水生植物对水体中营养因子作用的响应     

傅明辉  陈海林  李园枚 《海洋湖沼通报》2012,(2):142-150

水生植物在水生态系统中具有重要作用,水体中营养因子会影响水生植物的生理生化。本文综述了水生植物在生长生理和分子生理方面对水体中营养因子作用的响应,揭示植物适应营养环境的生理和分子机制。这方面的研究能够为水体生态系统的保护和水生植物的开发和利用提供理论基础。  相似文献   

我国荒漠植被中的C4植物种类分布及其与气候的关系     

苏培玺  解婷婷  周紫鹃 《中国沙漠》2011,31(2):267-276

C4植物水分利用效率高于C3植物,CAM植物具有最高的水分利用效率。在我国荒漠地区,CAM植物稀少,C4植物,特别是C4木本植物在荒漠生态系统中具有重要地位和作用。我国荒漠地区有C4木本植物45种,包括半木本植物,占我国荒漠植物总种数的6%,集中在藜科和蓼科,分别为19种和26种。C4草本植物共计107种,其中单子叶植物48种,双子叶植物59种。C4木本植物主要分布在贺兰山以西的西北干旱荒漠区。C4草本植物的耐旱性和抗旱能力不如C4木本植物,主要分布在荒漠地区潜水埋深较浅,水分条件较好的区域,在绿洲边缘广泛分布。C4木本植物丰度与干旱紧密相关,C4草本植物丰度随湿润条件而增加。  相似文献   

岩溶区和非岩溶区玉米光合作用与锌含量和碳酸酐酶关系的对比研究   总被引：3，自引：0，他引：3  

杨霄  刘再华  曹建华  张云鸽 《中国岩溶》2008,27(2):103-107

采用田间试验方法对比研究岩溶区和非岩溶区玉米叶片光合作用与锌含量和碳酸酐酶活性的关系, 结果表明: 岩溶区施加有机肥的土壤有效锌和玉米叶片锌含量均高于非岩溶区,岩溶区和非岩溶区的玉米叶片的锌含量分别为47. 85mg /kg 和43. 35 mg /kg ;岩溶区玉米叶片的碳酸酐酶活性和光合作用也高于非岩溶区,岩溶区的碳酸酐酶活性平均为5. 622U,非岩溶区的碳酸酐酶活性平均为3. 485U;碳酸酐酶活性随玉米叶片的锌含量增加而提高,而玉米光合作用效率随碳酸酐酶活性增加而提高,反映了土壤锌含量对玉米叶片锌含量、碳酸酐酶活性和光合作用的控制。   相似文献   

Relative influence of biotic and abiotic processes on travertine fabrics,Satono‐yu hot spring,Japan     

Fumito Shiraishi  Yuki Eno  Yuki Nakamura  Yusaku Hanzawa  Jiro Asada  Anelize Manuela Bahniuk 《Sedimentology》2019,66(2):459-479

The relative influences of biotic and abiotic processes on travertine fabrics are still not well understood, despite increasing interest in the last decade to better understand the record of ancient microbial life and sedimentary fabrics in microbial hydrocarbon reservoirs. This study examines travertines at Satono‐yu hot spring in Japan (the temperature of water flowing over the travertine was ca 35°C), to better understand the interaction between depositional, hydrochemical and microbial parameters at different flow settings. Characteristics of the bulk hydrochemistry, mineralogy (exclusively aragonite) and the driving force for precipitation (primarily abiotic CO₂ degassing with some photosynthetic microbial contribution) were similar among all of the flow settings. Conversely, the increase in flow velocity suppressed the influence of photosynthesis and enhanced the abiotic precipitation due to the thinner diffusive boundary layer at the travertine surface–water interface. Additionally, the increase in flow velocity changed the microbial composition and decreased the bacterial diversity by reflecting their adhesion efficiency on the travertine substrate. The acidity of the cyanobacterial sheaths controls the aragonite nucleation rate and the resulting calcification, even at significantly high equilibrium CO₂ partial pressure (ca 22 to 28 matm), high dissolved inorganic carbon concentration (ca 35 to 38 mmol l^?1), and elevated aragonite saturation state (ca 20‐fold to 34‐fold). Therefore, the increase in flow velocity suppresses the microbial influence with respect to the increase in the saturation state, the nucleation site supply and pore space generation. Overall, this results in the predominance of abiotic precipitation under high flow velocities. Consequently, a sparse‐micritic fabric with abundant interlamina porosity forms under lower flow velocity where the microbial influence is effective, while a dense‐sparitic fabric with little inter‐crystalline porosity forms under higher flow velocity where abiotic precipitation prevails. These findings provide an essential base for assessing the formation processes of ancient travertines and comparable deposits from petrological fabrics.  相似文献   

