BNS和BNS366小麦雄性不育与内源激素的关系

【目的】研究BNS和BNS366小麦雄性不育与小孢子发生过程中内源激素含量变化的关系,为激素调控温光敏雄性不育小麦花粉育性提供理论依据。【方法】选用BNS和BNS366为试验材料,分别以矮抗58和郑麦366（BNS366的近等基因系）为对照,进行正常秋季播种（2018年10月10日）和晚播（2018年12月2日）试验,用I₂-KI法测定花粉育性,用国内法和国际法测定自交结实率,采用间接酶联免疫法测定雌雄蕊原基分化期-三核期叶片、雌雄蕊原基分化期-四分体期幼穗和单核中位期-三核期花药中6种内源激素的含量。【结果】在正常秋季播种条件下,BNS和BNS366花粉可育率、国内法自交结实率和国际法自交结实率均为零,达到全不育水平,在晚播条件下,BNS的这三个指标分别为34.74%、43.12%和48.48%,达到低不育水平,BNS366则分别为92.63%、55.37%和67.94%,达到正常可育水平,播种期间差异均达到极显著水平;矮抗58和郑麦366在2种播期条件下,则为82.56%—94.00%、73.90%—82.31%和96.54%—139.26%,均为正常可育,播种期间差异不显著;BNS和BNS366花粉可育率-∆（正常秋季播种条件下比晚播条件下花粉可育率提高百分率）均分别极显著低于矮抗58和郑麦366。分别在2个试验组内进行内源激素含量的多重比较,BNS和BNS366与矮抗58和郑麦366内源激素含量-∆（正常秋季播种条件下比晚播条件下激素含量提高百分率）存在差异,对内源激素含量与花粉可育率、内源激素含量-∆与花粉可育率-∆进行了相关性分析,发现BNS和BNS366不育株在小麦幼穗发育过程中激素含量存在特征性变化。生长素（indole-3-acetic acid,IAA）含量在四分体期（BNS）和雌雄蕊原基分化期（BNS366）叶片中不足,在单核中位期（BNS）和单核靠边期（BNS366）花药中不足,在二核期花药中盈余;赤霉素（gibberellic acid,GA）含量在四分体期幼穗和单核中位期花药中不足;玉米素核苷（zeatin riboside,ZR）含量在叶片、幼穗和花药中均无一致盈亏特征;脱落酸（abscisic acid,ABA）含量分别在四分体期幼穗中存在偏低倾向（BNS）或确定存在不足（BNS366）现象;油菜素内酯（brassinosteroid,BR）含量在叶片、幼穗和花药中均无一致盈亏特征;茉莉酸甲酯（methyl jasmonate,MeJA）含量在雌雄蕊原基分化期、四分体期、单核靠边期（BNS）或单核中位期（BNS366）和三核期叶片中不足,在雌雄蕊原基分化期（BNS）或四分体期幼穗（BNS366）中不足,在单核靠边期花药中不足。【结论】正常秋季播种条件下,单核靠边期之前,BNS和BNS366中IAA、GA和ABA的含量不足,尤其是MeJA的含量不足,可能促进了二者雄性不育的发生。     

高寒牧区黑麦和箭筈豌豆混播对草产量和营养品质的影响研究

为筛选适宜甘肃高寒牧区的箭筈豌豆与黑麦混播组合及比例，采用裂区设计，研究了3个箭筈豌豆品种（绿箭1号、绿箭2号和绿箭431）与黑麦新品系C33在不同混播比例（0∶100、20∶80、30∶70、40∶60、50∶50、60∶40、70∶30、80∶20、100∶0）下的生产性能及营养品质。结果表明，从混播组合看，A?（C33×绿箭1号）的平均干草产量（7.16 t·hm^-2）和综合评价值（0.860）较高；从混播比例看，B?（60∶40）的平均干草产量（8.01 t·hm^-2）和综合评价值（0.691）最高；混播组合和混播比例间的交互作用表明，A?以B?比例混播时干草产量（9.03 t·hm^-2）和综合评价值（0.711）最高。     

桉树不同成熟度叶片营养元素内循环特征

揭示桉树人工林不同成熟度的叶片器官所需营养元素变化以及土壤肥力对其影响,对于桉树营林和科学施肥具有重要的生产指导意义。选取广西隆安县小林镇和田东县思林镇的桉树2代萌芽林作为研究对象,测定两个人工林嫩叶、成熟叶、黄叶的C、N、P、K、B、Ca、Mg以及土壤C、N、P、K、Ca、Mg元素含量,并进行相关分析。结果表明,植物叶片的N、P、K、Mg营养元素转移规律是黄叶向成熟叶和嫩叶转移,但C、Ca、B营养元素则是随着叶片的生长发育逐渐积累,黄叶中含量最高,说明施肥时应关注Ca、B元素的持续和有效供给。两片人工林都表现出类似的规律,说明土壤肥力的差异不影响桉树人工林叶片营养元素的内循环规律。桉树嫩叶营养元素含量及其生态化学计量比学特征具有与成熟叶和黄叶不同的表征,在营养物质研究中应予以足够重视。     

