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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。 相似文献
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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. 相似文献
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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。 相似文献
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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。 相似文献
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冯璐；汤袁；卜兆君；赵高林 《植物研究》2013,33(2):248-251
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。 相似文献
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作为优势植物, 泥炭藓(Sphagnum)在泥炭沼泽中缺乏有性更新的原因尚不清楚。针对影响孢子萌发的光强和养分条件, 以泥炭藓(S. palustre)为材料, 通过室内孢子萌发实验, 研究不同光强和养分浓度对孢子萌发率、萌发势及萌发指数的影响。4 种培养基中, 养分浓度高的营养液培养基中孢子萌发率最高, 达到60%, 其次为养分浓度与营养液相近的琼脂+营养液培养基, 萌发率为48%, 再次为养分水平很低的沼泽水培养基, 萌发率约为30%, 几乎无养分的蒸馏水培养基中萌发率最低, 约为5%。萌发势和萌发指数亦呈现相同的规律。琼脂+营养液和营养液培养基较沼泽水和蒸馏水培养基孢子萌发时间提前约3 天时间。增加光强使孢子萌发率仅提高10%。研究表明, 低养分浓度和弱光照均不利于孢子萌发, 相对而言, 泥炭沼泽的贫营养特征应是限制泥炭藓有性更新的更重要因素。 相似文献
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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。 相似文献
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泥炭藓繁殖体移植是影响泥炭地植被恢复的重要因素之一,不同移植方式的效果往往缺乏比较研究。选取长白山区白江河退化泥炭地为研究地,以自然生境的丘间种喙叶泥炭藓(Sphagnum flexuosum)和藓丘种中位泥炭藓(S.magellanicum)(后者耐旱能力较强)为实验材料,通过野外移植实验,研究水位提升与不同泥炭藓繁殖体移植方式对退化泥炭地植被恢复的影响。数据分析显示:水位条件显著影响了喙叶泥炭藓和中位泥炭藓的建植,随着水位上升,地表湿度增加,两种泥炭藓的盖度均呈明显的上升趋势;移植方式的变化短期内对泥炭藓的建植作用并不明显,但在移植2个月后,移植方式对喙叶泥炭藓表现出显著影响,即耐旱能力较强的中位泥炭藓置于上层时,喙叶泥炭藓盖度最高;水位和移植方式不存在交互作用,即在低水位条件下,中位泥炭藓置于上层的移植方式也未能提升泥炭藓的建植盖度。研究表明,水位提升是泥炭地植被恢复的十分有效的手段,因物种间存在对水分保持的差异,采用合理植物繁殖体移植方式,将会明显提升植被恢复的成效。 相似文献
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Abstract There is limited understanding of how fire‐related cues such as heat shock and smoke can combine to affect the germination response of seeds from fire‐prone vegetation because combinations of multiple levels of both cues have rarely been investigated. Germination response surfaces were determined for the combination of heat shock and smoke by applying factorial combinations of temperature (up to 100°C) and aerosol smoke (0–20 min) to 16 species that form soil seed banks in the Sydney region of south‐eastern Australia. Duplicate populations of three species were also examined to assess the constancy of a species response surface. Of the 19 populations examined, 16 showed a germination response to both the fire cues, which combined interactively in 14 populations, and independently in two. No population responded only to a single cue; however, seeds of 11 populations responded to heat in the absence of smoke, and nine responded to smoke in the absence of heat. Heat applied in the absence of smoke negatively affected germination in seven populations, either progressively as temperature increased, or above a set temperature. Negative germination responses over part of the temperature range were fully reversed at higher temperatures for unsmoked seeds of four populations (curvilinear heat response). Smoke effects were most frequently positive over all or part of the range of durations used, and when combined with heat frequently fully or partially reversed negative heat effects. Three populations required the obligatory combination of smoke and heat. A novel response to the cues was observed for three species, with smoke reversing negative heat effects at 75°C, being supplanted by a positive heat response of unsmoked seed at 100°C. The response surface for duplicate populations of two of the three species examined was variable. Heat shock and smoke frequently combined to affect germination, in both positive and negative ways. Consequently, to gain an accurate assessment of the response of seeds to fires, an experimental design that samples within the potential response zones of germination cues is essential. 相似文献
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Abstract The germination response of seeds from fire‐prone vegetation to fire‐related cues such as heat shock and smoke has usually been studied by applying the cues singly. The few studies that have applied the cues in combination have shown that interactions between the cues are possible. Here, the response of seeds from a number of species to combined heat shock and smoke is reported. Heat shock (25, 50, 75 and 100°C) and aerosol smoke (0, 5, 10 and 20 min) were applied factorially to nine species that form soil seed banks in the Sydney region of south‐eastern Australia. These species were from Epacridaceae (four species), Myrtaceae (four species) and Cyperaceae (one species) and ranged from fire‐sensitive obligate seeders to fire‐tolerant facultative resprouters. Germination of Dracophyllum secundum R. Br and Sprengelia monticola (A. Cunn. ex DC.) Druce was low and did not respond to the germination cues. The positive response of Gahnia sieberiana Kunth and Kunzea ambigua (Sm.) Druce to heat shock and smoke was independent and additive. The positive response of Kunzea capitata Rchb. to the interaction between heat shock and smoke was synergistic, and the response of Baeckea diosmifolia Rudge and