泥炭地苔藓植物孢子生活力的快速检测

适量的烟气能够促进有性繁殖体萌发,但迄今尚无辅助烟气处理探究孢子生活力快速检测方法的研究报道。该文选择毛缘泥炭藓（Sphagnum fimbriatum）、中位泥炭藓（S.magellanicum）和粗叶泥炭藓（S.squarrosum）作为材料,分别使用亚甲基蓝染色法、四唑（TTC）染色法、碘-碘化钾（I₂-KI）染色法和红墨水染色法对泥炭藓孢子进行染色,并比照营养液、烟溶液+营养液培养的孢子萌发试验,对比研究泥炭地苔藓植物孢子生活力快速检测的最佳方法。结果表明：亚甲基蓝染色法的染色效果最为明显,TTC和I₂-KI均未能使泥炭藓孢子着色,孢子对红墨水虽有着色反应但不清晰;与营养液培养相比,添加烟溶液使毛缘泥炭藓、中位泥炭藓和粗叶泥炭藓孢子萌发率分别提高5%、5%和18%;使用亚甲基蓝染色的孢子染色率与经烟溶液处理过的孢子萌发率最为接近。综上认为,亚甲基蓝染色法能快速检测泥炭藓孢子的生活力。     

长白山哈泥泥炭地持久孢子库的实验证据

有性繁殖体库对于植物种群的长存具有重要意义,迄今为止,泥炭地尚无苔藓植物长期的持久孢子库的直接实验证据。在长白山哈泥泥炭地,钻取50 cm表层泥炭样品,运用落叶松测年法推算泥炭地地层泥炭藓孢子的埋藏时间,经逐层提取和培养尖叶泥炭藓孢子,研究埋藏时间对孢子萌发率的影响。结果表明,随着埋藏时间的增加,尖叶泥炭藓孢子萌发率呈现对数函数递减的趋势。研究获得泥炭地苔藓植物具有长期的持久孢子库的实验证据,即埋藏112年的尖叶泥炭藓孢子仍具萌发潜力。据推算,泥炭藓孢子最大寿命可达396.4年。     

长白山哈泥泥炭地丘间生境泥炭藓孢子的寿命

长寿有性繁殖体对于植物种群的长存具有重要意义,迄今,泥炭地苔藓植物孢子长寿性研究还很少。在长白山哈泥泥炭地钻取丘间表层泥炭样品,测定泥炭腐殖化度和烧失量,逐层提取和培养泥炭藓孢子,研究埋藏时间对孢子萌发的影响。结果表明,丘间泥炭藓孢子埋藏环境中,随着埋深的增加即埋藏年限的增加,泥炭腐殖化度和烧失量总体上分别呈现增加和递减的趋势,而地层泥炭藓孢子萌发率呈现直线递减的规律,但在埋藏近150余年后孢子萌发率仍可达40%。研究进一步证明泥炭藓具有长期持久孢子库,根据推算,泥炭地丘间埋藏环境中,泥炭藓孢子最大寿命可超过400a。     

水位与光强变化对尖叶泥炭藓孢蒴生产动态的影响

选取尖叶泥炭藓(Sphagnum capillifolium)为试验材料, 在模拟水位与光强条件下, 对人工构建的苔藓植物群落进行室内培养, 每隔1-3天观察并记录植株高度、孢蒴变化过程及变化时间, 分析了不同水位与光强条件对孢蒴生产的植物功能属性动态的影响。水位上升促进了蒴柄伸长及植株高增长, 增加了孢蒴开裂率及遮蔽率。光强增加有助于孢蒴生长, 并提高了孢蒴开裂率。在孢蒴直径以及植株高增长性状上, 水位与光强存在交互作用。水位与光强对孢蒴增长率均没有影响。此外, 水位升高与光强增加使孢蒴成熟及蒴柄伸长时间提前, 总体上使孢子释放时间分别提前了4.0 d和4.8 d, 由此可能减小了孢子体因受夏季干旱影响而败育的风险。孢子释放后, 繁殖株高增长加速, 可为未来的再次繁殖奠定基础。     

Effects of water level and light intensity on capsule production dynamics of Sphagnum capillifolium

