Wang X.,Lanzhou University |
Song Y.,Lanzhou University |
Ma Y.,Hebei Normal University of Science and Technology |
Zhuo R.,Chinese Academy of Forest |
Jin L.,Lanzhou University
Environmental Pollution | Year: 2011
In order to evaluate Cd tolerance in wide-ranging sources of alfalfa (Medicago sativa) and to identify Cd tolerant genotypes which may potentially be useful for restoring Cd-contaminated environments, thirty-six accessions of alfalfa were screened under hydroponic culture. Our results showed that the relative root growth rate varied from 0.48 to 1.0, which indicated that different alfalfa accessions had various responses to Cd stress. The candidate fragments derived from differentially expressed metallothionein (MT) genes were cloned from leaves of two Cd tolerant genotypes, YE and LZ. DNA sequence and the deduced protein sequence showed that MsMT2a and MsMT2b had high similarity to those in leguminous plants. DDRT-PCR analysis showed that MsMT2a expressed in both YE and LZ plants under control and Cd stress treatment, but MsMT2b only expressed under Cd stress treatment. This suggested that MsMT2a was universally expressed in leaves of alfalfa but expression of MsMT2b was Cadmium (Cd) inducible. © 2011 Elsevier Ltd. All rights reserved.
Liang Z.,Fuzhou University |
Ling F.,Fuzhou University |
Chen E.,Chinese Academy of Forest
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2013
Considering the influence of the posterior and the statistic distributions of full-polarimetric SAR data, we proposed a new classification method of full polarimetric SAR data. First, the covariance matrix of polarization SAR data was converted to nine intensity quantities with normal distribution. Then, the probability of occurance for each class was calculated with iterative initial classification. Finally, the nine intensity images were classified with maximum likelihood classification method taking the probabilities of occurance for the classes into account. We applied the developed method to the ALOS PALSAR full-polarimetric data of Xunke County, Heilongjiang Province. The overall accuracy is 81.34% and the Kappa coefficient 0.84. The developed method showed higher accuracy than that from the traditional maximum likelihood classifier. This indicates that our method can improve the accuracy of classification.
Xu D.,Chinese Institute of Scientific and Technical Information |
Li C.,Chinese Academy of Forest |
Song X.,Kaifeng Academy of Agriculture and Forestry science |
Song X.,Henan Agricultural University
2012 2nd International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2012 - Proceedings | Year: 2012
China is one of the countries that seriously suffered desertification in the world, and it is very meaningful to develop a quantitative method to assess desertification at large scale. In this study, the MODIS images were selected as the data resources, and NDVI, land surface albedo, soil water index (the reflectance of MODIS band 7) were selected as the indicators for assessing desertification. Based on building the indicator rule sets of different desertification grades in different sub-regions, the authors developed a quantitative method for desertification assessment by using decision tree model. The results showed that, the method developed in this study that can reflect the heterogeneity of land surface at large scale, and the overall accuracy of the method can reach 85.5%, which was suitable to assess desertification at large scale. Based on using this method to assess the desertification in farming-pastoral region of north China in 2000 and 2010, the authors found that the areas of lands that experienced desertification reversion and desertification expansion were almost consistent, and the spatial distribution of these regions existed obvious differences. © 2012 IEEE.
Xu D.,Institute of Science and Technical Information of China |
Li C.,Chinese Academy of Forest |
Song X.,Henan Agricultural University |
Ren H.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Catena | Year: 2014
The farming-pastoral region of North China is a region that has suffered from serious desertification, and the multiple transitional characteristics in this region make it very difficult to link the progress of desertification to the driving forces behind it. This paper mainly focuses on the dynamics of desertification over the past 10years and their relationship to climate change and human activity. According to the MODIS images in 2000 and 2010, the farming-pastoral region had experienced significant desertification dynamics over the past 10years. The area of regions that had undergone desertification reversion and expansion were 186,240km2 and 199,525km2 respectively, and the spatial distribution of these regions showed great heterogeneity. The relationship between desertification dynamics and their driving forces was investigated by comparing the change in the NPP that was induced by climate change and human activity for each pixel that experienced desertification reversion and expansion. From 2000 to 2010, the coupling of climate change and human activity was the dominant factor behind desertification reversion. However, the human activity was the dominant factor that controlled the desertification expansion process between 2000 and 2010. The driving processes of desertification also had considerable spatial heterogeneity, and the dominant factors behind desertification reversion and expansion in each sub-region were not completely the same. So, the scale effect must be considered when explaining the results from similar studies. © 2014 Elsevier B.V.
