稻曲病菌交配型基因MAT1-2-1和MAT1-2-8的特性分析

 有性生殖在真菌的生活史和进化过程中具有重要作用,而交配型基因是控制有性生殖的关键因子。前期研究发现稻曲病菌(Villosiclava virens)MAT1-2型菌株中包含MAT1-2-1和MAT1-2-8两个交配型基因,但是它们如何调控稻曲病菌有性生殖依然不清楚。本文研究了它们在不同侵染和生长发育时期的表达模式和编码的蛋白结构特性。研究表明MAT1-2-1在侵染不同阶段一直下调表达;而MAT1-2-8在侵染早期(5 dpi)上调表达,在侵染后期下调表达。与营养菌丝阶段比较,MAT1-2-1和MAT1-2-8在有性发育过程菌核形成、菌核萌发、子座原基形成和子座成熟4个阶段的表达量都是下降的,在菌核形成阶段表达量最低。生物信息学分析显示MAT1-2-1和MAT1-2-8具有磷酸化位点,为非分泌蛋白,无明显的跨膜结构域。蛋白同源比对分析表明MAT1-2-1与香柱菌(Epichloë typhina)的MAT1-2-1同源性最高,而MAT1-2-8与绿僵菌(Metarhizium)的MBR_08192蛋白同源性最高。进一步研究发现MAT1-2-1和MAT1-2-8能够互作,并分别主要定位在细胞核和细胞基质中。通过质谱技术鉴定到MAT1-2-1的一些候选互作蛋白,如假定Ran交换因子Prp20/Pim1(KDB12229.1)、假定rRNA处理蛋白Ebp2(KDB12923.1)及组蛋白H1(KDB12711.1)等。因此,以上结果为研究稻曲病菌交配型基因MAT1-2-1和MAT1-2-8调控有性生殖的生物学功能奠定了基础。     

玉米-大豆带状间作下除草剂的筛选

采用单因素随机区组设计,研究了3种药剂(A1:60%乙·嗪·滴丁酯、A2:60%乙·嗪·滴丁酯+48%灭草松、A3:48%灭草松)与清水对照组(A4)在玉米-大豆间作条件下,玉米、大豆苗期农艺性状、株防效及药害等级和成熟期作物产量,考察了玉米-大豆带状复合种植模式下除草剂除草效果及安全性。结果表明:3种除草剂对反枝苋、马唐防效好,对刺儿菜防效较差。药后15 d,A1与A2对杂草的防除效果最好,均在75%以上,其中A2对马唐的株防效达到了100%。药后30 d,各处理下的鲜重防效均在80%以上,A1对反枝苋的株防除效果最好为88.89%。玉米、大豆产量在A2处理下最高,分别较清水对照组高33.7%、39.4%。3种除草剂对玉米、大豆幼苗都有一定的药害症状,但药害等级均小于1,从株防效和对作物产量的影响分析,A2更适用于玉米-大豆带状复合种植模式。     

不利气象条件对果业生产的影响及果园管理建议

针对近年来不利气象条件频发情况,分析了不利气象条件对果业生产的影响,提出减轻不利气象条件对果树影响的建议和不利气象发生后果园的管理要点。     

江西省主要人工混交林类型的优化与筛选

以杉木或湿地松为主要树种,用南酸枣、檫树、樟树、乐昌含笑、福建柏、鹅掌楸、蓝果树等作伴生树种,开展了13个类型的混交林试验研究,在定性分析筛选的基础上,初选出9个比较优良的混交类型,再依据Ii=P1h/H+P2d/D+P3v/V计算出混交类型的优选指标,用I标准=I单均+aδn计算出类型的优化标准为6.12.据此对参试的混交类型进行优选,选出的最佳混交类型为杉木+南酸枣、杉木+檫树、杉木+樟树和湿地松+鹅掌楸4个混交类型,供林业生产上推广应用.     

Differential levels of antioxidants in paraquat-resistant and -susceptible Erigeron canadensis biotypes in Korea

To characterize the biochemical differences in paraquat-resistant and -susceptible biotypes of Erigeron canadensis L. collected from Korea, we investigated the constitutive levels of various antioxidants such as antioxidant enzymes and low molecular weight antioxidants in leaves, as well as after paraquat treatment. The activities of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase were higher in the paraquat-resistant biotype than in the paraquat-susceptible biotype. Reduced ascorbic acid content was higher in the resistant biotype, but the content of reduced glutathione was higher in the susceptible biotype. These results indicate that one of the paraquat-resistant mechanisms in E. canadensis in the present study might be related to protecting the activities of antioxidant enzymes, such as superoxide dismutase, peroxidase ascorbate peroxidase, and catalase, as well as the contents of low molecular weight antioxidants such as ascorbate and glutathione.     

