围封对短花针茅植丛土壤颗粒组成和养分富集的影响

以一体化土壤采集器为试材,采用植丛内外差值百分比法,以围封退化短花针茅草地为研究对象,临近自由放牧草地为对照(CK),对比研究了荒漠草原短花针茅植丛对土壤颗粒组成和SOC和TN的富集效应在空间上的变化,以期探讨植丛对土壤富集作用的影响。结果表明:就富集率"E"值而言,粘粒(<2μm)和砂粒(50～2 000μm)的富集格局大致趋势相反,生境和土层深度对粉粒(2～500μm)的富集均无显著影响(P>0.05)。SOC在6～8 cm土层放牧区显著高于围封区,12～14 cm土层围封区显著高于放牧区;TN则在4～6 cm土层围封区显著高于放牧区,12～14 cm土层放牧区显著高于围封区(P<0.05)。沿土层深度垂直变化,颗粒组成仅放牧区砂粒在12～14 cm土层"E"值显著增高(P>0.05);SOC围封区0～2 cm土层"E"值显著高于其它土层(P<0.05),TN放牧区呈先减少后增高"V"型变化,4～8 cm土层"E"值显著降低(P<0.05),放牧区的SOC和围封区的TN都无显著变化(P>0.05)。粘粒与砂粒的"E"值均呈显著负相关(P<0.05),粉粒与粘粒、粉粒与砂粒的"E"值相关关系逆转;颗粒组成与SOC、TN的"E"值相关性都不显著(P>0.05)。总之,围封并未使短花针茅植丛对土壤粘粒的整体富集率增大,反而有所降低;但围封确推动了土壤粘粒和SOC表聚型富集;土壤SOC和TN的富集是2个独立的过程,围封都有利于任意土层TN的富集。     

能源作物甜高粱和玉米对土壤重金属的富集比较

采用盆栽实验研究不同浓度重金属胁迫下(Cd、Pb、Cr)能源作物甜高粱和玉米不同器官Cd、Pb、Cr含量、富集系数以及冠部累积量。结果表明,Cd胁迫下,甜高粱不同器官Cd含量、富集系数以及冠部累积量(6.28~59.71μg)均高于玉米;Pb胁迫下,玉米不同器官Pb含量、富集系数以及冠部累积量(223.71~652.44μg)均高于甜高粱;随Cr浓度增加,甜高粱和玉米不同器官Cr含量、富集系数以及冠部累积量均呈上升趋势,在Cr胁迫下甜高粱和玉米的生物量较小,冠部Cr累积量小。相比之下,甜高粱适合修复Cd污染土壤,玉米适合修复Pb污染土壤,两种作物均不适合修复Cr污染土壤。     

富集文库－菌落原位杂交法筛选栉孔扇贝的微卫星标记

应用微卫星富集文库─菌落原位杂交法,筛选得到了40个栉孔扇贝的微卫星标记.用固定了(AG)15和(AC)15探针的尼龙膜(Hybond N )捕捉含有微卫星DNA的片段,经洗脱、PCR扩增和TA克隆,构建栉孔扇贝的微卫星富集文库.利用ECL试剂盒(Amersham公司)标记的(AG)15和(AC)15探针进行菌落原位杂交筛选微卫星富集文库,阳性克隆经测序获得微卫星DNA.富集文库中1200个重组克隆经过菌落原位杂交后,532个(44.3%)为阳性克隆.任意挑选100个克隆测序,结果显示所有的克隆都至少含有一个微卫星位点.利用软件设计了65对特异性PCR引物,40对能扩增出清晰的带谱;利用48个栉孔扇贝个体评价微卫星位点,分析表明37个位点具有多态性.不同的位点获得的等位基因数目为2～14个不等,37个多态性位点共获得258个等位基因,平均每个位点获得7.0个等位基因.观测杂合度(Ho)、期望杂合度(He)及多态性信息含量值(PIC)的范围分别为0.1000～1.0000、0.1197～0.9831和0.1172～0.9782.结果表明,富集文库─菌落原位杂交法适合大规模筛选目标物种的微卫星标记.     

