楼梯草属四新种和一新变种

描述了荨麻科楼梯草属小叶楼梯草组一新变种,维西楼梯草,骤尖楼梯草组骤尖楼梯草系一新种,兜船楼梯草,南川楼梯草系二新种,罗氏楼梯草和异晶楼梯草,以及疏毛楼梯草系一新种,福贡楼梯草。     

滇东南荨麻科楼梯草属一新系和一新种

描述了采自云南省东南部楼梯草属一新种——柳叶楼梯草（Elatostemaneriifolia）和据其为模式建立的一新系——柳叶楼梯草系（ser．Neriifolia）,并讨论了这些新类群和相近类群在形态上的区别,并对柳叶楼梯草的保护等级进行了评估。     

Selenium hyperaccumulation reduces plant arthropod loads in the field

The elemental defense hypothesis proposes that some plants hyperaccumulate toxic elements as a defense mechanism. In this study the effectiveness of selenium (Se) as an arthropod deterrent was investigated under field conditions. Arthropod loads were measured over two growing seasons in Se hyperaccumulator habitats in Colorado, USA, comparing Se hyperaccumulator species (Astragalus bisulcatus and Stanleya pinnata) with nonhyperaccumulators (Camelina microcarpa, Astragalus americanus, Descurainia pinnata, Medicago sativa, and Helianthus pumilus). The Se hyperaccumulating plant species, which contained 1000-14 000 microg Se g(-1) DW, harbored significantly fewer arthropods (c. twofold) and fewer arthropod species (c. 1.5-fold) compared with nonhyperaccumulator species that contained < 30 microg Se g(-1) DW. Arthropods collected on Se-hyperaccumulating plants contained three- to 10-fold higher Se concentrations than those found on nonhyperaccumulating species, but > 10-fold lower Se concentrations than their hyperaccumulator hosts. Several arthropod species contained > 100 microg Se g(-1) DW, indicating Se tolerance and perhaps feeding specialization. These results support the elemental defense hypothesis and suggest that invertebrate herbivory may have contributed to the evolution of Se hyperaccumulation.     

贵州楼梯草属(荨麻科)植物种类组成及分布格局

荨麻科(Urticaceae)楼梯草属(Elatostema)植物种类繁多、形态相似、关系密切,是植物分类学界公认的疑难分类群之一。贵州省地理位置特殊,水热条件较好,喀斯特地貌复杂多变,是我国楼梯草属植物的重要分布区,但一直以来种类不清,分类不明。为进一步理清资源本底及分布特征,该文通过近年调查和查阅资料形成贵州楼梯草属植物名录,分析其物种组成,并基于分布地及海拔数据分析空间分布特征,以期为贵州植物多样性保护以及区系研究提供进一步的基础资料。结果表明:全省赤车类群植物有1组1系7种,楼梯草类群有5组20系69种,分别占全国种类的17.94%、20.78%。楼梯草属植物共76种,其中13种为贵州楼梯草属特有种。在地理分布上,赤车类群主要见于黔北-黔东-黔南部分地区,沿赤水、桐梓、习水、正安-江口、印江-剑河-都匀、荔波-望谟一线,总体分布反呈“C”状; 楼梯草类群植物主要分布在黔北-黔东-黔南-黔西南大部分地区,沿赤水、正安、江口-七星关、开阳、施秉、黄平-兴义、兴仁、安龙、贞丰、望谟、独山、荔波一带分布较多,总体分布呈“三”字状; 楼梯草属特有植物总体呈点状、不均匀分布。该属植物主要分布在海拔600～1 000 m的范围内。     

