Generation of 10 GHz, 1.9 ps optical pulse train using semiconductor optical amplifier and silica-based highly nonlinear fiber

We propose a simple approach to generate a high quality 10 GHz 1.9 ps optical pulse train using a semiconductor optical amplifier and silica-based highly nonlinear fiber. An optical pulse generator based on our proposed scheme is easy to set up with commercially available optical components. A 10 GHz, 1.9 ps optical pulse train is obtained with timing jitter as low as 60 fs over the frequency range 10 Hz-1 MHz. With a wavelength tunable CW laser, a wide wavelength tunable span can be achieved over the entire C band. The proposed optical pulse generator also can operate at different repetition rates from 3 to 10 GHz.

不同放牧强度下高山草甸生态系统碳氮分布格局和循环过程研究

本研究针对川西北高山草甸缺乏科学管理，过度放牧导致草场退化，并由此引发的一系列生态环境问题，选取红原县瓦切乡1996 年草地承包后形成的四个放牧强度草场，即不放牧、轻度（1.2 头牦牛hm-1）、中度（2.0 头牦牛hm-1）和重度放牧（2.9 头牦牛hm-1），作为研究对象，研究了不同放牧强度对草地植物-土壤系统中碳、氮这两个最基本物质的分布格局和循环过程的影响，并探讨了放牧干扰下高山草甸生态系统的管理。 1．放牧对草地植物群落物种组成，尤其是优势种，产生了明显的影响。不放牧、轻度、中度和重度放牧草地群落物种数分别为22，23，26，20 种，群落盖度分别是不放牧96.2%＞中度93.6%＞轻度89.7%＞重度73.6%。随放牧强度的增加， 原植物群落中的优势种垂穗鹅冠草（ Roegneria nutans ）、发草（Deschampsia caespitosa）和垂穗披碱草（Elymus nutans）等禾草逐渐被莎草科的川嵩草（Kobresia setchwanensis）和高山嵩草（Kobresia pygmaea）所取代成为优势种。同时，随放牧强度的增加，高原毛茛（Ranunculus brotherusii）、狼毒（Stellera chamaejasme）、鹅绒委陵菜（Potentilla anserina）和车前（Plantagodepressa）等杂类草的数量也随之增加。 2．生长季6～9 月份，草地植物地上和地下生物量（0～30cm）都是从6 月份开始增长，8 月份达到最高值，9 月份开始下降。每个月份，通常地上生物量以不放牧为最高，重度放牧总是显著小于不放牧；地下生物量随放牧强度的增加表现为增加的趋势，通常重度和中度放牧显著高于不放牧和轻度放牧草地。不放牧、轻度、中度和重度放牧草地6～9 月份4 个月的植物总生物量平均值分别是1543、1622、2295 和2449 g m-2，但随放牧强度的增加越来越来多的生物量被分配到了地下部分，地下生物量占总生物量比例的大小顺序分别是重度88%＞中度82%＞轻度76%＞不放牧69%。生物量这种变化主要是由于放牧使得群落优势种发生改变而引起的，其分配比例的变化体现了草地植物对放牧干扰的适应策略。 3．植物碳氮贮量的季节变化类似与生物量的变化。每个月份，不同放牧强度间植物地上碳氮的贮量有所不同，一般重度放牧会显著减少植物地上碳氮贮量。植物根系(0～30cm)碳氮贮量随放牧强度的增加表现为增加的趋势，通常重度和中度放牧显著高于不放牧和轻度放牧草地。不放牧、轻度、中度和重度放牧草地6～9 月份4 个月的植物总碳平均值分别是547、586、847 和909 g m-2，根系碳贮量占植物总碳的比例大小顺序分别是重度88%＞中度82%＞轻度76%＞不放牧69%；放牧、轻度、中度和重度放牧草地6～9 月份4 个月的植物总氮平均值分别是17、17、23 和26 g m-2，根系氮贮量占植物总氮的比例大小顺序分别是重度79%＞轻度71%＞中度70%＞不放牧65%。 4. 土壤有机碳贮量（0～30cm）的季节变化表现为7 月份略有下降，8 月开始增加，9 月份达到的最大值。土壤氮贮量的季节变化表现为随季节的推移逐渐增加的趋势。增加的放牧强度不同程度的增加土壤有机碳氮的贮量。不放牧、轻度、中度和重度放牧6～9 月份4 个月的土壤有机碳贮量的平均值分别是9.72、10.36、10.62 和11.74 kg m-2，土壤氮贮量分别为1.45、1.56、1.66 和1.83 kg m-2。土壤中有机碳（氮）的贮量都占到了植物-土壤系统有机碳（氮）的90%以上，但不同放牧强度之间的差异不明显。 5. 土壤氮的总硝化和反硝化，温室气体N2O 和CO2 的释放率的季节变化表现为从6 月份开始增加，7 月份达到最大值，8 月份开始下降，9 月份降为最小值。增加的放牧强度趋向于增加土壤氮的总硝化和反硝化作用，温室气体N2O和CO2 的释放率，通常情况下，中度放牧和重度放牧显著地加强了这些过程。 6．垂穗鹅冠草（Roegneria nutans）和川嵩草（Kobresia setchwanensis）凋落物在不同放牧强度下经过1 年的分解，两种凋落物的失重率及其碳氮的损失率3都随放牧增加表现为增加的趋势。在同一放牧强度下，川嵩草凋落物的失重率和碳氮的损失率都高于垂穗鹅冠草凋落物。 7. 尽管重度放牧显著增加了土壤碳氮的贮量，但同时也显著降低了植被群落盖度，降低了植物地上生物量，因此，久而久之会减少植物向土壤中的碳氮归还率；与不放牧和轻度放牧相比，重度放牧又显著增加了土壤CO2 和NO2 的排放量，这是草地生态系统碳氮损失的重要途径。由此可见，对于这些地处青藏高原的非常脆弱的高山草甸生态系统，长期重度放牧不仅导致植物生产力降低，而且将导致草地生态系统退化，甚至造成土壤中碳氮含量减少。 Long-term overgrazing has resulted in considerable deterioration in alpine meadowof the northwest Sichan Province. In order to explore management strategies for thesustainability of these alpine meadows, we selected four grasslands with differentgrazing intensity (no grazing-NG: 0, light grazing-LG: 1.2, moderate grazing-MG: 2.0,and heavy grazing-HG: 2.9 yaks ha-1) to evaluate carbon, nitrogen pools and cyclingprocesses within the plant-soil system in Waqie Village, Hongyuan County, Sichuan Province. 