Wang X.,Lanzhou University |
Li X.,Lanzhou University |
Zhang J.,Lanzhou University |
Feng G.,Lanzhou University |
And 4 more authors.
Australian Journal of Crop Science | Year: 2011
Alfalfa (Medicago sativa L.) is one of the most important forage species worldwide. In order to discover the mechanism of low seed production, two cytological experiments were carried out to investigate ovule numbers per floret and ovule fertility among nine different alfalfa varieties. Results showed that there was significant difference in ovule numbers per floret among the nine alfalfa varieties (P<0.05), and the number of ovules per floret ranged from 7 to 13. The highest ovule number was Huangyangzhen while the lowest one was Ladak. Results also showed that there was significant difference in ovule fertility among different alfalfa varieties (P<0.05), and the average percentage of ovule sterility was 34.90%. The highest percentage of ovule sterility was observed in Russia with 49.07%, while the lowest percentage sterility was 25.20% in Zhungeer. Alfalfa seed set under artificial-pollination showed a significantly linear correlation with ovules per floret (P<0.05) but no significant correlation under self-pollination treatments. The results showed that the fertile ovules per pistil accounted for 51-75% with total ovules per pistil, but the percentages of actual seed yields with potential seed yields of the nine varieties were only 2.49-6.06%, which suggested that ovule sterility maybe just one of the limiting factors for alfalfa seed production. Our results indicated that female fertility of alfalfa was remained in the nature reproductive ability, which was probably due to the breeding selection program of alfalfa that was mainly focused on yield or quality, but seldom on seed production.
Wang X.-Y.,CAS Institute of Remote Sensing Applications |
Guo Z.-F.,CAS Institute of Remote Sensing Applications |
Pang Y.,Chinese Academy of Forest |
Qin W.-H.,NASA |
And 2 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2011
The study of forest composition, structure and dynamic changes in the forestry remote sensing has been a hot issue. Forest canopy structure has an important effect on the energy distribution of solar radiation and the biophysical parameters of vegetation canopies. It is difficult for the computer simulation method to study radiation regime and estimate the structural parameters of forest canopies at large-scale. Simplified coniferous model, Radiosity-graphics combined model (RGM) was applied to investigate the radiance distribution of forest canopy in this study. Combined the forest growth model ZELIG and L-systems to render 3D forest scenarios, and the RGM model was used to calculate bidirectional reflectance factor(BRF) at visible and near-infrared regions. Finally, the spectra was compared between the simulated by RGM model and multi-angle the compact high resolution imaging spectrometer(CHRIS) data in the experimental field of Changbai mountain. The results show that they were both agreed well. It has an important value for inversion of the structure parameters of forest canopy with RGM model and multi-angle CHRIS data.
liu M.-H.,Chinese Academy of Forest |
Zhu J.-L.,CAS Shenyang Institute of Applied Ecology |
Zhu J.-L.,University of Chinese Academy of Sciences |
Xin Z.-M.,Chinese Academy of Forest |
And 6 more authors.
