中国云南兜兰属（兰科）一新种

20 0 0年 6～ 7月间 ,我们在云南文山、昆明和广西平南等地发现 ,该地生长或栽培的所谓“紫纹兜兰”已经相继开花。而在深圳市梧桐山的紫纹兜兰野生群落每年要到 1 0～ 1 2月左右才开花 ,这就引起我们的注意 ,并对两种不同产地和不同花期的实体进行了较为深入的比较。紫纹兜兰Ｐ .ｐｕｒｐｕｒａｔｕｍ (Ｌｉｎｄｌ.)Ｓｔｅｉｎ的模式标本采自香港 ,在民间被称为“香港小姐”。据说今天在香港地区已较难觅到其芳踪了。 1 990年夏天我们在靠近香港新界的梧桐山上发现了野生的紫纹兜兰居群。它生长在以杜鹃花科、山茶科等植物占优势的乔灌木群…     

基于灰色关联分析方法评价13种野生兜兰的迁地保护适应性

由于过度收集和对原生境地的破坏,我国野生兜兰已濒临灭绝,对其进行迁地保护十分必要。通过对引种的13种40份野生兜兰资源进行迁地栽培,并观测兜兰种质在迁移地的各种生长性状指标等,本研究利用灰色关联分析方法评价13种兜兰的迁地适应性,分析影响其迁地保护的关键因素。结果表明:(1)带叶兜兰、同色兜兰、长瓣兜兰、文山兜兰适应性较强,与理想种的关联度均在0.8以上;巨瓣兜兰、白花兜兰、小叶兜兰、紫纹兜兰、紫毛兜兰、硬叶兜兰适应性一般,与理想种的关联度在0.7~0.8之间;麻栗坡兜兰、杏黄兜兰、红旗兜兰适应性较差,与理想种的关联度均在0.6以下;(2)不同兜兰种类、同一种类不同产地兜兰种质的迁地生长适应性不同,来源地和栽培温度可能是影响其迁地保护的关键因子。     

珍稀濒危植物紫纹兜兰的种群结构和数量动态

通过对广东省河源市紫金县白溪省级自然保护区紫纹兜兰(Paphiopedilum purpuratum)进行样方调查,运用种群生命表、存活曲线、种群生存函数值和时间序列预测分析方法,研究紫纹兜兰种群的动态变化过程,揭示各龄级植株的数量动态和变化规律。结果表明,紫纹兜兰龄级以幼龄为主,幼龄阶段占整个种群的54.73%,年龄结构为稳定型。种群年龄结构的动态指数V_(pi)为0.33、V_(pi)'为0.07,均大于0,紫纹兜兰的存活曲线更接近Deevey-Ⅱ型,表明该种群目前属于稳定型种群。累计死亡率函数和危险率函数上升,生存率函数下降,死亡密度函数波动较大。从时间序列预测分析表明,种群具备一定的恢复能力,但是种群整体数量随时间的增加,成年植株逐渐增加,幼苗减少。平均开花和结实率仅为16.94%和3.29%,种子没有胚乳而营养不足,在自然环境下很难发育成幼苗,主要靠分蘖植株繁殖,因此对紫纹兜兰幼苗的保护很关键。     

濒危植物紫纹兜兰群落特征及其保护

对广东省河源市紫金县白溪自然保护区紫纹兜兰（Paphiopedilum purpuratum（Lindl.）Stein）所在的2个群落进行了样方调查，分析了其生境、物种组成、群落区系特点及群落结构特征。结果显示，调查样地内共有维管束植物47科79属94种。属的区系成分中泛热带和热带亚洲成分占主要地位，占非世界分布总属数的84.3%，具有热带向亚热带过渡的性质。群落1中扇叶铁线蕨（Adiantum flabellulatum Linn.）和中华苔草（Carex chinensis Retz.）为优势种，紫纹兜兰仅为伴生种，群落2中紫纹兜兰为优势种。两群落均以小高位芽植物为主，但缺乏大高位芽植物、地面芽植物及一年生草本，而藤本植物的丰富则进一步加大了林下的郁闭度。综合生境因素比较两个群落表明，紫纹兜兰对环境具有极强的依赖性，对坡度坡向及环境湿度有一定的要求，对伴生植物并无明显的选择性。建议加强对紫纹兜兰的就地保护，同时加大对其栽培繁殖技术的研究。     

