水位波动的幅度与频率对刺苦草(Vallisneria spinulosa)生物量和形态特征的影响     

丁明明  黎磊  金斌松  陈家宽 《湖泊科学》2021,33(1):192-203

沉水植物是维持浅水湖泊清水稳态以及湖泊生态系统结构与功能的关键生物类群.近年来,气候变化和人类活动的双重作用造成湖泊水文情势的明显改变,对沉水植物的生长、繁殖和演替有着较大的影响.本文选取2个水位波动幅度与2个波动频率(逐渐改变水位),以恒定水位作为对照,研究湿地中具有重要生态功能的沉水植物刺苦草(Vallisneria spinulosa)的生物量及地上和地下营养器官形态结构对水位波动的响应.结果表明,相对于恒定水位,波动水位(低幅度低频率、低幅度高频率、高幅度低频率、高幅度高频率)对刺苦草的总生物量和获取限制资源相关器官有显著影响.相比于对照组,水位波动能够显著降低刺苦草分株数、叶片数、根数、根长、匍匐茎数、总匍匐茎长以及叶、根、地上和地下生物量,但会显著增加其株高和比叶面积.不同波动频率(低频率和高频率)和幅度(低幅度和高幅度)对光合器官的形态特征都没有显著影响,但叶和地上部分的生物量积累均受到波动幅度的显著影响.水位波动幅度显著改变了刺苦草的根数和根长,而波动频率的影响不显著.因此,对浅水湖泊受损刺苦草群落进行重建时,应避免较大幅度的水位波动,从而有利于增强植株快速恢复的能力.  相似文献   

不同盐度下鲈鱼稚鱼鳃的显微结构观察   总被引：5，自引：0，他引：5  

王艳  胡先成 《海洋科学》2009,33(12):138-142

采用石蜡切片和显微摄影技术,研究了不同盐度下鲈鱼(Lateolabrax japonicus)稚鱼鳃的显微结构.结果显示,在15.00盐度组,稚鱼鳃的鳃丝和鳃小片上泌氯细胞数量较多,泌氯细胞集中分布在鳃小片基部,且黏液细胞较多.与15.00盐度组和淡水组相比,7.50盐度组稚鱼鳃的鳃小片较窄,泌氯细胞的分布、结构及数量变化均不明显.在0.00盐度组,稚鱼鳃中鳃小片较宽,排列紧密,泌氯细胞数量较少,且主要分布在近鳃小片基部.鲈鱼稚鱼鳃的结构能够适应外界水体盐度的变化,其中泌氯细胞的结构和数量变化是与鲈鱼稚鱼所处的环境相适应的.  相似文献   

文蛤多肽体外对人肺癌A549细胞的抑制作用     

康劲翮  任跃明  李华亮  范成成  张剑  邱乒乒  陈清西 《台湾海峡》2009,28(4):477-481

我们已从文蛤肉中提取得到1种具有抗癌活性的多肽,命名为Mer2．本文报道Mer2对体外培养的肺癌A549细胞的生物学效应．采用溴化二苯偶氮盐（MTT）法检测Mer2对肺癌A549细胞的抑制效果,并应用细胞形态观察法、Hoechst荧光染色和流式细胞术等方法,探讨了Mer2对细胞形态、细胞周期的影响．结果表明,Mer2对体外培养的肺癌A549细胞的生长有较强的抑制作用,对作用含量和时间均具有一定的依赖性．Met2使细胞形态发生明显变化,明显地出现凋亡峰,但并没有出现明显细胞周期阻滞现象．这表明文蛤多肽可能通过诱导细胞凋亡从而抑制癌细胞的生长．  相似文献   

近江牡蛎鳃细胞的原代培养     

王彬  张其中 《海洋科学》2010,34(6):1-5

采用改良的DMEM(HG)培养基,建立了近江牡蛎(Crassostrea hongkongensis)鳃细胞体外培养技术,包括鳃组织块培养法和胰酶消化培养法。结果表明,组织块培养法接种6 h后,细胞开始从组织块中迁出,细胞形态较小,呈圆形、椭圆形或多边形,直径3～6μm。培养至3 d时,细胞在组织块周围形成生长晕。培养至6 d时可进行细胞传代,本次实验细胞已传至第6代。胰酶消化法接种约2 h后,细胞逐渐贴壁,从形态上主要分为两类,一类为小型细胞,形态为圆形、椭圆形或多边形,直径3～6μm,数量多,增殖速度较快;另一类为大型细胞,形态为圆形、椭圆形或多边形,直径10～20μm,部分细胞内部含有颗粒,数量较少,增殖速度较慢。培养至2 d时可进行细胞传代,传代培养物中的优势细胞皆为小型细胞。本次实验细胞已传至第6代。  相似文献   

Sediment burial stimulates the growth and propagule production of Spartina alterniflora Loisel.     

