钾肥不同施用时期对烤烟产质量的影响

[目的]探讨钾肥不同施用时期对云南景东县烤烟品种K326产质量的影响。[方法]以烤烟品种K326为材料,测定不同钾肥施用时期下烤烟的农艺性状和产质量。[结果]移栽后35 d和移栽后50 d追施钾肥,在各方面表现最优,产量2 790.0 kg/hm~2、产值44 082.0元/hm~2均最高,中上等烟比例平均高出其他处理6.91%,且各部位的钾含量较高。同时,推迟钾肥的施用期,可使烟株的产量、产值、中上等烟比例有所提高,烟叶的含钾量也有所提高,内部主要化学成分的比例也更协调。[结论]该研究可为云南景东烤烟种植中钾的施用提供参考。     

Retracted: Gonad histology and serum 11‐KT profile during the annual reproductive cycle in sterlet sturgeon adult males,Acipenser ruthenus

The aim of this study was to assess monthly testicular development in the cultured breeding stock of sterlet, Acipenser ruthenus, using histological and serum sex steroid changes. Testicular development in the adult male was examined monthly and showed four distinct phases including resting, pre‐spawning, spawning and post‐spawning. Also, seasonal changes of the testes were described according to its variations in gonadosomatic index (GSI) during different phases of testicular development. Using histology, we identified continuous spermatogenesis and asynchronous gonad development pattern in the testes of male sterlet, which shows that regulation of annual gonadal cycle is influenced by season. Results also showed variation in the GSI value and number of spermatogenic cells according to each season during annual cycle of gonad, as the highest value of GSI was recorded during spawning phase (spring; March‐May). Hormonal profiles of 11‐ketotestosterone (11‐KT) showed peak, which indicated a seasonal pattern of gonadal development. The 11‐KT concentration increased considerably during the spermatogenesis (pre‐spawning phase) and remained quite high throughout the pre‐spermiation period. In the final phase of testicular development (spawning phase), the 11‐KT markedly dropped. This study undertook an examination of complete reproductive development in cultured sterlet sturgeon to provide a valuable guide for the future sterlet studies, and allows comparison of reproductive development between sturgeon species.     

Effect of microbial‐based inoculants on nutrient concentrations and early root morphology of corn (Zea mays)

Microbial‐based inoculants have been reported to stimulate plant growth and nutrient uptake. However, their effect may vary depending on the growth stage when evaluated or fertilizer applied. Thus, the objective of this study was to test the hypothesis that microbial‐based inoculants known to promote root growth and nutrient uptake will promote plant growth, enhance early root development, and increase nutrient concentrations of corn (Zea mays L.). Plants were evaluated at four different growth stages and in the presence of three different nitrogen (N) fertilizers. The microbial‐based treatments evaluated were: SoilBuilder™ (SB), a filtered metabolite extract of SoilBuilder™ (SBF), a mixture of four strains of plant growth‐promoting Bacillus spp (BM), and a water‐inoculated control. The experiment also included four fertilizer treatments: urea (U), urea‐ammonium nitrate (UAN), calcium‐ammonium nitrate (CAN), and an unfertilized control. Corn plants were evaluated at growth stages V2, V4, V6, and VT. Plant growth parameters for biomass, height, and SPAD readings were enhanced by the three microbial‐based treatments. A greater effect of microbial‐based treatments was observed when plants were evaluated at V6 and VT stages. Parameters of early root development such as total root length (TRL), root surface area (RSA), and length of fine roots were enhanced when microbial‐based treatments were applied. Concentrations of N, P, and K were also increased by microbial‐based treatments compared to the non‐inoculated control. Increases in plant N concentration due to microbial‐based treatments were on average 72% for CAN, 61% for UAN, 72% for urea, and 54% for the unfertilized control. Phosphorus concentration was increased most (138%) when BM was applied with CAN. In the same way, when CAN was present, K concentration was increased by 95% with BM and 65% when SB and SBF were applied. Overall, the results demonstrate that microbial‐based inoculants evaluated in this study can positively impact corn growth and nutrient concentration, especially during the late vegetative stages. Furthermore, the results indicate that the enhancement of nutrient concentrations (N, P, and K) in this case was related to the capacity of microbial‐based treatments to impact root morphology at early stages of corn growth.     

B型超声显像技术在实验猕猴繁殖中的应用

采用MEDISON SA-600型超声实时显像仪,以妊娠囊作为主要的判断依据,对658只配种实验猕猴进行早期妊娠诊断的探索。结果表明:妊娠15d诊断准确率为95.5%,20d诊断准确率为100%。同时对猕猴妊娠各期B超影像的特征及猕猴检测的操作特点进行论述。     

野桑蚕各发育时期酚氧化酶原基因的表达谱分析

酚氧化酶在昆虫的免疫防御机制中起着非常重要的作用。利用在GenBank上登录的野桑蚕酚氧化酶原基因的cDNA序列,设计正反向特异引物,通过半定量RT-PCR技术检测了酚氧化酶原基因PPO1及PPO2在野桑蚕不同发育时期(蚁蚕、一龄、二龄、三龄、四龄、五龄1~6 d、预化蛹和蛹)的转录表达活性。结果表明,PPO1基因除了五龄1 d无表达及二龄表达量较低外,其他时期的表达量均较高。PPO2基因在野桑蚕的不同发育时期中均有表达,并且没有明显的差异。说明在野桑蚕的不同发育时期,PPO1基因的表达是特异性的,而PPO2基因的表达是非特异的。     

八点黑獭兔不同发育时期盲肠组织结构变化的研究

为了研究獭兔不同发育时期盲肠组织结构变化特点,总结其发育规律,采用石蜡切片、HE染色技术,对相同条件下饲养的不同生长阶段(出生后1,15,30,60d)獭兔各6只进行解剖,并在显微镜下观察其盲肠组织结构.结果发现,獭兔盲肠黏膜的单层柱状上皮细胞的高度、杯状细胞的体积都随年龄的增长而变大,半环形皱襞间的距离随着年龄的增长逐渐变小,皱襞的长度和体积也随年龄增长有所增加.此外还发现,随年龄的增长八点黑獭兔盲肠蚓突内的淋巴小结数目明显增多,黏膜下层内的淋巴小结和弥散淋巴组织随年龄增长也越来越多,黏膜皱襞变得密集.     

氮磷钾分期施用对甘薯产量和品质的影响

在重庆市江津区甘薯主产地蔡家镇鸳鸯村2社、石佛村3社两个试验点,采用田间试验研究了相同施肥量下甘薯不同生育期氮磷钾肥分配比例的产量和品质效应。结果表明,与常规施肥相比,以分期施氮钾、分期施氮磷钾各处理均提高甘薯块茎产量,鸳鸯村2社试验点的增幅为6.8%~29.5%,石佛村3社试验点的增幅为7.7%~46.6%,两个试验点均以分期施氮磷钾3处理增产作用最大。分期施肥各处理对甘薯维生素C含量的影响以增加为主,鸳鸯村2社试验点增加4.8%~29.9%,石佛村3社试验点增加0.7%~7.3%。各处理对甘薯块茎淀粉和全钾含量以降低为主,鸳鸯村2社试验点的降幅分别为2.4%~5.5%和12.3%~69.5%;石佛村3社试验点的降幅分别为2.4%~17.4%和0.9%~22.8%。分期施肥对甘薯可溶性糖、全磷和粗蛋白含量的影响,两个试验点结果表现不一致。从总体上看,对甘薯进行分期施肥能明显提高薯块产量和改善部分营养品质。