Two New Records of Begonia L. (Begoniaceae) from China

Two species of Begonia L. (Begoniaceae), viz. Begonia demissa Craib and Begonia subperfoliata Parish ex Kurz are reported as new records in China, and the two species assigned to Begonia sect. Parvibegonia A. DC. and Begonia sect. Diploclinium (Wight) A. DC. respectively. The type locality of Begonia demissa is in Thailand and of Begonia subperfoliata in Myanmar. The distribution of Begonia demissa is now extended to Mengyuan, Mengla County of Xishuangbanna Dai Autonomous Prefecture and that of Begonia subperfoliata to Liushun Community, Pu’er City, both in Yunnan province, China.     

Pleistocene and pre-Pleistocene Begonia speciation in Africa

This paper presents a historical biogeographic analysis of African Begonia based on combined internal transcribed spacer (ITS) and trnL intron sequences. Age range estimates for Begonia in Africa ranged from only 1.5 Ma for some terminal nodes to 27 Ma for basal nodes when the ages of Réunion (2 Ma) andMayotte (5.4 Ma) were used to date the split between Begonia salaziensis and Begonia comorensis. Assuming a more recent origin age for Begonia salaziensis (2 Ma) provided age estimates in other parts of the phylogeny which agreed with patterns observed in other African organisms. A large proportion of the Begonia diversity seen today in Africa is of pre-Pleistocene origin. Species of Pleistocene origin are concentrated in species-rich groups such as sections Loasibegonia, Scutobegonia, and Tetraphila, which have their centre of diversity in western Central Africa. Phylogenetically isolated taxa such as Begonia longipetiolata, Begonia iucunda, and Begonia thomeana date to the late Miocene, a period of extended aridification on the African continent that had severe effects on African rain forest species. A general pattern is identified where phylogenetically isolated species occur outside the main identified rain forest refuges. Endemic species on the island of S?o Tomé such as Begonia baccata, Begonia molleri, and Begonia subalpestris appear to be palaeoendemics. Of these species, the most recent age estimate is for B. baccata, which is dated at ca. 3 Ma. Therefore, S?o Tomé appears to have functioned as an important (if previously unrecognised) pre-Pleistocene refuge. On the mainland, areas such as the Massif of Chaillu in Gabon, southern Congo (Brazzaville), and far western areas of Congo (Kinshasa) have played similar roles to S?o Tomé.     

Additional Notes on the Begonia Sect. Petermannia (Begoniaceae) from China

Begonia pellionioides YM. Shui & WH. Chen, a new species of the genus Begonia L. (sect. Petermannia (Klotzsch) A. DC., Begoniaceae), is described and illustrated. The new species is endemic to limestone areas in Southeastern Yunnan Province, China, and is most similar to Begonia hainanensis Chun & F. Chun but distinguished by its more elongated leaves with cuneate base and acuminate to caudate apex, tepals adaxially with spiny hairs and sharply triangular capsule wings with truncate superior margin. Besides, the unknown flower morphology of previously published Begonia sublongipes YM. Shui in Begonia sect. Petermannia is described.     

云南秋海棠挥发物抗微生物活性的研究

对云南产的16种秋海棠属（Begonia L．）植物进行了挥发物抗微生物活性实验,其中14种秋海棠为首次报道。结果表明,在所研究的16种秋海棠中,有8种秋海棠具有抗葡萄球菌（Staphyllococcus epidermidis）活性。而抗大肠杆菌（Escherichia coli）活性最强的是厚壁秋海棠（Begonia silletensis C．B．Clarke）,假厚叶秋海棠（B．pseudodryadis C．Y．Wu）和秋海棠（B．grandis Dryand．）。只有铁甲秋海棠（B．masoniana Irmsch．）和毛叶秋海棠（B．rex Putz．）对白假丝酵母菌（Candida albicans）有抗性。作为室内盆栽花卉被广泛应用的秋海棠,不仅可以美化室内环境,而且还可以作为药用和净化室内环境的生态产品进行推广应用。     

云南秋海棠属新分类群

记述云南产秋海棠属９个新种。即;麻栗坡秋海棠,古林箐秋海棠,圆叶秋海棠,圭山秋海棠,大围山峰为海棠,马关秋海棠,红斑秋海棠,紫叶秋海棠,河口秋海棠。     

云南秋海棠属植物叶片横切面比较解剖研究

报道30种主产于云南的秋海棠属植物叶片的横切面解剖构造特征。采用常规石蜡切片法切片观察,结果表明:云南秋海棠属植物叶片薄、横切面均为异面叶、呈典型的阴叶结构,叶肉组织虽有栅栏组织和海绵组织的分化,但栅栏组织不发达,占叶肉组织的比例较小。表皮多为单表皮,极稀复表皮,表皮毛均由多细胞组成。气孔集中于下表皮,孔下室或下陷气孔特大、通气组织极发达;角质层形状多样,呈均匀增厚、瘤状和片状突起;叶绿体椭球形、数多、个体大,主要分布于叶肉组织,集中于栅栏组织。解剖构造特征在各分类组内呈现不完全一致性,而在相同茎的形态类型中有些较一致的特征,在不同种间解剖特征各有差别;根状茎和直立茎类型种类的横切面组织结构表现为表皮细胞壁外的角质层薄、栅栏组织与叶肉组织厚度比例较小等弱光照、湿生等适应性较弱的特征。球茎类型的种类表现为角质层较厚、栅栏叶肉组织厚度比例较大等适应略为干燥和较强光照的特征。     

