Impact of climate change on maize yield in China from 1979 to 2016          下载免费PDF全文

Jian-zhai WU  Jing ZHANG  Zhang-ming GE  Li-wei XING  Shu-qing HAN  Chen SHEN  Fan-tao KONG 《农业科学学报》2021,20(1):289-299

Climate change severely impacts agricultural production, which jeopardizes food security. China is the second largest maize producer in the world and also the largest consumer of maize. Analyzing the impact of climate change on maize yields can provide effective guidance to national and international economics and politics. Panel models are unable to determine the group-wise heteroscedasticity, cross-sectional correlation and autocorrelation of datasets, therefore we adopted the feasible generalized least square(FGLS) model to evaluate the impact of climate change on maize yields in China from 1979–2016 and got the following results:(1) During the 1979–2016 period, increases in temperature negatively impacted the maize yield of China. For every 1°C increase in temperature, the maize yield was reduced by 5.19 kg 667 m–2(1.7%). Precipitation increased only marginally during this time, and therefore its impact on the maize yield was negligible. For every 1 mm increase in precipitation, the maize yield increased by an insignificant amount of 0.043 kg 667 m–2(0.014%).(2) The impacts of climate change on maize yield differ spatially, with more significant impacts experienced in southern China. In this region, a 1°C increase in temperature resulted in a 7.49 kg 667 m–2 decrease in the maize yield, while the impact of temperature on the maize yield in northern China was insignificant. For every 1 mm increase in precipitation, the maize yield increased by 0.013 kg 667 m–2 in southern China and 0.066 kg 667 m–2 in northern China.(3) The resilience of the maize crop to climate change is strong. The marginal effect of temperature in both southern and northern China during the 1990–2016 period was smaller than that for the 1979–2016 period.  相似文献   

‘哈伯’南天竹组织培养和快速繁殖     

张俊林  樊靖  胡玉春  杨浩  胡绍庆  沈柏春 《农学学报》2021,11(10):63-68

为建立‘哈伯’南天竹组织培养和种苗繁育技术体系,以半木质化带芽茎段为外植体材料开展植株再生研究。通过观察对比试验法、L₉(3⁴)正交试验设计完全随机法、极差分析、显著性检验、LSD多重比较,探讨了‘哈伯’南天竹组培的最适培养基配方。试验结果表明：最佳诱导培养基为MS + 6-BA 2.0 mg/L + IBA 0.1 mg/L +蔗糖30 g/L,诱导萌动率71.77%,成活率85.51%;最佳增殖培养基为WPM +6-BA 1.5 mg/L + IBA 0.01 mg/L + 蔗糖30 g/L,增殖系数6.3;最佳生根培养基为1/2 MS+ IBA 0.5 mg/L + NAA 1.0 mg/L + 蔗糖20 g/L + AC 0.2 g/L,生根率97.63%;试管苗移入泥炭土:珍珠岩=3:2(V/V)混合基质中,移栽成活率96.67%。该试验建立了高效稳定的组培快繁技术体系,得到的组培苗后代能够稳定的保持母本优良性状,为工厂化育苗提供了技术支撑。  相似文献   

Construction of Brucella abortus A19 VirB Promoter Deletion Strain and Study on Its Biological Characteristics     

DENG Xiaoyu  HE Jinke  YANG Qin  YI Jihai  WANG Yueli  XI Jing  WANG Zhen  CHEN Chuangfu 《中国畜牧兽医》2020,47(3):864-872

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圈养华南虎血液生化指标正常参考值初步研究     

任小冬  黄勉  李石洲  雷胜桥  虞坚颐  刘力军 《林业与环境科学》2021,(1)

以国内部分圈养的健康华南虎Panthera tigris amoyensis作为研究对象,通过收集华南虎血液生化报告和采集华南虎血液样本检测建立样本数据,血样检测采用自动血液生化分析仪干式试剂片生化技术测定,测定血液生化指标包括血糖(GLU)、总蛋白(TP)、总胆固醇(CHOL)、总胆红素(TBIL)、肌酐(CREA)等。得到华南虎血液生化共38项指标的正常参考值范围(95%概率),其中几项主要指标正常值范围如下:GLU(2.82-11.55)mmol/L、TP(56.58-85.93)g/L、CHOL(3.32-8.66)μmol/L、TBIL(0-5.30)μmol/L、CREA(52-349)μmol/L等。统计结果显示,雌雄华南虎间血液生化指标的部分项目有差异(P <0.05),幼龄组和成年组间各项生化指标差异不显著(P >0.05),与其他虎亚种相关血液生化报道的生化指标部分有差别。华南虎血液生化指标正常参考值范围不同于其他虎亚种,建立华南虎血液生化指标正常值对华南虎的饲养管理、疾病诊治预防和保育繁殖研究工作有重要作用。  相似文献   

不同杀青方式龙井茶自动化连续生产线加工工艺探讨   总被引：2，自引：0，他引：2  

金晶  邵宗清  张兰美 《茶叶》2017,43(3)

文章剖析了不同杀青方式龙井茶自动化连续生产线的设备配置和工艺流程,对生产线的龙井茶品质进行感官评价,为龙井茶生产线推广应用提供借鉴。  相似文献   

河西走廊玉米普通锈病生物学特性测定     

雷玉明  郑天翔  邢会琴 《耕作与栽培》2020,(6):15-17

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Screening and Verification of Low Nitrogen Tolerant and Nitrogen Sensitive Cotton Germplasm     

Wang Zhun  Zhang Hengheng  Dong Qiang  Gui Huiping  Wang Xiangru  Pang Nianchang  Li Yongnian  Niu Jing  Jin Dingsha  Wang Sujie  Zhang Xiling  Song Meizhen 《棉花学报》2021,32(6):538-551

