草玉梅种子休眠原因及解除休眠方法

为明晰草玉梅(Anemone rivularis)种子的休眠类型和破除休眠的方法、为草地改良和草玉梅的栽培提供基础,以未去除果皮的草玉梅瘦果为对照,研究了不同处理对草玉梅种子休眠的影响。结果表明:40~50 g·L-1的NaOH溶液浸泡3~5 h未能破除其休眠;经过2个月的贮藏,剪去草玉梅果皮上端、除去果皮的草玉梅种子在黑暗条件下的发芽率分别为3.3%和6.2%,与对照(2.0%)差异不显著(P0.05),而光照条件下的上述种子发芽率分别为38.7%和76.0%,显著高于对照(P0.05);剪去果皮基部的草玉梅种子在光照和黑暗条件下的发芽率与对照差异不显著(P0.05)。除去部分(1/5~1/4)果皮能使草玉梅种子发芽率提高到62.7%,显著高于对照(P0.05);果皮穿刺处理显著提高了草玉梅种子发芽率(19.3%)(P0.05),但显著低于除去果皮和部分去皮处理(P0.05);草玉梅果皮水提液对草玉梅种子萌发无抑制作用;10~30 mg·L-1GA3浸泡处理10 h未能提高草玉梅瘦果的发芽率;草玉梅种子在25/15℃变温条件下发芽率最高,15/5℃和10/5℃变温条件下不能发芽。综合分析认为,果皮的遮光引起了草玉梅种子的休眠,除去果皮能有效破除草玉梅种子的休眠。除去果皮后尚有部分种子仍然处于休眠状态,因此草玉梅种子(瘦果)的休眠为综合休眠类型。     

不同贮藏条件和发芽方法对羊草种子萌发的影响

贮藏条件(温度、水分和贮藏介质)和发芽方法(发芽床种类×播种方法)是影响羊草种子萌发的重要因素.研究了4种贮藏条件(4 ℃低温干贮、自然室温干贮和非盐碱土低温湿贮、盐碱土低温湿贮)、3种发芽床(滤纸、非盐碱土与盐碱土)和2种播种方法(表面与内部播种)对羊草种子发芽率的影响.结果表明,与室温干贮相比,低温干贮可以提高羊草种子的发芽速率和整齐度,但对最终发芽率没有显著影响.盐碱土低温湿贮显著降低羊草种子发芽率(28.8%);非盐碱土低温湿贮可显著提高羊草种子的发芽率(73.7%).6种组合发芽方法的发芽率大小和顺序依次为：非盐碱土表发芽法(89.3%)>纸间发芽法(68.0%)>纸上发芽法(64.0%)>非盐碱土内发芽法(61.3%)>盐碱土表发芽法(25.6%)>盐碱土内发芽法(6.0%).     

麻花秦艽种子休眠机理及其破除方法

通过对干燥贮藏后熟麻花秦艽种子透水性和粗提物活性的测定以及采用高锰酸钾、赤霉素、青霉素、硫酸、流水浸泡方法进行发芽试验,探讨了种子休眠机理和破除休眠的技术。结果表明:麻花秦艽种子吸水过程符合Logistic曲线,其种皮对种子吸水无阻碍作用;硫酸和高锰酸钾处理极显著提高了麻花秦艽种子的发芽率(P<0.01),说明种皮机械障碍是种子萌发的因素之一。种子粗提物在浓度为0.02—0.2 g/mL时具有很强的抑制活性,均对小麦、白菜和麻花秦艽种子萌发和生长产生抑制作用以及流水浸泡可以提高麻花秦艽种子发芽率,表明种子内源抑制物是影响其休眠的另一因素。不同处理均打破了种子休眠,显著提高了种子发芽率,其中1.5%高锰酸钾浸泡10 min光照培养下种子发芽率及发芽势、发芽指数和活力指数均显著高于其他处理(P<0.05)。相比对照,1.5%高锰酸钾处理的种子发芽率极显著提高106.9%。经1.5%高锰酸钾浸泡10 min的麻花秦艽种子粗提物对白菜种子萌发的抑制作用低于未处理,以浓度为0.02—0.04 g/mL时抑制显著,说明高锰酸钾可减弱麻花秦艽种子内源抑制物的活性。综上所述,麻花秦艽种子的休眠属综合休眠。     

