甜菜BvGSTU9基因的生物信息学及在镉胁迫下的表达分析

为了进一步研究甜菜谷胱甘肽转移酶BvGSTU9 (LOC104894060)在重金属胁迫过程中的功能。本研究以‘780016B/12优’为实验材料,对该基因序列特征、结构、功能进行预测分析,并利用qPCR检测该基因在不同浓度镉胁迫下的表达量变化。结果显示甜菜BvGSTU9基因全长925 bp,开放阅读框675 bp,编码了由224个氨基酸组成的不稳定膜外蛋白。BvGSTU9与菠菜、藜麦的氨基酸序列相似性较高,与系统发育进化树分析结果基本相符。二级和三级结构预测表明该基因主要由α-螺旋、β-折叠、延伸链及无规则卷曲组成。qPCR显示BvGSTU9基因在不同浓度的镉胁迫下均受到不同程度的诱导,因此可以推断甜菜BvGSTU9基因无论从结构还是功能上,与镉逆境胁迫存在着一定的应答关系。研究结果也为甜菜耐重金属镉机制研究提供参考依据。     

硒肥与钝化材料组配对土壤Cd钝化及稻米Cd消减效果

为了探讨不同硒肥施用方式联合钝化材料对土壤镉钝化和稻米镉消减的效果,采用盆栽试验的方式,选用亚硒酸钠作为硒肥,钙镁磷肥和硅藻土作为钝化材料,设置基施硒肥+钙镁磷肥+硅藻土和叶面喷施硒肥+钙镁磷肥+硅藻土2种方式,研究其不同用量对镉污染酸性稻田土壤修复与安全利用的影响。结果表明：随着施用量的增加,稻米产量增加,基施硒肥产量略高于叶面喷施硒肥,产量差为 2.115 g/pot,与对照(CK)相比,基施0.28%钙镁磷肥+0.12%硅藻土+0.004‰硒(T3)能够提高1.68倍的稻米产量;随着施用量的增加,pH升高,有效Cd降低,有机质与CEC变化不大;基施硒肥与叶面喷施硒肥处理对土壤pH、有机质与CEC差异不显著,但基施硒肥处理有效Cd含量略低于叶面喷施硒肥处理,T3对土壤Cd的钝化效果最佳;随着基施硒肥用量的增加,稻米Cd含量降低,随着叶面喷施硒肥用量的增加,稻米Cd含量先降低后升高,基施硒肥处理对稻米Cd的消减程度强于叶面喷施硒肥处理,相差 0.021 mg/kg,与对照(CK)相比,T3处理稻米Cd降低0.063 mg/kg。可见,硒对调控稻米镉累积具有重要作用,且基施硒肥强于叶面喷施。综上所述,基施0.28%钙镁磷肥+0.12%硅藻土+0.004‰硒对土壤Cd钝化与稻米Cd消减的效果最佳,值得在镉污染稻田推广应用。     

3种植物对镉污染土壤修复的试验研究

为探究植物修复技术在济源镉(Cd)污染土壤的应用特征和效果,笔者以不同Cd污染程度的实际土壤为对象,采用盆栽试验,对比三叶鬼针草、黑麦和印度芥菜对Cd的耐受、富集、转移能力及修复效率。结果表明:污染组植物的生物量无显著下降,供试植物均具有较强的Cd耐性。3类植物富集特征不同,地上部分富集Cd浓度顺序依次是:三叶鬼针草印度芥菜黑麦。3种植物中黑麦地下部分Cd含量最高,轻、重度污染组的Cd含量分别达到11.95、28.56 mg/L。三叶鬼针草对Cd具有较强的转移能力,其中在轻度污染土壤中转移系数(TF=2.23)最大。此外,三叶鬼针草修复效率最高,轻、重度污染组分别为2.04%、1.59%。综上所述,三叶鬼针草的生物量、富集转运系数和修复效率均高于黑麦和印度芥菜。因此,三叶鬼针草可作为济源Cd污染土壤修复植物之一,为当地土壤Cd污染治理提供理论参考和技术依据。     