Inhibition of hirame rhabdovirus growth by RNA aptamers

RNA aptamers are artificial nucleic acids that specifically bind to a wide variety of targets. They are an effective tool for pharmaceutical research and development of antiviral agents. Here, we describe four Hirame rhabdovirus (HIRRV)‐RNA aptamers (H1, H2, H3 and H4) that we obtained from an in vitro process called the systematic evolution of ligands by exponential enrichment (SELEX). The HIRRV‐RNA aptamers specifically bind to HIRRV. Hirame natural embryo (HINAE) cells treated with virus and the RNA aptamer showed a decrease in appearance of cytopathic effect when compared with control (treated only with virus). Rhodovulum sulfidophilum was transformed with genes for the RNA aptamers, and the aptamers were detected in the culture medium, indicating that they were secreted from the cells. Thus, the recombinant R. sulfidophilum might be a powerful tool for the prevention of HIRRV in aquaculture.     

Fortification of Bread Wheat Using Synthesized Zn-Glycine and Zn-Alanine Chelates in Comparison with ZnSO4 in a Calcareous Soil

ABSTRACT

Calcareous soils typically suffer from zinc deficiency and zinc sulfate is incorporated in many cultivated soils. Utilization of ZnSO₄ has some kinds of interaction with soil particles and organic matter. In this study, the efficacy of two znic(Zn)-amino acid chelates (Zn-ACs) i.e., Zn-alanine (Zn-Ala) and Zn-glycine (Zn-Gly) on wheat (Triticum aestivum, cv. N91-8) growth characteristics and zinc concentration in wheat was examined under greenhouse conditions and compared to the a commercial ZnSO₄. Results showed that Zn-Ala and Zn-Gly significantly increased the dry weight and shoot length of wheat in comparison to ZnSO₄ treatment. Soil application of Zn-Amino acid chelates proved to be the most influential source of zinc in increasing wheat growth and yield indices. Number of fertile spikelet and grain yield increased significantly respectively compared to ZnSO₄ treatment. Zn concentration and protein content of wheat grain in Zn-ACs treatment was significantly higher than the ZnSO₄ treatment. Soil application of Zn-ACs caused a significant decrease in the grain phytic acid (PA) concentration and also phytic acid to zinc molar ratio in comparison with ZnSO₄ treatment. According to the results, Zn-ACs could be utilized as a zinc fertilizer source for improving the zinc bioavailability in wheat.     

Effect of organic amendment amount on soil nematode community structure and metabolic footprints in soybean phase of a soybean-maize rotation on Mollisols

It has been well documented that organic amendment affects soil nematode community structure. However, little is known about the effect of organic amendment amount on soil nematodes. To assess the effect of the amount of organic amendments on soil nematode community structure and metabolic activity, the community composition, abundance, and metabolic footprints of soil nematodes were determined in a long-term field experiment with various amounts of organic amendment in Northeast China. Fertilization treatments included an unfertilized control (CK), chemical fertilizer without manure amendment (OM₀), manure applied at 7.5 Mg ha^-1 plus chemical fertilizer (OM₁), and manure applied at 22.5 Mg ha^-1 plus chemical fertilizer (OM₂). A total of 46 nematode genera were found. Treatments with the largest amount of organic amendment had the smallest number of plant parasite genera (5), but a largest number of dominant genera (7). Soil nematodes, bacterivores, and fungivores were the most abundant in OM₂, followed by OM₁, and the lowest in OM₀ and CK. Organic amendment increased the enrichment index (EI), and the large amount of organic amendment increased the metabolic footprints of bacterivore (Baf) and fungivore (Fuf) and enrichment footprint (Ef). The relationships between Baf (or Fuf) and the increases in soil organic carbon (ΔSOC) and total nitrogen (ΔTN) were stronger than those of bacterivore (or fungivore) abundance with ΔSOC and ΔTN, except for the relationship between bacterivore abundance and ΔSOC. The EI and Ef were positively correlated with ΔSOC and ΔTN. These findings suggest that the amount of organic amendment affects soil nematode activity and function at entry levels in soil food web, and that metabolic footprints of soil nematodes may be better indicators than their abundances in assessing their relationships with soil nutrients.     