箭筈豌豆、玉米产量对间作和施氮水平的响应

研究不同施氮水平下箭筈豌豆、玉米产量对单作和间作的响应,对于优化栽培措施、提高作物产量具有重要意义。本试验于2017年在甘肃河西绿洲灌溉区进行,重点研究是不同施氮水平下箭筈豌豆、玉米在单作及间作模式中干物质累积、产量构成、产量表现。结果表明,间作箭筈豌豆干物质累积量与单作相比在不施氮(N0)、减量施氮(N1)和常规施氮(N2)处理下分别提高44.0%、36.7%和37.2%;施氮水平间,间作模式下N1比N2和N0提高9.1%和25.5%,单作模式下提高9.4%和32.1%。间作玉米干物质累积量与单作相比在N0、N1和N2处理下分别提高23.3%、22.5%和23.0%;施氮水平间,间作模式下N1比N2和N0提高9.3%和19.8%,单作模式下提高9.9%和20.7%。间作模式下箭筈豌豆豆荚数和玉米穗数较相应单作分别增加7.6%和14.5%,两者的产量较单作分别提高34.9%和27.0%。由通径分析可知,箭筈豌豆产量决定次序是豆荚数>粒重>单荚粒数,玉米产量决定次序是穗数>粒重>穗粒数。间作结合施氮量240 kg/hm²能获得较高干物质积累量和产量,是河西灌溉区玉米间作箭筈豌豆适宜的施氮水平。     

七星瓢虫保幼激素环氧水解酶基因克隆及表达分析

保幼激素(juvenile hormone, JH)可以调控昆虫滞育,保幼激素环氧水解酶(juvenile hormone epoxide hydrolase, JHEH)是调节保幼激素代谢的关键酶之一。为探索JHEH在七星瓢虫Coccinella septempunctata L.滞育中的调控作用,利用RT-PCR和RACE技术克隆获得七星瓢虫JHEH全长基因,命名为Csjheh(GenBank登录号:MH932586),该基因cDNA全长2 077 bp,开放阅读框(ORF)1 380 bp,编码459个氨基酸,预测蛋白质分子量为51.39 kD,理论等电点(pI)为8.79。疏水性分析结果显示该基因具有典型环氧水解酶的N末端疏水结构。氨基酸序列比对结果表明,Csjheh与中欧山松大小蠹、赤拟谷盗、丽蝇蛹集金小蜂、内华达古白蚁保幼激素环氧水解酶同源性达到64.24%。利用实时荧光定量PCR技术研究其时空表达模式,结果表明Csjheh基因在七星瓢虫成虫初羽化阶段表达量较高,滞育诱导条件下表达量呈先下降后上升的趋势,滞育60 d时与初羽化阶段接近。本研究结果对揭示JHEH参与JH的调控作用,进而调控昆虫滞育提供了理论参考。     

Fungal colonization patterns in necrotic rootstocks and stem bases of dieback‐affected Fraxinus excelsior L.

European ash (Fraxinus excelsior) trees currently face the major threat of ash dieback caused by an invasive fungus, Hymenoscyphus fraxineus. Collar rots in F. excelsior have been increasingly associated with infections by this pathogen. However, the aetiology of the collar rots is still unclear and remains heavily debated. In contrast to most studies of this kind, entire rootstocks of four diseased ash trees were dug out to examine necrotic tissues in these rootstocks and stem bases in detail and to sample necrotic wood for fungal isolation. With the aid of morphological and molecular identification techniques, five to twelve fungal taxa were detected per tree. Members of the Nectriaceae family and Botryosphaeria stevensii, the causal agent of stem and branch cankers on many tree species, were frequently isolated from outer xylem. In contrast, H. fraxineus was the dominating species in interior wood layers. Microsatellite genotyping of 77 H. fraxineus isolates helped to identify up to six different genotypes per tree. The role of H. fraxineus and other isolated fungi in the aetiology of ash collar rots are discussed.     

Rapid mapping of candidate genes for cold tolerance in Oryza rufipogon Griff. by QTL-seq of seedlings

Cold stress is a major problem in rice production. To rapidly identify genes for cold tolerance in Dongxiang wild rice(DWR, Oryza rufipogon Griff.), sequencing-based bulked segregant analysis of QTL-seq method was used to resequence the extremely resistant(R) and susceptible(S) bulks of a backcross inbred lines(BILs) population(derived from Oryza sativa×O. rufipogon) and their parents. Single nucleotide polymorphisms(SNP)-index graphs and corresponding Δ(SNPindex) graphs(at 99 and 95% confidence levels) for R-and S-bulks detected a total of 2 609 candidate SNPs, including 58 candidate cold-tolerance genes. Quantitative real-time PCR analysis revealed that 5 out of the 58 candidate genes had significant differences in expression between O. sativa and O. rufipogon. Structural variation and functional annotations of the 5 candidate genes were also analyzed, and allowed us to identify 2 insertion-deletion(InDel) markers(12-7 and 12-16) that were linked with candidate genes on chromosome 12 in DWR. These results are helpful for cloning and using cold tolerance genes from common wild rice in cultivated rice.     