假酸浆种子发芽特性研究

在不同温度、不同贮藏时间和方法下,对来源于印度尼西亚的假酸浆种子发芽特性进行研究。结果表明:不同温度对假酸浆种子萌发的影响差异极显著,在15/25℃变温条件下种子发芽率最高,为84.3%,发芽快且整齐;假酸浆种子采收后立即播种其发芽率非常低,室温下贮藏6～9个月时在25℃恒温或15/25℃变温条件下均有较高发芽率,说明假酸浆种子有休眠性,通过延长贮藏时间能打破休眠,促进种子发芽;但室温贮藏15个月后,种子活力下降非常明显。低温冷藏在一定条件下能提高假酸浆种子萌发能力,能延长种子寿命。     

旱生灌木岷谷木蓝种子的休眠与萌发特征

岷谷木蓝(Indigofera lenticellata)是横断山区干旱河谷广泛分布的豆科灌木.本文对其种子的休眠与萌发特征进行了研究.结果表明:岷谷木蓝种子具有物理休眠,其萌发困难的原因在于种皮的不透水性;种子的硬实比率高(85%),针刺种皮和沙摩处理能有效打破种子休眠,提高发芽率,其中沙摩7 h最为快速有效.岷谷木蓝种子发芽温度范围较广,10℃～30℃均可发芽,最适温度范围为20℃～30℃,低温不利于种子萌发.岷谷木蓝具有一定的抗旱性,在聚乙二醇6000(PEG)溶液模拟水分胁迫条件下,种子在25% PEG胁迫下仍能达到100%的发芽率,但水分胁迫对种子发芽有一定的延缓作用,发芽率和发芽速度降低,发芽周期和发芽准备期增长,发芽高峰期滞后.其中对于发芽能力检测的各项指标对水分胁迫的敏感性顺序为发芽指数>发芽势>发芽率.岷谷木蓝种子的发芽特征是对干旱河谷生存环境长期适应的结果.野外播种的适宜时间为4月初,并在播种前对种子进行7 h的沙摩处理.     

中国杂草稻种群的发芽期耐冷性研究

以中国75个杂草稻种群及其对应采样田的水稻品种为试验材料,研究了不同处理(破除休眠与不破除休眠、常温25℃与低温15℃、7 d测定和14 d测定)对种子发芽率的影响。结果表明,杂草稻的发芽率与对应采样点水稻品种的发芽率呈现极显著相关性。杂草稻破除休眠处理的发芽率显著或极显著高于不破除休眠处理。破除休眠与不破除休眠下,15℃处理的杂草稻种子发芽率均显著高于对应采样田的水稻品种,证明杂草稻相对于采样田水稻品种具有更强的耐冷性,可能进化出了新的耐冷性机制。25℃处理下杂草稻和对应水稻品种的发芽率均与纬度呈显著或极显著负相关,表明休眠性有随着纬度的降低而减弱的趋势。     

不同处理方法对油楠成熟和过熟种子萌发特性的影响

为破除油楠(Sindora glabra Merr.ex de Wit)种子的物理休眠,研究不同处理方法对油楠种子萌发特性的影响。结果表明,所有处理方法对油楠成熟和过熟种子萌发均产生显著影响。40℃热水和50 mgL~(-1)萘乙酸有利于成熟种子的萌发,发芽率超过55%,较对照显著提高约10%,而其他方法处理的成熟种子发芽率为4.0%~46.0%,低于对照。采用98%浓硫酸浸泡25 min最有利于过熟种子的萌发,其发芽率、发芽势和发芽指数分别较对照显著提高90%、76%和7以上,且发芽时间显著缩短了9 d,对过熟种子处理的其他方法均能不同程度地促进萌发。因此,对于成熟种子,推荐采用低温热水浸泡或弱腐蚀性的化学处理;而对于过熟种子,宜采用浓硫酸浸泡25 min的处理。     

野豌豆属4种植物种子萌发的积温模型分析

以青藏高原野豌豆属窄叶野豌豆(Vicia angustifolia)、山野豌豆(V. amoena)、歪头菜(V. unijuga) 3种野生植物与一种当地栽培植物救荒野豌豆(箭筈豌豆) (V. sativa) ‘兰箭3号’种子为材料, 在5、10、15、20、25及30 ℃下进行萌发实验, 应用种子萌发的积温模型对上述4种植物萌发对温度的响应特征进行了比较分析。结果表明: 1)基于萌发速率(1/T_g)对种子萌发温度最低温T_b值的估计受萌发率(g)的影响较小; 与此不同, 除‘兰箭3号’种子外, 对萌发最高温T_c值的估计, 受到g的显著影响。 这表明种群内所有种子个体萌发的T_b值相对恒定, 但T_c值在有些物种中变异较大; 2)基于重复概率单位回归分析估计的种子萌发T_b值与基于萌发速率估计的值较为接近; 而由此方法估计的T_c值则与萌发率为50%时的估计值较为接近; 3)相比多年生豆科植物歪头菜和山野豌豆, 一年生豆科植物箭筈豌豆‘兰箭3号’与窄叶野豌豆具有相对较低的T_b与T_c值; 4)积温模型可准确地预测休眠破除后豆科植物种子在不同温度条件下的萌发进程。     

