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91.
Katrin Rosenvald Ivika Ostonen Veiko Uri Mats Varik Leho Tedersoo Krista Lõhmus 《European Journal of Forest Research》2013,132(2):219-230
The influence of forest ageing on fine-root morphology and relations between fine-root and leaf characteristics is poorly studied. The aim of this study was to analyse age-driven changes in ectomycorrhizal roots (EcM roots) and leaf morphology in a chronosequence of silver birch (Betula pendula Roth.), which would provide a better understanding of adaptation responses and acclimation capacity of tree roots and leaves. The chronosequence included six age classes (3, 6, 14, 32, 45, and 60 years.). All stands had regenerated naturally and grew in a highly productive Oxalis forest site type in Estonia. Most changes in the morphology of EcM roots and leaves of silver birch occur faster at a young age. The functional parameters—mean specific area of EcM root (SRA) and leaf specific area (SLA) as well as leaf N—decreased with age. EcM root SRA and specific root length (SRL) decreased with stand age as a result of increased mean diameter and tissue density. In age classes of 6, 14, and 32 years, the total number of dominating EcM taxa was 34, and the distribution of four different dominating EcM exploration types (contact-, short-, medium-, long-distance) was similar. We conclude that high values of SRA, SLA, and leaf N measured in young silver birch stands indicate high activity of physiological processes necessary for fast-growing young trees. A decrease of SLA and SRA and N in the chronosequence of fertile stands of silver birch is most probably caused by down-regulation of growth, affecting simultaneously leaves and fine roots. 相似文献
92.
Mats Brink 《中国乳业》2006,(9):36
利乐的无菌后添加工艺的优势主要有三点,一是能加速客户产品的创新.二是具有高度的灵活性,三是能满足市场机会到来时应对市场的要求。 相似文献
93.
Wang J O'Keefe J Orr D Loth L Banks M Wakeley P West D Card R Ibata G Van Maanen K Thoren P Isaksson M Kerkhofs P 《Veterinary microbiology》2008,126(1-3):11-19
Six laboratories participated in a ring trial to evaluate the reliability of a real-time PCR assay for the detection of bovine herpesvirus 1 (BoHV-1) from extended bovine semen. Sets of coded samples were prepared and distributed to each of the laboratories. The sample panel contained semen from naturally and artificially infected bulls, serial dilutions of positive semen with negative semen, semen from uninfected seronegative bulls, negative semen spiked with virus, as well as serial dilutions of reference virus. The samples were tested using a previously validated real-time PCR assay for the detection of BoHV-1 in each participating laboratory. The PCR tests were conducted with four different real-time PCR amplification platforms, including RotorGene 3000, Stratagene MX 3000/4000, ABI 7900, and Roche LightCycler 2.0. Virus isolation using one set of samples was performed in one laboratory. The results of the laboratories were compared with one another, and with those of virus isolation. It was found that the sensitivity and specificity of the real-time PCR test was greater than those of virus isolation (82.7% versus 53.6% and 93.6% versus 84.6%, respectively). A high level of agreement on PCR testing results between the laboratories was achieved (kappa value 0.59-0.95). The results of this study indicate that the real-time PCR assay is suitable for the detection of BoHV-1 in extended semen, and would be a good substitute for the slow and laborious virus isolation, for the screening testing at artificial insemination centres and for international trade. 相似文献
94.
Breeding induces an inflammatory response in the uterus. The inflammation is a physiological reaction with the purpose of clearing the uterus from excess spermatozoa, seminal plasma, and bacterial contamination. Breeding-induced endometritis is transient and most mares resolve the inflammation within 24 to 36 hours. If a mare fails to resolve the breeding-induced inflammation before an embryo enters the uterus, the pregnancy is likely to be lost. Susceptibility to persistent breeding-induced endometritis occurs in approximately 15% of a normal brood mare population. 相似文献
95.
Recent evidence suggests that many Australian agamids show temperature‐dependent sex determination (TSD) with variation in sex determining mechanisms among closely related taxa. However, as shown in other vertebrates, sex ratios can also be influenced by genetic or phenotypic differences among females in their propensity to produce sons or daughters, and these influences might confound any thermal effects of incubation per se. To address these issues, we investigated the determinants of sex ratios in the mallee dragon Ctenophorus fordi, together with a detailed analysis of karyotypes. There was no detectable variation in sex ratios arising from variation among females, clutches or incubation temperatures, which might indicate genetic sex determination for this species. However, there was no evidence of cytologically distinct sex chromosomes using standard banding techniques. The sex ratio pattern in C. fordi strongly contrasts with the results for the congener Ctenophorus pictus, where sex ratios show variation among females. Thus, Australian agamids offer promising opportunities to address fundamental issues in sex ratio biology. 相似文献
96.
97.
Leonova S Shelenga T Hamberg M Konarev AV Loskutov I Carlsson AS 《Journal of agricultural and food chemistry》2008,56(17):7983-7991
Oil quality and content were analyzed in 33 accessions from 13 wild species and 10 accessions of cultivated oat. Wild oat species tended to have higher oil and 18:1 fatty acid (FA) contents and lower amounts of 18:2 and 18:3 FAs as compared to cultivated oats. In addition to common FAs, minor amounts of several hydroxy and epoxy FAs were also present in the oat oil and mainly confined to specific lipid classes. These unusual FAs included the previously reported 15-hydroxy 18:2 (Delta9,12) (avenoleic acid) mostly found among polar lipids and a novel 7-hydroxyhexadecanoic acid located to 1,2-diacylglycerol. The present study highlights the potential of making use of the existing germplasm, consisting of wild oat species, in breeding programs for achieving new oat varieties that produce a range of oils with different FA compositions as well as having high oil contents. However, in one matter, oats apparently lack genetic diversity and that is for oil qualities that are highly enriched in the omega 3 (omega-3) FA 18:3. Consequently, developing oat cultivars with highly unsaturated oils will need involvement of other techniques such as biotechnology. 相似文献
98.
Robert G. Björk Mats P. Björkman Mats X. Andersson Leif Klemedtsson 《Soil biology & biochemistry》2008,40(1):266-268
Temporal variation in soil microbial communities was studied at a mid-alpine environment in Latnjajaure, northern Sweden, using phospholipid fatty acid (PLFA) analysis. The results show two seasonal shifts in microbial composition. The first shift was associated with snowmelt and mainly related to a decrease in fungal PLFAs, accompanied by an increase in branched 17:0 and methylated PLFAs (biomarkers for Gram-positive- and actinobacteria, respectively), resulting in a decrease in the ratio of fungi-to-bacteria. The second shift occurred across the growing season, and was associated with a switch from shorter to longer PLFAs and an increase in 18:1ω7 (biomarker for Gram-negative bacteria). Vegetation, snow cover dynamics, and N turnover seem to be of minor importance to broad-scale microbial community structure in this area. 相似文献
99.
Igor Drobyshev Mats Niklasson Olafur Eggertsson Hans Linderson Kerstin Sonesson 《Annals of Forest Science》2008,65(5):512-512
100.
Igor Drobyshev Mats Niklasson Hans Linderson Kerstin Sonesson Matts Karlsson Sven G. Nilsson Jan Lanner 《Annals of Forest Science》2008,65(4):401-401