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The road toward Cd-safe rice:From mass selection to marker-assisted selection and genetic manipulation

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The Crop Journal 2023年第4期11卷 1059-1071页

作者： Liang Sun Yongjun Tan Caiyan Chen key laboratory of agro-ecological processes in subtropical region Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125HunanChina

Rice is an important dietary source of the toxic mineral cadmium(Cd) for populations in which rice is the main staple *** grown in agricultural soils that are contaminated with Cd,rice often accumulates excessive Cd into the grains,which is a serious threat to agricultural sustainability and human *** limit Cd accumulation in rice grains,studies on the genetic basis of Cd accumulation in rice have been carried out extensively,and some low-Cd rice varieties have also been developed in recent ***,the challenges in low-Cd rice breeding still exist because the outcomes of the current genetic improvements for low-Cd rice cannot fully meet the requirements for the development of Cd-safe rice at *** this review,we outline the progress in understanding the physiological mechanisms and the genetic nature of Cd accumulation in rice and summarize the strategies and outcomes of low-Cd rice breeding over the past *** graphing the physiological mechanism of Cd transport in the rice plant,three key steps and some underlying genes are summarized and ***,two genetic features of the natural variation in rice grain-Cd accumulation,the phenotypic plasticity and subspecies divergence,and the potential genetic explanations for these features are also ***,we summarize and discuss current progress and the potential issues in low-Cd rice breeding using different breeding *** hope to propose strategies for future success in the breeding of low-Cd rice varieties over the next decade.

关键词： Rice Cadmium-safe Cadmium-free Gene manipulation MAS

Selection of Submergence Tolerant Homozygous Line by STS Marker and Twice Submergence Stress

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Journal of Integrative Agriculture 2012年第12期11卷 1940-1947页

作者： LI Jin-jiang XIAO You-lun XIAO Guo-ying key laboratory of agro-ecological processes in subtropical region Institute of Subtropical Agriculture Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences key laboratory of agro-ecological processes in subtropical region Institute of Subtropical AgricultureChinese Academy of Sciences Hunan Plant Protection Institute College of Bioscience and Biotechnology Hunan Agricultural University

One sequence tagged site marker Subl-1 and twice submergence stress method were used in selection of submergence tolerant homozygous line from Sub-lBS, a submergence tolerant, bentazon sensitive and photoperiod-sensitive and/or thermo-sensitive genic male sterile line that developed by our laboratory. The results revealed that the original Sub-lBS was heterozygous in SublA-1 locus even though it was identical in almost all of agronomical traits and the segregation of SublA-1 was in accordance with Mendelian law based on chi-square test. And then the original Sub-IBS was divided into two groups： one was ofSublA-1 introgression and the other was not; and the two groups were tested by twice submergence stress method. After the first submergence stress that lasted for 12 d, the average plant heights were significant difference at the 1% level between the two groups. After recovery for 10 d, the second submergence stress sustained for 18 d was carried on; and the group with SublA-1 gene was found apparently tolerant than the other group in submergence tolerance.

关键词： bentazon sensitivity photoperiod-sensitive and/or thermo-sensitive genic male sterile line rice SublA-1gene submergence tolerance STS marker

Nitrous Oxide Emissions from a Masson Pine Forest Soil in subtropical Central China

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Pedosphere 2015年第2期25卷 263-274页

作者： CHEN Dan FU Xiao-Qing WANG Cong LIU Xin-Liang LI Hang SHEN Jian-Lin WANG Yi LI Yong WU Jin-Shui Changsha Research Station for Agricultural and Environmental Monitoring Key Laboratory of Agro-ecological Processes in Subtropical RegionInstitute of Subtropical AgricultureChinese Academy of Sciences

The forest ecosystem plays a pivotal role in contributing greenhouse gases to the *** order to characterize the temporal pattern of nitrous oxide(N_2O) emissions and identify the key factors affecting N_2O emissions from a Masson pine forest in a hilly red-soil region in subtropical central China,we measured the N_2O emissions in Jinjing of Hunan Province using the static chambergas chromatographic method for 3 years(2010-2012) and analyzed the relationships between the N_2O fluxes and the environmental *** results revealed that the N_2O fluxes over the 3 years varied from-36.0 to 296.7 μg N m^(-2) h^(-1),averaging 18.4±5.6 μg N m^(-2) h^(-1)(n=3).The average annual N_2O emissions were estimated to be 1.6±0.3 kg N ha^(-1) year^(-1).The N_2O fluxes exhibited clear intra-annual(seasonal) variations as they were higher in summers and lower in *** with other forest observations in the subtropics,N_2O emissions at our site were relatively high,possibly due to the high local dry/wet N deposition,and were mostly sensitive to variations in precipitation and soil ammonium N *** this work,a multiple linear regression model was developed to determine the influence of environmental factors on N_2O emissions,in which a category predictor of "Season" was intentionally used to account for the seasonal variation of the N_2O *** a model explained almost 40%of the total variation in daily N_2O emissions from the Masson pine forest soil studied(P<0.001).

