[目的]筛选抗倒伏性强的番木瓜根际优势微生物,挖掘番木瓜抗倒伏差异表达的关键基因,为揭示番木瓜抗倒伏机制及相关品种选育提供参考.[方法]试验设常规施肥量处理(每株施用2.5 kg有机肥,CK)、缺肥处理(不施有机肥,WLR)和高有机肥处理(每株施用10 kg有机肥,SLR)3个处理,根据其转录组数据和根际微生物数据,利用加权基因共表达网络(WGCNA)关联分析番木瓜抗倒伏相关的关键基因,并分析根际微生物变化情况.[结果]SLR处理的植株抗倒伏性最强,其次是CK,WLR处理植株的抗倒伏性最差.WLR处理植株的株高、节间长度和茎粗均显著低于CK和SLR处理的植株(P＜0.05).通过微生物组数据分析得到影响抗倒伏性状优势微生物为链丝菌属(Streptomy-ces)、慢生根瘤菌属(Bradyrhizobium)、RB41菌属及噬几丁质菌属(Chitinophaga).通过WGCNA分析得到2个与番木瓜抗倒伏性能相关的品蓝模块和淡黄模块,进而对这2个模块构建基因共表达网络,筛选出可能与番木瓜抗倒伏性能密切相关的乙酰辅酶A乙酰转移酶基因(AACT)、聚腺苷酸结合蛋白基因(RBP47)、线粒体输入内膜转位酶亚基基因(TIM9)、钙依赖通道7TM区域基因(HYP1)、韧皮部蛋白质丝网络蛋白基因(SEO)和半胱氨酸蛋白酶抑制剂a基因(CPI)等6个核心基因.核心基因功能分析结果显示,品蓝模块涉及番木瓜萜类代谢调控,而淡黄色模块涉及番木瓜韧皮部生长代谢调控.[结论]根际优势微生物与番木瓜抗倒伏性密切相关,其可通过调控番木瓜茎的生长从而提高抗倒伏性,可作为抗倒伏性强番木瓜品种选育的微生物筛选标记之一.

转录组学的发展为挖掘番木瓜的功能基因及探索相关分子机制提供了有效手段.通过检索番木瓜相关转录学研究的文献并进行了分析、总结,发现目前的研究主要集中在组培、性别分化、逆境胁迫、病害、成熟机制等方面.提出了今后在番木瓜转录组研究方面的展望:一是加强转录组、蛋白组、代谢组等多组学的联合研究;二是加强对番木瓜蛋白酶表达起关键调控作用的基因挖掘;三是探索针对番木瓜第三代测序技术的应用研究.

重金属(类金属)污染是威胁农产品质量安全的一个重要因素.重金属快速检测技术以其快速、高通量的技术优势在农产品质量安全监测及受污染农用地安全利用中发挥着重要的作用.文中主要介绍了基于免疫识别、X射线荧光、电化学及高光谱技术重金属快速检测方法,同时对相关技术的优势与劣势进行了探讨.并对相关技术在农产品质量安全控制中的应用前景进行了展望.

为了观察不同番木瓜种质在广西的表现,记录了 10份番木瓜种质的植物学性状、农艺性状、品质性状、抗花叶病性状,并进行主成分分析、相关性分析、聚类分析.结果表明,10份种质表现出不同程度的差异,主要表现在株产与单果质量.主成分分析显示,10份番木瓜种质的15个数量性状可划分为4个主成分,累计贡献率达80.74％;相关性分析显示,10份番木瓜种质的15个数量性状间表现出不同程度的正相关性,说明所选指标间的影响密切.其中株产与两性瓜单果质量、叶长、花序长度,两性瓜单果质量与叶长、叶宽、花序长度、每节位花量等存在极显著正相关.聚类分析在平方欧氏距离5的临界点可将10份种质分为2类,即大果型和小果型,分类特征主要表现在两性瓜单果质量和株产.

Sedum alfredii Hance is a zinc (Zn) and cadmium (Cd) hyperaccumulator plant. However, the regulatory role of plant hormones in the Zn or Cd uptake and accumulation of S. alfredii remains unclear. In this work, the growth, Cd accumulation, abscisic acid (ABA) synthesis and catabolism, malonaldehyde (MDA) content, and transcriptional level of some Cd stress response genes under ABA and Cd co-treatment were investigated to reveal the impact of ABA on Cd resistance and Cd accumulation of S. alfredii. The results show that 0.2 mg/L ABA and 100 μmol/L Cd co-treatment enhanced Cd accumulation and growth in S. alfredii, whereas lower or higher ABA concentrations weaken or even reverse this effect, which was positively correlated with endogenous ABA content. The increase in endogenous ABA content might be the results of the increasing ABA synthetase activities and decreasing ABA lytic enzyme, which was induced by the application of 0.2 mg/L ABA under 100 μmol/L Cd treatment. Principal component analysis (PCA) indicated that ABA impacted the expression pattern of Cd stress response genes, which coincided with the Cd accumulation pattern in the shoots of S. alfredii. Cross-over analysis of partial least squares-discriminant analysis (PLS-DA) and correlation analysis indicated that HsfA4c, HMA4 expression in roots, and HMA2, HMA3, CAD, NAS expression in shoots were correlated with endogenous ABA, which suggests that endogenous ABA improves Cd resistance of seedlings, switches the root-to-shoot transporter from HMA2 to HMA4, and transports more Cd into apoplasts to promote Cd accumulation in the shoots of S. alfredii. Taken together, ABA plays an essential role not only in Cd resistance but also in Cd transport from root to shoot in S. alfredii under Cd stress.

