濒危植物光叶蕨的珠芽形成与特征

珠芽胎生繁殖是蕨类植物孢子繁殖的有益补充,丰富了植物的繁殖再生系统,影响着种群遗传多样性和对环境的适应能力。该研究以国家Ⅰ级重点保护野生植物光叶蕨(Cystopteris chinensis)为对象,通过形态学与解剖学方法,探究其羽片后面不明突起——珠芽的形态与解剖特征,揭示其生殖结构和发育过程,追溯珠芽胎生起源和生态适应机制。结果显示:(1)珠芽和孢子囊群同期出现在光叶蕨羽片背面末级细脉中部,只是珠芽位于顶端裂片。珠芽形成包括启动期、膨大期和成熟期3个时期,由黄绿色球状体逐渐成长为深绿色纺锤状,基部变黑形成离层时成熟。(2)珠芽起源于维管束鞘延伸区的薄壁细胞,不断分裂生长形成珠芽原基,逐渐突破叶下表皮形成圆球形珠芽;随着珠芽不断膨大,中下部细胞分化形成贮藏细胞和维管束,顶端分化出生长点形成芽。(3)极少数珠芽在叶片上可直接萌动形成新的自养个体。成熟珠芽掉落在土壤内1周后开始萌发,基部长出圆柱形根,顶部萌发出拳芽。残留珠芽第2年仍可萌发形成新叶,与茎芽产生的叶片形态有别。

市售寿司中砷的人体健康风险

砷是一种在自然界中广泛存在的有毒有害污染物,摄入受污染的食物是人体砷暴露的重要途径.食品添加剂联合专家委员会(Joint FAO/WHO Expert Committee on Food Additives,JECFA)第72次会议指出,海苔、米饭和米制品是总砷含量较高的食物.寿司是一种日本传统美食,近年来颇受中国大众喜爱,其主要食材即是海苔和米饭,可能存在一定的砷污染和人体健康危害问题.本研究从我国南京市20家店面采集了共20份寿司样品,测定样品中总砷含量,并对部分样品进行砷形态分析,进而评估市售寿司中砷的人体健康风险.对寿司进行食物成分分类,发现海苔、米饭和其他馅料的鲜重在整个寿司中的重量占比平均值分别为3.31%±0.88%、69.48%±9.57%、27.20%±10.10%;海苔、米饭和整个寿司样品(n=20)中总砷的含量分别为3.14—27.18、0.10—0.85、0.34—1.57 mg·kg^(-1),平均值分别为(9.67±6.65)、(0.31±0.22)、(0.63±0.27)mg·kg^(-1).对4份寿司及对应成分海苔和米饭进行砷形态分析,发现海苔中砷主要为低毒的砷甜菜碱(arsenobetaine,AsB)、二甲基砷酸盐(dimethylated arsenic,DMA)、砷糖(arsenosugar),占比分别为8.02%±6.57%、37.40%±12.70%和54.59%±17.31%,未检测出高毒性的无机砷;米饭中除了含有低毒性的DMA(22.44%±5.79%)外,含有高毒性的亚砷酸盐(arsenite,As(Ⅲ),49.15%±9.52%)、二甲基一巯基砷(dimethylatedmonothioarsenate,DMMTA,12.48%±2.36%)和砷酸盐(arsenate,As(Ⅴ),11.59%±9.65%);整个寿司样品包含了海苔和米饭的特征砷形态,包括AsB(10.32%±7.91%)、DMA(34.40%±22.04%)、砷糖(32.87%±22.87%)、As(Ⅲ)(15.94%±9.19%)、As(Ⅴ)(2.44%±4.87%)等.基于寿司中砷含量和形态,成人每天通过食用寿司导致的无机砷摄入量平均为(0.21±0.09)μg·kg^(-1)·d^(-1)bw,远低于世界卫生组织规定的BMDL0.5的基准剂量3μg·kg^(-1)·d^(-1)bw,表明食用寿司的癌症风险较低.本研究对南京市场销售的寿司样品进行砷含量、砷形态测定以及开展健康风险评价,对理解食用寿司导致的砷暴露和健康风险具有重要意义.