国产兜兰属植物观赏价值评价及其在华南地区的应用前景分析

以植株的生长状况、整株姿态、叶片观赏性、开花性、花形、花色和花朵观赏期为评价指标,利用灰色关联分析,对我国原产的27种兜兰属植物的观赏价值进行了综合评价并分析了它们在华南地区的应用前景。结果表明:多花长瓣型的飘带兜兰与理想种的关联度最高,达到0.7304,是最值得在华南地区栽培的兜兰种类,其次为白旗兜兰。而紫纹兜兰、汉氏兜兰;文山兜兰、格利兜兰、带叶兜兰、亨利兜兰、同色兜兰,它们的关联度系数超过0.6;紫毛兜兰、巨瓣兜兰、红旗兜兰、天伦兜兰、长瓣兜兰、根茎兜兰的关联度均超过0.5;也是值得推广兜兰种类;杏黄兜兰、硬叶兜兰、白花兜兰由于生长状况差、开花性差等原因与理想种的关联度分别只有0.1900、0.1921、0.2917,不适于华南地区栽培;其它9种兜兰的关联度虽然介于0.35~0.50之间,但其中有些种类如虎斑兜兰、麻栗坡兜兰、波瓣兜兰、德氏兜兰等由于具有独特的观赏价值和育种潜力,也是值得在华南地区栽培的兜兰种类。     

贵州省野生兜兰属植物资源现状及保护成效分析

兰科(Orchidaceae)兜兰属(Paphiopedilum)植物花形奇特,研究价值和观赏价值都很高,对环境要求严格,是生物多样性保护中的“旗舰”类群。为掌握贵州省野生兜兰属植物资源现状和保护成效,该研究对野生兜兰属植物进行专项调查,对其资源量、分布格局、受威胁因素和就地保护等进行分析。结果表明:(1)共调查到8种兜兰属植物的103个分布点,分布于27个县,以南部、西南部为主要分布区,生境复杂多样,自然分布不均衡。(2)各物种分布面积从大到小的顺序为硬叶兜兰>小叶兜兰>麻栗坡兜兰>巨瓣兜兰>带叶兜兰>长瓣兜兰>白花兜兰>同色兜兰,资源丰富度从高到低的顺序为硬叶兜兰>小叶兜兰>带叶兜兰>巨瓣兜兰>麻栗坡兜兰>白花兜兰>长瓣兜兰>同色兜兰。(3)该类群受干扰因素复杂,受威胁较为严重,其中过度采挖、干旱、生境退化和破碎化是其濒危的主要原因。(4)该属“有效保护(EP)”2种,“较好保护(WP)”1种,“一般保护(GP)”2种,“较少保护(LP)”3种,未找到目标物种以致“保护状况不明(PSU)”2种。已调查到的物种保护率达100%,但分布点保护率仅29.13%,各物种分布点保护率差异显著; 建议相关部门有针对性地提升全省兜兰属植物的保护强度,进一步优化保护方式和范围,确保这些珍稀濒危的植物资源得到持续的生存发展。     

心启兜兰，兜兰属宽瓣亚属的一个新增种

描述了兰科兜兰属的一个新种——心启兜兰Paphiopedilum singchii Z．J．Liu et J．Y．Zhang。模式标本系深圳市梧桐山苗圃总场的栽培植物。原植物可能采自云南南部近中越边境处。     