Chinese Journal of Ecology | Year: 2015
A portable wind tunnel, which was designed for investigating the seed dispersal by wind, was built by the Institute of Applied Ecology, Chinese Academy of Sciences and the Experimental Center of Desert Forest, Chinese Academy of Forestry. The wind tunnel was designed to satisfy the requirements of investigations at diaspore, plant individual and landscape scales. Therefore, the experiment section was determined as 2 mX2 m and the segments were fixed by a fluctuation way. The experiments on test and evaluation of the flow field, carried out under three wind speeds of 4.6, 5.7 and 8.0 m • s-1, indicated that the flow stability coefficient was less than 4%, the transverse uniformity was less than 7%, the turbulence was about 6%, and the thicknesses of the bottom boundary layer and side wall boundary layer were 28 cm and '5 cm, respectively. This study suggests that the wind tunnel meets the experiment requirements of seed dispersal by wind at diaspore, plant individual and landscape scales. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved.
Liang Y.,Central South University |
Jiang X.M.,Central South University |
Hu Q.,Central South University |
Li X.,Central South University |
And 4 more authors.
Indian Journal of Biochemistry and Biophysics | Year: 2014
3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) plays an important role in catalyzing the first committed step of isoprenoids biosynthesis in mevalonic acid (MVA) pathway. Here, we cloned a full-length transcript of Paris fargesii Franch. The full-length cDNA of P. fargesii HMGR (Pf-HMGR, GenBank accession no. JX508638) was 1,973 bp and contained a 1,728 bp ORF encoding 576 amino acids. Sequence analysis revealed that the deduced Pf-HMGR had high similarity with HMGRs from other plants, including Ricinus communis (77%), Litchi chinensis (76%), Michelia chapensis (75%) and Panax quinquefolius (72%). It had a calculated molecular mass of about 62.13 kDa and an isoelectric point (pI) of 8.47. It contained two transmembrane domains, two putative HMGR binding sites and two NADP(H)-binding sites. The predicted 3-D structure revealed that Pf-HMGR had a similar spatial structure with other plant HMGRs. Three catalytic regions, including L-domain, N-domain and S-domain were detected by structural modeling of HMGR. Tissue expression analysis revealed that Pf-HMGR was strongly expressed in roots and stems than in leaves. Taken together, our data laid a foundation for further investigation of HMGR's functions and regulatory mechanisms in plants.
Zhu J.,CAS Shenyang Institute of Applied Ecology |
Zhu J.,University of Chinese Academy of Sciences |
Liu M.,Chinese Academy of Forest |
Xin Z.,Chinese Academy of Forest |
And 2 more authors.
Journal of Plant Ecology | Year: 2016
Aims How seed dispersal distance is related to various factors is a major challenge for seed ecologists. However, there are different answers as to which factor is most important in determining wind dispersal distance. This study is to quantitatively describe the relationship between various factors and primary wind dispersal distance of winged diaspores. Methods The dispersal distances of five morphologies of winged diaspores in Zygophyllum xanthoxylum (Zygophyllaceae) were measured under controlled conditions in a wind tunnel. The explanatory power of environmental factor (i.e. wind speed), plant trait (i.e. release height) and diaspore attributes (i.e. wing loading (the ratio of diaspore mass to projected area), settlement-velocity, shape index (the variance of diaspore length, width and thickness)) to the variation in dispersal distance was assessed by releasing diaspores at varying wind speeds and release heights. Important Findings Wind speed and seed release height were the strongest explanatory factors to dispersal distance, contributing 41.1% and 24.8% (P < 0.01) to total variation in dispersal distance, respectively. Wind speed accounted more for relatively light disc-shaped seeds than for relatively heavy spherical seeds. Wing loading, shape index and settlement-velocity explained 9.0% (P < 0.01), 1.4% (P < 0.01) and 0.9% (not significant) of the variation in dispersal distance, respectively. From disc-shaped to four-winged diaspores, relative contributions of wing loading and shape index decreased but contribution of settlement-velocity increased. The relative contributions of various factors to wind seed dispersal distance may change with the change in seed morphology. © The Author 2015. Published by Oxford University Press on behalf of the Institute of Botany, Chinese Academy of Sciences and the Botanical Society of China.