气相色谱-串联质谱法测定柑橘中5种杀螨剂残留

建立了气相色谱-串联质谱法(GC-MS/MS)检测柑橘中5种杀螨剂残留分析方法。样品经乙腈提取、氯化钠盐析后,取有机相用Qu EChERS方法净化,利用GC-MS/MS在多反应监测(MRM)模式下进行测定,外标法定量。5种杀螨剂在0.005~0.5mg/L浓度范围内呈现良好的线性关系,相关系数r^2均>0.996,方法定量限为0.005 mg/kg。在0.005、0.01和0.1mg/kg 3种添加水平下,加标回收率为70.6%~111.3%,相对标准偏差(RSD)为1.07%~14.64%。本方法简便、重现性良好,可用于柑橘类水果样品中杀螨剂的日常检测。     

蔬菜高效水肥一体化灌溉技术的实践与发展建议

水肥管理是直接影响蔬菜稳产高产和品质提升的关键因素。总结了我国蔬菜高效灌溉的4种主要模式,介绍了不同种类蔬菜的高效灌溉模式,分析了我国蔬菜高效水肥一体化灌溉技术存在的问题,并提出了发展建议。     

A pioneering survey of deep-diving and off-shore cetaceans in the northern South China Sea

A pioneering boat-based survey was conducted in 2019, to gather baseline information regarding the presence, composition, relative abundance, and spatial distribution of deep-diving and off-shore cetaceans in the northern South China Sea (SCS). A total of 27 sightings comprising at least 8 cetacean species were recorded during the 13-day survey, including 5 deep-diving species (i.e. Risso's dolphin [Grampus griseus], short-finned pilot whale [Globicephala macrorhynchus], sperm whale [Physeter macrocephalus], Cuvier's beaked whale [Ziphius cavirostris], and an unidentified beaked whale [either the ginkgo-toothed beaked whale, Mesoplodon ginkgodens, or Deraniyagala's beaked whale, Mesoplodon hotaula]), as well as 3 off-shore dolphins (i.e. pantropical spotted dolphin [Stenella attenuate], striped dolphin [Stenella coeruleoalba], and Fraser's dolphin [Lagenodelphis hosei]). With the exception of pantropical spotted dolphins, all other species were sighted and recorded at sea in the northern SCS for the first time. The pantropical spotted dolphin was the most frequently sighted species, comprising 30% of the total sightings. Deep-diving cetaceans were mainly sighted in the northern Xisha Archipelago, whereas off-shore dolphins were distributed across the survey area. The pantropical spotted dolphin was observed in aggregations of more than 100 individuals and nearly all encountered species included calves; these findings suggested that the survey area functions as an important feeding and calving ground for various cetacean species. This pioneering survey provides fundamental information regarding cetacean fauna in the northern SCS and highlights the need to strengthen research and conservation efforts concerning these species.     

Conditional Value-at-Risk and Its Use in Credit Risk Measurement of Banks

Credit risk, the major risk of bank, is more and more intense during the period of economic restructuring in China. In view of the flaw of present risk measurement system, Conditional Value-at-Risk is used for the credit risk measurement which is better than Value-at-Risk. This paper creates the model ,while gives the method and procedure for solving it. So CVaRof credit combination is produced, which is just the early warning value of credit risk. At last, it is concluded that the CVaRrisk measurement is too difficult to use widely at present in china, then some advice is provided.     

空间电场调控植物体内Ca2+量的试验研究

采用同位素示踪测定方法,对空间电场调控植物吸收与输运各种离子性营养物质进行了研究。试验表明,空间电场强度的变化可以调控Ca2 离子流的流动方向,正向空间电场强度的迅速下降能使植株根区的Ca2 离子流向植株的地上部分;当该电场强度迅速增加时,地上部分的Ca2 阳离子则流向植株根区。为此,通过实验证明了正向空间电场与足量的CO2相配合能大幅度提高温室果菜产量和果实硬度、糖度。