Weed–barley interactions affect plant acceptance by aphids in laboratory and field experiments

Increased botanical diversity can lead to suppression of insect pests. One route by which botanical diversity is increased in crops is through the occurrence of weeds, which increasingly interact with crop plants as organic production expands. However, the mechanisms by which this might affect insect herbivores are poorly understood. This study examined whether volatile chemical interactions between weeds and barley, Hordeum vulgare L. (Poaceae), can affect plant acceptance by the bird cherry oat aphid, Rhopalosiphum padi L. (Hemiptera: Aphididae). In laboratory experiments, exposure of barley to volatiles from Chenopodium album L. (Amaranthaceae) and Solanum nigrum L. (Solanaceae) resulted in significantly reduced aphid acceptance compared with unexposed plants. In a series of field experiments in which the occurrence of weeds was manipulated in plots of barley, significantly lower aphid acceptance was recorded on barley plants grown in plots with C. album compared with barley plants in weedless plots. The results indicate that interaction between weeds and barley can affect aphid–plant interactions in the field as well as in the laboratory and provide further evidence that the effects of chemical interactions between visibly undamaged plants can extend to higher trophic levels.     

重金属Pb(Ⅱ)对3种藜科植物种子萌发的影响

以珍珠猪毛菜（Salsola passerina Bunge）、地肤（Kochia scoparia(L.)Schrad.）和白藜（Chenopodium album L.）3种藜科植物为研究对象,研究不同浓度（0、50、150、300、600、800、1 000 mg·L^-1）的Pb(Ⅱ)处理对植物种子萌发和幼苗生长的影响。结果表明：当Pb(Ⅱ)浓度为50和150 mg·L^-1时,珍珠猪毛菜和地肤种子的发芽率、发芽势和发芽指数与对照相比差异不显著,Pb(Ⅱ)浓度为150 mg·L^-1时,对白藜种子发芽率、发芽势和发芽指数有明显影响,Pb(Ⅱ)浓度大于300 mg·L^-1对3种植物种子萌发均有抑制作用,对白藜和地肤的抑制大于珍珠猪毛菜。3种植物的种子活力指数除珍珠猪毛菜在50 mg·L^-1时与对照无显著差异,其余各处理均与对照有极显著差异。Pb(Ⅱ)浓度为50 mg·L^-1时,对3种植物的胚根长和胚芽长都影响不大,随着Pb(Ⅱ)浓度的升高,对3种植物的胚根长和胚芽长都有明显的抑制作用,对地肤和白藜的抑制强度更大。地肤和白藜幼苗分别在Pb(Ⅱ)浓度为300和600 mg·L^-1时死亡,当Pb(Ⅱ)浓度达到1 000 mg·L^-1时,珍珠猪毛菜仍可生长,但生长比较缓慢。3种植物幼苗对Pb(Ⅱ)的耐受性为：珍珠猪毛菜＞白藜＞地肤。     

盐胁迫下藜的形态结构与生理响应

本文采用石蜡切片、扫描电镜和体视显微镜对藜进行了形态结构观察和多种生理指标检测,研究在盐胁迫下藜的结构和生理变化。结果表明：在花期,藜的株高和茎粗显著降低,叶未产生明显肉质化。高盐（300mmol·L^-1）胁迫下,叶维管束的导管数量及形成层层数增加,茎的维管束密度增加,根木质化程度增强,大导管密度显著降低。叶下表面的盐囊泡较上表面多,叶和茎细胞中均含有簇状结晶。随着盐浓度的升高,叶片中含水量降低,相对电导率升高,丙二醛（MDA）含量无显著变化,叶绿素含量在苗后期先升高后降低,在花期,其含量随盐浓度升高而降低。300mmol·L^-1盐胁迫下,苗后期的可溶性糖、脯氨酸7L-N-菜碱含量显著增J／w;至花期,脯氨酸及甜菜碱含量显著高于对照。以上结果初步显示,高浓度盐胁迫对花期的藜形态结构及部分生理指标均比苗期产生显著影响,但300mmol·L^-1盐胁迫下藜仍能完成其生活史。     

藜的营养成分及作为新型蔬菜资源的评价

对藜的营养成分进行了测定并对其作为新型蔬菜进行了评价。藜具有较高含量的维生素C,β-胡萝 卜素,以及Fe、Zn、Mn和Cu等微量元素,氨基酸的种类达17种,其中7种为人体必需氨基酸。藜种子中粗脂 肪的含量是16．4％,含有多种油酸,其中亚油酸和亚麻酸是人体必需脂肪酸,尤其是亚油酸含量高达 53．86％。还讨论了藜的生物学特性、对环境的适应性及食用处理方法。并认为藜是一种很有开发利用前景 的野生蔬菜资源。     