Baeckea imbricata (Gaertn.) Druce was unitive, with germination increase only occurring following combined heat and smoke application. Epacris coriacea A. Cunn. ex DC. and Epacris obtusifolia Sm. had low levels of dormancy and hence it was not possible to find a fire response. Gahnia sieberiana and K. capitata responded differently to the combination of heat shock and smoke than has previously been reported. Germination of species from habitats that are infrequently burnt was not affected by heat shock or smoke. Low‐intensity fire or patches within fire may be important for seedling recruitment as the 50°C heat shock stimulated germination in four of the five species that responded to the heat cue, and germination of Baeckea imbricata declined within the 100°C heat shock treatment. Germination of one species, Baeckea imbricata, was only stimulated by a specific combination of cues, indicating that regeneration niches may be narrow for some species and that the application of a range of heat and smoke doses is required to find such responses. Of the species positively responding to heat shock and smoke, a requirement for both cues was prevalent, therefore the response to these cues in isolation cannot be relied upon to give a true indication of the fire response of a species. 相似文献
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Sedge meadows can be difficult to restore from farmed fields if key structural dominants are missing from propagule banks. In hand‐cultivated soybean fields in northeastern China, we asked if tussock‐forming Carex and other wetland species were present as seed or asexual propagules. In the Sanjiang Plain, China, we compared the seed banks, vegetative propagules (below‐ground) and standing vegetation of natural and restored sedge meadows, and hand‐cultivated soybean fields in drained and flooded conditions. We found that important wetland species survived cultivation as seeds for some time (e.g. Calamogrostis angustifolia and Potamogeton crispus) and as field weeds (e.g. C. angustifolia and Phragmites australis). Key structural species were missing in these fields, for example, Carex meyeriana. We also observed that sedge meadows restored without planting or seeding lacked tussock‐forming sedges. The structure of the seed bank was related to experimental water regime, and field environments of tussock height, thatch depth, and presence of burning as based on Nonmetric Multidimensional Scaling analysis. To re‐establish the structure imposed by tussock sedges, specific technologies might be developed to encourage the development of tussocks in restored sedge meadows. 相似文献
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Austrostipa compressa, a native ephemeral of southwest Western Australia was stimulated to germinate under a range of temperatures, in the presence of light, and exposure to smoke-water. This combination of environmental cues results in winter-maximum germination in immediate postfire and disturbed-soil environments of this Mediterranean-type climate. In contrast, Ehrharta calycina, an introduced perennial grass from southern Africa that has invaded Banksia woodlands, germinated under a wide range of temperature and light conditions, but showed no promotive response to smoke-water. Although A. compressa seeds tolerated heat shock better than E. calycina, the self-burial mechanism of A. compressa seeds ensures protection from fire. High-intensity fire could have a greater impact on E. calycina, as the seeds of this species tend to accumulate in the top of the soil profile where they are more susceptible to high temperatures. Although seeds of E. calycina are more susceptible to high temperatures, survival of mature individuals by postfire resprouting ensures continued survival in native woodlands. Estimates of soil seed bank densities showed extreme variability, but some recently burnt areas of the Yule Brook Botany Reserve contained up to 8000 seed m?2 of A. compressa and nearly 75 000 seeds m?2 of E. calycina. Viable soil seed bank densities of A. compressa are reduced with time-since-last fire, but areas of greater than 45 years since the last fire, still contained up to 119 seeds m?2. In both species, only about half their soil seed bank germinates following fire, thus ensuring the potential for later recruitment. Massive soil seed populations of E. calycina in native Banksia woodlands pose a major problem to management of this plant community type. 相似文献
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《Ecohydrology》2017,10(8)
