited the lowest polymorphism (0.09%). In addition, BSI factor showed a marked difference between the two studied algae that it was 0.87 % in D. dichotoma and 0.77 % in S. dentifolium. Variation in geographical location affects genetic variation and phytochemical composition of D. dichotoma and S. dentifolium. The difference in the responses of the two studied algae to the change of locality and environmental conditions may reflect differences in their gene expression. Moreover, the efficiency of SCoT markers to discriminate between algal species collected from different localities has been confirmed.

Ismailia Canal is one of the main artificial branches of River Nile in Egypt, it is the most important one as a source of water supply for several governorates in the east of Nile Delta. In this study, phytoplankton composition and some physico-chemical parameters have been studied in twelve points along the main route of Ismailia canal between Cairo and Ismailia governorates to follow up changes in the water quality of the canal. Samples have been collected monthly in the period from February 2015 to January 2016. A total of 143 phytoplankton taxa related to 55 genera were identified related to six algal divisions namely; Chlorophyta (69 taxa), Bacillariophyta (51 taxa), Cyanophyta (18 taxa), Euglenophyta and Dinophyta (each represented by 2 taxa) and finally Xanthophyta represented by one taxon. Quantitatively, Bacillariophyta was the most dominant division with algal density represented more than 86% of average total phytoplankton count. The highest phytoplankton density was recorded in winter, while the minimum was recorded in summer. Water of Ismailia Canal was found to be slightly alkaline. Concentrations of nitrogen, phosphorus and silicate were found to be markedly affected by the water level of the canal along the year as well as the pollution runoff from ambient pollution sources. Phytoplankton composition of the canal also seems to be affected by pollutants especially at the far eastern part of the canal that located in Ismailia city. On the long run increasing of industrial and agricultural runoff may affect the water quality of the canal, so continuous studies must be carried out to follow up the changes in water of the canal.

Light and scanning electron microscope observations are made on some members of the section Obtusae in the genus Nitzschia (Bacillariales, Bacillariophyceae). We use type and other material derived from both the National Water Quality Assessment (NAWQA) program in the USA and from Egypt to assess five different taxa, two of which are described as new to science (Nitzschia lowei, sp. nov., Nitzschia potapovae, sp. nov.) and another is made as a new nomenclatural combination (Nitzschia kurzeana var. multistriata (Hohn) comb. nov.). Other names used in the literature for some of these taxa are considered and discussed. Based on the features of sigmoid valves, eccentric raphe not in an elevated keel, lack of a conopeum, strongly bent, elongated external proximal raphe ends extending onto the valve face, and presence of a differentiated central 'nodule', members of this group are clearly differentiated from the generitype of Nitzschia and most other recognized sections of the genus.

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