Growth,survival rate and fatty acid composition of sterlet (Acipenser ruthenus) larvae fed fatty acid‐enriched Artemia nauplii

We evaluated the growth and survival rate of sterlet (Acipenser ruthenus) larvae fed Artemia nauplii enriched with Olioω3 or Red Pepper commercial emulsions (BernAqua NV, Belgium). Sterlet larvae, 0.022 ± 0.002 g body weight, were randomly assigned to one of three feeding regimes with two different feeding durations. After administering live feed for 7 or 14 days, larvae were weaned onto commercial food and reared to 36 days posthatching (28 days of feeding). There were no significant differences in body weight among groups at the end of the trial. A significantly higher survival rate (p < 0.05) was observed in larvae fed Artemia enriched with Red Pepper for 14 days compared to other feeding regimes. Based on the analysis of growth parameters, we can conclude that 7 days of live feeding to be sufficient for efficient rearing of sterlet larvae. And longer duration of live feeding with use of special enrichment can be recommended for a higher survival rate.     

我国稻田系统镉污染风险与阻控

过去30年的工业化和环保措施不到位导致我国部分地区农田土壤Cd污染较为严重。南方部分地区稻米Cd含量超标严重,危害农产品安全和人体健康。农田Cd不断输入、土壤酸化以及种植Cd积累能力较强的籼稻品种是部分地区稻米Cd含量超标的主要原因。我国人群Cd平均摄入量在过去30年里增加了一倍。本文综述了人体Cd摄入量的安全阈值,鉴于食用大米是我国人群Cd摄入的主要来源,重点介绍稻田系统控制稻米Cd积累的主要生物地球化学过程以及水稻Cd吸收积累与转运的分子遗传机制,在此基础上还建议了稻米Cd积累阻控的农艺和育种措施。     

Effects of thyroxine,cod liver oil and potassium iodide on growth and survival of juvenile seahorse,Hippocampus barbouri

Low survival at early stage is the bottleneck in seahorse aquaculture, particularly in the feeding aspect since newborn seahorses must feed immediately upon birth to sustain themselves. Seahorses are visual predator, therefore preferred live feed such as zooplankton. In aquaculture, the most common live feed used is Artemia. In this study, two experiments were conducted to determine the effect of different Artemia enrichment on the growth and survival of newborn Hippocampus barbouri. In the first experiment, six treatments using Artemia enriched with Culture Selco Plus? (SELCO), thyroxine (T4), potassium iodide (KI), cod liver oil (CLO), cod liver oil in combination with thyroxine (CLO + T4) and potassium iodide (CLO+KI) were fed to newborn H. barbouri. Newly hatched Artemia were used as control. At the end of first experiment, treatments using CLO + T4 produced juvenile H. barbouri with the best (p < .05) wet weight (0.142 ± 0.000 g), while juvenile in treatment CLO+KI recorded the highest (p < .05) standard length (3.947 ± 0.014 cm). Subsequently, a second experiment was carried out using the two best enrichment (CLO + T4 and CLO + KI) from the first experiment, but given at different frequency (daily, twice a week, once a week, once in 2 weeks). Daily enrichment using both CLO + T4 and CLO + KI showed no significant (p > .05) difference in growth performance and survival of juvenile of H. barbouri. Interestingly, juvenile fed CLO + T4 enriched Artemia at frequency of twice a week also has no significant difference (p > .05) in survival and growth performance (except for final standard length) when compared with treatment CLO + T4 at daily frequency.     