Zifa Deng  Shuqing An  Congjiao Zhao  Lin Chen  Changfang Zhou  Yingbiao Zhi  Hongli Li 《Estuarine, Coastal and Shelf Science》2008,76(4):818-826

Spartina alterniflora Loisel., an extensively invasive species on the Chinese coast, is a focus of increasing management concern due to its high expansion rate in estuaries and tidal zone, and the significant damage it causes to native ecosystems. In order to understand the processes and mechanisms of invasion of S. alterniflora in China, the impact of three sediment types (sand, sand–loam mixture and loam) and five buried patterns (unburied, 50% burial of initial plant height, 75% burial of initial plant height, complete burial and repeated burial) on the growth of seedlings or ramets was investigated. Results showed that each of the three factors (sediment types, burial pattern and plant materials) and interactions between/among them, significantly affected height and clonal growth, and biomass accumulation and allocation. Plant height, total biomass and number of new vegetative propagules significantly increased with progressive burial treatments. However, the complete burial treatment resulted in the death of all plant materials, and the maximum values of three parameters were found in the 50% burial or repeated burial treatments. Plant responses were determined by the instantaneous thickness of sediment of each time burial rather than by the total quantity of repeated burial. The growth of S. alterniflora was not shown to be dependent on specific types of sediment in sedimentation environment. In contrast to the unburied control, the proportion of primary tillers produced directly from initial individuals and the ratio between the aboveground and belowground biomass were greater under burial treatments. Seedlings produced more new vegetative propagules than vegetative offspring in all experimental treatments, and the former were apt to produce ramets from rhizomes rather than primary tillers. It is concluded that under various sedimentation environments, the clonal spread efficiency of seedlings was higher than that of vegetative offspring, and there is a positive feedback relationship between sedimentation and the growth of S. alterniflora. Thus, moderate sedimentation may stimulate the invasion of exotic species, S. alterniflora in coastal China.  相似文献   

Sediment deposition and overland flow hydraulics in simulated vegetative filter strips under varying vegetation covers          下载免费PDF全文

Chun‐hong Zhao  Jian‐en Gao  Meng‐jie Zhang  Fei Wang  Tong Zhang 《水文研究》2016,30(2):163-175

Vegetative filter strips (VFSs) can effectively trap sediment in overland flow, but little information is available on its performance in controlling high‐concentration sediment and the runoff hydraulics in VFS. Flume experiments were conducted to investigate the sediment deposition, hydraulics of overland flow and their relationships in simulating VFS under a great range of sediment concentrations with four levels of vegetation cover (bare slope and 4%, 11% and 17%) and two flow rates (15 and 30 L min^?1). Sediment concentrations varied from 30 to 400 kg m^?3 and slope gradient was 9°. Both the deposited sediment load and deposition efficiency in VFS increased as the vegetation cover increased. Sediment concentration had a positive effect on the deposited load but no effect on deposition efficiency. A lower flow rate corresponded to greater deposition efficiency but had little effect on deposited load. Flow velocities decreased as vegetation cover increased. Sediment concentration had a negative effect on the mean velocity but no effect on surface velocity. Hydraulic resistance increased as the vegetation cover and sediment concentration increased. Sediment deposition efficiency had a much more pronounced relationship with overland flow hydraulics compared with deposited load, especially with the mean flow velocity, and there was a power relationship between them. Flow regime also affected the sediment deposition efficiency, and the efficiency was much higher under subcritical than supercritical flow. The results will be useful for the design of VFS and the control of sediment flowing into rivers in areas with serious soil erosion. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

水杨酸通过提高抗氧化酶系统活力增强拟南芥悬浮细胞的耐寒性     

石玉兰  陈宣  岳君  安黎哲  李新荣  陈国雄 《冰川冻土》2010,32(6)

与未经水杨酸(SA)处理的低温对照相比,0.1 mmol.L-1SA处理提高了拟南芥悬浮细胞在整个低温胁迫期间超氧化物歧化酶(SOD),过氧化物酶(POD)和过氧化氢酶(CAT)的活性,并在低温胁迫初期提高了细胞抗坏血酸过氧化物酶(APX)的活性.在抗氧化酶系统活力提升的同时,还伴随着相对电导率的降低和丙二醛(MDA)含量的减少,即细胞膜状态的恢复.相关性研究显示,膜状态的恢复与抗氧化酶系统中各类酶活力的增加呈显著正相关.上述结果表明,SA可以通过提高拟南芥悬浮细胞的抗氧化酶系统活力避免氧化损伤,从而协助膜系统在低温胁迫下的自我恢复,使细胞抗寒性得以增强.  相似文献   