Effects of Fermented Nori (<i>Pyropia yezoensis</i>) Liquid Fertilizer on Plant Growth Characteristics and Nutrient Content of Komatsuna (<i>Brassica rapa</i>L. var. Wakana Komatsuna) Cultivated in Vermiculite

We conducted plant growth experiments in microbe-free vermiculite to study the effects of four types of fermented seaweed liquid fertilizer (SLF) made from nori (Pyropia yezoensis) seaweed on the germination, plant growth characteristics, SPAD value, and nutrient content and uptake of komatsuna (Brassica rapa L. var. wakana komatsuna). The four types of fermented nori SLF used in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). Komatsuna seeds treated with 200-, 300-, and 400-fold dilutions of SLFs exhibited improved relative germination ratios (RGRs) at 3 and 4 days after sowing (DAS). At 4 DAS, the RGRs of seeds treated with 10-, 100-, 200-, 300-, and 400-fold SLF dilutions showed no differential effect. Seeds treated with undiluted SLFs did not germinate by 4 DAS. SLF1 may promote komatsuna seed germination. The nitrogen (N), calcium, magnesium, sodium (Na), and iodine (I) contents of plants treated with SLF1 were significantly increased relative to plants treated with the other SLFs. Moreover, the I and Na contents of plants were significantly increased by foliar spray application of different dilutions of SLF1. However, SLF treatment markedly reduced the shoot dry weight compared with 1/2-strength modified Hoagland nutrient (MHN) solution, although the same amounts of N and K were applied. SPAD values of the plants treated with SLFs were significantly higher than those of plants treated with MHN. Foliar treatment with SLFs had no significant effect on plant growth, SPAD value, or uptake of nutrients (except Na) relative to the control, but the I content was increased. Plants treated with SLF1 and SLF2 exhibited the highest Na uptake. Foliar spray treatments with SLF1 resulted in the highest I contents in plants. Based on our results, SLF1 is suitable for use as a liquid fertilizer to promote germination and increase nutrient content in komatsuna. These results need to be followed up in soil experiments in the presence of microbes in the rhizosphere.

Tissue Culture and Gemmae Propagation of Shoot Tipof Huperzia serrata

To solve the problems of microbial contamination and no rooting during the tissue culture of Huperzia serrata, wild seedlings of Huperzia serrata were cultured by indoor hydroponics or soil cultivation methods, then the stem tips were used in tissue culture. The above operation significantly reduced microbial contamination during tissue culture process. Different types and concentrations of hormones were added into the basic medium MS to screen the optimal formula for induced plantlet growth and rooting. It was found that 1/2MSCO was the best medium on which stem, leaves and roots of tissue culture plantlets of Huperzia serrata grew quickly. At the same time, sand planting was a convenient and effective approach for gemmae propagation of Huperzia serrata, the survival rate of seedlings germinated from gemmae was nearly 100%.

Effects of Fermented Nori (<i>Pyropia yezoensis</i>) Seaweed Liquid Fertilizers on Growth Characteristics, Nutrient Uptake, and Iodine Content of Komatsuna (<i>Brassica rapa</i>L.) Cultivated in Soil

We investigated the effects of fermented nori (Pyropia yezoensis) liquid fertilizers on plant growth, soil plant analysis development (SPAD) values, and nutrient uptake of komatsuna (Brassica rapa L. var. wakana komatsuna) plants. The four types of fermented nori seaweed liquid fertilizers (SLFs) evaluated in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). In Experiment 1, the highest plant growth, SPAD, and nutrient uptake values were obtained from treatment with SLF2 and SLF4. There were no significant differences between the effects of basal and foliar application of SLFs, except for iodine (I) content;plants treated with SLF1 had the highest I content. In Experiment 2, plant growth and nutrient uptake decreased with higher concentrations of SLFs. Plants treated with 25% SLF2 + 75% chemical fertilizer (CF) or 25% SLF4 + 75% CF exhibited significantly higher plant growth and nutrient uptake. The highest I content resulted from treatment with 75% SLF1 + 25% CF or 100% SLF1. Taken together, our results showed that 25% SLF + 75% CF produced the best plant growth characteristics, nutrient uptake, and I content relative to the controls. Therefore, basal application of these liquid organic fertilizers can be used to increase productivity, nutrient uptake, and I content and to reduce nitrate-nitrogen content in komatsuna production.

魔力女孩Gemma Ward

曾经我们以为，不会再有人能赶上Kate Moss在Calvin Klein那些性感而漂亮的广告中造成的影响，那些画面似乎永不褪色的存在于我们的记忆中．无论已经从青涩女孩化身为人母的Kate Moss现在或即将变成什么模样，记忆中的她都永远是那样清瘦羞涩。

长白母猪断奶至配种间隔全基因组关联分析

该研究旨通过全基因组关联分析定位影响长白母猪断奶至配种间隔的候选基因,以期为我国种猪育种工作提供理论参考。本研究以国家某核心育种场1063头长白母猪的断奶至配种间隔记录和50 K基因数据为研究材料,利用GEMMA软件的混合线性模型进行全基因组关联分析(GWAS),鉴定关联分析显著位点。结果表明,长白母猪第一胎次和第三胎次共存在5个显著SNPs。对5个显著位点进行单倍型分析,获得4个单倍型块。筛选到的BTG1、FUT1、FUT2、SCNN1G和CBLB基因可能是影响断奶至配种间隔性状的重要基因,该研究结果可作为以后种猪育种实践提供参考。

