No 2 (2022)
Articles
Spatial and temporal variations of physical-chemical parameters of the Akor River in Ikwuano local government of Abia state, Nigeria
Abstract
Physical-chemical parameters of the Akor River were investigated. The river water was sampled for seven months (February –August) in 2019 and analysed following standard procedures and protocols. The results revealed that there were no significant differences (P > 0.05) among all the investigated physical-chemical parameters across stations. Mean values of all the investigated physical-chemical parameters were within Federal Ministry of Environment set standards (2011) except for chemical oxygen demand and pH. Spatiotemporal results revealed that turbidity, total suspended solids, total dissolved solids, and the major cations (Na+, K+, Ca2+, and Mg2+) as well as the major anions (PO43-, NO3- and SO42-), were high during the rainy season months, but water temperature, pH, dissolved oxygen, and biochemical oxygen demand were higher during the dry season months. The percentage of Na+ contents ranged from 15.85 to 16.39%, indicating that Akor River has excellent irrigation water quality. The Nemerow pollution index varied from 0.59 to 0.63, also indicating that the river water is of good quality. The water quality index results varied from 52.70 to 54.50%, indicating that Akor River has a good water quality status. The result of water pollution index revealed that Akor River status is excellent and capable of sustaining biodiversity as well as crop irrigation.
1217-1228
Cytomorphology of the ‘wound healing’ process in the green filamentous algae, Ulothrix zonata (F. Weber & Mohr) Kützing 1833
Abstract
For the first time, we present a cytomorphological description of the self-healing (repair) process of damaged thalli sites, ‘wound healing’, in the green filamentous algae, Ulothrix zonata (F. Weber & Mohr) Kützing 1833. In the filaments of this species from Lake Baikal and the Angara (Baikal outflow), Zhilishche (Baikal inflow) and Ida (Angara inflow) rivers, light microscopy methods revealed dome-like and conical protrusions and elongations of transverse cell walls directed into adjacent dead (without protoplast) and defective (with deformed chloroplasts) cells. At the same time, there were mostly patterns where two cells formed protrusions directed into the same damaged filament site between them, i.e. towards each other. The growth of previously unconnected cells towards each other led to their convergence and adjacency. This had two important physiological consequences that ensured the restoration of the filament integrity. The first consequence was the formation of intercellular junctions. The second one was the fusion of the protoplasts and nuclei of the adjacent cells (cell fusion) with the formation of vegetative polyploid cells with increased size. During subsequent divisions of these cells, extended areas emerged with a two- to three-fold increase in the diameter of the algal filaments. It was also found that the process of ‘wound healing’ promoted the development of giant hypnospores. We showed that the H-shaped septa between cells of filamentous algae were not thickenings of the outer walls but the sheaths of the dead cells preserved after this reparation process. Analysis of the ‘wound healing’ patterns revealed that the Ulothrix cell nuclei did not migrate to the polarized regions of the cells but retained their central position, which testifies to their fixation in the protoplast. We observed sporadic cases of the development of lateral filaments in U. zonata were due to the self-repair of defective cells and their subsequent division during ‘wound healing’. A comparison of various cell deformations allowed us to determine the characteristic stages of the ‘wound healing’ process in U. zonata, which have some similarities and differences with those in marine red filamentous algae. Our study indicates that ‘wound healing’ is an evolutionarily developed and genetically programmed adaptation that may be widespread in the population of filamentous algae.
1229-1243