磷胁迫对大豆不同磷素基因型光合作用的影响

2002年和2003年通过大田试验。探讨了3种不同磷效率的基因型大豆在不同磷素水平下的净光合速率(Pn)、气孔导度(CS)、胞间隙CO2浓度(Ci)及蒸腾速率(Tr)的差异．结果表明：4项指标间存在着显著的正相关。低磷胁迫下大豆磷高效基因型光合能力明显高于磷低效基因型．     

磷胁迫下大豆叶片及根部超氧化物歧化酶酶谱的研究

通过营养液栽培试验,研究了低磷胁迫下4种不同磷效率基因型大豆叶片和根部超氧化物歧化酶（SOD）同工酶的酶谱．结果表明,大豆叶片和根部SOD同工酶含量在低磷处理第10天、20天、30天均比对照高,酶谱染色加深和谱带条数的增加,说明低磷胁迫增加该酶活性,磷高效基因型酶活性升高的幅度大于磷低效基因型．     

磷胁迫下不同基因型大豆苗期磷吸收利用差异的研究

在缺磷和低磷胁迫条件下，对不同基因型大豆苗期磷吸收利用的差异进行了研究．结果表明：缺磷胁迫下，磷高效基因型（K1、K2）叶部的吸磷量均大于磷中效（Z1、Z2）、低效（M1、M2）基因型，但根、茎的吸磷量与磷中效基因型差异不明显；低磷胁迫下，磷高效基因型根、叶的吸磷量均大于磷中、低效基因型，但茎部吸磷量与磷中效基因型差异不明显．缺磷和低磷胁迫下，磷高效基因型磷利用率的适应性均未表现出优势．磷高效基因型并非所有性状的适应性均能表现出优势。     

福建杉木林下红壤的磷素吸附与解吸特性

通过对福杉木林下红壤的磷素吸附与解吸特性研究,结果表明：杉林林下红壤的磷素吸附容量大,吸磷能力强,且吸附的磷素较难解吸。土壤磷素吸附量和吸附能与ｐＨ、吸湿水及粘粒含量呈正相关,与有机质,有效磷,全磷含量呈负相关。     

作物不同基因型的磷素营养研究进展

介绍了近年来植物磷素营养研究的发展趋势,强调了开发不同基因型作物品种耐低磷机理研究的重要性;综述了作物不同基因型低磷胁迫的根系形态构造的差异、根系分泌物及pH值的变化;低磷胁迫对水分利用效率、碳水化合物同化作用的影响、对膜脂过氧化及保护酶系统活性的影响、对叶片特征的影响、酸性磷酸酶(APA)活性与耐低磷胁迫的关系;磷素利用效率的基因位点(分子标记)的研究进展.     

不同磷效率基因型大豆的筛选

在对东北地区226个大豆品种进行磷效率鉴定分类的基础上,对筛选出的43个大豆品种在同一地块上进行了再次评价,筛选出4个磷高效基因型大豆和5个磷低效基因型大豆品种.     

磷素水平对水稻幼苗生长发育的影响

以4种不同基因型水稻为材料,研究磷素水平对水稻幼苗的生物学和营养学性状的影响.结果表明:低磷处理对水稻幼苗各生物学性状影响很大,低磷条件下水稻幼苗株高、鲜重、干重均低于对照处理,根长伸长,根冠比增大;供磷过量处理水稻幼苗株高和干重低于对照.四种水稻幼苗相比,高优35的磷素利用效率明显低于其它三个品种.     

磷胁迫对不同基因型大豆苗期叶片特征的影响

通过砂培试验，对不同基因型大豆苗期的叶面积、叶绿素含量、叶厚度、栅栏组织厚度、海绵组织厚度进行了研究，结果表明：在缺磷和低磷胁迫下，各基因型的叶面积增大，磷低效基因型的叶绿素含量减少，而磷高、中效基因型却增大；叶片的各厚度指标在磷胁迫下并未表现出明确的变化趋势．此外，不同基因型对缺磷和低磷的反应程度存在显著差异，但磷高效基因型的叶面积、叶绿素含量的适应性均未表现出优势．     

品种更替对冬小麦磷素养分吸收累积和利用效率的影响

选用１４个在不同时期推广的冬小麦品种进行田间试验,分析不同生育期不同器官、部位植物样本的磷素含量。结果表明,各时期品种不同器官、部位中磷素含量随生长发育进程的推进均逐渐降低。生育前期,植株体内磷含量较高,成熟期最低;冬小麦植株对磷的吸收累积动态一致;随品种的更替,叶片、叶鞘中的磷素输出率增加,总输出磷的贡献率反而降低;磷收获指数增大。     

