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931.
Wibke Himmelsbach Eduardo J. Treviño-Garza Humberto González-Rodríguez Marco A. González-Tagle Marco V. Gómez Meza Oscar A. Aguirre Calderón A. Eduardo Estrada Castillón Ralph Mitlöhner 《European Journal of Forest Research》2012,131(2):355-367
Water availability and salt excess are limiting factors in Mexican mixed pine-oak forest. In order to characterise the acclimatation
of native species to these stresses, leaf water (Ψw) and osmotic potentials (Ψs) of Juniperus flaccida, Pinus pseudostrobus and Quercus canbyi were measured under natural drought and non-drought conditions under two different aspects in the Sierra Madre Oriental.
Factorial ANOVA revealed significant differences in Ψw and Ψs between two aspects, species and sampling dates. In general, all species showed high predawn and low midday values that declined
progressively with increasing drought and soil–water loss. Seasonal and diurnal fluctuation of Ψw and Ψs were higher for J. flaccida and Q. canbyi than for P. pseudostrobus. Leaf Ψw and Ψs were mainly correlated with soil water content, while Ψs of P. pseudostrobus were hardly correlated with environmental variables. Thus, species have different strategies to withstand drought.
P. pseudostrobus was identified as a species with isohydric water status regulation, while J. flaccida and Q. canbyi presented water potential patterns typical for anisohydric species. The type of water status regulation may be a critical
factor for plant survival and mortality in the context of climate change. Nevertheless, for precise conclusions about the
advantages and disadvantages of each type, further long-term investigations are required. 相似文献
932.
Ashraful Alam Antti Kilpeläinen Seppo Kellomäki 《European Journal of Forest Research》2012,131(3):655-667
An ecosystem model (Sima) was utilised to investigate the impact of forest management (by changing both the initial stand
density and basal area thinning thresholds from current recommendations) on energy wood production (at energy wood thinning
and final felling) and management-related carbon dioxide (CO2) emissions for the energy wood production in Finnish boreal conditions (62°39′ N, 29°37′ E). The simultaneous effects of
energy wood, timber and C stocks in the forest ecosystem (live and dead biomass) were also assessed. The analyses were carried
out at stand level during a rotation period of 80 years for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) growing in different fertility sites. Generally, the results showed that decreased basal area thinning thresholds,
compared with current thinning, reduced energy wood (logging residues) and timber production, as well as carbon stocks in
the forest ecosystem. Conversely, increased thinning thresholds increased energy wood production (ca. 1–27%) at both energy
wood thinning and final felling and reduced CO2 emissions (ca. 2–6%) related to the production chain (e.g. management operations), depending on the thinning threshold levels,
initial stand density, species and site. Increased thinning thresholds also enhanced timber production and carbon stocks in
the forest ecosystem. Additionally, increased initial stand density enhanced energy wood production for energy wood thinning
for both species, but this reduced energy wood production at final felling for Scots pine and Norway spruce. This study concluded
that increases in both initial stand density and thinning thresholds, compared with the current level, could be useful in
energy wood, timber and carbon stocks enhancement, as well as reducing management-related CO2 emissions for energy wood production. Only 2.4–3.3% of input of the produced energy (energy wood) was required during the
whole production chain, depending on the management regime, species and sites. However, a comprehensive substitution analysis
of wood-based energy, in respect to environmental benefits, would also require the inclusion of CO2 emissions related to ecosystem processes (e.g. decomposition). 相似文献
933.
934.
935.
936.
Patrizia Erre Innocenza Chessa Concepción Muñoz-Diez Angjelina Belaj Luis Rallo Isabel Trujillo 《Genetic Resources and Crop Evolution》2010,57(1):41-54
The genetic relationships within and between wild and cultivated olives were examined and clarified in an isolated and restricted
area, such as the Mediterranean island of Sardinia. Wild (21 individuals) and cultivated olive trees (22 local cultivars from
a germplasm collection and 35 ancient trees) were genotyped by means of 13 SSR loci. Five cases of synonymy were observed
and nine distinct genotypes were identified in the collection. Five novel genotypes were also detected among the ancient trees.
Differences on the allelic composition and heterozygosity levels were found between wild and cultivated trees. Model-based
clustering method classified the olive trees into two major gene pools: (a) wild genotypes and (b) local cultivars from the
collection and from heritage olives. Regarding the cultivated plant material, we observed that: (a) most of the Sardinian
cultivars shared the same allelic profiles with the ancient cultivated trees and (b) the majority of these cultivars and all
the novel genotypes were not related to any other cultivars included in this study. These findings as well as the detection
of unique alleles and a certain wild genetic background at some cultivars revealed by the Bayesian analysis may indicate their
autochthonous origin. The synonymy cases found between local cultivars and Italian mainland cultivars indicate interchange
of genetic material among these growing areas, suggesting thus a possible allochthonous origin. The information obtained can
assist in the management of an olive collection and sheds some light on the survival of true oleasters and the origin of Sardinian
cultivars. 相似文献
937.