1. Grazing obviously changed the plant species composition, especially ondominant plant species. Total number of species is 22, 23, 26, and 20 for NG, LG, MGand HG, respectively. Vegetation coverage under different grazing intensity ranked inthe order of 96.2% for HG＞93.6% for MG＞89.7% for LG＞73.6% for NG. Thedominator of HG community shifted from grasses-Roegneria nutans andDeschampsia caespitosa dominated in the NG and LG sites into sedges-Kobresiapygmaea and K. setchwanensis. At the same time, with the increase of grazingintensity, the numbers of forbs, such as Ranunculus brotherusii, Stellera chamaejasme,Potentilla anserine and Plantago depressa, increased with grazing intensity. 2. Over the growing season, aboveground and belowground biomass showed a 5single peak pattern with the highest biomass in August. For each month, abovegroundbiomass usually was the highest in the NG site and lowest in the HG site.Belowground biomass showed a trend of increase as grazing intensity increased and itwas significantly higher in the HG and MG site than in the NG and LG sites. Totalplant biomass averaged over the growing season is 1543, 1622, 2295 and 2449 g m-2for NG, LG, MG and HG, respectively. The proportion of biomass to total plantbiomass for NG, LG, MG and HG is 88%, 82%, 76% and 69%, respectively. Higherallocation ratio for is an adaptive response of plant to grazing. 3. Carbon and nitrogen storage in plant components followed the similar seasonalpatterns as their biomass under different grazing intensities. Generally, heavy grazingsignificantly decreases aboveground biomass carbon and nitrogen compared to nograzing. Carbon and nitrogen storage in root tended to increase as grazing increasedand they are significantly higher in the HG and MG sites compared to the LG and NGsite. Total Carbon storage in plant system averaged over the growing season is 547,586, 847 and 909 g m-2 for NG, LG, MG and HG, respectively, while 17, 17, 23 and 26g m-2 for nitrogen. The proportion of carbon storage in root to total plant carbon forNG, LG, MG and HG is 88%, 82%, 76%, 69%, respectively, while 65%, 71%, 70%and 79% for nitrogen. 4. Carbon storage in soil (0-30cm) decreased slightly in July, then increased inAugust and peaked in September. Nitrogen storage in soil tended to increase withseason and grazing intensity. Total Carbon storage in soil averaged over the growingseason is 9.72, 10.36, 10.62 and11.74 kg m-2 for NG, LG, MG and HG, respectively,while 1.45, 1.56, 1.66 and 1.83 for nitrogen. The proportion of carbon (nitrogen)storage in soil to plant-soil system carbon (nitrogen) storage for NG, LG, MG and HGis more than 90%, which is not markedly different among different grazing intensities. 