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Yuan J.-h.,Beijing Forestry University | Yuan J.-h.,CAS Institute of Botany | Yuan J.-h.,Gansu Forestry Technological College | Cheng F.-Y.,Beijing Forestry University | And 2 more authors.
PLoS ONE | Year: 2012

Background: Tree peonies are great ornamental plants associated with a rich ethnobotanical history in Chinese culture and have recently been used as an evolutionary model. The Qinling Mountains represent a significant geographic barrier in Asia, dividing mainland China into northern (temperate) and southern (semi-tropical) regions; however, their flora has not been well analyzed. In this study, the genetic differentiation and genetic structure of Paeonia rockii and the role of the Qinling Mountains as a barrier that has driven intraspecific fragmentation were evaluated using 14 microsatellite markers. Methodology/Principal Findings: Twenty wild populations were sampled from the distributional range of P. rockii. Significant population differentiation was suggested (F ST value of 0.302). Moderate genetic diversity at the population level (H S of 0.516) and high population diversity at the species level (H T of 0.749) were detected. Significant excess homozygosity (F IS of 0.076) and recent population bottlenecks were detected in three populations. Bayesian clusters, population genetic trees and principal coordinate analysis all classified the P. rockii populations into three genetic groups and one admixed Wenxian population. An isolation-by-distance model for P. rockii was suggested by Mantel tests (r = 0.6074, P<0.001) and supported by AMOVA (P<0.001), revealing a significant molecular variance among the groups (11.32%) and their populations (21.22%). These data support the five geographic boundaries surrounding the Qinling Mountains and adjacent areas that were detected with Monmonier's maximum-difference algorithm. Conclusions/Significance: Our data suggest that the current genetic structure of P. rockii has resulted from the fragmentation of a formerly continuously distributed large population following the restriction of gene flow between populations of this species by the Qinling Mountains. This study provides a fundamental genetic profile for the conservation and responsible exploitation of the extant germplasm of this species and for improving the genetic basis for breeding its cultivars. © 2012 Yuan et al. Source

Wen A.C.,Gansu Agricultural University | Wen A.C.,Gansu Forestry Technological College | Zhang H.J.,Gansu Agricultural University
Advanced Materials Research | Year: 2014

An experiment was carried out to determine the effect of water deficit regulated with mulched drip irrigation on plant growth of processing tomato in an arid environment. The results indicated that Water deficit had little effect on plant height of processing tomato at full fruiting and late fruiting except that at seedling and flowering. Still, no effect of water deficit regulation on stem diameter was found at all measured growth stages. However, leaf area index and dry matter was significantly (p<0.05) reduced at all growth stages of tomato subjected to high water deficit at seedling. Therefore, low level of water deficit at seedling while free of deficit from flowering to late fruiting as well as proper levels of water deficit at flowering or full fruiting or late fruiting while free of deficit at seedling could be used to effectively regulate leaf growth and dry matter accumulation of processing tomato in arid areas. © (2014) Trans Tech Publications, Switzerland. Source

Liu Y.,Tianshui Normal University | Liu Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Yang H.,Gansu Forestry Technological College | Li X.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Xing Z.,University of New Brunswick
Applied Soil Ecology | Year: 2014

Biological soil crusts (BSCs) cover up to 70% of the sparsely-vegetated areas in arid and semiarid regions throughout the world and play a vital role in dune stabilization in desert ecosystems. Soil enzyme activities could be used as significant bioindicators of soil recovery after sand burial. However, little is known about the relationship between BSCs and soil enzyme activities. The objective of this study was to determine whether BSCs could affect soil enzyme activities in revegetated areas of the Tengger Desert. The results showed that BSCs significantly promoted the activities of soil urease, invertase, catalase and dehydrogenase. The effects also varied with crust type and the elapsed time since sand dune stabilization. All the soil enzyme activities tested in this study were greater under moss crusts than under cyanobacteria-lichen crusts. The elapsed time since sand dune stabilization correlated positively with the four enzyme activities. The enzyme activities varied with soil depth and season, regardless of crust type. Cyanobacteria-lichen and moss crusts significantly enhanced all test enzyme activities in the 0-20. cm soil layer, but negatively correlated with soil depth. All four enzyme activities were greater in the summer and autumn than in spring and winter due to the vigorous growth of the crusts. Our study demonstrated that the colonization and development of BSCs could improve soil quality and promote soil recovery in degraded areas of the Tengger Desert. © 2014 Elsevier B.V. Source

Zhang H.J.,Gansu Agricultural University | Zhang J.D.,Gansu Forestry Technological College
Applied Mechanics and Materials | Year: 2014

A trial was conducted to investigate water sensitivity index (WSI) and water production function (WPF) of processing tomato subjected to water deficits in an arid environment. The WSI at various growth stages of processing tomato were maintained and a periodical WPF was established based on Blank model. The maximum WSI of processing tomato was marked at flowering with 0.7108 while the minimum was maintained at seedling with -0.0854. In addition, WSI was extremely lower at full fruiting compared to at flowering but notably higher than at seedling. Therefore, processing tomato was extremely sensitive to water deficit at flowering and high levels of soil moisture contents should be maintained while was not sensitive to water deficit at seedling and high levels of water deficits could be controlled without causing yield reduction. © (2014) Trans Tech Publications, Switzerland. Source

Yuan J.-H.,Beijing Forestry University | Yuan J.-H.,Gansu Forestry Technological College | Cheng F.-Y.,Beijing Forestry University | Cheng F.-Y.,National Flower Engineering Research Center | Zhou S.-L.,CAS Institute of Botany
International Journal of Plant Sciences | Year: 2010

In Paeonia, hybridization is an important path for both the development of new cultivars and species formation in nature, but the characterization of hybrids has long been a problem. To establish the relationship among Paeonia yananensis, P. jishanensis, and P. rockii, we sampled 159 individuals from 11 populations around the core population of P. yananensis. Samples were subjected to morphological analysis of 22 characters and molecular analysis of three chloroplastDNA(cpDNA) fragments and 14 microsatellites. Paeonia yananensis was distinguishable from the other two species on the basis of morphological characteristics. The phylogenetic tree based on three intergenic spacers in the chloroplast genome (petB-petD, rps16-trnQ, and psbA-trnH) demonstrated that P. yananensis was very closely related to P. jishanensis. However, analysis of 14 microsatellite loci revealed that P. yananensis shared a considerable number of alleles with both P. jishanensis and P. rockii. These results demonstrated that P. yananensis (P × 3 yananensis) is of hybrid origin, with P. jishanensis as a maternal parent and P. rockii as a paternal parent. Our success in documenting the hybrid origin of P. yananensis suggests that combined evidence from morphology, maternally inherited cpDNA, and biparentally inherited microsatellites could serve as a powerful tool in hybrid studies. © 2010 by The University of Chicago. All rights reserved. Source

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