二氧化碳浓度升高对茶树生理代谢的影响及应对技术

大气中的二氧化碳(CO2)浓度升高是工业革命以来全球范围内最重要的生态变化之一,将直接影响植物的生长发育和代谢过程。尽管CO2浓度升高对粮食作物的影响已经得到了广泛的研究,但其对茶树等重要经济作物的影响却很少受到关注。本文回顾和总结了CO2浓度升高对茶树的初级代谢(包括光合作用、呼吸作用和碳氮代谢)和次级代谢的影响,并探讨了CO2浓度升高环境下茶叶生产过程中的应对技术,旨在为CO2浓度升高背景下茶树优质高产栽培提供一定的理论基础和科学依据。     

黑豆—油菜与大豆—油菜轮作模式土壤镉修复能力比较

通过设置黑豆-油菜、大豆-油菜的轮作模式在湖南醴陵进行大田试验,结果发现黑豆表现出较强的镉富集能力,其根、茎、叶及果壳中镉含量分别为2.14、2.63、4.10及1.34 mg/kg,富集系数均在1以上。油菜各个部位镉含量较高的分别为叶与茎,达到了7.13和4.73 mg/kg。黑豆各部位镉转运系数均高于大豆,各油料作物提取的重金属主要集中在茎与叶。大豆叶的镉富集系数为2.06,茎的镉富集系数为0.86,明显低于黑豆同部位的富集能力。每公顷土地经过一轮黑豆-油菜、大豆-油菜轮作分别能够从土壤中提取73.52 g和51.68 g的镉,对土壤重金属镉的修复效率约为3%。     

不同温度下TMV侵染枯斑三生烟的LncRNA差异表达

【目的】 筛选不同温度下烟草花叶病毒（Tobacco mosaic virus,TMV）侵染后枯斑三生烟（Nicotiana tabacum var. Samsun NN）差异表达的长链非编码RNA（long non-coding RNA,lncRNA）,研究lncRNA在枯斑三生烟抗性反应中的作用。【方法】 N基因的温度敏感性使枯斑三生烟在25℃时具备对TMV的抗性、在31℃抗性丧失,在这两个温度条件下对枯斑三生烟接种TMV和磷酸盐缓冲盐水（phosphate buffered saline,PBS）,48 h后提取系统叶总RNA,构建链特异性文库后进行深度测序。对测序结果进行过滤后利用HTSeq将有效数据与近缘品种TN90（N. tabacum var. TN90）基因组比对,筛选得到lncRNA后利用FPKM法估计lncRNA的表达水平。通过edgeR筛选差异表达lncRNA（differentially expressed lncRNA,DElncRNA）,并利用qRT-PCR技术对这一结果进行验证。通过共定位及共表达分析预测DElncRNA的靶基因,通过参考基因组注释、GO和KEGG富集分析研究靶基因的功能。【结果】 4个处理共12个样本经lncRNA-seq各测得约8 000万条clean reads,共获得4 737条已知lncRNA、40 169条新lncRNA。其中64个lncRNA在不同温度条件下TMV侵染后存在差异表达,qRT-PCR测定结果显示这些lncRNA的测序正确率在80%左右,表明本研究所得测序数据具备较高的可信度。对DElncRNA进行靶基因预测,发现一些基因同时被25℃下调和31℃上调的DElncRNA靶向。靶基因注释功能丰富,主要参与植物抗病、激素和代谢等生理过程。部分可能与激素通路相关的lncRNA,在25℃下TMV侵染时呈现下调趋势,而在31℃下TMV侵染则呈现上调趋势。GO富集分析显示靶基因主要参与构成膜、囊泡等组分,具备钙、钾离子通道抑制剂活性等分子功能,使相应离子得以转运引发随后的反应,同时也参与发病、抗原加工和呈现、细胞分裂素代谢等生理过程。KEGG分析发现靶基因显著富集在植物激素信号转导通路,25℃下调和31℃上调的DElncRNA靶基因同时富集在激素信号传导、ABC运输蛋白、苯丙烷类生物合成等通路。【结论】 不同温度（25℃和31℃）条件下TMV侵染枯斑三生烟后,长链非编码RNA差异表达,DElncRNA通过作用于激素信号传导、物质转运等过程参与寄主系统获得性抗性反应。研究结果可为揭示植物系统获得性抗性中lncRNA的调控功能以及新型抗病毒技术开发提供依据。     

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.