5. Gross nitrification, denitrification, CO2 and N2O flux rates in soil increasedfrom June to July and then declined until September, all of which tended to increasewith the increase of grazing intensity. Generally, heavy and moderate grazing intensitysignificantly enhanced these process compared to no and light grazing intensity. 6. After decomposing in situ for a year, relative weight, carbon and nitrogen loss in the litter of Roegneria nutans and Kobresia setchwanensis tended to increase asgrazing intensity increased. Under the same grazing intensity, relative weight, carbonand nitrogen loss in the litter of Kobresia setchwanensis were higher than these in thelitter of Roegneria nutans. 7. Although heavy grazing intensity resulted in higher levels of carbon andnitrogen in plant and soil, it decreased vegetation coverage and aboveground biomass,which are undesirable for livestock production and sustainable grassland development.What is more, heavy grazing could also introduce potential carbon and nitrogen lossvia increasing CO2 and N2O emission into the atmosphere. Grazing at moderateintensity resulted in a plant community dominated by forage grasses with highaboveground biomass productivity and N content. The alpine meadow ecosystems inTibetan Plateau are very fragile and evolve under increasing grazing intensity by largeherbivores; therefore, deterioration of the plant-soil system, and possible declines insoil C and N, are potential without proper management in the future.

黄龙世界自然遗产地岷江冷杉原始林群落结构与植物多样性：生境差异性研究

黄龙世界自然遗产地岷江冷杉林(Abies faxoniana)生境类型多样，群落结构复杂，群落植物种类组成多样性丰富。揭示不同生境的生物多样性及其差异是认识生物多样性格局、形成及维持机制的前提和进行多样性保育的基础。本文采用样方法对黄龙钙化滩生境、阴坡非钙化生境及半阳坡非钙化生境的岷江冷杉原始林植物群落结构及植物多样性进行了研究。结果表明： 黄龙岷江冷杉林具有明显的复层异龄结构，垂直结构明显，乔木、灌木、草本、苔藓层次分明。共发现高等植物386 种，其中维管植物46 科103 属163 种，苔藓植38 科83 属物223 种。各层片结构及物种组成如下: (1)钙化滩生境、阴坡非钙化生境、半阳坡非钙化生境分别发现乔木18 种、13种、8 种。乔木层均可分为两个亚层，第一亚层优势种均为岷江冷杉，第二亚层主要为岷江冷杉异龄树或其它大高位芽物种。钙化滩生境第一亚层除优势种岷江冷杉外混生有巴山冷杉(Abies fargesii)、粗枝云杉(Picea asperata)以及阔叶树种白桦(Betula platyphylla)等，第二亚层主要为岷江冷杉异龄树；阴坡非钙化生境第一亚层除优势种岷江冷杉外间有巴山冷杉和白桦，第二亚层物种主要为川滇长尾槭(Acer caudatum var. prattii)；半阳坡非钙化生境第一亚层除优势种岷江冷杉外混生有巴山冷杉，第二亚层主要为岷江冷杉异龄树。依乔木层优势种的差异，钙化滩生境及半阳坡非钙化生境为岷江冷杉纯林，阴坡非钙化生境为岷江冷杉－川滇长尾槭混交林。不同生境乔木层郁闭度、乔木密度、树高结构、直径结构均存在差异。 (2)钙化滩生境发现灌木41 种，平均盖度为18.49±1.72(％)，平均高度为52.12±4.45(cm)，优势种为直穗小檗(Berberis dasystachya)；阴坡非钙化生境发现灌木30 种，平均盖度为29.33±2.56 (％)，平均高度为119.55±8.01 (cm)，优势种为箭竹 (Fargesia spathacea) 、唐古特忍冬(Lonicera tangutica) 和袋花忍冬(Lonicera saccata)；半阳坡非钙化生境发现灌木29 种，平均盖度为31.35±1.93 (％)，平均高度为107.55±4.24 (cm)，优势种为箭竹(Fargesia spathacea)。不同生境灌木层结构和物种组成多样性差异显著，钙化滩生境的灌木盖度、高度总体上较非钙化的坡地生境低, 钙化滩生境灌木以小型叶的落叶灌木为主，沟两侧非钙化的坡地生境上则发育了丰富箭竹。 (3)钙化滩生境发现草本46 种，平均盖度为7.18±0.79 (％)，平均高度为5.04±0.26(cm)，以山酢浆草(Oxalis griffithii)为优势种；阴坡非钙化生境发现草本物种71 种，平均盖度达29.04±2.31(％)，平均高度为9.08±0.52(cm)，以钝叶楼梯草(Elatostema obtusum)、山酢浆草为优势种；半阳坡非钙化生境草本物种50 种，平均盖度为以8.79±0.82(％)，平均高度为7.67±0.43 (cm)，以扇叶铁线蕨(Adiantum flabellulatum)、双花堇菜(Viola biflora)、华中蛾眉蕨(Lunathyrium shennongense)、山酢浆草为优势种。阴坡非钙化生境草本层片发育良好，多样性最为丰富，盖度和物种丰富度均显著高于钙化滩生境和半阳坡非钙化生境。 (4)钙化滩生境发现苔藓物种140 种，平均盖度达84.25±1.30 (％)，以仰叶星塔藓(Hylocomiastrum umbratum) 等大型藓类为优势种；阴坡非钙化生境发现苔藓物种115 种，平均盖度为79.29±1.64 (％)，以刺叶提灯藓(Mnium spinosum)、大羽藓(Thuidium cymbifolium)、毛尖燕尾藓(Bryhnia trichomitra)等个体较小的物种为优势种；半阳坡非钙化生境发现苔藓物种91 种，平均盖度为60.64±1.93 (％)，也以刺叶提灯藓为优势种。 (5)钙化滩生境、阴坡非钙化生境、半阳坡非钙化生境的物种数分别为234 种、221 种、175 种。乔木层的Shannon-Wiener 指数分别为0.75 ±0.12、1.87±0.12、1.78±0.07（灌木层，0.44±0.08、1.71± 0.15、2.49±0.06；草本层，0.33±0.13、1.31±0.15 、2.15±0.08； 苔藓层1.30±0.11、2.08±0.04、1.73±0.11，）；Pielou 均匀度指数分别为0.45±0.05、0.29±0.06、0.28±0.08（灌木层，0.75±0.03、0.68±0.05、0.52±0.06；草本层，0.68±0.02、0.77±0.02、0.74±0.02；苔藓层，0.40±0.03、0.63±0.02、0.52±0.03）；Simpson's 优势度指数分别为0.63±0.06、0.78±0.04、0.83±0.07（灌木层，0.21±0.03、0.28±0.05、0.45±0.06；草本层，0.25±0.02、0.12±0.01、0.17±0.01；苔藓层，0.45±0.04、0.18±0.01、0.31±0.04）。三种生境间乔木层、草本层的Sorenson 群落相似性系数较低, 灌木层、苔藓层的的Sorenson 群落相似性系数较高。 综上所述，黄龙岷江冷杉林的群落结构、植物多样性在三种生境间存在差异性，这将意味着我们在进行黄龙世界自然遗产地的森林经营管理时要较多地关注岷江冷山林群落在不同生境中的差异性。 There were multiplex habitat types, complicated community structure and abundant species composition in the Huanglong World Natural Heritage Site. Uncovering the differences of biodiversity among different habitats was a precondition to understand the distribution, formation and sustaining mechanism of the biodiversity, and the foundation of biodiversity conservation. In the present study, using plenty of quadrants, we investigated the community structure and the biodiversity of the primitive Abies faxoniana forest in different habitats (travertine bottomland, semi-sunny-slope non-calcified habitat and shady-slope non-calcified habitat) in the Huanglong World Natural Heritage Site. The main results are as follows: All the primitive Abies faxoniana forests in the three habitats were uneven-aged with obvious vertical structure including tree layer, shrub layer, herb layer and bryophyte layer. A total of 386 higher plants including 163 vascular plant species (103 generic, 46 families) and 223 bryophyte species (83 generic, 38 families) were investigated. The structure and species composition of each layer are as follows: (1) There were 18, 13 and 8 tree species in travertine bottomland, shady-slope non-calcified habitat and semi-sunny-slope non-calcified habitat, respectively. The tree layers in all habitats can be divided into two clear sub-layers. The upper tree layers were dominated by Abies faxoniana, and the lower tree layers were dominated by uneven-aged Abies faxoniana or other phanerophytes species. There were Abies fargesii , Picea asperata and Betula platyphylla besides the dominated species (Abies faxoniana) in the upper tree layer in travertine bottomland, and the lower tree layers were dominated by uneven-aged Abies faxoniana; There were Abies fargesii and Betula platyphylla besides the dominated species (Abies faxoniana) in the upper tree layer in shady-slope non-calcified habitat, and the lower tree layers were dominated by Acer caudatum var. prattii; There was Abies fargesii besides the dominated species (Abies faxoniana) in the upper tree layer semi-sunny-slope non-calcified habitat, and the lower tree layers were dominated by uneven-aged Abies faxoniana. According to composition percentage of dominate species in tree layer, both the forest in travertine bottomland and in semi-sunny-slope non-calcified habitat could be ranked as pure forest, and the forest in shady-slope non-calcified habitat could