 选取尖叶泥炭藓(Sphagnum capillifolium)为试验材料, 在模拟水位与光强条件下, 对人工构建的苔藓植物群落进行室内培养, 每隔1-3天观察并记录植株高度、孢蒴变化过程及变化时间, 分析了不同水位与光强条件对孢蒴生产的植物功能属性动态的影响。水位上升促进了蒴柄伸长及植株高增长, 增加了孢蒴开裂率及遮蔽率。光强增加有助于孢蒴生长, 并提高了孢蒴开裂率。在孢蒴直径以及植株高增长性状上, 水位与光强存在交互作用。水位与光强对孢蒴增长率均没有影响。此外, 水位升高与光强增加使孢蒴成熟及蒴柄伸长时间提前, 总体上使孢子释放时间分别提前了4.0 d和4.8 d, 由此可能减小了孢子体因受夏季干旱影响而败育的风险。孢子释放后, 繁殖株高增长加速, 可为未来的再次繁殖奠定基础。     

火烧高温对泥炭藓孢子萌发力影响的模拟实验

作为生态系统稳定性维持的一个重要因素,火对泥炭地优势植物泥炭藓(Sphagnum)孢子库的影响尚不清楚.以采自长白山区泥炭地的泥炭土和3种泥炭藓的成熟孢子为实验材料,室内模拟火烧,以此设置不同温度水平(20、40、60或100℃,持续0.5、1、2、4或10 min),对泥炭藓孢子进行热激处理,经萌发实验后,研究火烧高温对孢子萌发率的影响.结果显示,火烧期间各层土温随深度而递减,表层泥炭可达300℃的极端高温,而1 cm深温度仅为70℃,体现出泥炭土良好的热缓冲性;40℃的热激可使锈色泥炭藓(S.fuscum)与中位泥炭藓(S.magellanicum)孢子萌发率提高20%与50%;60℃的热激使尖叶泥炭藓(S.capillifolium)孢子的萌发率提高1倍;100℃热激对3种泥炭藓孢子萌发则有强烈的抑制作用.研究表明,泥炭藓孢子耐受高温的能力有限,但土壤中的孢子凭借泥炭的良好热缓冲性,可以躲避火烧高温造成的致命伤害,适度的热激甚至能提高其萌发力,对其在火后的建植及种群的长存可能有重要意义.     

泥炭地特征性环境因子促进泥炭藓持久孢子库的形成

研究泥炭地特征性环境因子——淹水、少氧和化感物质对泥炭藓孢子持久性的影响, 可深入理解泥炭地泥炭藓持久孢子库的形成机制, 为退化泥炭地泥炭藓地被恢复研究提供参考。该研究以藓丘种和丘间种两种泥炭藓的孢子为试验材料, 通过室内模拟控制实验的方法, 研究泥炭藓孢子在空气、超纯水、泥炭地地表水和泥炭藓沥出液中, 及3种速率充气下, 孢子萌发力持久性的变化。经充气处理后, 泥炭藓孢子持久性显著低于不充气处理。不充气时, 泥炭藓孢子在含有化感物质的泥炭地地表水和泥炭藓沥出液中保存, 持久性显著高于在超纯水中保存。通径分析结果显示, 溶解氧是影响泥炭地泥炭藓孢子持久性的主要因子和限制因子, 养分元素氮(TN)和磷(TP)的浓度为孢子持久性的负作用因子。研究结果表明, 泥炭藓孢子散布于苔藓地被基质或淹水的丘间生境中, 比暴露于空气或在无化感物质的水中, 能更好地维持萌发力。泥炭地中, 泥炭藓孢子和其他植物的繁殖体的超长寿命可能归因于少氧、养分贫乏和丰富的化感物质等泥炭地特征性环境因子。     

