Assessment of frozen ground organic carbon pool on the Qinghai-Tibet Plateau

Purpose

Under rapid climate change, soil organic carbon (SOC) dynamic in frozen ground may significantly influence terrestrial carbon cycles. The aim of this study was to investigate the storage, spatial patterns, and influencing factors of SOC in frozen ground on the Qinghai-Tibet Plateau, which known as the earth’s Third Pole.

Materials and methods

Using the observed edaphic data from China’s Second National Soil Survey, we estimated the SOC storage (SOCS) of frozen ground (including permafrost, seasonally, and short time frozen ground) on the plateau with a depth of 0–3 m. Furthermore, the effect of vegetation and climate factors on spatial variance of SOC density (SOCD) was analyzed.

Results and discussion

The SOCD decreased from the southeastern to the northwestern part of the plateau, and increased with shorten of freezing duration. SOCS of permafrost, seasonally, and short time frozen ground were calculated as 40.9 (34.2–47.6), 26.7 (24.1–29.4), and 6 (5.6–6.4) Pg, making a total of 73.6 (63.9–83.3) Pg in 0–3 m depth on the plateau. Normalized difference vegetation index and mean annual precipitation could significantly affect the spatial distribution of SOC in permafrost and seasonally frozen ground.

Conclusions

The soil in plateau frozen ground contained substantial organic carbon, which could be affected by plant and climate variables. However, the heterogeneous landform may make the fate of carbon more complicated in the future.

     

亚致死剂量双氧威和虫酰肼对亚洲玉米螟幼虫生长发育的影响

测定亚致死剂量昆虫生长调节剂双氧威和虫酰肼对亚洲玉米螟5龄幼虫发育历期、化蛹率、体重、脂质含量及血清中糖和蛋白含量的影响。结果表明:双氧威LC₃₀、LC₂₀、LC₁₀依次为22.23、14.75、4.37μg/mL,虫酰肼LC₃₀、LC₂₀、LC₁₀依次为48.20、37.11、21.73μg/mL。LC₃₀亚致死剂量双氧威处理可使5龄幼虫的发育历期延长至8.33±0.69天,而虫酰肼处理则使其缩短至5.49±0.66天。亚致死剂量双氧威和虫酰肼处理均使幼虫体重及化蛹率明显降低(P<0.01),其体内脂质含量和血清中糖和蛋白含量也低于对照组(P<0.01),同时5龄幼虫血清中储存蛋白的合成受到抑制。     

农药残留快检仪可检蔬菜种类的研究

采用LZDN-16T蔬菜农残快检仪,对海南省常食用的10种类别,57个蔬菜品种进行快速检测。检测显示,可直接进行检测的蔬菜品种52个,经特殊处理后可检测的蔬菜品种4个、不可检测的蔬菜品种1个。     

枇杷品种类胡萝卜素和水解氨基酸研究

本文分析了51个品种类型枇杷的类胡萝卜素含量和组成的百分数含量。品种间含量差异较大,‘软条白砂’最低(299.4μg/100g),‘山里本’最高(4391.2μg/100g),两者相差达13.6倍。枇杷类胡萝卜素的主要组成是β-胡萝卜素,隐黄质、叶黄质和玉米黄质,试验品种其组分虽不尽相同,但上述4种类胡萝卜素占绝大部分,其中又以β-胡萝卜素为主。根据类胡萝卜素的含量结合其组分,将枇杷品种划分为3大类群。此外,还分析了3大类群中典型品种的蛋白质和17种水解氨基酸。     

做好进口奶牛采血工作确保实验室检疫顺利进行

@@口岸进口奶牛隔离检疫工作特点：一是隔离时间长,工作程序复杂,操作上具有很强的法规性、技术性和强制性;二是由于活动物传播疫病风险高、检疫把关责任大,因此检疫工作要求非常严格,既要现场驻场监管临床检疫,又要逐头采血进行实验室检疫;三是专业技术性强,人员业务水平要求高;四是工作量重,经常在对几千头牲畜采血样时还要同时进行其他试验,例如：根据检疫条款和动物隔离场实际情况,隔离期采血过程需要对进口种牛进行结核病和副结核病皮内变态反应试验;为确保隔离期动物安全,防止进口动物感染国内动物疫情,按照相关规定,常常在采血当天,还需对每头牛实施相应的疫苗接种。     

Nitrous oxide emissions from three temperate forest types in the Qinling Mountains,China

To understand soil N2O fluxes from temperate forests in a climate-sensitive transitional zone,N2O emissions from three temperate forest types(Pinus tabulaeformis,PTT;Pinus armandii,PAT;and Quercus aliena var.acuteserrata,QAT)were monitored using the static closed-chamber method from June 2013 to May 2015 in the Huoditang Forest region of the Qinling Mountains,China.The results showed that these three forest types acted as N2O sources,releasing a mean combined level of 1.35±0.56 kg N2O ha^-1 a^-1,ranging from0.98±0.37 kg N2O ha^-1 a^-1 in PAT to 1.67±0.41 kg N2O ha^-1 a^-1 in QAT.N2O emission fluctuated seasonally,with highest levels during the summer for all three forest types.N2O flux had a significantly positive correlation with soil temperature at a depth of 5 cm or in the water-filled pore space,where the correlation was stronger for temperature than for the water-filled pore space.N2O flux was positively correlated with available soil nitrogen in QAT and PAT.Our results indicate that N2O flux is mainly controlled by soil temperature in the temperate forest in the Qinling Mountains.     

亚洲玉米螟幼虫体内抗菌肽的诱导

外源物侵染可引起亚洲玉米螟幼虫产生免疫应激反应,并诱导产生抗菌肽.为深入研究抗菌肽作用机制,作者给亚洲玉米螟5龄幼虫注射大肠杆菌,诱导其产生抗菌肽,并分析该抗菌肽的部分性质.结果表明:亚洲玉米螟幼虫注射3.0×10~6个/mL大肠杆菌后可诱导其体内产生一种相对分子量为12.1 kD的抗菌肽,在12～36h内该抗菌肽的诱导表达量与时间成正比.此抗菌肽对大肠杆菌和金黄色葡萄球菌都有一定的抑制作用,100℃高温处理5 min后具有明显的抑菌活性,pH为8.0时抑菌活性最强,抑菌圈直径达6.9±0.3 mm,且具有一定的温度稳定性和酸碱稳定性.     

新型白藜芦醇类衍生物的合成研究

以没食子酸为原料, 通过甲基化、还原、溴代、Arbuzov重排、Wittig-Horner反应、O - 异戊烯基或O - 法尼烯基化等反应步骤,以总收率30%～35%合成了6种未见文献报道的新型的白藜芦醇类衍生物1a,1b,2a～2d. 所合成的化合物已通过MS,1HNMR和IR等波谱方法进行了结构确证. 该合成方法具有反应条件温和、后处理方便、产率较高和立体选择性强的优点.