ASSESSMENT OF EMERGENT AND FLOATING MACROPHYTES IN RELATION TO SOME PHYSICOCHEMICAL PARAMETERS OF WAYA POND, BAUCHI, NIGERIA

Emergent and floating macrophytes in relation to some physicochemical parameters were assessed in Waya pond, Bauchi. Water and macrophytes were sampled monthly between October 2019 to March 2020. Ten physicochemical parameters were measured and twelve macrophytes species recorded. The diversity index was 1.38, evenness (0.55) and abundance were 12 species. The site was polluted as all the values of dissolved oxygen (DO) were ˂ 5 mg/L, nitrogen ˃ 18 mg/L and pH ˂ 7 except for December. Pearson’s correlation coefficient revealed that DO correlated with Total Dissolved Solids (TDS) (r = 0.936, p˂0.01), Phosphate (r = 0.927, p˂0.01) and Nitrate (r = -0.953, p˂0.01). TDS correlated with Phosphate (r = 0.969, p˂0.01) and Nitrate (r = - 0.938, p˂0.01). The significant correlation between physicochemical parameters and macrophytes were: Nymphaea nouchali with DO (r = - 0.849, p˂0.05), TS (r = 0.88, p˂0.05). Panicum repens was negatively correlated with TDS, DO, TS, Phosphate but not Nitrates. Eichhornia crassipes, Nymphaea micrantha and Nymphaea lotus at p˂0.05 were negatively associated with TDS, DO, and Phosphate but positively with Nitrate. Nuphar lutea, Nelumbo nucifera and Echinochloa colona related positively with Turbidity. Nuphar lutea positively related with Nitrate but negative with DO, and TS. Typha latifolia with TS (r = - 0.871, p˂0.05). Potamogeton natans with phosphate (r = 0.927, p˂0.01). The state of water pollution in the study-area corresponded with low diversity, evenness and abundance of species. This puts biodiversity and sustainability at risk.

Ростові ознаки Potamogeton natans L. у різних еколого-ценотичних умовах водойм басейну Десни

З опорою на величини восьми динамічних метричних морфопараметрів та п’яти динамічних алометричних надано інформацію про швидкість росту раметів Potamogeton natans L. у водоймах басейну річки Десни. Оцінено вплив на ріст Potamogeton natans низки екологічних чинників (проективного покриття, товщі води, її прозорості, характеру донних відкладів). Показано, що в регіоні досліджень у рослин цього виду найбільші значення більшості динамічних морфопараметрів припадають на ценопопуляції з угруповань Potamogeton natans subpurum (р. Свига) та Potamogeton natans subpurum варіант зі Spirodela polyrrhiza і Lemna trisulca, а найменші – на Potamogeton natans subpurum (із заплавного озера).

Water parameters and species composition of macrophytes in reclamation lakes in the area of a former sulphur borehole mine (SE Poland)

Macrophytes and selected physical-chemical water properties were studied in 17 post-mining lakes of Jeziórko Sulphur Mine – one of the largest borehole sulphur mines in the world. Artificial lakes were constructed in subsidence depressions during the reclamation process of mining fields. They were characterized by high mineralization – conductivity ranged from 723 to 2295 μS/cm. The reaction was near neutral, or more frequently, slightly alkaline. Concentrations of phosphorus and organic matter were low. In the group of hydrophytes, Ceratophyllum demersum, Myriophyllum spicatum, Najas marina, Utricularia vulgaris, Eleocharis acicularis, Potamogeton pectinatus, Potamogeton natans and Potamogeton pusillus were frequently dominant. In several lakes, large macroscopic algae dominated – charophytes forming large, dense Chara meadows. In marsh communities, Phragmites australis was the most expansive. Reclamation process had a positive effect on diversity, some of the species found in the study area are regionally rare, including one species which is threatened in Poland (Najas minor). No alien species were recorded.

Caldesia Parnassifolia – not extinct in Lithuania

Caldesia parnassifolia (L.) Parl. is a “near threatened” species in Europe and it has been treated as extinct in Lithuania, the latest gathering dating back to 1957. Occurring there at the northern border of its range, this species was recorded only once at the beginning of the 19th century and twice in separate localities in the middle of the 20th century. In summer 2015, after an interval of almost 60 years, C. parnassifolia was found in a new locality, more than 100 km north of those previously known. A very abundant population composed of vegetative and flowering (turion forming) individuals was spread over about 3.5 ha area in Lake Rūžas, known as a unique Lithuanian habitat of Aldrovanda vesiculosa. C. parnassifolia formed almost monodominant stands along swampy shores and less abundantly occurred in communities of floating leaved species (mainly Nuphar luteum and Potamogeton natans) at a depth of 0.5–1 m. It is likely that implemented measures to improve the habitat condition for A. vesiculosa were favourable for the appearance of C. parnassifolia.