泥炭地特征性环境因子促进泥炭藓持久孢子库的形成

研究泥炭地特征性环境因子——淹水、少氧和化感物质对泥炭藓孢子持久性的影响,可深入理解泥炭地泥炭藓持久孢子库的形成机制,为退化泥炭地泥炭藓地被恢复研究提供参考。该研究以藓丘种和丘间种两种泥炭藓的孢子为试验材料,通过室内模拟控制实验的方法,研究泥炭藓孢子在空气、超纯水、泥炭地地表水和泥炭藓沥出液中,及3种速率充气下,孢子萌发力持久性的变化。经充气处理后,泥炭藓孢子持久性显著低于不充气处理。不充气时,泥炭藓孢子在含有化感物质的泥炭地地表水和泥炭藓沥出液中保存,持久性显著高于在超纯水中保存。通径分析结果显示,溶解氧是影响泥炭地泥炭藓孢子持久性的主要因子和限制因子,养分元素氮(TN)和磷(TP)的浓度为孢子持久性的负作用因子。研究结果表明,泥炭藓孢子散布于苔藓地被基质或淹水的丘间生境中,比暴露于空气或在无化感物质的水中,能更好地维持萌发力。泥炭地中,泥炭藓孢子和其他植物的繁殖体的超长寿命可能归因于少氧、养分贫乏和丰富的化感物质等泥炭地特征性环境因子。     

白江河泥炭地泥炭藓孢子萌发力对排水的响应

排水严重改变泥炭地的环境和生态过程,但对泥炭藓孢子萌发力的影响尚不清楚。在长白山地区白江河泥炭地,分别在优势植物为苔藓的近原始地段和优势植物为小灌木的排水地段,钻取泥炭柱芯为试验材料,逐层测试泥炭理化指标,提取泥炭藓孢子并进行萌发试验,统计孢子数量和萌发力;经过泥炭样品年代测定,建立深度年代关系曲线,研究泥炭藓孢子萌发力对排水的响应和机制。结果表明: 整个柱芯对比,近原始地段平均孢子数略高于排水地段,两地段的平均孢子萌发力无差异,排水地段的泥炭容重、总碳和总氮都显著高于近原始地段。柱芯上部对比,排水(1987年)以后两地段孢子累积速率无显著差异,但近原始地段的平均孢子萌发力(34%)远低于排水地段(72%)。近原始地段的碳氮比与孢子萌发力呈显著正相关;排水地段的总碳、pH和埋藏时间与孢子萌发力呈显著负相关。30年前的泥炭地排水虽对孢子累积影响不大,但通过加速分解而改变了泥炭的理化性质,提升了表层泥炭中孢子萌发力,因此降低孢子库的持久性,可能导致泥炭藓在灾变性干扰后的种群持续更新潜力下降。     

月亮山自然保护区苔藓植物垂直分布初步研究

该研究通过采集、鉴定和测量苔藓植物标本并用SPSS软件进行数据分析,对贵州省月亮山自然保护区苔藓植物的垂直分布规律进行了初步分析。结果表明：月亮山自然保护区苔藓植物共有69科147属374种,苔藓植物呈明显的带状分布;不同海拔苔藓植物科属种所占的百分比均呈先升高后降低,优势科灰藓科( Hypnaceae)和细鳞苔科( Lejeuneaceae)和优势属凤尾藓属( Fissidens)、耳叶苔属( Frullania)、真藓属( Bryum)、疣鳞苔属( CoLoLejeunea)和细鳞苔属( Lejeunea)内种数在不同海拔也呈相同趋势;该地区苔藓植物石生群落和土生群落分布最广,木生群落次之,水生群落分布最少;苔藓植物雌雄异株数量在不同海拔均比同株数量多,比例约为7∶3;随着海拔升高,多种不利环境使长柄绢藓( Entodon macropodus)的叶片显著变小、叶长与叶宽的比显著增大,叶片由卵圆形变为卵状披针形,孢蒴极显著缩短、孢子直径显著增大,孢子的产量逐渐减少,不利苔藓植物的繁殖,蒴柄显著增长,有利于孢子的传播,体现了苔藓植物在不同的海拔的适应性。该研究结果为进一步研究苔藓植物的分布及环境适应性提供了基本资料。     