云南秋海棠属三新种

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丽格海棠的组织培养

由于丽格海棠通过扦插获得的量有限,进口种子的价格又很昂贵,所以以它的叶、茎、花茎、叶柄等营养器官作为外植体,进行组织培养来快速获得丽格海棠。通过诱导芽分化和诱导愈伤两种途径,研究不同植物生长调节剂及浓度,对外植体萌发和生根的影响。研究表明基本培养基为MS,最佳分化培养基为6-BA1．00mg／L NAA0．10mg／L;最佳生根培养基为1／2MS NAA0．mg/L;花土：沙子=1：1,是丽格海棠最佳的驯化移栽基质,在该基质中生根苗移栽成活率达90％。     

Studies on Middle American Begonia (Begoniaceae) I

Begonia xilitlensis, a new species inBegonia sectionGireoudia from Mexico is described, illustrated, and discussed, and the taxonomic and nomenclatural status of two others,Begonia glandulosa andB. stigmosa, is evaluated with a lectotype chosen for the former.     

Influence of plant morphology on root exudation of maize subjected to mechanical impedance in hydroponic conditions

Microbial ethylene (C2H4) consumption was studied as a method of reducing the ethylene concentration during ethylene exposure of Begonia elatior in transport simulation boxes. Potted plants were exposed to an air flow (ca. 164 L h-1) with 0–1.03 ppm ethylene for 4 days in the presence of horticultural peat-soil that was induced to microbial ethylene consumption or in the presence of ethylene-oxidizing bacteria added to the peat-soil in the Begonia pots (referred to as plant soil). Ethylene consumption during transport simulation was enhanced by both procedures. However, the maximal extent of the reduction in ethylene concentrations (11–50%) was too low to significantly improve the keeping quality of the Begonia, which are known to be sensitive to ethylene exposure. A distinct ethylene consumption was due to the presence of potted Begonia in the transport simulation boxes. Batch experiments with plant soil verified such a capacity of microbial ethylene consumption. In addition, plant soil with added ethylene-oxidizing bacteria proved to be highly efficient for ethylene removal even to levels below our 0.002 ppm detection limit. With an optimized scrubber system such ethylene removal could be of further interest as a novel method of ethylene removal during transport and storage of horticultural produce.     

中国秋海棠属 (秋海棠科) 植物的DNA条形码评价

秋海棠属植物种类繁多,形态变异多样,导致种类的系统放置混乱,近缘种类鉴定困难。利用DNA条形码实现物种快速准确的鉴定技术具有不受形态特征约束的优势,为秋海棠属植物的分类鉴定提供了新的方法。本研究选择4个DNA条形码候选片段（rbcL,matK,trnH psbA,ITS）对中国秋海棠属26种136个个体进行了分析。结果显示：叶绿体基因rbcL,matK和trnH psbA种内和种间变异小,对秋海棠属植物的鉴别能力有限;ITS/ITS2种内和种间变异大,在本研究中物种正确鉴定率达到100%/96%,可考虑作为秋海棠属DNA条形码鉴定的候选片段。研究结果支持中国植物条形码研究组建议将核基因ITS/ITS2纳入种子植物DNA条形码核心片段中的观点。     

广西秋海棠属(秋海棠科)4新种

描述了广西秋海棠属(秋海棠科) 的侧膜胎座组和秋海棠组4新种。     

Four new species of Begonia L. (Begoniaceae) from Guangxi,China

Four new species of the genus Begonia L. (Begoniaceae) from Guangxi, China are described and illustrated.     

秋海棠属植物种质亲缘关系的ISSR分析

应用ISSR标记方法对秋海棠属(Begonia L.)植物33个种的种质亲缘关系进行分析,从70条引物中筛选出13个多态性引物,并通过POPgen 32软件以UPGMA法分析其亲缘关系。结果表明:33份秋海棠属植物的遗传距离在0.188 9～0.932 8之间,多态性百分率达到97.54%,Shannon信息指数为0.551 9,Nei基因多样性指数为0.376 0。秋海棠属植物具有丰富的遗传变异,UPGMA聚类分析结果与现有属下分类学表现较为一致,且生态地理条件相似的种群优先聚集。     

竹节秋海棠的组织培养与液培快速繁殖

本文叙述竹节秋海棠(Begonia President-Carnot)的器官培养与植株再生。用幼叶及叶柄切段接种在附加不同浓度的BA及NAA的MS培养基上。以诱导芽与根的形成,经6—9周可再生出大量完整植株,年增殖率很高。幼苗移植成活率约95％。经试验竹节秋海棠的芽增殖与生根两步培养都已采用免去琼脂的液体培养基静置培养。液体培养比固体培养有生长快、出苗多、成本低等优点。     

The Auxin Level of Begonia Leaves in Relation to their Regeneration Ability

The level of endogenous growth substances in leaves of Begonia × cheimantha Everett plants grown under various temperature and day-length regimes has been studied. In the acidic fraction of ether extracts two main growth promoting factors were present. Evidence is presented indicating that one of these is indole-3-aeetic acid (IAA), the other a gibberellin-like factor. The level of both these factors was always higher in extracts of long day grown plants than in those from short days. Similarly, high temperature (20 and 25°C) caused an increase in the level of the auxin, whereas the gibberellin activity was not much affected by temperature. Several growth promoting factors were present also in the non-acidic fraction, but their identity is not known. The results are discussed in relation to the effect of environment on the regeneration ability of the Begonia leaves. The results of these and previous investigations strongly support the hypothesis that short days and low temperature increase the budding ability and reduce the rooting ability of Begonia leaves through a lowering of the ratio of endogenous auxins to endogenous cytokinins in the leaves. The author wishes to thank professor Poul Larsen for advice and criticism. He also gratefully acknowledges financial support from the Agricultural Research Council of Norway.