Effects of Basic Fibroblast Growth Factor and Insulin-like Growth Factor on Cultured Cartilage Cells from Skate Raja porasa   总被引：1，自引：0，他引：1  

樊廷俊  晋凌云  汪小锋 《中国海洋湖沼学报》2003,21(4):305-311

Effects of basic fibroblast growth factor (bFGF) and insulin-like growth factor Ⅱ(IGF-Ⅱ) on cartilage cells from proboscis of skate, Raja porasa Glinther, were investigated in this study. The cartilage cells were cultured in 20% FBS-supplemented MEM medium at 24℃. Twelve hours after culture initiation, the cartilage cells were treated with bFGF and IGF-Ⅱ at different concentration combinations. It was found that 20 ng/ml of bFGF or 80 ng/ml of IGF-Ⅱ was enough to have obvious stimulating effect on the growth and division of skate cartilage cells. Test of bFGF and IGF-Ⅱ together, revealed that 20 ng/ml of bFGF and 80 ng/ml of IGF-Ⅱ together had the best stimulating effect on the growth and division of skate cartilage cells. The cartilage cells cultured could form a monolayer at day 7.  相似文献   

Upper-bound general circulation of coupled ocean–atmosphere: Part 1. Atmosphere     

《Dynamics of Atmospheres and Oceans》2013

We consider the general atmospheric circulation within the deductive framework of our climate theory. The preceding three parts of this theory have reduced the troposphere to the tropical and polar air masses and determined their temperature and the surface latitude of their dividing boundary, which provide the prior thermal constraint for the present dynamical derivation. Drawing upon its similar material conservation as the thermal property, the (columnar) potential vorticity (PV) is assumed homogenized as well in air masses, which moreover has a zero tropical value owing to the hemispheric symmetry. Inverting this PV field produces an upper-bound zonal wind that resembles the prevailing wind, suggesting that the latter may be explained as the maximum macroscopic motion extractable by random eddies – within the confine of the thermal differentiation.With the polar front determined in conjunction with the zonal wind, the approximate leveling of the isobars at the surface and high aloft specifies the tropopause, which is colder and higher in the tropics than in the polar region. The zonal wind drives the meridional circulation via the Ekman dynamics, and the preeminence of the Hadley cell stems from the singular Ekman convergence at the equator that allows it to supply the upward mass flux in the ITCZ demanded by the global energy balance.  相似文献   

基于机载Ka波段云雷达和粒子测量系统同步观测的积层混合云对流泡特征     

张佃国  王烁  郭学良  王洪  樊明月 《大气科学》2020,44(5):1023-1038

利用机载Ka波段云雷达（Airborne Ka-Band Precipitation Cloud Radar, KPR）和粒子测量系统（Droplet Measurement Technologies, DMT）,分析了2018年4月22日黄淮气旋背景系统下积层混合云中对流泡的动力和微物理特征。首先,对Ka波段云雷达观测的山东地区春季36个对流泡样本按照回波强度、水平尺度、回波顶高三个参量进行统计,结果表明平均回波强度为20～30 dBZ的对流泡占69%。对流泡水平尺度为15～30 km,占61%。对流泡最大回波顶高集中在6～8 km,比周边层云高2～4 km。之后,对4月22日积层混合云中的对流泡个例微物理参数进行统计,结果表明对流泡内部以上升气流为主,最大上升气流速度达到1.35 m s?1,平均上升气流速度为0.22 m s?1;对流泡内过冷水含量比较高,最大含水量为0.34 g m?3,平均含水量为0.15 g m?3。对流泡内冰晶数浓度是泡外的5.5倍,平均直径是泡外的1.7倍。结合云粒子图像探头,发现对流泡前沿和尾部冰粒子以柱状和辐枝状为主,而对流泡核心区域冰粒子以聚合体形式存在。冰粒子通过凇附过程和碰并过程增长,过冷水含量不足时冰粒子的凇附增长形成柱状粒子,含量充足时可迅速凇附成霰粒子。对流泡内降水形成的微物理机制不完全相同,主要依赖过冷水含量。当云中有充足的过冷水分布时,高层冰晶通过凇附增长形成霰粒子,通过融化层后形成降水;当云中缺少过冷水时,降水的形成主要通过水汽凝华过程形成冰雪晶,然后雪晶通过聚合过程实现增长。  相似文献