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Wuhan, China

Wan Z.,Nanjing Forestry University | Wan Z.,Huangshan University | Li Y.,Nanjing Forestry University | Chen Y.,Nanjing Forestry University | And 3 more authors.
Phytoparasitica | Year: 2013

Epidemic outbreaks of rust disease have been observed in most of the black cottonwood (Populus trichocarpa) plantations in the south of China in recent years. However, the exact pathogens that cause rust disease in this area remain largely unknown. In this study we collected rust fungi from black cottonwood plantations at four different places in the south of China. Examination of these fungi by scanning electron microscope (SEM) and light microscopy (LM) revealed that the morphological characteristics of urediniospores for all the collected fungi were very close to that of Melampsora larici-populina. Using species-specific primers, these pathogens were confirmed to be M. larici-populina. In a survey on the resistance to rust disease for 88 genotypes of black cottonwood, nine potential candidate genotypes were detected that may be free from infection of rust pathogen. The results of this study provide essential information for breeding new rust-resistant black cottonwood cultivars. © 2013 Springer Science+Business Media Dordrecht.

Feng X.-H.,Chinese Academy of Forestry | Cheng R.-M.,Chinese Academy of Forestry | Xiao W.-F.,Chinese Academy of Forestry | Wang R.-L.,Chinese Academy of Forestry | And 3 more authors.
Chinese Journal of Ecology | Year: 2011

Longer growth season has been confirmed due to the elevated temperature in recent decades. Though the changes in the duration of growth season could affect tree productivity, it's unclear how the growth season with different initiating temperature affects the radial growth of tree. In order to investigate the effects of growth season's variability in temperature to the radial growth of Masson pine (Pinus massoniana) and search for the sensitive temperature to the growth, old Masson pine stands in Hanzhong, the northwest margin of north subtropical region, were chosen as test objects, with their tree ring width index chronology from 1945 to 2009 measured by dendrochronology method. The air temperatures on the first day, last day, and in the whole growth season as well as the active accumulative temperature during growth season were determined based on the daily mean temperature of Hanzhong, and the relationships between the temperatures and chronology were analyzed. The results showed that the growth season with initiating temperature 6.0 °C-7.5 °C had negative effects on the tree ring width index chronology, with 6.0 °C being most significan. 10.5 °C on the last day had significant positive effects on tree ring growth. 10.0 °C and 10.5 °C in growth season were significantly positively correlated with the tree ring growth, and the active accumulative temperature during growth season was also significantly positively correlated with the growth. These sensitive temperatures were respectively corresponding to the onset of photosynthesis, needle emergence in spring, and shutting down of cambium activity in autumn. Our study suggested that elevated temperature led to the changes in phenophase, and thereby, affected the radial growth of P. massoniana in Hanzhong.

Wang R.,Chinese Academy of Forestry | Cheng R.,Chinese Academy of Forestry | Xiao W.,Chinese Academy of Forestry | Feng X.,Chinese Academy of Forestry | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011

North Subtropical Area of China, located in the transition from warm temperate zone to the subtropical, is more sensitive to environmental changes. Therefore, study on the relationship between masson pine (Pinus Massoniana) tree-ring width data and NDVI in north subtropical region where masson pine growth is more sensitive to changes of climatic factors, is of much importance to reveal how the terrestrial ecosystems respond to global climate change. As the northern boundary of masson pine natural distribution, Nanzheng county of Shanxi Province and Jigongshan National Nature Reserve of Henan Province were selected. Using masson pine tree-ring width indices, monthly normalized difference vegetation index (NDVI) and climatic data from 1982 to 2006, the relationships between tree-ring width indices, NDVI, and climatic data, including monthly mean temperature, precipitation and the Palmer Drought Severity Index (PDSI) were analyzed firstly. Then, the relationship between tree-ring width indices and NDVI of forest was explored. The results showed that North Subtropical vegetation index NDVI was influenced by the hydrothermal conditions, and monthly NDVI was mainly positive to monthly mean temperature, negatively related to monthly mean precipitation and PDSI. In addition, the correlation coefficient between NDVI and temperature was larger than other factors. Masson pine radial growth was positive to temperature of last growing season, while negative to precipitation and PDSI. Temperature and precipitation during the growing season of the same year promoted the pine radial growth, the influences of PDSI on Nanzheng county and Jigognshan were opposite. In northern subtropical region, the relationship between masson pine tree-ring width and forest NDVI was not significant (P > 0. 05). However, NDVI of Nanzheng County in March, August and December were significantly associated with two chronologies, NDVI of Jigongshan region in September associated with the RES chronology with the biggest correlation coefficient. Through analyzing synthetically, we figure out that the tree growth of Nanzheng county was mainly affected by temperature, that of Jigongshan was influenced by the interaction of temperature and precipitation. In conclusion, we imply that long time series of ring width data does not reflect well the long-term vegetation changes in the northern subtropical region, and it is unreasonable to model and reconstruct the long-term vegetation changes and productivity using tree radial growth. Therefore, the further study is still required to reconstruct regional NDVI using tree-ring width chronologies in the North Subtropical Region.

Induri B.R.,West Virginia University | Ellis D.R.,West Virginia University | Slavov G.T.,West Virginia University | Slavov G.T.,Aberystwyth University | And 5 more authors.
Tree Physiology | Year: 2012

Understanding genetic variation for the response of Populus to heavy metals like cadmium (Cd) is an important step in elucidating the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa Torr. & Gray and Populus deltoides Bart. was characterized for growth and performance traits after Cd exposure. A total of 16 quantitative trait loci (QTL) at logarithm of odds (LOD) ratio ≥2.5 were detected for total dry weight, its components and root volume. Major QTL for Cd responses were mapped to two different linkage groups and the relative allelic effects were in opposing directions on the two chromosomes, suggesting differential mechanisms at these two loci. The phenotypic variance explained by Cd QTL ranged from 5.9 to 11.6 and averaged 8.2 across all QTL. A whole-genome microarray study led to the identification of nine Cd-responsive genes from these QTL. Promising candidates for Cd tolerance include an NHL repeat membrane-spanning protein, a metal transporter and a putative transcription factor. Additional candidates in the QTL intervals include a putative homolog of a glutamate cysteine ligase, and a glutathione-S-transferase. Functional characterization of these candidate genes should enhance our understanding of Cd metabolism and transport and phytoremediation capabilities of Populus. © The Author 2012. Published by Oxford University Press. All rights reserved.

Li S.,Nanjing Forestry University | Zhang X.,Hubei Forestry Academy | Yin T.,Nanjing Forestry University
Journal of Microbiology and Biotechnology | Year: 2010

In this paper, we analyzed the microsatellites in the transcript sequences of the whole Laccaria bicolor genome. Our results revealed that, apart from the triplet repeats, length diversification and richness of the detected microsatellites positively correlated with their repeat motif lengths, which were distinct from the variation trends observed for the transcriptional microsatellites in the genome of higher plants. We also compared the microsatellites detected in the genic regions and in the nongenic regions of the L. bicolor genome. Subsequently, SSR primers were designed for the transcriptional microsatellites in the L. bicolor genome. These SSR primers provide desirable genetic resources to the ectomycorrhizae community, and this study provides deep insight into the characteristics of the microsatellite sequences in the L. bicolor genome.

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