广西楼梯草属五新种

描述了在中国广西发现的楼梯草属五新种:小果楼梯草Elatostema microcarpum W.T.Wang & Y.G.Wei在体态方面与荔波楼梯草E.liboense W.T.Wang极为相似,但茎较低矮,不具软鳞片,叶上面无毛,钟乳体较小而可区别。圆序楼梯草Elatostema gyrocephalumW.T.Wang &Y.G.Wei在体态上与浅齿楼梯草E.crena-tum W.T.Wang相似,但叶两面均有糙伏毛,侧脉较少,4-6对,钟乳体较小,长约0.1 mm而不同。对序楼梯草 Elatostema binatum W.T.Wang &Y.G.Wei在亲缘关系方面与深绿楼梯草E.atroviride W.T.Wang相近,但茎和叶无毛,雄花序托较小,近方形,长度及宽度约6.5 mm,小苞片较小,长约1.5 mm,无毛,可以区别。河池楼梯草Elatostema hechiense W.T.Wang &Y.G.Wei似华南楼梯草E.balansae Gagnep.但叶的渐尖头全缘,钟乳体较小,长0.1-0.15 mm,雌花序苞片顶端无角状突起,可以区别。环江楼梯草Elatostema huanjiangense W.T.Wang & Y.G.Wei可能与樟叶楼梯草Elatostema petelotii Gangnep.有亲缘关系,但后者的叶全缘,钟乳体较大,长0.3-0.7 mm,侧脉在狭侧3条,在宽侧4条,但后者的叶全缘,钟乳体较大,长0.3-0.7 mm,侧脉在狭侧3 条,在宽侧4条,雌花序常有长花序梗,而与本种相区别。     

New Taxa of Lappula from China

Two new species and one new variety are described from China. They are L.ramulosa, L. gansuensis and L. microcarpa var. heterogenea.     

Notulae de Elatostemate (Urticaceae) Sinensi

In the present paper two series, 11 species and three varieties of the genus Elatostema are described as new from China and one variety is elevated to specific rank. Four species and one variety are reported from Medog, Xizang Autonomous Region, for the first time.     

小果博落回的生物碱分离与鉴定

以D101大孔吸附树脂为吸附剂,将对小果博落回全草的酸水提取物分为50%乙醇洗脱部分和丙酮洗脱部分.对两部分洗脱物分别进行硅胶柱色谱分离,由50%乙醇洗脱部分得到5个生物碱:二氢血根碱(1),二氢白屈菜红碱(2),6-乙氧基血根碱(3),6-丙酮基血根碱(4)和Bocconarborine A (5).由丙酮洗脱部分得到原阿片碱(6),α-别隐品碱(7),β-别隐品碱(8)和小檗红碱(9).采用波谱分析对化合物进行了结构表征,结果表明,化合物3、4、5、9是首次从该植物中分离得到.     

低夜温后不同光强对榕树叶片PSⅡ功能和光能分配的影响

研究了自然低夜温后全光照与遮荫对榕树叶片PSⅡ功能及光能分配的影响。结果表明低夜温后全光照条件下叶片吸收光能分配于光化学反应部分减少,而热耗散部分和反应中心过剩光能则增加,从而导致了PSⅡ功能的下降,遮荫条件下光能分配于光化学反应的程度增加．虽然用于热耗散的比例下降了,但反应中心过剩光能相对较少,从而有利于PSⅡ功能的恢复。     

Phenolic compounds from the leaves and stem bark of Pseudospondias microcarpa (A. Rich.) Engl. (Anacardiaceae)

Phytochemical study of the leaves and the stem bark of Pseudospondias microcarpa (A. Rich.) Engl. afforded eight phenolic compounds: scopoletin (1), ferulic acid (2), isovitexin (3), rhoifolin (4), quercetin 3-O-α-L-rhamnopyranoside (5), justicialoside A (6), granduloside A (7) and pithecellobiumol B (8). The structures of the isolated compounds were elucidated by spectroscopic means including 1D and 2D NMR and MS, and by comparison with previously reported data. This is the first report on the isolation of these compounds from the genus Pseudospondias. The chemotaxonomic significance of the isolated compounds within the family Anacardiaceae is discussed.