During rain‐free periods, the water table in peatlands falls and the moisture content (MC ) of top 10 cm, including the moss layer, depends upon the hydrophysical properties and the responses of the local composition of species to water deficit. Thus, the ecosystem becomes vulnerable to surface peat fires. The spread of such fires is often irregular; however, there is little understanding of how the fine‐scale variation of peat MC can affect the spread of smouldering fire. We analyse the fine‐scale distribution of surface MC from a degraded blanket bog (i.e., horizontal intervals of 10 cm), thus indirectly analysing the effect of fine‐scale MC distribution on peat fire spread. We determine the relationship of vegetation and microtopography to the spatial distribution of near surface MC and the moisture gradient around patches of dry peat (less than 250% MC , moisture content in a dry mass basis). We found that the MC of the surface peat was distributed in clusters with dry patches (less than 250% MC ) averaging 40 ± 15 cm in size. The MC gradient surrounding dry patches was 10 ± 7% MC ∙cm−1. A mixed‐effects model showed that dry patches were associated with lawns (of feather moss or Sphagnum ) and hummocks of feather moss. Our model showed that wet patches were associated with both hummocks and hollows of Sphagnum . Therefore, the characterization of the surface MC in a fine‐scale is critical if we are to understand the spread of fires in peatlands. 相似文献
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The effects of dry heat, wet heat, charred wood and smoke on the germination of dormant soil‐stored seeds from a Eucalyptus woodland in western Victoria were tested by using a glasshouse seed‐bank germination experiment. Seedling density, species richness and species composition were compared between replicated treated and control samples. A total of 5922 seedlings, comprising 59 plant species, was recorded from the soil samples over a period of 150 days. While a few species dominated (including Centrolepis strigosa, Wahlenbergia gracilenta and Ixodia achillaeoides), 26 species were represented by fewer than five seedlings and 18 species were restricted to single treatment types. With the exception of charred wood, all treatments led to a significant increase in seed germination relative to the control. The highest number of germinants was obtained for the smoke treatment, with a mean (± SE) of 12 547 ± 449 seedlings m–2. Heat treatments yielded intermediate densities, with means (± SE) varying between 7445 ± 234 and 9133 ± 445 seedlings m–2. In comparison with the estimates of seed‐bank sizes from other fire‐prone ecosystems, these densities are high. Species richness differed significantly among treatments. Highest mean richness was recorded in the smoke treatment and lowest for the control and charred wood treatments. There were significant differences in seed‐bank species composition between treatment types based on analysis of similarity (Anosim) using Bray–Curtis similarity. While heat was a specific requirement for triggering germination in hard‐seeded species (e.g. Fabaceae), smoke was the most effective trigger for species from a broad range of other families. The potentially confounding effect of physical and chemical mechanisms of germination stimulation in heated bulk soil samples is raised as an issue requiring further investigation in relation to the role of smoke as a germination trigger. 相似文献
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Mariana Dairel;Alessandra Fidelis; 《植被学杂志》2024,35(3):e13268
Fire is an important ecological factor influencing plant communities in many fire-prone ecosystems. Savannas in the Cerrado are resilient to fire, with plants exhibiting fire-related traits, allowing them to persist in post-fire environments. Therefore, excluding fire may result in changes in plant community dynamics, thus affecting their resilience. We investigated the effect of the reintroduction of fire in savannas where fire has been excluded for longer periods (>12 years) on seedling recruitment. We asked the following questions: (i) how does fire affect seed bank germination in sites with different fire histories; and (ii) how did fire exclusion affect species composition of the seed bank? 相似文献
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Abstract This study consists of a series of investigations designed to determine the potential of concentrated smoke products to stimulate seed germination and assist in the rehabilitation of degraded landscapes. Aerosol smoke and conventional smoke water products are not practical for use in broad‐scale seed bank regeneration programmes due to infrastructure limitations and the high rate of application required for their use. Concentrated smoke products have been found to be effective in stimulating soil seed banks and are suitable for broad‐scale use due to the lower rate of application required to elicit germination within smoke‐responsive species. The use of concentrated smoke products on undisturbed soil seed banks at 50 and 100 mL m‐2 increased total seedling numbers 10‐fold, while species richness more than doubled over untreated controls. Although aerosol smoke applied directly to soil promoted 10 times more seedlings compared to concentrated smoke products, species richness levels in each treatment were similar. Concentrated smoke products cause leaf scorch when applied directly over plants in active growth, with limited to nil damage when plants are not actively growing. The affected plants generally recovered following application of concentrated smoke products as a foliar spray. 相似文献
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