THE MACROPHYTE FLORA AND VEGETATION OF THE PAUČKO LAKE (MT. KONJUH)

UDK: 581.9:574.5 (497.6) (285) The study presents the first data on biodiversity of macrophyte flora and vegetation of Paučko Lake, which is recognized as an area of great natural, landscape and hydrological value in the Protected Landscape “Konjuh”. Paučko Lake has a small surface and it’s located at 711 m a.s.l. in the catchment area of the Drinjača River. The aquatic and marsh vegetation were studied during spring and summer in 2018 using the traditional Zürich-Montpellier approach. The vegetation of Paučko Lake is comprised of aquatic and marsh associations of the classes Potamogetonetea Klika in Klika et Novák 1941 and Phragmito-Magnocaricetea Klika in Klika et Novák 1941. The following aquatic and marsh plant associations were identified: Myriophyllo-Potametum Soó 1934, Scirpo-Phragmitetum australis W. Koch 1926, Thelypterido palustris-Phragmitetum australis Kuiperex van Donselaar et al. 1961, Schoenoplectetum lacustris Chouard 1924, Typhetum latipholiae Lang. 1973 and Scirpetum silvatici Ht et H-ić prov. (in Ht et al.1974). Rare vulnerable taxa Thelypteris palustris Schott and Menyanthes trifoliata L. were recorded in emerged littoral communities, whose habitats are under successional changes caused by excessive macrophyte overgrowth by competitor species. Restoration measures are necessary to be taken to preserve the habitats of endangered species of the Paučko Lake.

Asexual Regeneration Response of Ilex canariensis Poir. to Management of the Canopy of Pinus radiata D.Don

Exotic afforestation can provide suitable conditions for native shade-tolerant species restoration without threatening native forests. This study analyzes the impact of different thinning intensities of the canopy of an exotic Pinus radiata stand on the asexual regeneration response of Ilex canariensis, a native laurel forest species in the Canary Islands, Spain. The results provide useful indications for how to manage P. radiata stands to promote recovery of native plant communities. For different stand treatments were selected: stand clear cut, low intensity thinning (10–15%), high intensity thinning (25%), and a control. The stand clear cut management revealed Ilex canariensis individuals with a higher number of sprouts and more leaf cover; however, the height of these sprouts two years after the cut did not reach the values of individuals prior to this management. Consequently, the vitality index following clear cut management is significantly lower with respect to the other treatments. Thinning management is shown not to be so useful to promote the growth and vitality of Ilex canariensis individuals. The results suggest that thinning over 50% could be more appropriate in the case of Pinus radiata, allowing resprouting of Ilex canariensis in the understory and improvement in the vitality index.

Sourcing and Propagation of Pontechium maculatum for Horticulture and Species Restoration

Pontechium maculatum, a species of ornamental, apicultural, health and medicinal value, is threatened in some Central European countries including Poland. Its propagation using seeds or in vitro techniques is needed for multiple applications including conservation. Generative propagation efficacy of P. maculatum plants representing different genetic resources (received from botanical gardens in Germany and in Poland) propagated from seeds or in tissue culture was assessed. Moreover, an efficient technique of propagation of P. maculatum using in vitro shoot culture from seedlings was elaborated for the first time. The highest propagation efficacy was noted for German plants of seed origin. The ability of seeds to germinate was similar for all plants; however, seeds were in a state of dormancy, which was broken by GA3. After two years of storage, the seeds still retained the ability to germinate though seeds from propagated in vitro plants germinated more poorly than those from seed-originated plants. The ploidy assessment showed that some in vitro-origin plants had altered DNA content. The results indicate that efficacy of generative propagation of P. maculatum is resource dependent. Furthermore, results suggest that cultivation in vitro influenced some generative features of examined species, which makes this way of P. maculatum propagation a valuable source of genetic variation and a potential breeding tool.

The Chinese chestnut genome: a reference for species restoration

Forest tree species are increasingly subject to severe mortalities from exotic pests, diseases, and invasive organisms, accelerated by climate change. Forest health issues are threatening multiple species and ecosystem sustainability globally. While sources of resistance may be available in related species, or among surviving trees, introgression of resistance genes into threatened tree species in reasonable time frames requires genome-wide breeding tools. Asian species of chestnut (Castaneaspp.) are being employed as donors of disease resistance genes to restore native chestnut species in North America and Europe. To aid in the restoration of threatened chestnut species, we present the assembly of a reference genome with chromosome-scale sequences for Chinese chestnut (C. mollissima), the disease-resistance donor for American chestnut restoration. We also demonstrate the value of the genome as a platform for research and species restoration, including new insights into the evolution of blight resistance in Asian chestnut species, the locations in the genome of ecologically important signatures of selection differentiating American chestnut from Chinese chestnut, the identification of candidate genes for disease resistance, and preliminary comparisons of genome organization with related species.