新疆干旱区植物藜的种子异型性及其萌发机理

新疆干旱区分布的植物藜(Chenopodium album)的种子有黑色和褐色两种类型。对藜的异型性种子从形态结构、不同环境因素及激素或化学物质对萌发的影响以及同工酶谱等方面进行了研究,并对其萌发及适应异质环境的机理进行了讨论。结果表明:(1)藜的异型性种子在形态结构、萌发休眠特性等方面都存在明显差异:黑色种子种皮厚且硬,休眠,萌发慢,萌发率低;褐色种子种皮薄而软,不休眠,萌发快且萌发率高;(2)黑色种子的休眠可通过切除胚根外缘种皮得以完全解除;(3)赤霉素、乙烯利对黑色种子的萌发无明显促进作用;KNO3可较显著促进黑色种子的萌发;协同使用乙烯利和KNO3时,可显著提高黑种子萌发率,完全打破休眠;(4)黑色种子和褐色种子的酯酶、过氧化物酶及过氧化氢酶同工酶谱带存在差异;(5)黑色种子的萌发需要光照,而褐色种子则对光不敏感;低温贮藏对二者的萌发均无显著影响,尽管黑色种子的萌发率有波动。研究结果初步显示黑色种子的休眠是内源(胚)和外源(种皮)因素共同所致。藜的种子异型性及其萌发机理的形成是其对新疆干旱区异质化环境的高度适应。     

Mass emergence of a specialist sawfly species on unpalatable herbs under severe feeding pressure by sika deer

In recent years, the increase in sika deer populations has had a significant impact on forest ecosystems. Many studies have reported that this increase has led to the dominance of plants unpalatable to the deer; however, few studies have investigated the effects of this dominance on the specialist sawfly species that feed on the unpalatable plants. We observed the mass emergence of Aglaostigma amoorensis (Hymenoptera: Tenthredinidae), a rare specialist sawfly of the false helleborine Veratrum plants unpalatable to sika deer, in areas under severe feeding pressure by sika deer. An exponential increase in the number of emergent A. amoorensis adults was observed to occur with an increase in Veratrum album patch sizes. In addition, the increase in the A. amoorensis density had a negative effect on reproductive success of V. album. Our findings suggest that the relative abundance of specialist sawfly to the host‐plant abundance has changed for successive years after sika deer irruption.     

山东省长岛县南部四岛藜（Chenopodium album L.）天然种群遗传多样性的ISSR分析

采用ISSR分子标记对分布于山东省长岛县南部的北长山、南长山、大黑山和小黑山4个岛屿上的藜天然种群共81个个体进行了遗传多样性及遗传结构的研究。13个引物共检测到157个可重复的位点。遗传多样性研究结果表明：种内的多态位点比率为66.24％,具有较高的遗传多样性（Shannon（I）指数在物种水平上为0.332 0）;种群间有一定的遗传分化,根据G_st值,种群间的遗传多样性占总群体的9.27％。遗传距离分析表明,XHS种群和NCS种群的遗传一致度最高,与地理距离无相关性。     

Poisonous plants: Effects on embryo and fetal development

Poisonous plant research in the United States began over 100 years ago as a result of livestock losses from toxic plants as settlers migrated westward with their flocks, herds, and families. Major losses were soon associated with poisonous plants, such as locoweeds, selenium accumulating plants, poison‐hemlock, larkspurs, Veratrum, lupines, death camas, water hemlock, and others. Identification of plants associated with poisoning, chemistry of the plants, physiological effects, pathology, diagnosis, and prognosis, why animals eat the plants, and grazing management to mitigate losses became the overarching mission of the current Poisonous Plant Research Laboratory. Additionally, spin‐off benefits resulting from the animal research have provided novel compounds, new techniques, and animal models to study human health conditions (biomedical research). The Poisonous Plant Research Laboratory has become an international leader of poisonous plant research as evidenced by the recent completion of the ninth International Symposium on Poisonous Plant Research held July 2013 in Hohhot, Inner Mongolia, China. In this article, we review plants that negatively impact embryo/fetal and neonatal growth and development, with emphasis on those plants that cause birth defects. Although this article focuses on the general aspects of selected groups of plants and their effects on the developing offspring, a companion paper in this volume reviews current understanding of the physiological, biochemical, and molecular mechanisms of toxicoses and teratogenesis. Birth Defects Research (Part C) 99:223–234, 2013. Published 2013 Wiley Periodicals, Inc.     

翠雀属一新变型

本文发表了翠雀属一新变型,即白花翠雀ＤｅｌｐｈｉｎｉｕｍｇｒａｎｄｉｆｌｏｒｍＬ．ｆ．ａｌｂｕｍＴ．Ｊ．ＦｅｎｇｅｔＪ．Ｘ．Ｈｕａｎｇ．