[Objective] The aim of this study is to evaluate nitrogen efficient cotton germplasms and improve nitrogen use efficiency. [Method] Eighty cotton germplasms were selected and evaluated in the hydroponic experiment under low (0.25 mmol·L^－1) and high (5 mmol·L^－1) nitrogen concentration. Different traits for screening were identified and nitrogen use efficiency types were classified. Field experiments were also performed for comparison and confirmation of the identified germplasms. [Result] The results showed that there were significant differences in the total plant dry matter, shoot nitrogen accumulation and nitrogen absorption efficiency in cotton germplasms at the two nitrogen levels. Based on coefficient of variation, principal component analysis and correlation, six traits including total plant dry matter, shoot dry matter, root dry matter, total nitrogen accumulation, shoot nitrogen accumulation and nitrogen absorption efficiency were used as screening indicators. According to the Heatmap clustering analysis and the nitrogen efficiency comprehensive index, two germplasms (Lu05R59 and CCRI 69) were identified as low nitrogen tolerant and nitrogen efficient, and two germplasms (Coker 201 and Xinluzhong 30) as low nitrogen sensitive and nitrogen inefficient. The results of field experiment were consistent with the results of the hydroponic culture at the seedling stage. [Conclusion] It was finally determined that Lu05R59 and CCRI 69 were the low nitrogen tolerant and nitrogen efficient germplasms, and Coker 201 and Xinluzhong 30 were low nitrogen sensitive and nitrogen inefficient germplasms. The results of these studies provide the possibility for screening and rapid identification of nitrogen use efficiency in cotton at the seedling stage, and provide the ideal materials and theoretical basis for further study of cotton nitrogen efficient.  相似文献   

Regulatory role of l-proline in fetal pig growth and intestinal epithelial cell proliferation     

Jing Wang  Bi'e Tan  Jianjun Li  Xiangfeng Kong  Minjie Tan  Guoyao Wu 《动物营养（英文）》2020,6(4):438

l-proline (Pro) is a precursor of ornithine, which is converted into polyamines via ornithine decarboxylase (ODC). Polyamines plays a key role in the proliferation of intestinal epithelial cells. The study investigated the effect of Pro on polyamine metabolism and cell proliferation on porcine enterocytes in vivo and in vitro. Twenty-four Huanjiang mini-pigs were randomly assigned into 1 of 3 groups and fed a basal diet that contained 0.77% alanine (Ala, iso-nitrogenous control), 1% Pro or 1% Pro + 0.0167% α-difluoromethylornithine (DFMO) from d 15 to 70 of gestation. The fetal body weight and number of fetuses per litter were determined, and the small and large intestines were obtained on d 70 ± 1.78 of gestation. The in vitro study was performed in intestinal porcine epithelial (IPEC-J2) cells cultured in Dulbecco''s modified Eagle medium-high glucose (DMEM-H) containing 0 μmol/L Pro, 400 μmol/L Pro, or 400 μmol/L Pro + 10 mmol/L DFMO for 4 d. The results showed that maternal dietary supplementation with 1% Pro increased fetal weight; the protein and DNA concentrations of the fetal small intestine; and mRNA levels for potassium voltage-gated channel, shaker-related subfamily, member 1 (Kv1.1) in the fetal small and large intestines (P < 0.05). Supplementing Pro to either gilts or IPEC-J2 cells increased ODC protein abundances and polyamine concentrations in the fetal intestines and IPEC-J2 cells (P < 0.05). In comparison with the Pro group, the combined administration of Pro and DFMO reduced the expression of ODC protein and spermine concentration in the fetal intestine, as well as the concentrations of putrescine, spermidine and spermine in IPEC-J2 cells (P < 0.05). Meanwhile, the percentage of cells in the S-phase and the mRNA levels of proto-oncogenes c-fos and c-myc were increased in response to Pro supplementation, whereas depletion of cellular polyamines with DFMO increased tumor protein p53 (p53) mRNA levels (P < 0.05). Taken together, dietary supplementation with Pro improved fetal pig growth and intestinal epithelial cell proliferation via enhancing polyamine synthesis.  相似文献   

基于SRP模型的南雄丹霞梧桐自然保护区生态脆弱性评价     

李芮芝  胡希军    杜心宇  雷雨菁  张伟 《西北林学院学报》2021,36(5):152-160

通过建立生态敏感性-生态恢复力-生态压力度（SRP）模型，利用主成分分析法确定指标权重，对南雄丹霞梧桐自然保护区进行生态脆弱性评价。结果表明:1）从生态敏感性角度，研究区高度脆弱和极度脆弱面积分别为756.50 hm²和773.58 hm²，占比之和>50%，主要集中分布于北部和中部，而主要影响要素为土壤侵蚀强度，其次为距水源距离；2）从生态恢复力角度，研究区不脆弱和轻度脆弱面积分别为777.71 hm²和676.73 hm²，占比之和>50%，主要集中分布于西部和西南部，主要影响要素为生物多样性，其次为植被覆盖度；3）从生态压力度角度，研究区不脆弱和轻度脆弱面积分别为551.33 hm²和1 205.12 hm²，占比之和>60%，主要集中分布于西部及东部，而主要影响要素为GDP密度和人口密度；4）研究区整体生态脆弱性较高，中度及以上脆弱性面积之和达到67.72%，主要集中于研究区的中部和北部，其中生态敏感性对生态脆弱性的影响最大，说明研究区整体生态脆弱性较强，应做好生态保护工作。  相似文献   

耐热小麦生理特征分析     

吕丽华  李谦  雷明帅  姚艳荣  贾秀领 《华北农学报》2020,35(z1):138-144

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