Zoonotic Pathogens Detected in Ticks in Kenyan Game Reserves

Little is known on tick-borne pathogens and their role in disease in game reserves in Kenya. Ticks were collected by sterile forceps from restrained cattle hide and placed into labeled falcon tubes. Ticks were screened for pathogens by High Resolution Melting (HRM) analysis and sequencing of specific RT-PCR products of Anaplasma, Ehrlichia, and Rickettsia species. A total of 317 ticks (281 adult ticks and 36 nymphs) comprising seven species were collected around the Tsavo National Reserve (TNR) in Taita Taveta County with Amblyomma gemma being the most commonly collected species (n = 135, 42.6%). From near Shimba Hill game reserve (SHNR), a total of 240 adult’s ticks were sampled, representing eight species, with again Amblyomma gemma being the most sampled species (n = 156, 65%). From Tsavo, a total of three pools of Rhipicephalus appendiculatus were positive for Theileria parva, two pools of Rhipicephaline evertsi for Anaplasma platys and one pool of Amblyomma variegatum nymphs for Rickettsia africae. Rickettsia africae, which causes African tick-bite fever, was detected in two pools of Am. variegatum and one pool of Amblyomma gemma collected near Shimba Hill game reserve. Rickettsia sp. and Anaplasma sp. were detected in Am. gemma and Rh. evertsi respectively. Rickettsia aeschlimannii was detected in a pool of Am. gemma. These findings highlight the risk of transmission of zoonotic pathogens to humans in regions with high human-wildlife interfaces. Of specific importance, we provide evidence of R. aeschlimannii in A. gemma for the first time, representing a potential new R. aeschlimannii vectors.

小扭口藓(Barbula indica)芽胞发育特征的实验研究

在光照培养箱中人工对照培养小扭口藓(Barbula indica(Hook.)Spreng)的芽胞,显微镜下观察并记录其发育成配子体的全过程.结果表明:小扭口藓芽胞在3～4d即可萌发;10 d左右开始分化出绿丝体、轴丝体及假根;18 d,轴丝体上的侧枝顶端细胞以分生缢割的方式产生单细胞或多细胞芽胞;40 d,轴丝体上开始出现配子体原始细胞;之后,配子体原始细胞发育成桑椹状的幼小配子体.还对芽胞形态发育、生理生态及配子体发生过程的特点进行了分析和讨论.

沙坡头固定沙丘结皮层藓类植物繁殖生物学特性研究

采用撒茎法和芽胞培养土生对齿藓Didymodonvinealis的实验表明 :芽胞由植物体叶腋腋毛顶端细胞反复再生 ,原丝体由芽胞和叶基部细胞产生或由腋毛直接生长为原丝体 ,附着在叶背面的芽胞比未附着芽胞产生的原丝体生长更好 ;老茎不直接生长为植物体 ,产生新生枝后死去。同时 ,实验室培养的真藓Bryumargenteum其植物体、叶和细胞形态特征与野生种有明显差异。为人工促进固定沙丘结皮层的形成提供理论和实验依据。

长柄石杉芽胞及芽胞植株形态研究

为研究石杉属植物芽胞形态特征以及芽胞在石杉属植物无性繁殖中的作用,对野外采集和移栽后新生的长柄石杉(Huperzia javanica)芽胞体、芽胞的形态特征、芽胞萌发形成芽胞植株的过程进行了描述,并对芽胞和芽胞残体发生数量进行计数。结果表明,芽胞体由芽胞和芽托部组成,前者是6个小叶围住的小芽,后者为具有6个鳞状叶的柄状体;芽胞脱落后一周开始萌发并进一步发育为芽胞植株;芽胞体发生枝条上平均有5个芽胞发生;芽胞发生具有一定程度的周期性,可以据此估计石杉植株株龄和生长速度。

地质导向钻井技术的现场应用

地质导向钻井是以井下实际地质特征来确定和控制井眼轨迹的钻井技术。使用这一技术 ,可以精确地控制井下钻具命中最佳地质目标。新疆油田MBHW 0 4水平井是国内第一口使用地质导向钻井技术的井。重点介绍了地质导向钻井技术的具体步骤及其在新疆油田MBHW 0 4井中的应用情况 ,包括自然伽马测井资料的解释和应用。应用地质导向钻井技术 。