be ranked as mingled forest. There were significant differences in crown density, plant density, height structure and diameter structure among the three habitats. (2) A total of 41 shrub species (average coverage 18.49±1.72％; average height 52.12±4.45 ㎝)were found in travertine bottomland, and the dominate species was Berberis dasystachya; A total of 30 shrub species (average coverage 29.33±2.56 ％;average height 119.55±8.01 ㎝)were found in shady-slope non-calcified habitat, and the dominate species was Fargesia spathacea, Lonicera tangutica and Lonicera saccata. A total of 29 shrub species (average coverage 31.35±1.93％; average height 107.55±4.24 ㎝) were found in semi-sunny-slope non-calcified habitat, and the dominate species was Fargesia spathacea. There were significant differences in structure and species diversity of the shrub layers among the three habitats. The coverage and height of shrub had lower value in travertine bottomland than in two non-calcified habitats. Moreover, travertine bottomland was dominated by deciduous shrub species with microphyll and non-calcified habitats developed abundant Fargesia spathacea species. (3) A total of 46 herb species (average coverage 7.18±0.79％;average height 5.04±0.26 ㎝)were found in travertine bottomland, and the dominate species was Oxalis griffithii; A total of 71 herb species (average coverage 29.04±2.31％;average height 9.08±0.52 ㎝)were found in shady-slope non-calcified habitat, and the dominate species was Elatostema obtusum and Oxalis griffithii. A total of 50 herb species (average coverage 8.79±0.82％;average height 7.67±0.43 ㎝) were found in semi-sunny-slope non-calcified habitat, and the dominate species was Adiantum flabellulatum, Viola biflora, Lunathyrium shennongense and Oxalis griffithii. Herb layers developed well in shady-slope non-calcified habitat and had the higher species richness and coverage than travertine bottomland and semi-sunny-slope non-calcified habitat. (4) A total of 140 bryophyte species (average coverage 84.25±1.30％)were found in travertine bottomland, and the dominate species was big bryophyte species such as Hylocomiastrum umbratum and so on; A total of 115 bryophyte species (average coverage 79.29±1.64％)were found in shady-slope non-calcified habitat, and the dominate species was small bryophyte species such as Mnium spinosum, Thuidium cymbifolium, Bryhnia trichomitra and so on. A total of 91 bryophyte species (average coverage 60.64±1.93％) were found in semi-sunny-slope non-calcified habitat, and the dominate species was Mnium spinosum. (5) There were 234, 221 and 175 plant species in travertine bottomland, shady-slope non-calcified habitat and semi-sunny-slope non-calcified habitat, respectively. Shannon-Wiener index of the tree layer was 0.75 ±0.12, 1.87±0.12 and 1.78±0.07 (the shrub layer, 0.44±0.08, 1.71± 0.15 and 2.49±0.06; the herb layer, 0.33±0.13, 1.31±0.15 and 2.15±0.08; the bryophyte layer, 1.30±0.11, 2.08±0.04 and 1.73±0.11.) for the three habitats, respectively; Pielou index of the tree layer was 0.45±0.05, 0.29±0.06 and 0.28±0.08 (the shrub layer, 0.75±0.03, 