关键词： environmental factors multiple linear regression model N deposition season subtropical forests

Effects of long-term phosphorus fertilization and straw incorporation on phosphorus fractions in subtropical paddy soil

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Journal of Integrative Agriculture 2015年第2期14卷 365-373页

作者： LI Yu-yuan YANG Rui GAO Ru WEI Hong-an CHEN An-lei LI Yong key laboratory of agro-ecological processes in subtropical region Institute of Subtropical Agriculture Chinese Academy of Sciences School of Environmental and Municipal Engineering Xi'an University of Architecture and Technology

Study on soil phosphorus（P） fraction is an important aspect in probing the mechanisms of soil P accumulation in farmland and mitigating its losing risk to the environment. We used a sequential extraction method to evaluate the impacts of long-term fertilization and straw incorporation on inorganic, organic, and residual P（Pi, Po, and Pre） fractions in the plow layer（0–20 cm） of acidic paddy soil in southern China. The experiment comprised of six treatments：（i） no fertilizer control（CK）;（ii） straw incorporation and green manure（SG）;（iii） nitrogen and P fertilizer（NP）;（iv） NP＋SG;（v） NP＋K fertilizer（NPK）; and（vi） NPK＋SG. The results showed that, compared to the initial total soil P content（TSP, 600 mg kg^–1 in 1990）, long-term（20 years） combined continuous P fertilizer and SG significantly increased P accumulation（by 13–20%） while single fertilization（39.3 kg P ha^–1 yr^–1） could maintain soil P status at the most. The average soil P fractions comprised of extractable Pi, Po, and Pre by 51.7, 33.4, and 14.9% in total soil P, respectively. With comparison of no fertilizer addition（CK）, long-term single fertilization significantly（P〈0.05） increased the accumulation of Na HCO3^–, Na OH^–, and HCl^– extractable Pi fractions accounting for two- to three-fold, while SG increased the accumulation of Na HCO3^– and Na OH^– extractable Piand Po accounting for 12–60%. Though the mobilization of Pre fractions was not significant（P〉0.05）, our data indicate that SG may partially substitute for fertilizer P input and minimizing soil P accumulation and subsequent environmental risk in the subtropical paddy soil.

关键词： soil organic P soil inorganic P sequential extraction method soil P accumulation soil P mobilization manure application

Effect of traditional Chinese medicine compounds on rumen fermentation, methanogenesis and microbial flora in vitro

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Animal Nutrition 2019年第2期5卷 185-190页

作者： Shui Ping Wang Wen Juan Wang Zhi Liang Tan Guo Wei Liu Cheng Fu Zhou Meng Jie Yin College of Animal Science Southwest University key laboratory of agro-ecological processes in subtropical region Institute of Subtropical AgricultureChinese Academy of Sciences

This study was conducted to investigate the effects of traditional Chinese medicine compounds(TCMC)on rumen fermentation, methane emission and populations of ruminal microbes using an in vitro gas production technique. Cablin patchouli herb(CPH), Atractylodes rhizome(AR), Amur Cork-tree(AC) and Cypsum were mixed with the weight ratios of 1:1:1:0.5 and 1:1:1:1 to make up TCMC1 and TCMC2,respectively. Both TCMC were added at level of 25 g/kg of substrate dry matter. In vitro gas production was recorded and methane concentration was determined at 12 and 24 h of incubation. After 24 h, the incubation was terminated and the inoculants were measured for pH, ammonia nitrogen, volatile fatty acids(VFA). Total deoxyribonucleic acid of ruminal microbes was extracted from the inocula, and populations were determined by a real-time quantitative polymerase chain reaction. Populations of total rumen methanogens, protozoa, total fungi, Ruminococcus albus, Fibrobacter succinogenes and Ruminococcus flavefaciens were expressed as a proportion of total rumen bacterial 16 S ribosomal deoxyribonucleic acid. Compared with the control, the 2 TCMC decreased(P < 0.05) total VFA concentration,acetate molar proportion, acetate to propionate ratio, gas and methane productions at 12 and 24 h,hydrogen(H) produced and consumed, and methanogens and total fungi populations, while the 2 TCMC increased(P < 0.05) propionate molar proportion. Traditional Chinese medicine compound 1 also decreased(P ≤ 0.05) R. flavefaciens population. From the present study, it is inferred that there is an effect of the TCMC in suppressing methanogenesis, probably mediated via indirect mode by channeling H2 utilized for methanogenesis to synthesis of propionate and direct action against the rumen microbes involved in methane formation. In addition, the relative methane reduction potential(RMRP) of TCMC2 was superior to that of TCMC1.