濒危物种杏黄兜兰的保育生态学

杏黄兜兰(Paphiopedilum armeniacum)是中国特有的兰科濒危物种。自2000年4月1日至2005年10月10日,在云南省怒山的落砂坡山选取66个调查点进行杏黄兜兰保育生态学研究:对443基株共1302分株进行了繁殖式样、物候和生命周期等主要生物学特性,以及对该物种的生境要求、群落结构特征等生态学习性进行了观察研究,并在广东省深圳进行迁地保护和迁地繁殖后重返原产地的试验,研究了原产地的气候、植被和其他环境因素与杏黄兜兰之间的关系以及杏黄兜兰迁地栽培和繁殖的无性后代重返原生长地的生物学特性。研究结果表明:落砂坡山的杏黄兜兰在石灰岩上的次生灌木丛或草丛内生长良好;它兼具有性和无性繁殖,无性繁殖的目的就是实现有性繁殖和延长基株的寿命;无性繁殖有二种形式:产生分蘖或根茎;灌木丛或草丛的落叶为杏黄兜兰生长提供腐殖质,杏黄兜兰根茎繁殖是它对落叶等覆盖的一种适应;分株的开花率为7.39%±1.02%,开花分株的结果率为32.23%±12.08%;杏黄兜兰具有入侵适度破坏和正处于恢复初期的森林环境的能力,而在茂密连片的大树森林内不能生长。杏黄兜兰在深圳人工疏林下生长良好并繁殖许多无性的克隆分株,将繁殖的克隆分株重返原产地能正常开花和结实。试验结果显示,杏黄兜兰可以进行迁地保护以保存种质资源和迁地繁殖的植株回归原产地。基于杏黄兜兰濒危机制的分析,认为,杏黄兜兰生存所面临的威胁是生长空间被完全剥夺和人为灭绝性采集而不是其自身存在的生物学缺陷,为此,提出了相应的保育对策。     

珍稀濒危飘带兜兰叶绿体全基因组种内变异研究(附录)

飘带兜兰(Paphiopedilum parishii)分布范围狭窄,仅在中国、缅甸、泰国以及老挝有少量分布。近年来,因生境破坏和人为滥采而导致飘带兜兰野生种群极度缩减。为开发种内多态性的分子标记用于保护生物学研究,该研究对飘带兜兰4个野生个体经测序、组装、注释获得的叶绿体基因组序列,与已公布的飘带兜兰2个个体的叶绿体全基因组序列进行比对,分析飘带兜兰叶绿体基因组的种内差异。结果表明:(1)飘带兜兰叶绿体基因组具有典型被子植物叶绿体基因组环状四分体结构,基因组长度为154 403～154 809 bp,共编码129个基因,包括78个蛋白质编码基因、39个tRNA基因、8个rRNA基因,以及4个假基因。(2)在飘带兜兰6个个体叶绿体基因组中检测到103～107个SSRs(simple sequence repeats)位点,其中21个SSR位点具有多态性。此外,在6个个体叶绿体基因组中还检测到60个长序列重复,包括17～21个正向重复、18～29个反向重复、9～16个回文重复、4～9个互补重复。(3)通过比较6个个体叶绿体基因组序列的核苷酸多样性,共发现70处变异,包括10个SNPs(single nucleotide polymorphism)、60个插入缺失(InDels)。其中,有3个SNP位点发生了非同义替换,导致编码功能基因的氨基酸发生改变; 19个插入缺失多态性较高,具有开发为分子标记的潜力。(4)通过计算核苷酸多样性值(P_i)共发现8个有变异的区域,P_i值为0～0.006 32,其中变异度较大的是rps3-rpl22、trnL-UAC-rpl32、rpoB-trnC-GCA以及ycf4,这些高变区可开发为分子标记用于评估飘带兜兰遗传多样性。(5)系统发生分析结果表明,飘带兜兰6个个体叶绿体基因组序列聚在一起,与长瓣兜兰互为姐妹群。综上表明,飘带兜兰叶绿体基因组的SSRs、长序列重复、SNPs、InDels以及核苷酸序列呈现了足够的种内多样性,可开发成分子标记用于该种的系统演化及保护生物学研究。     

兜兰属植物杂交育种研究进展

兜兰属(Paphiopedilum)的杂交育种已有150 多年的历史,目前已有20262个杂交种在英国皇家园艺协会(RHS)登录。对兜兰属植物的种质资源、杂种登录,杂交方法、杂交亲本的选择、属间杂交、不同兜兰种类在花色遗传育种中的作用、杂交育种存在的问题等进行了综述, 并结合我国兜兰属植物育种现状, 提出了我国兜兰属植物育种的方向。     