0.68±0.05 and 0.52±0.06; the herb layer, 0.68±0.02, 0.77±0.02 and 0.74±0.02; the bryophyte layer, 0.40±0.03, 0.63±0.02 and 0.52±0.03.) for the three habitats, respectively. Simpson's index of the tree layer was 0.63±0.06, 0.78±0.04 and 0.83±0.07 (the shrub layer, 0.21±0.03、0.28±0.05、0.45±0.06; the herb layer, 0.25±0.02, 0.12±0.01 and 0.17±0.01; the bryophyte layer, 0.45±0.04, 0.18±0.01 and 0.31±0.04.) for the three habitats, respectively. There were low Sorenson index both in the tree layer and in the herb layer among the three habitats, whereas, high Sorenson index occurred both in the shrub layer and in the bryophyte layer. To sum up, there were differences both in community structure and plant diversity among the three different habitats, which means that we should pay more attention to habitats heterogeneities of the primitive Abies faxoniana forest when we take action to manage the forest in the Huanglong World Natural Heritage Site.

若尔盖自然保护区高原林蛙(Rana kukunoris)扩散模型与景观连接分析

揭示水体中繁殖的两栖动物在异质性景观中的空间扩散特点，探讨景观面积丧失和破碎化对于两栖动物的影响，为两栖动物的保护提供理论依据。本文以四川西北部若尔盖湿地自然保护区的高原林蛙(Rana kukunoris)为研究对象，通过运用地理信息系统及建立景观模型等方法，在分析若尔盖湿地自然保护区范围内现有景观格局的基础上，建立了高原林蛙的景观扩散模型，并模拟了“沼泽→草甸”的湿地逆演化过程下高原林蛙的空间分布与景观连接的变化特点。主要结果是： 1．若尔盖湿地自然保护区呈典型的沼泽—草甸式斑块—基质景观格局。草甸面积占整个景观面积的79.42%，景观蔓延度指数（CONTAG）为79.00远离最小值0而更趋向于最大值100，面积和景观蔓延度指数表明草甸是整个景观中面积占绝对优势且景观连接好的类型，构成了景观的基质，对景观的动态格局演变起主导作用。沼泽面积仅占整个景观面积的18.08%，但却是整个景观中斑块数目最多的单元，占所有斑块数的82.9%。因此沼泽斑块与草甸基质之间的动态结构对高原林蛙的扩散起着决定性的作用。 2．空间扩散模型表明，其它类型的景观不但扩展了高原林蛙的活动范围，而且也为高原林蛙在不同沼泽斑块间的连接提供了通道。高原林蛙的空间扩散区域使得彼此间成斑块化隔离状分布的沼泽形成了潜在景观功能连接，促进了不同斑块间物种的交流。小型沼泽作为垫脚石（stepping-stone），使得整个景观中的相隔距离较远的大型斑块联结为一个功能整体，促进了高原林蛙在整个景观中的相互动态联系。 3．模拟“沼泽→草甸”的湿地逆演化过程表明，大量小型沼泽湿地的消失将会 对在沼泽中繁殖并扩散到其它景观类型中去的高原林蛙造成潜在影响。逆演化过程不仅使沼泽斑块的分布范围，沼泽源斑块的面积和空间扩散面积减少，而且对景观连接也有很大影响。小型沼泽的消失，将使得景观斑块的功能连接变小，使得依靠小型沼泽作为跳板的动物在沼泽斑块之间的移动将变得更加困难。 本文是对生境丧失与破碎化影响下两栖动物的行为反应的一种尝试。影响模型的因素很多，包括动物对各种类型景观的偏好程度，地理数据的精度，及模型的可靠程度都是制约模型准确度的因素。 The spatial diffusion of water—breeding amphibian through heterogeneous landscape and the effects of landscape losing and fragmentation to amphibian were the core theory of the landscape ecology of amphibian. Geographical information system (GIS) and landscape model were used to model the diffused area of Rana kukunoris in Zoige Wetland Natural Reserve. Model was also used to analysis the spatial distribution variation of R. kukunoris and the change of landscape connectivity when simulated the retrogressive succession of landscape. The main results are below: 1. There was peatland—meadow pattern which was typical patch—matrix landscape pattern in Zoige Natural Reserve. The meadow area occupied 79.42% of the entire landscape area, contagion index (CONTAG) was 79.00 which was far away the minimum value (0) but tend to the maximum value (100). Both of these showed that meadow was the largest part and the most continue units. It was shown that meadow was matrix of the landscape, which evolved the leading role to the landscape dynamic pattern. Though their area only occupies 18.08% of entire landscape area, peatlands were according to 82.9% of the total patches. Dynamic of the pattern between peatlands and meadows decided the spatial diffusion of R. kukunoris. 