蛇足石杉扦插及芽胞繁殖研究

目的：针对蛇足石杉Huperzia serrata（Thunb.ex Murray）Trev.野生资源急剧减少,野生种群遭到毁灭性采挖而面临枯竭的现状,利用蛇足石杉带茎尖插条和芽胞进行野外半人工辅助繁殖,以期建立一套稳定、有效的人工繁殖体系。方法：以湘西古丈高望界林场岩陀寨为实验地,采用2年生以上顶技为试材,设计4因素3水平正交试验,研究了插条长度、NAA浓度和插条在NAA溶液中的浸泡时间对扦插生根的影响;通过2年时间的野外定点观测,对蛇足石杉芽胞发生、散落和生长动态进行跟踪研究,并对置于不同土壤层的芽胞萌发进行研究。结果：在原生境中,长6 cm的插条在NAA质量浓度20 mg/L中浸泡5 min的处理为最佳,60 d后即有白色不定根产生,90 d后成活率达90%,210 d后插条有明显生长量;蛇足石杉芽胞大多形成于每年7~9月,次年3~4月成熟后从母株上脱落,遇到适合条件随即萌发生长为幼苗,6个月即可成独立植株;萌发实验表明,光照和湿度是影响芽胞萌发的主要因素。结论：在自然生境中,建立蛇足石杉扦插繁殖体系切实可行;利用芽胞进行人工繁殖可建立稳定有效的幼苗再生体系。该研究对缓解蛇足石杉资源匮乏有重大意义。

海南蛇足石杉株龄及年生长量研究

蛇足石杉因含有丰富的石杉碱甲而引起广泛关注,需求巨增,但该植物生长缓慢,野生资源濒临灭绝,且人工培植相关技术尚未成熟。为保护野生资源及今后开展繁育研究工作,需进一步了解蛇足石杉的生物学特性。据此开展了对海南蛇足石杉天然群体的调查,调查内容主要涵盖芽胞层数、层间距、株高及环境条件等。结果表明,芽胞逐年产生,集中分布于分枝顶端,其层数可作为判定株龄的重要指标;生长半年的幼苗平均高度为1.42cm,幼株3年生长高度平均为7.94cm;而成株生长相对稳定,平均年生长量在2.0～2.5cm之间。根据株高及芽胞(或芽托)层数可判定成株株龄为芽托层数+3。

单芽狗脊蕨的生境观测及其芽胞发育初步研究

初步观察了单芽狗脊蕨的生长环境及其芽胞的发育过程。结果表明,单芽狗脊蕨喜阴湿环境和偏酸性土壤。5月的复叶上开始分化出芽胞,7月成熟的芽胞可在母体上萌发,长出不定须根,芽胞脱离母体后即能在土壤中萌发生长。芽胞越大,其萌芽率和生长速度越大。单芽狗脊蕨一年可产生两代芽胞。进行胎生的单芽狗脊蕨的孢子囊缺失或数目减少。

真藓科(Musci:Bryaceae)芽孢形态特征及其分类学意义

在光学显微镜(LM)和扫描电子显微镜(SEM)下对6属15种真藓科(Bryaceae)植物的芽孢进行了形态特征观察。结果显示,真藓科芽孢形态多样,可以作为该科种间分类鉴定的重要标准。芽孢在不同发育时期,形态特征差异较大。无性芽孢在环境条件许可的情况下才会产生,产生芽孢的植株一般不易发生有性生殖。

山苍子精油对白色念珠菌生物被膜芽管形成的抑制作用研究

目的研究山苍子精油在体外对白色念珠菌生物被膜芽管形成初始阶段的抑制作用,为预防由白色念珠菌生物被膜引起的难治性感染提供新思路。方法通过血清芽管实验,观察不同浓度山苍子精油对白色念珠菌出芽生长现象的抑制作用。结果 2~5μL/mL的山苍子精油对白色念珠菌出芽生长的抑制率为100.0%,但不具有杀菌作用,0.25μL/mL的山苍子精油对白色念珠菌芽管生长的抑制率为85.0%。结论 2~5μL/mL的山苍子精油可完全抑制白色念珠菌初始阶段生物被膜的形成,但不能杀灭酵母细胞。0.25μL/mL几乎不能抑制芽管生长。

蛇足石杉的芽胞特性和芽胞繁育技术

[目的]研究蛇足石杉的芽胞特性及芽胞繁育技术。[方法]用植物解剖学方法对芽胞的结构进行了观察和描述,在充分了解蛇足石杉芽胞特性的基础上,建立了芽胞繁育体系。[结果]蛇足石杉芽胞有5胞片和1幼芽构成,极易萌发成新植株。[结论]以芽胞为繁殖材料进行规范种植是切实可行的,同时对缓解其资源压力有重要意义。