Plant-parasitic nematodes and yellowing of leaves associated with black pepper plants in Vietnam

Thirty-five nematode species belonging to 19 genera were extracted from 432 soil and root samples collected in 19 districts in six provinces in the North Central Coast, Central Highlands and Phu Quoc Island. Based on our study, the predominant nematode species associated with black pepper plants in Vietnam is Meloidogyne incognita: almost every soil and root sample examined during our study was infected with this root-knot nematode species. No difference in frequency of occurrence of M. incognita among the three agro-ecological regions surveyed was observed. However, the root population density of M. incognita in black pepper plants was on average about five times higher in the North Central Coast and Central Highlands than in Phu Quoc Island. Large differences in root population density of M. incognita on black pepper plants were observed in different districts within the same agro-ecological region. Black pepper roots infected with M. incognita showed the same type of galls as described in the literature. The percentage of root galling averaged about 40% in all the three agro-ecological regions. The percentage of black pepper plants with yellow leaves was on average about 20–25% in the North Central Coast and Central Highlands, which was somewhat higher compared to Phu Quoc Island (16.9%). Large differences in percentage of black pepper plants with yellow leaves were observed in different districts within the same agro-ecological region. The same type of yellow leaves as described in the literature for black pepper plants infected with Meloidogyne species was observed in our study. In general, a positive relationship between the soil and root population densities of M. incognita on black pepper plants and percentage of plants with yellow leaves was observed. However, in one district (Quang Tri) a relatively low nematode population density was associated with a high percentage of plants with yellow leaves. Five nematode species were recorded for the first time on black pepper plants in Vietnam. Our study reconfirms previous reports that Radopholus similis does not occur in Vietnam.     

The status of noxious plants in lower subtropical region of China

Recent decades, more and more noxious plants developed fast in tropical and subtropical region. Guangdong Province, located in lower subtropical region, is densely populated and its economy is developing very quickly, it is vulnerable to be damaged. It was observed that there were many noxious plants affected forest ecosystem in this area. It is crucial to understand the destructive status and the distribution of the noxious plants. Thus, we conducted investigations of noxious plant in Baiyun Mountain and Xiqiao Mountain, Guangdong Province through point, line and plot methods. The results showed that there were 39 noxious plant species from 26 families in the two sites (Baiyun Mountain and Xiqiao Mountain). Most noxious plants reached III grade, 13 species reached III grade in Baiyun Mountain and 18 species reached III grade in Xiqiao Mountain. The exotic plant Wedelia trilobata(L.) Hitchc was the most abundant species, followed by another exotic plant Ipomoea cairica (Linn.) Sweet (Fig. 2B). All the 39 noxious plants covered over 273 hm² in the two sites, about occupied 10% of the forests. Over 90% of the noxious plants are lianas, the rest are herbs or shrubs. Of the 39 noxious species, six species were exotic plants, while 33 species were indigenous, suggesting that more attention should be paid to indigenous plants when we concerned invasive plants. Furthermore, global climate change (e.g., global warming, elevated CO₂) may shorten the latency of the plants and trigger the expansion of the noxious plants. Further studies are needed to reveal the relationship between global climate change and noxious plants, and to study why more and more native plants turned to threaten the ecosystem.     

