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31.
Marjo Palviainen Leena Finér Hannu Mannerkoski Sirpa Piirainen Michael Starr 《Ecological Research》2005,20(6):652-660
Rapid growth of ground vegetation following clear-cutting is important to site productivity because vegetation retains nutrients in the ecosystem and can decrease nutrient leaching prior to stand re-establishment. Aboveground biomass, nutrient contents (N, P, K and Ca) and species composition of ground vegetation were determined 1 year before and for 7 years after clear-cutting of a mixed forest dominated by Norway spruce [Picea abies (L.) H. Karst.] in eastern Finland. The biomass of the feather mosses [Pleurozium schreberi Brid. and Hylocomium splendens (Hedw.) B. S.& G.] and the dwarf shrubs (Vaccinium myrtillus L. and V. vitis-idaea L.), which had dominated the ground vegetation in the mature forest, significantly decreased after clear-cutting. However, with the exception of H. splendens, these species had recovered within 3–5 years. The biomass of Deschampsia flexuosa (L.) Trin. considerably increased soon after clear-cutting, and Epilobium angustifolium L. appeared 3–5 years after cutting. These species contributed to the retention of nutrients not simply because of their biomass but also because of higher nutrient concentrations in their tissues. Total biomass and nutrient contents of the ground vegetation exceeded those of the pre-cutting levels. The proportion of ground vegetation biomass and nutrient contents represented by mosses decreased after cutting, while V. myrtillus, although reduced after cutting, remained a marked nutrient sink. The results suggest that H. splendens is the most sensitive species to cutting, but the biomass of P. schreberi, V. myrtillus and V. vitis-idaea return to initial levels soon after clear-cutting as do the nutrient contents of ground vegetation. 相似文献
32.
Changes in the Above- and Below-ground Biomass and Nutrient Pools of Ground Vegetation After Clear-cutting of a Mixed Boreal Forest 总被引:3,自引:0,他引:3
Marjo Palviainen Leena Finér Hannu Mannerkoski Sirpa Piirainen Michael Starr 《Plant and Soil》2005,275(1-2):157-167
Ground vegetation may act as a sink for nutrients after clear-cutting and thus decrease leaching losses. Biomass and nutrient
(N, P, K, Ca) pools of ground vegetation (mosses, roots and above-ground parts of field layer) were determined one year before
and five years after clear-cutting of a Norway spruce (Picea abies (L.) H. Karst.) dominated boreal mixed forest stand in
eastern Finland (63°51′ N, 28°58′ E). Before clear-cutting the average biomass of ground vegetation was 5307 kg ha−1, with nutrient contents of 46.9 kg N ha−11, 4.1 kg P ha−11, 16.2 kg K ha−11 and 13.9 kg Ca ha−11. The biomass and nutrient pools decreased after clear-cutting being lowest in the second year, the biomass decreasing by
46–65% in the cut plots. The nutrient pools decreased as follows: N 54–72%, P 36–68%, K 51–71% and Ca 57–74%. The decrease
in ground vegetation nutrient uptake, and the observed reduced depth of rooting may decrease nutrient retention after clear-cutting
and decomposing dead ground vegetation is a potential source of leached nutrients. These negative effects of clear-cutting
on the nutrient binding capacity of ground vegetation was short-lived since the total biomass and nutrient pools returned
to pre-cutting levels or were even greater by the end of the 5-year study period. 相似文献
33.
34.
Sander A. Peters Erwin Datema Dóra Szinay Marjo J. van Staveren Elio G.W.M. Schijlen Jan C. van Haarst Thamara Hesselink Marleen H.C. Abma-Henkens Yuling Bai Hans de Jong Willem J. Stiekema René M. Klein Lankhorst Roeland C.H.J. van Ham 《The Plant journal : for cell and molecular biology》2009,58(5):857-869
35.
36.
Anne Duplouy Luisa Woestmann Juan Gallego Zamorano Marjo Saastamoinen 《Insect Science》2018,25(2):284-296
In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males’ contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food‐deprivation, and is not influenced by developmental food‐limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult‐resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior. 相似文献
37.