Dietary available phosphorus requirement for juvenile gibel carp (Carassius auratus gibelio var. CASIII)

A 57‐day growth experiment was conducted with juvenile gibel carp (13.48 ± 0.10 g) in a flow‐through system to study the effect of dietary phosphorus on growth performance, body composition, nutrition utilization, phosphorus loading and enzymes activities. Seven semipurifed diets were formulated to contain 0.07 (the basal), 2.27, 5.32, 8.10, 12.06, 15.24 and 19.48 g available phosphorus/kg diet. The results showed that specific growth rate, body length and feed efficiency significantly increased in the fish fed diets containing 0.07 to 15.24 g available P/kg diet (p < .05). Ash and P content increased in fish fed diets containing 0.07–12.06 P g/kg (p < .05) and then levelled off, while moisture, crude protein and lipid had no significant difference (p > .05). The protein retention efficiency increased in the fish fed with diets 0.07–5.32 g/kg P (p < .05) and then reached a plateau. The P content in faeces was higher in fish fed diets containing 15.24 and 19.48 g available P/kg. Total P concentration in tank water increased in fish fed 0.07–12.06 g available P per kg diet (p < .05). The plasma P was higher in the fish fed with 15.24 g available P/kg diet (p < .05), triglycerides was lower in the fish fed diet containing 15.24 and 19.48 g available P/kg (p < .05), no significant differences were observed in plasma Ca, plasma glucose and calcitonin (p > .05). Based on SGR, whole body P content and FE, dietary available P requirement for juvenile gibel carp were 13.37, 13.97 g/kg and 15.06 respectively.     

Interactive effects of coffee bean supplementation and waterborne zinc toxicity on growth performance,biochemical variables,antioxidant activity and zinc bioaccumulation in whole body of common carp,Cyprinus carpio L.

Roasted coffee powder (RCP; Coffea arabica) is usually used as a beverage for human but there are few attempts to use it as a natural feed supplement in fish diets. In this study, common carp, Cyprinus carpio L., (11.8 ± 0.09 g) were reared in zinc (Zn)‐containing water at concentrations of 0.0 or 5.0 mg/L and cosupplemented with 0.0 or 1.0 g RCP/kg diet for 6 weeks to investigate effects of RCP supplementation, Zn exposure and their interaction on fish performance, biochemical variables, antioxidant activity and Zn bioaccumulation in whole fish body. Fish growth and feed intake were significantly affected by RCP supplementation, Zn toxicity and their interaction. However, fish fed a RCP‐supplemented diet did not exhibit better performance than those fed the RCP‐free diet and both diets produced higher fish performance than the Zn‐toxicated fish. It is noticed that RCP supplementation to Zn‐toxicated fish enhanced their growth, and feed utilization as compared to Zn‐toxicated fish alone. Fish fed control and RCP‐enriched diets showed no significant differences in biochemical variables, which were significantly altered due to waterborne Zn toxicity. Moreover, Zn reduced significantly; meanwhile, RCP supplementation increased significantly superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. Notably, Zn exposure could reduce fish growth and antioxidant activity and increase Zn deposition in whole fish body. And RCP intake could enhance the antioxidant activity exerting a protective effect against Zn toxicity, thereby reducing Zn bioaccumulation in whole fish body.     

Genetic structuring and diversity patterns along rivers – local invasion history of Ambrosia artemisiifolia (Asteraceae) along the Danube River in Vienna (Austria) shows non‐linear pattern

Ambrosia artemisiifolia is an annual weed from North America that nowadays is invasive in many countries worldwide. In Austria, numerous populations of A. artemisiifolia are located along the Danube River, especially along the ‘New Danube’ (Vienna). This area is characterised by ruderal and riparian sites, which are regularly flooded. To better understand the spread of A. artemisiifolia and its colonising behaviour along the Danube River, we analysed genetic structure and diversity based on 23 populations linearly arranged along the Viennese Danube riverbed and upstream, utilising the Amplified Fragment Length Polymorphism (AFLP) fingerprint method. We generated 284 polymorphic AFLP markers across 446 A. artemisiifolia plants. The genetic diversity within populations was higher (HW = 0.091) than among populations (HB = 0.007). This result indicates A. artemisiifolia introductions from similar mixtures of sources or spread from a single already mixed introduction. Within our local setting, we were unable to identify neither source or sink populations nor an obvious linear genetic structuring. Genetic among‐population differentiation was low to moderate (amova ‐derived F_ST = 0.124). Lack of geographical structuring is indicative of highly dynamic gene flow, which is further supported by the absence of an isolation‐by‐distance pattern. Multiple introductions and non‐directional gene flow are most likely promoted by anthropogenic disturbance and human‐mediated dispersal. Our results demonstrate the ability and speed of A. artemisiifolia to settle in newly disturbed areas and the difficulties to predict invasion directions, as downstream river dispersal was negligible.