The status of noxious plants in lower subtropical region of China

Recent decades, more and more noxious plants developed fast in tropical and subtropical region. Guangdong Province, located in lower subtropical region, is densely populated and its economy is developing very quickly, it is vulnerable to be damaged. It was observed that there were many noxious plants affected forest ecosystem in this area. It is crucial to understand the destructive status and the distribution of the noxious plants. Thus, we conducted investigations of noxious plant in Baiyun Mountain and Xiqiao Mountain, Guangdong Province through point, line and plot methods. The results showed that there were 39 noxious plant species from 26 families in the two sites (Baiyun Mountain and Xiqiao Mountain). Most noxious plants reached III grade, 13 species reached III grade in Baiyun Mountain and 18 species reached III grade in Xiqiao Mountain. The exotic plant Wedelia trilobata(L.) Hitchc was the most abundant species, followed by another exotic plant Ipomoea cairica (Linn.) Sweet (Fig. 2B). All the 39 noxious plants covered over 273 hm² in the two sites, about occupied 10% of the forests. Over 90% of the noxious plants are lianas, the rest are herbs or shrubs. Of the 39 noxious species, six species were exotic plants, while 33 species were indigenous, suggesting that more attention should be paid to indigenous plants when we concerned invasive plants. Furthermore, global climate change (e.g., global warming, elevated CO₂) may shorten the latency of the plants and trigger the expansion of the noxious plants. Further studies are needed to reveal the relationship between global climate change and noxious plants, and to study why more and more native plants turned to threaten the ecosystem.     

Occurrence of Dictyla monotropidia Stål (Hemiptera: Tingidae) on Cordia verbenacea Al. DC in Brazil

Recently, Dictyla monotropidia St?l was observed feeding on plants of black sage (Cordia verbenacea Al. DC). The colonies of this insect were observed on abaxial surface of leaves, with nymphs and adults sucking the phloem sieve, causing spot, yellow aspect and leaf fall. D. monotropidia was already related as pest in other Cordia species in countries of Central and South America. Although, this is the first report of this insect attacking plants of C. verbenacea in Brazil.     

Cytomixis in pollen mother cells of Medicago sativa L

Cytomixis (i.e., chromatin migration between meiocytes) has been detected in many plant species, but not in Medicago sativa spp. In the present study we report the identification of a few cytomictic alfalfa plants. Those plants, the "mother plants," were selfed and crossed with a normal control plant. Microsporogenesis analysis was performed on the mother plants, on the S(1) and F(1) plants, and on controls. The S(1) and F(1) plants, like the mother plants, were found to be cytomictic. Single or multiple chromatin bridges between two or more meiocytes were observed almost exclusively in prophase I. Some completely empty meiocytes were also observed. In addition to cytomixis, other meiotic abnormalities were found. Control plants showed an almost regular meiosis. The highest values of cytomixis were observed in the mother plants, and the lowest in their F(1) progenies. Variability of cytomixis in the F(1) plants is probably due to a heterozygotic condition of the parents for this trait. No significant correlation was found between cytomixis and pollen viability, even if the cytomictic plants showed low values of pollen viability.     

Variability of ribosomal RNA genes in Rauwolfia species: parallelism between tissue culture-induced rearrangements and interspecies polymorphism

An analysis of 18S-25S and 5S rRNA genes in intact plants and cultured tissues of some Rauwolfia species was performed to compare these sequences variability occurred as a result of the species evolution in nature and that induced by tissue culture. The restriction fragment length polymorphism of 18S-25S and 5S rDNA was found both in intact plants of various Rauwolfia species and in long-term Rauwolfia serpentina tissue cultures. In addition, changes in the amount of 18S-25S rRNA genes were observed in long-term R. serpentina tissue cultures. The results demonstrate that rDNA variability observed in intact plants as well as in long-term cultures is attributed to differences in the same regions of ribosomal RNA genes.     

海口市外来入侵植物现状及防控对策

基于野外调查及文献资料及标本信息查阅,基本查清海口市外来入侵植物的种类组成、原产地、生活型、入侵途径,并对外来入侵植物在海口市的入侵危害进行等级划分。结果表明,海口市目前发现外来入侵植物115种,隶属于32科83属,其中菊科种数最多,有23种,占海口外来入侵植物总种数的20.0%;有92种原产地为美洲,占80.0%;有84种为草本植物,占73.0%;有111种为人类有意或无意引入,占96.5%;入侵植物中严重危害类(1级)有12种,一般危害类(2级)有24种,潜在危害类(3级)有25种,一般外来类(4级)有22种,32种还有待观察(5级)。文中提出对海口外来植物入侵的防控及管理对策。     

The role of pre- and post-imaginal experience in the host-finding and oviposition behaviour of the cabbage moth