38.
Tanacetum vulgare (Tansy) was established in vitro on Murashige and Skoog (MS) medium supplemented with naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP) using shoot tips and embryos. From petiole expiants 93% formed callus, and 27% produced shoots on MS medium containing 4.5 mg l-1 NAA and BAP. NAA alone induced root formation from leaf expiants. Up to 7 ×106 viable protoplasts were obtained by macerating 1 g of leaves in 0.5 % Macerozyme R-10, 1.0% Cellulase R10, and 1.0% Cellulysin. Cell division was observed 3–4 days after protoplast isolation at the optimum plating density of 0.2-0.4×106 cells ml-1. A total of 350 protoplast-derived calluses were produced on which nodules with meristematic zones developed. Roots regenerated on MS medium supplemented with BAP 3.0 mg 1-1, NAA 2.0 mg l-1, and 250 mg l-1 casein hydrolysate, however no shoots have been obtained yet.Abbreviations BAP
6-benzylaminopurine
- CH
casein enzymatic hydrolysate
- 2.4 D
dichlorophenoxyacetic acid
- FDA
fluorescein diacetate
- GA3
gibberellic acid
- IBA
indole butyric acid
- IPA
6-dimethylallylamino purine
- KIN
Kinetin
- MS
Murashige and Skoog medium
- NAA
-naphthaleneacetic acid 相似文献
39.
Marjo K. Hyt?nen Meharji Arumilli Anu K. Lappalainen Marta Owczarek-Lipska Vidhya Jagannathan Sruthi Hundi Elina Salmela Patrick Venta Eva Sarkiala Tarja Jokinen Daniela Gorgas Juha Kere Pekka Nieminen Cord Dr?gemüller Hannes Lohi 《PLoS genetics》2016,12(5)
One to two percent of all children are born with a developmental disorder requiring pediatric hospital admissions. For many such syndromes, the molecular pathogenesis remains poorly characterized. Parallel developmental disorders in other species could provide complementary models for human rare diseases by uncovering new candidate genes, improving the understanding of the molecular mechanisms and opening possibilities for therapeutic trials. We performed various experiments, e.g. combined genome-wide association and next generation sequencing, to investigate the clinico-pathological features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified pathogenic variants in the canine SLC37A2 (truncating splicing enhancer variant), SCARF2 (truncating 2-bp deletion) and FAM20C (missense variant) genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease), for which SLC37A2 is a new candidate gene. SLC37A2 is a poorly characterized member of a glucose-phosphate transporter family without previous disease associations. It is expressed in many tissues, including cells of the macrophage lineage, e.g. osteoclasts, and suggests a disease mechanism, in which an impaired glucose homeostasis in osteoclasts compromises their function in the developing bone, leading to hyperostosis. Mutations in SCARF2 and FAM20C have been associated with the human van den Ende-Gupta and Raine syndromes that include numerous features similar to the affected dogs. Given the growing interest in the molecular characterization and treatment of human rare diseases, our study presents three novel physiologically relevant models for further research and therapy approaches, while providing the molecular identity for the canine conditions. 相似文献
40.
Marjo Neuvonen Eija Pouta Jenni Puustinen Tuija Sievänen 《Journal for Nature Conservation》2010,18(3):224-229
Understanding the relationship between the number of visits to national parks and their characteristics is crucial for park planning and management. Visitation has a key role in existing national parks, but also in assessing the social and economic impacts of new parks. This study examined how the natural characteristics of a park, the recreation facilities and services inside a park and tourist services in surrounding communities, as well as the park's location in relation to the population, are associated with the number of visits. Regression modelling was used to analyse the visitation to thirty-five national parks in Finland. The results demonstrated that recreation opportunities, the number of biotopes, the provision of trails and the park's age increase the number of visits, while the park location in relation to the population only has a significant effect in southern Finland. The results imply the dual role of national parks as resource-based destinations if the natural characteristics are outstanding, but also as more user-oriented areas fulfilling recreation needs in the most populated parts of the country. 相似文献