丘陵区紫色土不同土地利用方式下磷的吸附解吸特性

磷素是水体富营养化的重要限制营养元素,农地磷肥过量施入造成的磷流失导致水污染问题引起世界范围的普遍关注.本研究主要针对紫色土集中分布的四川盆地丘陵区土地利用方式多样、农业非点源污染显著等特点,采集不同土地利用方式(林地、坡耕地)下的典型酸性、中性及石灰性紫色土,开展磷素等温吸附解吸热力学实验,并结合Langmuir模型研究了不同类型紫色土对磷素的吸附-解吸特征的影响.结果表明,四川盆地丘陵区紫色土林地土壤磷素最大吸附量(Qm)及磷吸附缓冲容量(MBC)高于同类型紫色土农地土壤;林地土壤生物有效磷含量低于农地;农地磷素释放风险高于林地.相较中性及石灰性紫色土,酸性紫色土磷素最大吸附量、吸附缓冲容量低,但磷素解吸能力较高,表明酸性紫色土磷素释放风险较大.多重相关分析表明,尽管不同类型紫色土pH、有机质、土壤质地等因素对磷素吸附解吸并无单一的显著影响,从而无法针对所有3种土壤找出其影响磷素吸附解吸的共性因素,但因子分析结果表明pH、土壤质地及土壤总磷含量对磷素吸附解吸特性仍有直接影响.     

不同磷素水平下大豆农艺性状对产量贡献的通径分析

以东北地区广泛栽培的226个大豆品种为材料，在常磷与低磷处理下，测定了与产量有关的百粒重、株高、节数、分枝数4个农艺性状。并进行通径系数分析．结果表明：磷高效基因型大豆在常磷条件下百粒重与株高负相关，株高与节数呈极显著正相关，节数与分枝数呈正相关，百粒重与节数负相关。百粒重与分枝数呈极显著负相关，株高与分枝数呈负相关；低磷条件下百粒重与株高负相关，相关系数小于常磷条件。株高与节数为极显著正相关，节数与分枝数相关显著，百粒重与节数为负相关．通径系数表明，磷高效基因型在常磷条件下对产量直接贡献最大的是节数，株高对产量负的影响最大，粒重对产量是正影响，分枝数对产量无影响。     

Characterization of root architecture in an applied core collection for phosphorus efficiency of soybean germplasm

In the present study, we constructed an “applied core collection“ for phosphorus (P) efficiency of soybean germplasm using a GIS-assisted approach. Systematic characterization and comparative analysis of root architecture were conducted to evaluate the relationship between root architecture and P efficiency and its possible evolutionary pattern. Our results found that: i) root architecture was closely related to P efficiency in soybean. Shallow root architecture had better spatial configuration in the P-rich cultivated soil layer hence higher P efficiency and soybean yield; ii) there was a possible co-evolutionary pattern among shoot type, root architecture and P efficiency. The bush cultivated soybean had a shallow root architecture and high P efficiency, the climbing wild soybean had a deep root architecture and low P efficiency, while the root architecture and P efficiency of semi-wild soybean were intermediate between cultivated and wild soybean; iii) P availability regulated root architecture. Soybean roots became shallower with P addition to the topsoil, indicating that the co-evolutionary relationship between root architecture and P efficiency might be attributed to the long-term effects of topsoil fertilization. Our results could provide important theoretical basis for improving soybean root traits and P efficiency.     

Isolation and application of effective nitrogen fixation rhizobial strains on low-phosphorus acid soils in South China

Soybean (Glycine max L.) is a very important food and oil crop in China. Legume-rhizobium symbiotic nitrogen (N) fixation is an important biological character and also the base of improving soil fertility of soybean. However, soybean production and development is severely limited in tropical and subtropical areas in China due to a lack of effective rhizobial inoculants adapting to low-phosphorus (P) acid soils. In the present study, 12 soybean rhizobial strains were isolated and purified from the nodules of two soybean genotypes contrasting in P efficiency, which were grown on different low-P acid soils with different soybean cultivation histories. Results from 16S rDNA sequence analysis showed that these 12 rhizobial strains belonged to the genus of Bradyrhizobium, which had higher nitrogenase activities compared to the control strain, Bradyrhizboium japonicum USDA110. A field experiment was carried out by applying rhizobial inoculants, a mixture of three rhizobial strains that showed the highest nitrogenase activity, on a typical low-P acid soil in South China. The results showed that, without inoculation, no nodules were formed in the three soybean genotypes tested; with inoculation, the nodulation rates in all were 100%. Inoculation with rhizobial inoculants not only made many nodules formed, but also increased soybean shoot biomass and yield, and improved nitrogen (N) and P nutrient status. Among which, shoot dry weight, N and P content of a soybean genotype, Huachun 3, inoculated with rhizobium were increased 154.3%, 152.4% and 163.2% compared to that without inoculation, respectively. We concluded that: (i) The effective indigenous rhizobial strains isolated in this study from soybeans on low-P acid soils in South China have the characters of broad host range, high nodulation efficiency, efficient N fixation, great low pH and low P tolerance. (ii) Soil environment and host types are the key factors to screen the effective rhizobial strains. Considering soil pH values and P efficiency of the host genotypes might increase the screening efficiency. (iii) Improving N status and facilitating root growth might be the mechanisms of increasing the P uptake in soybean plants inoculated with the effective rhizobial strains on low-P acid soils. (iv) Inoculation with the effective rhizobial inoculants could significantly improve growth, N and P content of soybean on low-P acid soils, which might be an effective approach to enhance soybean cultivation and development in these areas. Therefore, application and extension of inoculation techniques with effective rhizobial inoculants in legumes would result in great economical, environmental and ecological benefits. The authors contributed equally to this work Supported by National Key Basic Research and Development of China (Grant No. 2005CB120902), McKnight Foundation Collaborative Crop Research Program (USA) (Grant No. 05-780) and National Natural Science Foundation of China (Grant No. 30571111)     