Endozoochory by slugs can increase bryophyte establishment and species richness

Herbivory can affect plant community composition and diversity by removing biomass and reducing light competition. Herbivory may particularly benefit low growing species such as bryophytes, which are frequently limited by light competition. Gastropods are important herbivores of seed plants and cryptogams, furthermore, they can disperse propagules such as seeds and spores via endozoochory. However, whether gastropod herbivory can reduce the dominance of vascular plants and thereby promote the germination and establishment of endozoochorously dispersed bryophyte spores has never been tested experimentally. Moreover, it is unclear whether these possible interacting effects can influence bryophyte species richness. Here, we tested for endozoochorous spore dispersal by slugs, in combination with sowing of vascular plants, in a fully factorial common garden experiment. Enclosures contained either slugs previously fed with bryophyte sporophytes, control slugs, or no slugs. After 21 days the bryophyte cover was on average 2.8 times higher (3.9% versus 1.4%) and after eight months the bryophyte species richness 2.6 times higher (5.8 versus 2.2) in enclosures containing slugs previously fed with bryophyte sporophytes than in the other treatments. Furthermore, after eight months high vascular plant cover reduced bryophyte diversity. On average enclosures without seed sowing harboured 1.6 times more bryophyte species than the ones with seed sowing (4.2 versus 2.6), indicating competitive effects of vascular plants on bryophytes. Our findings suggest that slugs are important dispersal vectors for bryophytes and that they can increase bryophyte populations and maintain bryophyte diversity by reducing the dominance of vascular plants.     

Fern and bryophyte endozoochory by slugs

Endozoochory plays a prominent role for the dispersal of seed plants, and dispersal vectors are well known. However, for taxa such as ferns and bryophytes, endozoochory has only been suggested anecdotally but never tested in controlled experiments. We fed fertile leaflets of three ferns and capsules of four bryophyte species to three slug species. We found that, overall, spores germinated from slug feces in 57.3 % of all 89 fern and in 51.3 % of all 117 bryophyte samples, showing that the spores survived gut passage of slugs. Moreover, the number of samples within which spores successfully germinated did not differ among plant species but varied strongly among slug species. This opens new ecological perspectives suggesting that fern and bryophyte endozoochory by gastropods is a so-far-overlooked mode of dispersal, which might increase local population sizes of these taxa by spore deposition on suitable substrates.     

Effects of temperature and desiccation on ex situ conservation of nongreen fern spores

? Premise of the study: Fern spores are unicellular and haploid, making them a potential model system to study factors that regulate lifespan and mechanisms of aging. Aging rates of nongreen spores were measured to compare longevity characteristics among diverse fern species and test for orthodox response to storage temperature and moisture. ? Methods: Aging of spores from 10 fern species was quantified by changes in germination and growth parameters. Storage temperature ranged from ambient room to -196°C (liquid nitrogen); spores were dried to ambient relative humidity (RH) or using silica gel. ? Key results: Survival of spores varied under ambient storage conditions, with one species dying within a year and two species having greater than 50% survival after 3 years. Few changes in germination or growth were observed in spores stored at either -80°C or -196°C over the same 3-yr study period. Spores stored at -25°C aged anomalously quickly, especially those dried to ambient RH or subjected to repeated freeze-thaw cycles. ? Conclusions: Spore longevity is comparable to orthodox seed longevity under ambient storage conditions, with wide variation among species and shelflife extended by drying or cooling. However, faster aging during freezer storage may indicate a similar syndrome of damage experienced by seeds categorized as "intermediate". The damage is avoided by storage at -80°C or liquid nitrogen temperatures, making cryoconservation an effective and broadly applicable tool to extend fern spore longevity. The study demonstrates that spore banks are a feasible approach for ex situ conservation of this important plant group.     

Effect of desiccation level and storage temperature on green spore viability of Osmunda japonica

In order to effectively preserve green spores, which have relatively higher water content and lose viability more quickly than non-green spores, we studied the effect of desiccation level and storage temperature on Osmunda japonica spores. The water content of fresh spores was 11.20%. After 12 h desiccation by silica gel, the water content decreased to 6% but spore viability did not change significantly. As the desiccation continued, the decrease in water content slowed, but spore viability dropped. For almost all storage periods, the effects of storage temperature, desiccation level, and temperature × desiccation level were significantly different. After seven days of storage, spores at any desiccation level stored at 4 °C obtained high germination rates. After more than seven days storage, liquid nitrogen (LN) storage obtained the best results. Storage at −18 °C led to the lowest germination rates. Spores stored at room temperature and −18 °C all died within three months. For storage at 4 °C and in LN, spores desiccated 12 and 36 h obtained better results. Spores without desiccation had the highest germination rates after being stored at room temperature, but suffered the greatest loss after storage at −18 °C. These results suggest that LN storage is the best method of long-term storage of O. japonica spores. The critical water content of O. japonica spores is about 6% and reduction of the water content to this level improves outcome after LN storage greatly. The reason for various responses of O. japonica spores to desiccation and storage temperatures are discussed.     