Distribution and Ecology of a New Species of Water-lily, Nymphaea loriana (Nymphaeaceae), in Western Canada

Nymphaea loriana Wiersema, Hellq. & Borsch (Lori’s Water-lily) is a newly described, Canadian endemic species that has been found in central Manitoba and east-central Saskatchewan. To assess the status of a species, data regarding its distribution, population size, habitat, and search effort are needed. The purpose of this paper is to document these factors for this species. The extent of occurrence of N. loriana is approximately 15 100 km2 but the known area of occupancy is a mere 20 km2. The estimated population size of N. loriana is about 750 individual plants, although more may exist on poorly explored rivers and lakes within the extent of occurrence and possibly in northeastern Ontario. Nymphaea loriana occurs in fresh, stagnant, or slowly moving water in boreal lakes and rivers and is typically associated with N. leibergii (Dwarf Water-lily), Schoenoplectus tabernaemontani (Soft-stemmed Bulrush), Potamogeton natans (Floating-leaved Pondweed) and Nuphar variegata (Variegated Pondlily). Potential threats to the persistence of this species include low water quality resulting from mining, forestry, and agriculture, and changes to water flow because of dam construction and climate change. Monitoring known populations and searching for additional ones may be needed to assess the status of this species.

ЧИСЛА ХРОМОСОМ НЕКОТОРЫХ ВИДОВ СОСУДИСТЫХ РАСТЕНИЙ ИЗ БАССЕЙНА АМУРА И ИЗ ПРИМОРЬЯ (РОССИЙСКИЙ ДАЛЬНИЙ ВОСТОК), "БОТАНИЧЕСКИЙ ЖУРНАЛ"

Приведены новые результаты определения чисел хромосом (2n) для 44 видов из 39 родов и 22 семейств флоры России, в том числе для ряда редких и слабо изученных видов, а также некоторых сорных и ушедших из культуры. Впервые числа хромосом установлены у Elsholtzia serotina Kom. (2n = 16) и Heteropappusprobatovae Tzvel. (2n = 18), а для Calamagrostis macrolepis Litv., Eragrostis multica-ulis Steud., Potamogeton natans L., Quercus mongolica Fisch. ex Ledeb., Violayazawana Makino установлены новые (неизвестные ранее) значения чисел хромосом. Для многих таксонов хромосомные числа определены впервые в РФ или на РДВ.

Mechanical strength of stems in aquatic macrophytes

In populations of submerged macrophytes, individuals are selected in terms of resistance to the effect of hydrodynamic forces. The aim of this study was to check whether individuals growing in river water are more tensile and bending resistant than plants occurring in places not exposed to flow stress. We determined the ultimate tensile strength of stems in four macrophyte species, <em>Potamogeton natans</em>, <em>P. pectinatus</em>, <em>Batrachium fluitans</em> and <em>Chara fragilis</em>, which occur in two environmental variants: in running (current velocity of 0.1-0.6 m/s^-1) and stagnant water. In addition, flexure of <em>P. natans</em> stems from both environmental variants was examined. What is more, the type and arrangement of strengthening structures in stems of the plants under study were determined. <em>Potamogeton natans</em> stems are the most resistant to stretching (15.6±4.7 N), while stems of <em>P. pectinatus</em> (3.3±1.0 N) and <em>Batrachium fluitans</em> (2.6±0.8 N) are less resistant. <em>Chara fragilis</em> (0.6±0.3 N) has the least resistant stems. <em>Batrachium</em>, <em>Chara</em> and <em>P. pectinatus</em> are more resistant to stretching if they occur in a river current, whereas <em>P. natans</em>, in stagnant lake water. Ultimate bending moment of <em>P. natans</em> stems from lakes is also much greater than of stems from a river (9.75•10^-3 – 4.25•10^-3 Nm as compared to 2.12•10^-3 – 1.00•10^-3 Nm). The resistance of stems to breaking is directly proportional to the stem and thallus cross sectional areas. On the one hand, in all the studied <em>Cormophyta</em> species, the more resistant stems (in <em>P. natans</em> from stagnant water, in the others from running water) are thicker and characterised by a higher contribution of air spaces in the overall stem cross-section. On the other hand, the stems retain their species specific structure and have a similar proportion of strengthening elements.