云南改良稻及元阳地方稻磷高效研究

 在土壤有效磷质量比分别为0.26mg·kg^-1和80.0mg·kg^-1条件下对云南111份改良稻和77份元阳地方稻进行形态性状与程氏指数间的磷高效研究,以明确籼粳分化和米色与磷高效间相互关系,对比改良稻和地方稻间磷高效差异.结果表明:①相对地上干物质量、相对地下干物质量、相对总干物质量和相对分蘖力4个耐低磷指标性状可作为水稻耐低磷能力强弱评价的理想指标,能明确反映出磷高效能力强弱;②元阳地方稻各亚种间平均耐低磷能力均明显高于云南改良稻,且差异明显,4个耐低磷指标性状平均值为籼>偏籼>偏粳>粳,无色米>有色米,耐低磷能力随程氏指数的增大呈递减趋势;③总体而言,程氏指数和耐低磷指标性状间多数呈显著负相关,磷高效特性和籼粳分化密切相关.     

温度和降水对赣江流域土地利用方式与河流氮磷营养盐相关性的影响

针对赣江流域的10个子流域,研究温度和降水如何影响土地利用方式与河流氮磷营养盐浓度的相关性.土地利用类型划分为水田、旱地、林地、草地、水域和建设用地,氮磷指标为2014年每月对赣江7条支流测定的氨氮(NH⁺₄-N)、硝酸盐氮(NO^-₃-N)和总磷(TP)浓度,用相关分析得到土地利用方式与水体氮磷的相关性.结果表明:(i)不考虑温度和降水的影响,旱地与河流NH⁺₄-N具有显著相关性,建设用地与河流NO^-₃-N具有显著相关性;(ii)旱地、草地和林地在中温条件下与河流氮营养盐的相关性更高,在低温条件下与磷营养盐的相关性更高.水田和水域在高温条件下与河流氮营养盐的相关性更高,在中温条件下与磷营养盐的相关性更高;(iii)除林地外,其他土地利用方式在高降水量情况下与河流氮磷营养盐的相关性更高.     

Matrix-bound phosphine: A new form of phosphorus found in sediment of Jiaozhou Bay

Matrix-bound phosphine (PH3),a new form of phosphorus,was found in sediment of Jiaozhou Bay in December 2001,Concentration and distribution of PH3 in different layers of sediment with different stations were analyzed.The results show that PH3 concentrations are various with different layers and different stations.PH3 concentrations in the bottom layer of sediment (20-30 cm) are usually higher than those in the surface layer (0-4cm) ,The highest PH3 concentration in our investigation reaches 685 ng/kg (dry),which is much higher than those in terrestrial paddy soil ,marsh and landfill that have been reported up to now,The correlation analysis indicates that there is no apparent correlation between the concentrations of PH3 and inorganic phosphorus in sediment.However,the correlation between the concentrations of phosphine and organic phosphorus in the bottom layer of sediment is remarkable (R^2=0.83).It is considered that PH3 in sediment of Jiaozhou Bay is mainly produced from the decomposition of organic phosphorus in the anaerobic condition,and so PH3 concentrations are related to organic phosphorus concentration and anaerobic environment in sediment,The discovery of PH3 in sediment will give people some new ideas on the mechanisms of phosphorus supplement and biogeochemical cycle in Jiaozhou Bay.     

我国科技型小微企业融资效率的实证研究

结合科技型小微企业的特点,构建了以企业资产总额、主营业务成本和资产负债率为投入指标,以净资产收益率、主营业务收入增长率和总资产周转率为产出指标的融资效率评价体系.根据数据包络分析(DEA)方法的基本模型,对在新三板(NEEQ)挂牌的54家科技型小微企业2011年、2012年的融资效率进行实证分析.研究结果表明:2012年科技型小微企业的融资效率低于2011年,且科技型小微企业中的高技术服务业、电子信息业和生物医药业科技型小微企业的融资效率处于较高融资效率区间,新能源与高效节能及环保业则处于低融资效率区间.