濒危植物羽叶丁香种子休眠与萌发特性研究

以濒危植物羽叶丁香(Syringa pinnatifolia)种子为材料,通过形态观察、种子吸水规律测定及其种子水浸液对白菜种子发芽率的影响等几个方面探究了羽叶丁香种子的基本休眠机制。通过室内发芽试验探究了不同浸种温度和赤霉素(GA3)浓度对羽叶丁香种子萌发特性的影响,并且模拟了不同温度和光照条件对种子萌发特性的影响。结果显示,羽叶丁香种子随温度升高吸水速率加快,最终吸水率在96%~121%之间,表明种子吸水性良好,不具有物理休眠特性;种子内部含有水溶性萌发抑制物,具有化学休眠特性,可通过控制浸种时间解除萌发抑制物的限制;30°C是羽叶丁香种子最好的浸种温度,发芽率和发芽势分别达到了86.00%±4.00%和54.00%±8.71%,发芽指数为5.44±0.44;浸种处理后的种子放在15和25°C恒温无光照条件下测试所得的发芽指标最好,发芽起始时间最短,回归分析结果显示光照是影响发芽率最显著的生态因子;GA3处理并没有显著提高种子发芽率和发芽势,但高浓度(400~800 mg·L-1)GA3处理能够加快胚的生长速率,缩短萌发持续时间,说明羽叶丁香种子具有部分形态休眠特性。     

温水浸种对蒙古黄芪种子萌发特性的影响

研究温水浸种破除蒙古黄芪（Astragalus membranaceus Bge.var.mongholicus（Bge.） Hsiao）种子休眠的适宜条件,采用恒温和变温2种浸种方式,测定蒙古黄芪种子在不同时间、不同温度梯度条件下的发芽率、发芽势和发芽指数。结果表明,温水浸种破除蒙古黄芪种子休眠的效果显著,变温浸种效果略优于恒温浸种。不同温度破除休眠效果排序依次为60℃> 70℃> 80℃,其中60℃变温浸种2 min和5 min的发芽率分别为对照的2.87倍和2.31倍。浸种时间、浸种温度均可显著影响蒙古黄芪种子萌发,与对照相比,随着浸种时间增加,发芽率总体呈现出先急速升高后逐渐降低的趋势;发芽指数与浸种温度极显著正相关;浸种温度与发芽势和发芽指数均显著正相关。本研究结果表明温水浸种可以提高种子发芽率,保持种子活力。     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Die GattungKarschia — Bindeglied zwischen bitunicaten Ascomyceten und lecanoralen Flechtenpilzen?

The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.

     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Demographic characteristics of an intertidal bay goby (Lepidogobius lepidus)

Synopsis In a fourteen month study (May 1976 – June 1977) I examined the following characteristics of an intertidal bay goby (Lepidogobius lepidus) in Morro Bay, California, U.S.A.: annual and seasonal patterns of abundance, age composition and growth rates, survivorship and mortality patterns, and the reproductive cycle for female gobies. Fishes were collected with the aid of quinaldine and otoliths and ovaries removed. Age and growth rates were estimated from otolith annuli using a back calculation formula and a Brody-Bertalanffy growth curve. Mortality rates were derived using the methods of Heincke (1913), Robson & Chapman (1960), mean age, and a catch curve (Ricker 1975). A gonad index was used to describe the annual reproductive cycle. Results indicated that abundance fluctuated seasonally and that these fluctuations appeared to be caused by reproductive emigrations. Bay gobies reached an age of 7+ and a standard length of 87 mm. Growth was relatively constant (6 mm yr⁻¹) until age 5, at which point it began to decline. The mean rates of survivorship, mortality, and instantaneous mortality were 0.75, 0.25, and 0.29 respectively. Mortality rates for individual age classes ranged from 0.13 to 0.51 and increased with age. This stock appears to reproduce mainly during the winter.