2．The model indicated that the other types of landscape not only expanded diffusion of R. kukunoris, but also have provided the potential channels for frog's connections among different peatlands. The spatial diffusion zone of R. kukunoris forced isolated patch peatlands to be potential landscape functional connectivity. The small peatlands, as stepping-stone, made the large peatlands connect as a functional one and promoted the integrated and dynamic connectivity of R. kukunoris in the whole landscape. 3. The simulation of “peatlands→meadows”retrogressive succession process indicated that the decrease of small peatlands will have potential effect to R. kukunoris because they must bred in peatlands and diffuse to other type of the landscape. Retrogressive succession process not only made the decrease of distribution of peatlands, patches number of peatlands and diffused area of R. kukunoris, but also reduced the connectivity among source patches. As stepping-stone, the disappearance of small peatlands will made the migration of R. kukunoris among patches more difficult. The model was an experiment of the amphibian behavior reaction to habitat losing and fragmentation. There were many factors that could influence the accuracy of model, such as the preference of animals to each type of landscape, the geographical data precision, reliable degree of model.

捷安肽素对采后柑桔青绿霉菌抑制效果及作用机理研究

捷安肽素是一种由枯草芽孢杆菌（Bacillus subtilis）ZK 产生的抗真菌多肽。本文以柑桔青霉菌（Penicillium italicum）和绿霉菌（Penicillium digitaum）为供试真菌，研究了捷安肽素的抑菌性能及作用机理，为捷安肽素开发为有效的生物杀菌剂提供理论依据。全文共分两部分：第一部分：捷安肽素对柑桔青霉菌和绿霉菌抑制效果研究。采用琼脂扩散法测定捷安肽素对柑桔青霉菌和绿霉菌的抑菌活性。53.9 µg/mL 捷安肽素对绿霉菌和青霉菌的抑菌圈直径分别为26.7mm 和24.1mm。结果表明捷安肽素能够抑制柑桔青绿霉菌的生长，柑桔绿霉菌比青霉菌对捷安肽素敏感。在柑桔果实上，研究了不同浓度、不同接入时间的捷安肽素对柑桔青霉病和绿霉病的防治效果，并与常用化学杀菌剂抑霉唑、咪鲜胺、甲基硫菌灵和多菌灵作比较。53.9 µg/mL捷安肽素处理柑桔果实，柑桔青霉病和绿霉病发病率分别为5.0 %和5.3 %,比对照低95.0 %和94.7 %；柑桔青霉病和绿霉病的病情指数分别为1.87 和2.18，比对照低73.73 和97.82。结果表明，捷安肽素能够有效地防治柑桔青绿霉病。与对照相比，捷安肽素先于或后于柑桔青绿霉菌接入时，对柑桔青绿霉菌均有抑制作用，但抑制效果随接入间隔时间的增长而降低。第二部分：捷安肽素对绿霉菌作用机理研究。首先在光学显微镜和透射电镜下观察捷安肽素处理后绿霉菌菌丝表面形态结构与菌丝体内超微结构的变化。形态观察发现，捷安肽素处理24h以内，绿霉菌菌丝结构无变化。捷安肽素作用36h后，绿霉菌菌丝不规则缢缩和膨大。48h后，在绿霉菌菌丝顶端、中部、末端的多处细胞均可发生畸形的球状结构，这种畸变结构随处理的延长而增加，致使细胞成为捻珠状。处理72 h后，畸变球形细胞开始断裂离解。处理96h后，镜下几乎无完整菌丝，成单个的球状细胞，部分细胞出现破裂。而对照菌丝表面光滑，结构完整。通过透射电镜观察发现，与对照相比，捷安肽素处理后，绿霉菌细胞壁、细胞膜轮廓模糊不清，细胞质外泄。推测捷安肽素能够使绿霉菌细胞膜通透性发生改变。进一步实验利用紫外-可见分光光度计检测捷安肽素作用后绿霉菌胞外液紫外吸光度的变化，表明捷安肽素作用于绿霉菌菌丝后，细胞内蛋白质、核酸缓慢泄漏。通过Atomscan Advantage单道扫描等离子体发射光谱仪(ICP)测定捷安肽素作用后菌丝体内K+浓度的改变，结果表明捷安肽素作用于柑桔绿霉菌1h内，菌丝体内K+含量迅速下降，为对照绿霉菌K+含量的37.53 %，1 h后菌丝体内K+含量变化趋于平缓。K+的迅速泄漏，以及蛋白质、核酸的泄漏表明捷安肽素通过迅速改变绿霉菌细胞膜通透性，使绿霉菌菌丝生长受到抑制。Jiean-peptide produced by Bacillus subtilis ZK has broad-spectrumresistance to plant pathogens. In this study, we investigated the antifungal propertyand the possible antifungal mechanism of jiean-peptide against two commonphytopathogenic fungi of citrus fruits: blue molds (P. italicum) and green molds (P.digitatum).The paper involved two parts:Part 1 is the study of the antifungal property of jiean-peptide against blue moldsand green molds of citrus fruits. The in vitro inhibition