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Zheng Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zheng Y.,University of Chinese Academy of Sciences | Yang Q.,CAS Shenyang Institute of Applied Ecology | Xu M.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 7 more authors.
Scandinavian Journal of Forest Research | Year: 2012

Masson pine (Pinus massoniana Lamb.), a native species widely distributed in temperate forests in central China, and Loblolly pine (Pinus taeda L.), an exotic tree species introduced to China from southeastern United States, are dominant evergreen conifers that play a pivotal role in maintaining forest structure and functions for the region. We examined the effects of freezing on these species with chlorophyll fluorescence and electrolyte leakage using both field- and laboratory-based experiments in September 2009 and January 2010, respectively. We found that freezing could cause a greater impact on the Loblolly pine than the Masson pine. Although the two species showed similar values of F v/F m and electrolyte leakage before freezing, the Masson pine needles showed lower F v/F m and higher electrolyte leakage ratios than those of the Loblolly pine when treated in low temperatures (-15 to 0°C). We also found that cold-acclimation was crucial for both species to adapt to low temperatures with the F v/F m ratio decreased approximately by 80% in the first freezing hour for the non-acclimated needles of both species while the cold-acclimated needles showed little changes in the F v/F m ratio. This finding is also supported by our measurements of electrolyte leakage. These results suggest that the Loblolly pine could be more susceptible to freezing damages than the Masson pine in central China. © 2012 Copyright Taylor and Francis Group, LLC.


Yang Q.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yang Q.,University of Chinese Academy of Sciences | Xu M.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Chi Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 7 more authors.
Journal of Plant Ecology | Year: 2012

Aims: Although stem CO 2 efflux is critical to ecosystem carbon and energy balance and its feedback to future climate change, little information is available on stem CO 2 efflux and its responses to temperature, especially in subtropical China. This study aims to (i) evaluate the temporal and spatial variations of stem CO 2 efflux of three species, including oak (Quercus acutissima Carr.), masson pine (Pinus massoniana Lamb.) and loblolly pine (Pinus taeda Linn.) in subtropical China and (ii) analyze the temperature sensitivity of stem CO 2 efflux in the three species based on 2-year field measurements.Methods: We measured stem CO 2 efflux and stem temperature (at 3 cm depth) of the three species using the horizontally oriented soil chamber technique from September 2008 to August 2010. We also conducted a 24-h measurement to examine the diurnal variation of stem CO 2 efflux in three consecutive days in April 2009.Important findings: The temporal dynamics of stem CO 2 efflux followed the change of the stem temperature in a 3-cm depth with a bell-shaped curve in the three species. Stem temperature explained 77-85% of the seasonal variations of stem CO 2 efflux over the entire study period in the three species. The temperature sensitivity (Q10) of stem CO 2 efflux was obviously different among the three species with higher Q10 value found in oak (2.24) and lower values in the coniferous species (1.76 and 1.63). Our results also showed that the Q10 values of stem CO 2 efflux in all the three species were lower in the growing season than that in the non-growing season, indicating that the growth and maintenance respiration had different temperature responses. Moreover, we found that the temperature-normalized stem CO 2 efflux (R10) changed greatly between the growing and non-growing seasons in oak and masson pine, but not in loblolly pine. Additionally, we also found that in the non-growing season, the principal factor responsible for the spatial variation of stem CO 2 efflux among the 15 sampling trees was sapwood volume, whereas in the growing season, stem CO 2 efflux was closely related to annual dry-matter production in the three subtropical species. © 2011 The Author. Published by Oxford University Press on behalf of the Institute of Botany, Chinese Academy of Sciences and the Botanical Society of China. All rights reserved.


Niu J.,Beijing Forestry University | Zhu B.,Beijing Forestry University | Cai J.,Beijing Forestry University | Li P.,Jigongshan National Nature Reserve | And 8 more authors.
PLoS ONE | Year: 2014

Quantitative real time reverse transcription polymerase chain reaction has been applied in a vast range of studies of gene expression analysis. However, real-time PCR data must be normalized with one or more reference genes. In this study, eleven putative consistently expressed genes (ACT , TUA, TUB, CYP, DNAj, ELFA, F-box27, RPL12, GAPDH, UBC and UBQ) in nine Siberian Apricot Germplasms (including much variability) were evaluated for their potential as references for the normalization of gene expression by NormFinder and geNorm programs. From our studies, ACT, UBC, CYP, UBQ and RPL12 as suitable for normalization were identified by geNorm, while UBC and CYP as the best pair by NormFinder. Moreover, UBC was selected as the most stably expressed gene by both algorithms in different Siberian Apricot seed samples. We also detected that a set of three genes (ACT, CYP and UBC) by geNorm as control for normalization could lead to accurate results. Furthermore, the expression levels of oleosin gene were analyzed to validate the suitability of the selected reference genes. These obtained experimental results could make an important contribution to normalize real-time PCR data for gene expression analysis in Siberian Apricot Germplasm. © 2014 Niu et al.


Niu J.,Beijing Forestry University | Hou X.,Beijing Forestry University | Fang C.,Jigongshan National Nature Reserve | An J.,Beijing Forestry University | And 9 more authors.
Gene | Year: 2015

The Lindera glauca, an economically and ecologically important tree species, has emerged as a novel potential plant for the intensive studies of essential oil owing to its characteristic aroma and medicinal property in distinct tissues. However, the transcriptome information and molecular research on this species is still unknown to date. To reveal the formation and accumulation mechanism of essential oil in distinct L. glauca tissues, it is crucial to analyze transcriptome and to identify the full repertoire of potential unigenes involved in terpenoid biosynthesis. In this paper, the transcriptomes of the roots, sarcocarps, stems, leaves and kernels of L. glauca were analyzed for the first time by using short-read sequencing technology (Illumina). A total of 27.2. GB valid reads (the average length = 92.7. bp) was obtained from distinct L. glauca tissues, and then assembled de novo into 264,831 unigenes by Trinity strategy (mean size = 560.2. bp). The resulting 98,141 unigenes (38%) of all the assembled unigenes were annotated in multiple public databases, of which 114 potential unigenes were identified to be involved in the terpenoid biosynthetic accumulation in L. glauca. Additionally, the differential expression profiles revealed 675, 697, 432, 1702 and 844 high tissue-specificity expressions of unigenes in the roots, sarcocarps, stems, leaves and kernels of L. glauca, respectively. Overall, these obtained comprehensive unigene resources will contribute to advance the research regarding the specific plant and more specifically discovery of genes participating in the terpenoid pathway and its regulation in specific tissues of the L. glauca, but also could help the understanding of the differential accumulation of secondary metabolites in distinct plant tissues. © 2015 Elsevier B.V.

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