外来假马鞭草的特征特性及控制

假马鞭草为马鞭草科假马鞭属多年生草本植物,原产中南美洲,19世纪末出现在中国香港,现在我国福建、广东、广西、云南南部、香港、海南和台湾有分布.文章在调查研究及查阅大量文献的基础上,归纳了外来杂草假马鞭草的形态特征、起源、入侵途径、在我国的分布、经济和生态影响、预防控制和管理措施等.     

Arambarria the pathogen involved in canker rot of Eucalyptus,native trees wood rots and grapevine diseases in the Southern Hemisphere

Arambarria (Hymenochaetales, Basidiomycota) is a monotypic genus recently described to accommodate specimens from the Patagonian forests of Argentina wrongly assigned in the past to Inocutis jamaicensis. On the basis of a wide sampling of strains and phylogenetic analysis inferred from combined sequences including the nuc rDNA ITS1‐5.8‐ITS2 region, 28S rDNA D1‐D2 domains and partial sequences of translation elongation factor 1‐a (tef1‐α), we demonstrate that this genus is associated with an important canker rot of eucalypt plantations in Uruguay, to wood rots of many native and exotic hosts, and to “hoja de malvón” and chlorotic leafroll of grapevines diseases in Central Chile, Central Argentina and Uruguay, formerly assigned to I. jamaicensis and/or Fomitiporella sp. The combined phylogenetic analysis showed the existence of three closely related clades that corresponded to (1) the Pampas of Uruguay and Argentina (“uruguay” clade), (2) the Monte, Chaco Serrano and Yungas forests of Argentina (“cognata” clade) and (3) the Patagonian Andes forests and Chilean Province (“destruens” clade). Lack of morphological differences between taxa from the three clades, their occurrence in both native and exotic hosts, previous results showing interfertility between isolates from Uruguay and Argentina, and the lack of full support in the concatenated ITS + 28S + tef1‐α analysis, prevents us to distinguish and describe three different taxa; the proper name of the taxon being Arambarria cognata comb. nov. A fourth, distinctly separated clade corresponded to South African strains isolated from vineyards representing an undescribed taxon associated with Esca grapevine disease in that country. Arambarria is shown to be unrelated to Inocutis, with which it was confused in the past and, so far, remains restricted to the Northern Hemisphere in America (Mexico, Jamaica and the USA).     

贮藏方式和培养温度对药用植物假马鞭种子萌发的影响

为探查药用植物假马鞭(Stachytarpheta jamaicensis)种子破除休眠的贮藏方法以及萌发的最佳温度条件,将假马鞭种子分别进行30 天的室温干燥贮藏、15℃湿润贮藏、4℃低温层积和0℃冰冻贮藏后,测定其萌发率;种子在6 个温度梯度(15、20、25、30、35、40℃)、12 h 光照/12 h 黑暗条件下培养,观测其萌发率和萌发进程。结果表明：假马鞭种子具有较高活性(92%),初始萌发率为10%~49.3%;经过室温干燥贮藏、15℃、4℃湿润贮藏的种子,在变温(25℃/15℃)培养下其萌发率分别达到55.3%、70%和56.7%,经0℃冰冻贮藏后萌发率降低至9.3%;假马鞭种子对6 种培养温度显示出不同的响应,在30℃和35℃培养下,萌发开始时间较早（1~7 天）,累积萌发率不足20%;在20℃和25℃培养下,萌发开始时间较晚（7~11天）,累积萌发率分别达到72.7%和56%。假马鞭种子具有中度生理休眠,经过室内干燥贮藏、15℃湿润贮藏和4℃层积可以破除种子部分休眠,获得较高萌发率,种子达到最高萌发率(70%)的最佳贮藏条件是15℃湿润贮藏、变温培养(25℃/15℃);未经贮藏处理的种子达到最高萌发率(72.7%)的培养温度是20℃。     

假马鞭花器官水浸液对6种植物种子萌发和幼苗生长的影响

为弄清假马鞭对本地农作物的化感效应,利用培养皿滤纸法,初步研究了假马鞭花器官水浸提液对6种受体植物种子萌发和幼苗生长的影响。结果表明:假马鞭花器官浸提液均抑制6种植物种子的发芽率和发芽指数,且随处理浓度的增加抑制作用增强;低浓度对植物根长具有促进作用,高浓度则抑制根的生长,对苗高既起抑制作用也起促进作用;对叶绿素a含量及CAT活性总体上表现出抑制作用;假马鞭花器官各浓度浸提液对油菜的化感综合效应表现为轻微的促进作用,而对其他5种受试植物总体表现为抑制作用,抑制作用强度依次为上海青>莴苣>苋菜>空心菜>黄瓜。