关键词： Traditional Chinese medicine compound Fermentation characteristics Methanogenesis Ruminal microbes In vitro

Influence of Humic Acid on Interaction of Ammonium and Potassium Ions on Clay Minerals

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Pedosphere 2013年第4期23卷 493-502页

作者： ZHANG Wen-Zhao CHEN Xiao-Qin ZHOU Jian-Min LIU Dai-Huan WANG Huo-Yan DU Chang-Wen State key laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences key laboratory of agro-ecological processes in subtropical region Institue of Subtropical Agriculture Chinese Academy of Sciences

Interaction of ammonium (NH+4) and potassium (K+) is typical in field soils. However, the effects of organic matter on interaction of NH+4 and K+have not been thoroughly investigated. In this study, we examined the changes in major physicochemical properties of three clay minerals (kaolinite, illite, and montmorillonite) after humic acid (HA) coating and evaluated the influences of these changes on the interaction of NH+4 and K+on clay minerals using batch experiments. After HA coating, the cation exchange capacity (CEC) and specific surface area (SSA) of montmorillonite decreased significantly, while little decrease in CEC and SSA occurred in illite and only a slight increase in CEC was found in kaolinite. Humic acid coating significantly increased cation adsorption and preference for NH+4, and this effect was more obvious on clay minerals with a lower CEC. Results of Fourier transform infrared spectrometry analysis showed that HA coating promoted the formation of H-bonds between the adsorbed NH+4 and the organo-mineral complexes. HA coating increased cation fixation capacity on montmorillonite and kaolinite, but the opposite occurred on illite. In addition, HA coating increased the competitiveness of NH+4 on fixation sites. These results showed that HA coating affected both the nature of clay mineral surfaces and the reactions of NH+4 and K+with clay minerals, which might influence the availability of nutrient cations to plants in field soils amended with organic matter.

关键词： adsorption illite kaolinite montmorillonite organo-mineral complex

Effects of Land Cover on Soil Organic Carbon Stock in a Karst Landscape with Discontinuous Soil Distribution

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Journal of Mountain Science 2014年第3期11卷 774-781页

作者： CHEN Xiang-bi ZHENG Hua ZHANG Wei HE Xun-yang LI Lei WU Jin-shui HUANG Dao-you SU Yi-rong key laboratory of agro-ecological processes in subtropical region Institute of Subtropical Agriculture Chinese Academy of Sciences Huanjiang Observation and Research Station for Karst Eco-systems Guangxi Institute of subtropical Crops

Land cover type is critical for soil organic carbon （SOC） stocks in territorial ecosystems. However, impacts of land cover on SOC stocks in a karst landscape are not fully understood due to discontinuous soil distribution. In this study, considering soil distribution, SOC content and density were investigated along positive successional stages （cropland, plantation, grassland, scrubland, secondary forest, and primary forest） to determine the effects of land cover type on SOC stocks in a subtropical karst area. The proportion of continuous soil on the ground surface under different land cover types ranged between 0.0% and 79.8%. As land cover types changed across the positive successional stages, SOC content in both the 0-20 cm and 20-50 cm soil layers increased significantly. SOC density （SOCD） within O-lOO cm soil depth ranged from 1.45 to 8.72 kg m^-2, and increased from secondary forest to primary forest, plantation, grassland, scrubland, and cropland, due to discontinuous soil distribution. Discontinuous soil distribution had a negative effect on 8OC stocks, highlighting the necessity for accurate determination of soil distribution in karst areas. Generally, ecological restoration had positive impacts on SOC accumulation in karst areas, but this is a slow process. In the short term, the conversion of croplandto grassland was found to be the most efficient way for SOC sequestration.