effect of jiean-peptide againstblue molds and green molds was detected by agar diffusion method. The diameters ofinhibition zones of green molds and blue molds are 26.7mm and 24.1mm respectivelyby treating with 53.9 µg/mL jiean-peptide. It shows that jiean-peptide effectivelyinhibits the both phytopathogenic fungi, and it is more effective for inhibiting greenmolds than blue molds. The effectiveness of jiean-peptde to inhibit green molds andblue molds in vivo was investigated compared with four conventional fungicides thatare imazalil, prochloraz, carbendazin and methylthiophanate. The result is that the incidences of the blue mold disease and green mold disease are 5.0 % and 5.3 %, thedisease severities are 1.87 and 2.18 respectively when citrus are inoculated with 53.9µg/ml jiean-peptide. The decay incidences and disease severities were significantlyreduced by treating with jiean-peptide compared with the control. The results indicateJiean-peptide is effective for controlling blue molds and green molds on citrus. Theoptimized inoculation time was also investigated. When inoculated with jiean-peptideat 0 h, 6 h, 12 h, 24 h and 48 h before or after pathogens’ inoculation, Jiean-peptidecan suppress the occurrence of blue molds and green molds compared with the control, but the effect of later inoculation decreases compared with the inoculation at the sametime.In Part 2, we investigated the possible antifungal mechanism against greenmolds of citrus. At first, we observed the exterior morphological changes andultrastructural changes of blue molds under light microscopy (LM) and transmissionelectron microscopy (TEM). Compared with untreated control cells which aregenerally uniform in shape, the appearances of treated hyphae change obviously. Itshows that some cells of hyphae irregularly shrink or enlarge when cultured for 36h.When the treating time of jiean-peptide increases, the aberrance of the hyphaebecomes more obvious, and hyphae exhibit the moniliform appearances. Finally, thereis no intact hypha leaved except only single cells, and some of which appear fractured.By transmission electron microscopy (TEM) observation, we find that the outline ofthe cell wall and the cell membrane of hyphae are blurry, and the cytoplasma oozesout. The observation result under LM and TEM suggests that jiean-peptide mightchange the permeability of the cell membrane. So we conducted further experiment todetect the change of permeability when the cells of blue molds were treated withjiean-peptide. And the effect of jiean-peptide on non-growing cells of blue molds wastested. By the spectrophotometer measurement, we found that compounds with lightabsorption at 260 nm and 280 nm were released and amounts increased within 12 hcompared with the control. Moreover, by the ICP measurement, the leakage of K+occurred immediately in the presence of jiean-peptide within 1 h, but with nearly nofurther change after 1 h. All these results indicate that jiean-peptide could change themembrane permeability of blue molds immediately and result in leaking nucleotides,proteins and K+ from cells.