通过探究锌(Zn)对水稻吸收、积累镉(Cd)的影响,为揭示水稻体内Zn、Cd互作机制提供理论依据.通过水培实验,研究Cd胁迫下施加Zn对水稻生物量、Cd含量、Cd积累量、根表铁膜成分、细胞壁组分及吸附解析动力学特征的影响.结果表明:与单Cd处理相比,Cd+Zn处理地上部生物量显著下降;根及地上部Cd含量、积累量显著提高;根表铁膜中Fe含量及Cd含量分别提高18.70％和29.99％;比较单Cd与Cd+Zn的细胞壁组分发现,Zn显著降低了水稻根细胞壁中的果胶及半纤维素1(HCl)成分,导致Cd+Zn处理细胞壁吸附能力下降而解吸能力增强.研究表明,Zn促进Cd在根表铁膜中Cd积累量,降低细胞壁的阻隔作用,进而促进水稻对Cd的吸收及转运.

综合交通优势度与区域经济发展之间存在耦合关系,以中国—东盟为研究区域,选取综合交通网络密度、基础设施质量水平、综合交通可达性等指标,构建综合交通优势度多属性决策模型.运用ArcGIS网络分析技术,定量分析综合交通网络的地域空间特征;进一步解析综合交通优势度与经济发展的耦合协调机制,分析两者的空间发展格局.结果显示:综合交通优势度区域差异明显,但与区域经济耦合度较高,且呈正相关关系;综合交通优势度与区域经济的协调发展度差异显著,且大部分国家综合交通基础设施建设质量水平相对落后,综合交通优势度普遍处于较低发展水平,对区域经济发展的支撑力不足.

为缓解未饱和状态下交通流不确定性对交通信号控制方案实施效果的影响,针对单交叉路口定时控制信号周期时长优化问题,通过分析比较交通流不确定性、周期时长设计、控制实施效果三者之间的相互影响程度,依据区间数多属性决策评价方法,在属性权重完全未知、属性值为区间数且对方案无偏好的情形下,提出了基于相离度和可能度的交叉口信号周期时长多属性决策模型,最后运用VISSIM仿真软件对北京市某相交路口晚高峰时段进行模拟分析.结果表明:该周期时长区间决策方法可行有效,且当该交叉口交通流量比介于[0.804,0.909]时,机动车平均延误、交叉口通行能力分别较Webster方法优化了17.4％与6％.

[Objective] The study aims to provide a theoretical basis for the heavy metal pollution control,the heavy metal pollution of paddy soil and its health risk in Northwestern Guangxi had been evaluated.[Method]98 soil and rice samples were collected from paddy fields in Northwestern Guangxi,and each contents of Cu,Pb,Cd,Cr,Zn and As were determined respectively,to evaluate the pollution and health risk of heavy metal.The soil environmental quality was evaluated by the single factor pollution index method,the Nemerow index method and potential ecological hazard index method,as well as using the grade Ⅱ] in Environmental quality standard for soils (GB15618-1995) as a reference value.The health risk of the grain to residents was evaluated by the high risk quotient (HQ) method and High risk index (HI) method.[Result] The average contents of Cu,Pb,Cd,Cr,Zn and As of soil were 18.21,64.97,0.98,45.55,147.88 and 11.62 rng · kg-1,respectively.There were large variations of heavy metal contents in 98 soil samples.The Nemerow index of research area was 1.416,which reached to the grade Ⅱ standard of soil environmental quality assessment classification,meant the soil were lightly polluted by heavy metals.According to the single factor pollution index,the main pollution element in research area was Cd,followed by Zn,and there were Pb and As pollution in very few research areas.According to the potential ecological risk index (RI),the soil in the study area was in a slight degree of ecological harm,and the contribution rate of Cd to RIwas the largest,followed by As.The average contents of Cu,Pb,Cd,Cr,Zn and As in rice were 5.6400,0.3668,0.1625,0.3879,26.7800 and 0.2974 mg· kg-1,respectively.According to the high-risk index (HI),there might be a health risks in rice grains collected in research area.Among the 6 heavy metals,As made the highest contribution to HI.[Conclusion] The heavy-metal pollution of research area was at the slight pollution level,and the main pollutants were Cd andZn.In rice,the main pollutants were Pb and Cd,but the potential health risks of rice were most likely due to As.