关键词： Soil organic carbon (SOC) Karst area Discontinuous soil distribution Land cover type Carbon sequestration potential

Rumen methane output and fermentation characteristics of gramineous forage and leguminous forage at differing harvest dates determined using an in vitro gas production technique

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Journal of Integrative Agriculture 2016年第2期15卷 414-423页

作者： ZHONG Rong-zhen FANG Yi SUN Hai-xia WANG Min ZHOU Dao-wei Northeast Institute of Geography and agroecology Chinese Academy of Sciences key laboratory of agro-ecological processes in subtropical region/Huanjiang Experimental Station of Karst agro-Ecosystem Institute of Subtropical AgricultureChinese Academy of Sciences

An in vitro rumen gas production technique was employed to determine the methane production and fermentation characteristics of Leymus chinensis and Medicago ruthenica at differing harvest dates（May 15,May 30,June 30,July 30,August 30 and September 30）,which are sequential phases within a single continuous growth of two 10-year-old *** quantify the rate of degradation and compare in vitro rumen fermentation characteristic,a logistic-exponential model,where initial gas volume was zero（LE_0）,was used to fit gas production and methane output ***,milled forage samples were incubated in vitro for 72 h at 39℃ and gas production was recorded intermittently throughout the incubation and gas samples were collected to measure methane *** showed that there were significant interactions between species and harvest for all chemical composition variables（P〈0.001） and condensed tannin content（P〈0.001）.*** produced more total gas and methane than ***（P〈0.001）.Both total gas and methane production decreased lineally（P〈0.001） with advancing harvest *** degradation rates of *** and *** harvested on September 30 were lower than those on the other harvest dates（P〈0.01）.*** fermented fluid had higher concentration of ammonia N（P〈0.05） and molar proportions of isobutyrate（P〈0.01）,valerate（P〈0.001） and isovalerate（P〈0.01） in total volatile fatty acids than L ***,concentration of isovalerate decreased cubically with advancing harvest date（P〈0.05）.In conclusion,*** produced less methane than *** and the total gas and methane production decreased with advancing harvest date for both species,which may be due to the changes in contents of chemical compositions and condensed tannin in forages.

关键词： methane production gramineous forages leguminous forages harvests in vitro rumen fermentation

Modified Method for Estimating Organic Carbon Density in Discontinuous Karst Soil Using Ground-Penetrating Radar and Geostatistics

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Journal of Mountain Science 2015年第5期12卷 1229-1240页

作者： LI Lei XIA Yin-hang LIU Shu-juan ZHANG Wei CHEN Xiang-bi ZHENG Hua QIU Hu-sen HE Xun-yang SU Yi-rong key laboratory of agro-ecological processes in subtropical region Institute of Subtropical Agriculture Chinese Academy of Sciences Huanjiang Observation and Research Station for Karst Eco-systems University of Chinese Academy of sciences Guangxi Institute of subtropical Crops

The conventional method which assumes the soil distribution is continuous was unsuitable for estimating soil organic carbon density(SOCD) in Karst areas because of its discontinuous soil distribution. The accurate estimation of SOCD in Karst areas is essential for carbon sequestration assessment in China. In this study, a modified method,which considers the vertical proportion of soil area in the profile when calculating the SOCD, was developed to estimate the SOCD in a typical Karst peak-cluster depression area in southwest China. In the modified method, ground-penetrating radar(GPR) technology was used to detect the distribution and thickness of soil. The accuracy of the method was confirmed through comparison with the data obtained using a validation method, in which the soil thickness was measured by excavation. In comparison with the conventional method and average-soil-depth method,the SOCD estimated using the GPR method showed the minimum relative error with respect to that obtained using the validation method. At a regional scale, the average SOCDs at depths of 0-20 cm and 0-100 cm, which were interpolated by ordinary kriging,were 1.49(ranging from 0.03-5.65) and 2.26(0.09-11.60) kgm-2based on GPR method in our study area(covering 393.6 hm2), respectively. Therefore, the modified method can be applied on the accurate estimation of SOCD in discontinuous soil areas such as Karst regions.

关键词： Discontinuous soil Organic carbondensity Soil distribution Estimation method Ground penetrating radar Karst Peak clusterdepression