19 research outputs found
Defence Is a Priority in Female Juveniles and Adults of Taxus baccata L.
Female individuals of dioecious plants invest their resources more in storage and defence, and the males have higher nitrogen content invested in the production of pollen grains. An unresolved problem is whether this strategy occurs only in sexually mature plants or can also occur in juvenile plants. To answer this, Taxus baccata (L.) needles from the mature plants and rooted cuttings (juveniles) in a pot experiment were compared for the content of carbon, nitrogen, starch, total non-structural carbohydrates (TNC), and total phenolic compounds (TPhC). The results indicate that the differences between sexes occurred mainly in sexually mature plants, where the starch content was higher in females and nitrogen in males. However, the novelty of the results is that TPhC was generally higher in females than males in both adults and juveniles, suggesting that defence is a priority for females from an early age. We do not know if this is an innate trait because the strobili production (albeit at a very low level) of juveniles was observed in all individuals after the autumn of the first year. We found no effect of fertilization on sex-specific response in the pot experiment, which may be related to the lower reproductive effort of juveniles
The yew (Taxus baccata L.) of the Cisowy Jar reserve near Olecko
The present paper describes the current situation of yews in the Cisowy Jar Reserve: number, their state of health, height and diameter structure, and the sex ratio. In the result only 25 yews were found. Their state of health was relatively good, but many yews that grew on very heavily shaded stands were characterized by little height accretion and greater leaf reduction than those growing on more sunny positions. There is no continuity of population. No specimens in the height range between 51-100 cm were found. Sparse seedlings die in first years after appearing. Active human help is necessary to protect and to reconstruct the yew population in the reserve
Zastepcze zbiorowiska brzozy [Betula pendula Roth.] w strefie zamierania lasu w Gorach Izerskich
Variation in sex expression in Polish and Ukrainian populations of Taxus baccata L.
The aim of the present study was to analyse the occurrence of monoecious individuals in selected populations of Taxus baccata in Poland and Ukraine. The investigation showed the monoecy in Taxus baccata to be extremely rare phenomenon. Only four cosexual individuals were found in three by seven populations examines and the frequency of monoecy was 0.13% on average among 2986 trees verified. Isolated seeds were found on individuals with large number of male flowers. Only one tree was found with numerous macro- and microstrobiles
Dendroecological differences between Taxus baccata males and females in comparison with monoecious Abies alba
Taxus baccata L. is a rare and endangered dioecious species in Europe. Species of this mating system
are considered to be the most vulnerable to extinction. It is believed that one reason for this state may be the
uneven reproductive effort and different habitat requirements of the two sexes. Silver fir and European yew
have very similar ecological requirements, but fir is a monoecious species. The aim of this study was to compare
the growth rate andthe effect of precipitation andtemperature on the annual tree-ring width of silver fir
and both sexes of European yew. The study site was the Knyazhdvir reserve in western Ukraine, located near
the limit of the geographical range of both species. Knyazhdvir reserve is the site of one of the last yew populations
in Europe with a large number of individuals (about 15,000 individuals above 1.3 m height) growing
alongside fir.Woodsamples were taken from 15 male and15 female specimens of T. baccata andfrom 15 specimens
of A. alba and were subjected to a standard dendrochronological procedure. The results showed high
positive correlation between the temperatures in February andMarch andthe tree-ring width in the studied
species and genders. The response of annual tree-ring width to the examined climatic factors was relatively similar
in yew andfir. However slight differences were foundbetween males andfemales of T. baccata. The growth
rate decreased more rapidly in females compared to males, probably following sexual maturation. Precipitation
in April hada positive effect on firs andfemale yews, but not on male yews. This confirms earlier reports of the
requirement of female specimens of dioecious species for a higher humidity than male individuals
Influence of initial light intensity and deer browsing on Taxus baccata saplings: a six years field study
European yew (Taxus baccata L.) is a rare species, but is the focus of great interest because of the species recovery attempts and its use in medicine. The aim of this study was to determine the optimum conditions for the development of the young generation of this species. Four-year old yew seedlings were grown under artificial light reduction: 2, 8, and 30%, as well as in full light. The seedlings were then planted in natural conditions in fenced and unfenced areas. The results of six years field studies indicated that the
greatest impact on survival was shown by the light conditions from the period before planting under the canopy of trees. Seedlings from the 2 and 8% of light showed the greatest mortality. The reason was the sudden change in light conditions, because at the time of planting (early spring), there was no reduction of light under deciduous trees. Almost all of the unfenced yew seedlings were grazed by deer, but yew survival in the unfenced group was surprisingly high despite the permanent grazing. This was explained by
the high resistance of yew to cutting and the protection of seedlings by a dense layer of Rubus. The results indicated that yew trees require protection against animals for normal development, even if animals have not previously had contact with Taxus and that yew seedlings are very sensitive to sudden changes in light. Both conclusions can be applied in the development of natural and artificial regeneration of European yew and other endangered plants
Development of microsatellite markers for horse-chestnut (Aesculus hippocastanum), their polymorphism in natural Greek populations, and cross-amplification in related species
New nuclear microsatellite markers (SSRs) were developed for Aesculus hippocastanum, a relict
tree species from the Balkan Peninsula. The development of microsatellites was done using the Illumina
MiSeq PE300 platform. Out of a set of 500 SSRs designed, a subset of 13 loci was tested using 290 individuals from seven natural populations. Twelve species-specific loci were polymorphic. The number of alleles
per locus ranged from 2 to 17 and expected heterozygosity from 0.089 to 0.800 with a mean value of 0.484.
The population of Kalampaka had the lowest value of allelic richness (2.63) and gene diversity in comparison to the remaining populations. STRUCTURE analysis confirmed isolation of population Mariolata from
the southern edge of the species range and genetic similarity among populations from the Pindos Mts. Additionally, the utility of new SSRs in 29 individuals from nine other Aesculus taxa was tested. Eleven markers
gave polymorphic products for all tested species. For 24 individuals, a high-quality product was obtained
for each marker. Results confirmed the utility of specific markers for future population genetics studies
Pinus uliginosa G.E. Neumann ex Wimm. — a new taxon for the Ukrainian flora
Приведена краткая информация о находке нового для флоры Украины таксона гибридного происхождения — Pinus uliginosa G.E. Neumann ex Wimm. на олиготрофном болоте в долине р. Мшана в окрестностях с. Осмолода (Горганы, Ивано-Франковская область). Описано основные морфологические параметры деревьев. Дана ценотическая характеристика локалитета, впервые для Украины приводятся описания ассоциаци Pinetum rotundatae Kastner et Flossner 1933 corr. Mucina 1993 класса Oxycocco-Sphagnetea Br.-Bl. et Tx. ex Westhoff et al. 1946