The influence of pre- and post-imaginal experience on the orientation, landing, and oviposition of the female cabbage moth, Mamestra brassicae (L.) (Lepidoptera: Noctuidae) was studied in a wind tunnel. The results of experiments on the influence of pre-imaginal experience do not support the Hopkins host selection hypothesis because the females’ responses to host plants were not affected by the plant species used for feeding the larvae. The females were initially attracted to and landed on chrysanthemum whether or not they were fed on this plant species. In addition, the oviposition preference for cabbage plants was not changed by the larval feeding regimen. Imaginal experience influenced the females’ subsequent orientation/landing responses: exposure of the females to chrysanthemum plants for 5 min decreased their subsequent responses to this species, but subsequent responses to cabbage were not changed when the females were exposed to cabbage plants. Overnight exposure of females to a chrysanthemum or cabbage plant decreased the subsequent orientation/landing on the same species offered in non-choice tests. A similar effect was observed in responses to chrysanthemum plants after overnight contact, and possibly to cabbage plants, in the two-choice tests. Overnight exposure to cabbage or chrysanthemum had no effect on subsequent oviposition: females from both treatments oviposited more often on cabbage.     

The effects of windthrow on plant species richness in a Central European beech forest

The effects of soil disturbance caused by the uprooting of a single or a few canopy trees on species richness and composition of vascular plant species and bryophytes were examined in a temperate beech forest (Fagus sylvatica) in northern Germany. We recorded the vegetation in 57 pairs of disturbed and adjacent undisturbed plots and established a chronosequence of mound ages to study the effect of time since microsite formation on plant species richness and composition. We found significant differences in plant species richness and composition between disturbed and adjacent undisturbed plots. Species richness of both vascular plants and bryophytes was higher in the disturbed than in the undisturbed plots, but these differences were more pronounced for bryophytes. We suggest that three main factors are responsible for this differential response. The availability of microsites on the forest floor that are suitable for the recruitment of bryophytes is lower than for vascular plants. Establishment of bryophytes in disturbed microsites is favoured by a greater abundance of propagules in the close vicinity and in the soil of the disturbed microsites, as well as by a greater variety of regeneration strategies in bryophytes than in vascular plants. Time since mound formation was a major factor determining plant species richness and composition. A significant decrease in the mean number of species was found from young mounds to intermediate and old mounds. However, differences were observed between vascular plants and bryophytes in the course of changes through time in species richness and composition. A large number of exclusive and infrequent vascular plant species was observed on young mounds, among them several disturbance specialists. We suggest that the establishment of many vascular plant species was infrequent and short-lived due to unfavourable light conditions and a low abundance of propagules. By contrast, the development of a litter layer was the main reason for the decreased mean number of bryophytes on old mounds. Our study supports the view that groups of species differing in important life history traits exhibit different responses to soil disturbance.     

Spatial distribution of discrete RAPD phenotypes of a root endophytic fungus, Phialocephala fortinii, at a primary successional site on a glacier forefront

Phialocephala fortinii is among the few identified hyphomycetes belonging to the Mycelium radicis atrovirens complex. This 'dark-septate endophyte' has a global distribution and colonizes a wide variety of host plants. In this study, the spatial distribution of discrete genets of P. fortinii on the forefront of a receding glacier was analysed using the randomly amplified polymorphic DNA (RAPD) technique to determine plants colonized and patterns of colonization. In two consecutive years of sampling, a total of 74 isolates of P. fortinii were obtained from nine plant species, typically ectomycorrhizal, ericoid mycorrhizal or non-mycorrhizal. The isolates showed substantial variation, sharing on average approx. half the RAPD markers. In the first year, three isolates belonging to a single genet were obtained from two plants separated by a distance of nearly 1.5 m. The continuity of this genet was assessed by a sampling the following year. No isolates similar to that, or any of the genets collected the year before were observed. Consequently, the identical isolates from the previous year were concluded to represent discontinuous ramets. Two additional large genets were observed during the second year of sampling, which inhabited roots of several plants representing three different species. These data suggest that the sharing of P. fortinii genets among plant species might play a fundamental role in adaptation and interaction within the whole plant community in a system undergoing primary succession.