Yang Yang Yuezhi Pan Xun Gong Moutian Fan 《Genetic Resources and Crop Evolution》2010,57(8):1239-1248
Citrus hongheensis is a critically endangered species endemic to the Honghe river region in southeastern Yunnan, China. Its genetic diversity
and differentiation were investigated using Inter-Simple Sequence Repeat (ISSR) markers. One hundred primers were screened,
and a total of 245 loci were amplified from seven natural populations by 13 informative and reliable primers. Of these 245
ISSR loci, 233 were polymorphic and the detected variations revealed a relatively high level of intraspecific genetic diversity.
At the population level, the mean percentage of polymorphic loci (PPB) was 36.50%, while the average expected heterozygosity (He) and Shannon diversity index (Ho) were 0.1327 and 0.1972, respectively. At the species level (across all populations), PPB was 95.10%, while He and Ho were 0.3520 and 0.5195, respectively. A high Gst value (0.6247) indicated that there is significant differentiation among populations, which was confirmed by AMOVA analysis
(Φst = 0.6420). Pairwise genetic identity (I) values among populations ranged from 0.6341 to 0.7675, with a mean of 0.7008. We propose that the high level of genetic
differentiation may be the result of habitat fragmentation and limited gene flow (Nm = 0.1502). For effective in situ conservation and population restoration of C. hongheensis it will be important to maintain historical processes, including high outbreeding rates, sufficient gene flow, and large
effective population sizes. 相似文献
938.
Saowaluck Bua-in Yingyong Paisooksantivatana 《Genetic Resources and Crop Evolution》2010,57(3):405-414
The genetic relatedness among 51 accessions, 14 species of the genus Zingiber and genetic variability of a clonally propagated species, Zingiber montanum (Koenig) Link ex Dietr., from Thailand were studied using random amplified polymorphic DNA (RAPD) profiles. Twenty-nine random
primers gave reproducible amplification banding patterns of 607 polymorphic bands out of 611 scored bands accounting for 99.40%
polymorphism across the genotypes. Jaccard’s coefficient of similarity varied from 0.119 to 0.970, indicative of distant genetic
relatedness among the genotype studied. UPGMA clustering indicated eight distinct clusters of Zingiber, with a high cophenetic correlation (r = 1.00) value. Genetic variability in Z. montanum was exhibited by the collections from six regions of Thailand. High molecular variance (87%) within collection regions of
Z. montanum accessions was displayed by AMOVA and also explained the significant divergence among the sample from six collection regions.
Our results indicate that RAPD technique is useful for detecting the genetic relatedness within and among species of Zingiber and that high diversity exists in the clonally propagated species, Z. montanum. 相似文献
939.
Anna A. Filatenko Karl Hammer Sulaiman Al Khanjari Andreas Buerkert 《Genetic Resources and Crop Evolution》2010,57(8):1135-1139
Due to its geographic position on the northeastern tip of the Arabian Peninsula and its sea trade relationships with Asia,
East Africa and the Middle East, Oman has for millennia been at the cross-roads of inter-regional exchange of cultivated plants.
This is reflected in recent findings of new cultivars of banana (Musa spp.) and wheat (Triticum spp.) in remote oases of the Hajar Mountains in northern Oman. Material collected in 2003 and 2004 contained six new botanical
varieties of wheat which are described here. One of them belongs to the tetraploid T. aethiopicum, the others are hexaploid. 相似文献
940.
Francesco Carimi Francesco Mercati Loredana Abbate Francesco Sunseri 《Genetic Resources and Crop Evolution》2010,57(5):703-719
A total of 82 grapevine genotypes were sampled from several areas of the Italian region of Sicily where vineyards are widely
spread. The grapevines were characterized using six microsatellite markers (VVS2, VVMD5, VVMD7, VVMD27, VrZAG62 and VrZAG79)
to evaluate genetic diversity. Thirty-seven of the 82 cultivars sampled had their names quoted in historical and literary
sources, while 45 cultivars from old vineyards did not have their names reported in ancient literature. According to their
genetic profiles at SSR loci, 70 different cultivars were found, while interesting cases of synonymies (Regina and Moscato
bianco, Alicante and Dolcetta or among different clones of Zibibbo and Catarratto) and cases of homonymy (Frappato and Nerello
Mascalese) were discovered. Several genetic parameters were calculated to assess the efficacy of the loci chosen in this work.
Pairwise genetic distances between all cultivars were calculated. A dendrogram representing the genetic similarities among
cultivars was depicted using the UPGMA method to investigate their relationships, explaining them from a historical point
of view. The cluster distribution of cultivars clearly does not reflect their current geographical distribution, suggesting
successive introductions of cultivars in Sicily from different areas of origin. 相似文献