Storage of Resting Spores of the Gypsy Moth Fungal Pathogen, Entomophaga maimaiga

The fungal pathogen, Entomophaga maimaiga causes epizootics in populations of the important North American forest defoliator gypsy moth ( Lymantria dispar ). Increasing use of this fungus for biological control is dependent on our ability to produce and manipulate the long-lived overwintering resting spores (azygospores). E. maimaiga resting spores undergo obligate dormancy before germination so we investigated conditions required for survival during dormancy as well as the dynamics of subsequent germination. After formation in the field during summer, resting spores were stored under various moisture levels, temperatures, and with and without soil in the laboratory and field. The following spring, for samples maintained in the field, germination was greatest among resting spores stored in plastic bags containing either moistened paper towels or sterile soil. Resting spores did not require light during storage to subsequently germinate. In the laboratory, only resting spores maintained with either sterile or unsterilized soil at 4°C (but not at 20 or -20°C) germinated the following spring, but at a much lower percentage than most field treatments. To further investigate the effects of relative humidity (RH) during storage, field-collected resting spores were placed at a range of humidities at 4°C. After 9.5 months, resting spore germination was highest at 58% RH and no resting spores stored at 88 or 100% RH germinated. To evaluate the dynamics of infections initiated by resting spores after storage, gypsy moth larvae were exposed to soil containing resting spores that had been collected in the field and stored at 4°C for varying lengths of time. No differences in infection occurred among larvae exposed to fall-collected soil samples stored at 4oC over the winter, versus soil samples collected from the same location the following spring. Springcollected resting spores stored at 4°C did not go into secondary dormancy. At the time that cold storage of soil containing resting spores began in spring, infection among exposed larvae was initiated within a few days after bringing the soil to 15°C. This same pattern was also found for spring-collected resting spore-bearing soil that was assayed after cold storage for 2-7 months. However, after 31-32 months in cold storage, infections started 14-18 days after soil was brought to 15°C, indicating a delay in resting spore activity after prolonged cold storage.     

Germination of spores of Bacillus subtilis with dodecylamine

AIMS: To determine the properties of Bacillus subtilis spores germinated with the alkylamine dodecylamine, and the mechanism of dodecylamine-induced spore germination. METHODS AND RESULTS: Spores of B. subtilis prepared in liquid medium were germinated efficiently by dodecylamine, while spores prepared on solid medium germinated more poorly with this agent. Dodecylamine germination of spores was accompanied by release of almost all spore dipicolinic acid (DPA), degradation of the spore's peptidoglycan cortex, release of the spore's pool of free adenine nucleotides and the killing of the spores. The dodecylamine-germinated spores did not initiate metabolism, did not degrade their pool of small, acid-soluble spore proteins efficiently and had a significantly lower level of core water than did spores germinated by nutrients. As measured by DPA release, dodecylamine readily induced germination of B. subtilis spores that: (a) were decoated, (b) lacked all the receptors for nutrient germinants, (c) lacked both the lytic enzymes either of which is essential for cortex degradation, or (d) had a cortex that could not be attacked by the spore's cortex-lytic enzymes. The DNA in dodecylamine-germinated wild-type spores was readily stained, while the DNA in dodecylamine-germinated spores of strains that were incapable of spore cortex degradation was not. These latter germinated spores also did not release their pool of free adenine nucleotides. CONCLUSIONS: These results indicate that: (a) the spore preparation method is very important in determining the rate of spore germination with dodecylamine, (b) wild-type spores germinated by dodecylamine progress only part way through the germination process, (c) dodecylamine may trigger spore germination by a novel mechanism involving the activation of neither the spore's nutrient germinant receptors nor the cortex-lytic enzymes, and (d) dodecylamine may trigger spore germination by directly or indirectly activating release of DPA from the spore core, through the opening of channels for DPA in the spore's inner membrane. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide new insight into the mechanism of spore germination with the cationic surfactant dodecylamine, and also into the mechanism of spore germination in general. New knowledge of mechanisms to stimulate spore germination may have applied utility, as germinated spores are much more sensitive to processing treatments than are dormant spores.