水稻籽粒不同部位P与Al、Cd、Pb含量的关系

利用环境扫描电镜结合X射线电子探针显微分析技术,研究了水稻籽粒不同部位P与Al、Cd、Pb含量的关系.结果表明:金属元素Al、Cd、Pb和其他矿质元素一样,也在糊粉层中积累最多;水稻籽粒中P的积累与Al、Cd、Pb的富集有密切关系;其中,籽粒不同部位P与Al的含量存在极显著的正相关关系,而Pb和Cd的含量并不随着P含量的增加而增加,其变化幅度较小.说明P对Al的富集具有促进作用.     

A possible mechanism of mineral responses to elevated atmospheric CO2 in rice grains

Increasing attentions have been paid to mineral concentration decrease in milled rice grains caused by CO2 enrichment, but the mechanisms still remain unclear. Therefore, mineral(Ca, Mg, Fe, Zn and Mn) translocation in plant-soil system with a FACE(Free-air CO2 enrichment) experiment were investigated in Eastern China after 4-yr operation. Results mainly showed that:(1) elevated CO2 significantly increased the biomass of stem and panicle by 21.9 and 24.0%, respectively, but did not affect the leaf biomass.(2) Elevated CO2 significantly increased the contents of Ca, Mg, Fe, Zn, and Mn in panicle by 61.2, 28.9, 87.0, 36.7, and 66.0%, respectively, and in stem by 13.2, 21.3, 47.2, 91.8, and 25.2%, respectively, but did not affect them in leaf.(3) Elevated CO2 had positive effects on the weight ratio of mineral/biomass in stem and panicle. Our results suggest that elevated CO2 can favor the translocation of Ca, Mg, Fe, Zn, and Mn from soil to stem and panicle. The CO2-led mineral decline in milled rice grains may mainly attribute to the CO2-led unbalanced stimulations on the translocations of minerals and carbohydrates from vegetative parts(e.g., leaf, stem, branch and husk) to the grains.     

Higher than optimum temperature under CO2 enrichment influences stomata anatomical characters in rose (Rosa hybrida)

There is little available information on the effects of temperature and CO₂ enrichment on stomata anatomical characteristics of plants. Effect of these two microclimates was studied on five rose (Rosa spp.) cultivars, viz. ‘First Red’ (used as check), ‘Arjun’, ‘Raktima’, ‘Raktagandha’ and ‘Pusa Pitamber’. Budded, single-stemmed rose cultivars having five lateral buds were grown in controlled environment growth cabinets under enriched CO₂ (1000 μmol mol⁻¹) and optimum (28/18 °C, T₀) or high (35/25 °C, T₁) temperature for 50 days. All observations were made on the abaxial leaf surface. Significant increases in stomatal density (68.7%), index (29.6%) and epidermal cell density (37.3%) were recorded in plants grown at high temperature over control with CO₂ enrichment. The cultivars responded differently in terms of length and width of guard cell and stoma (pore) under high temperature, however, the values averaged over treatments showed a significant reduction in these parameters. Further, number of stomata per leaf was higher (28.3%) in plants grown at high temperature, except First Red. A reduction in mean leaf area (26.7%) and dry mass (32.0%) was recorded at high rather than optimum temperature. The specific leaf area was maximum in Arjun (87%) while in First Red, a 14% reduction was noted at high temperature.     

马尾松种源对磷肥的遗传反应及根际土壤营养差异

利用5a生马尾松种源与磷肥互作试验林，研究不同种源对磷肥的遗传反应式样以及在低(缺)磷环境下的根际营养差异。结果发现，广东高州和广西岑溪两种源对磷肥的反应显著，属于对磷肥敏感型种源。广东信宜和福建武平两种源对磷肥反应不敏感，属于耐低磷型或对磷肥不敏感型种源，而江西崇义种源显著的磷肥效应仅在造林后头2～3年显示。对于根际土的的化学性质，不同种源虽有较大差异，但根际土的有机质、全氮、水解氮和有效磷含量一般显著高于非根际土。不同种源根际对土壤中的磷都具有活化作用和富集作用，尤其是广东信宜和福建武平两种源对土壤磷的活化和富集作用最为强烈，这可初步解释这两个种源对磷肥不敏感、能适应低(缺)磷胁迫的遗传机制。马尾松不同种源根际土壤并未发生明显的酸化。