荒漠植物红砂在持续干旱胁迫下的光保护机制研究   总被引：10，自引：7，他引：3  

周生荟  刘玉冰  谭会娟  王进 《中国沙漠》2010,30(1):69-73

红砂（Reaumuria soogorica）是一种广泛分布于中国半荒漠地区的多年生半灌木,自然生境下具有很强的耐旱、耐高温和高辐射的能力。本实验在人为控制水分进行持续干旱胁迫的过程中,通过测定红砂的气体交换和叶绿素荧光参数的日变化来研究红砂干旱胁迫下的光保护机制。结果表明,土壤相对含水量下降的过程中,红砂叶片水势也相应地下降;净光合速率（Pn）的日变化由‘双峰型’逐渐趋向‘单峰型’;水分利用效率（WUE）随着干旱程度的增加而升高,植物接近休眠时下降;净光合速率 (Pn)、PSⅡ最大光化学效率 (Fv/Fm)和PSⅡ非循环式电子传递效率(ΦPSⅡ)在中午都明显降低;干旱胁迫下初始荧光(F0)出现明显的升高,日变化趋势为先上升后下降。说明红砂在干旱期间,采取了依赖于叶黄素循环的热能耗散和PSⅡ反应中心可逆失活两种光抑制的保护机制来度过干旱维持生存。  相似文献   

生态系统氮磷比化学计量特征研究进展   总被引：11，自引：4，他引：7  

邬畏  何兴东  周启星 《中国沙漠》2010,30(2):296-302

通过对国内外关于氮磷比化学计量特征研究文献的大量阅读,总结了在陆地生态系统和水域生态系统中氮磷比化学计量特征的意义。在陆地生态系统中,土壤中的氮磷比与固氮共生体及非共生体的生物固氮量呈反比例关系;土壤中的氮磷比化学计量特征发生变化会影响植被动态;土壤中氮磷比化学计量特征的变化对物种多样性及生产力产生影响,尤其是磷限制濒危物种的生产力及丰富度;植物体中的氮磷比化学计量特征可以体现氮和磷两种营养元素的供应状况及相对有效性,对植被恢复和濒危物种管理工作起到重要作用。在水域生态系统中,水体中的氮磷比与水生生物的固氮量呈反比例关系,并且会影响水生植物的生长及水生生物群落的组成。  相似文献   

Effect of submerged aquatic vegetation on turbulence induced by an oscillating grid   总被引：1，自引：0，他引：1  

Dolors Pujol  Jordi ColomerTeresa Serra  Xavier Casamitjana 《Continental Shelf Research》2010

In wetlands wind-induced turbulence significantly affects the bottom boundary, and the interaction between turbulence and plant canopies is therefore particularly important. The aim of this study is to advance understanding of the impact of this interaction in submerged aquatic vegetation (SAV)¹ on vertical mixing in a fluid dominated by turbulence. Wind-generated turbulence was simulated in the laboratory using an oscillating grid. We quantify the vertical distribution of turbulent kinetic energy (TKE)² above and within different types of vegetation, measured by an acoustic Doppler velocimeter. Experimental conditions are analysed in two canopy models (rigid and semi-rigid) with seven solid plant fractions (SPFs)³, three stem diameters (d)⁴ and three oscillation grid frequencies (f)⁵ and four natural SAVs (Cladium mariscus, Potamogeton nodosus, Myriophyllum verticillatum and Ruppia maritima).  相似文献   

Overwintering of Vaccinium vitis-idaea in two sub-Arctic microhabitats: a reciprocal transplantation experiment     

Timo Saarinen  & Robin Lundell 《Polar research》2010,29(1):38-45

Northern plants have to cope with a wide range of overwintering conditions, as the depth and physical properties of snow show high spatial variation in the Arctic. The overwintering of lingonberry ( Vaccinium vitis-idaea ) was studied in a reciprocal transplantation experiment between two sub-Arctic microhabitats in northern Finland. The experiment was set up in the autumn, and physiological traits related to overwintering were measured at the time of snowmelt in the following spring. The origin of the plants was not a significant source of variation for most of the traits measured, whereas major differences were observed between the two sites. Plants that overwintered at an exposed site above the treeline showed high relative winter damage, assessed by the electrolyte leakage of the leaves. No severe winter damage was observed in the plants that overwintered under a moderate snowpack at a sheltered birch forest site. These plants were able to maintain their photosynthetic capacity through the winter. A low capacity of photosystem II and a very low capacity of CO₂ uptake were characteristic of the exposed site, where low temperatures and high irradiation predominate during late winter. However, photosynthetic capacity was recovered within a few days when the plants were kept under favourable conditions after the field experiment. The content of nonstructural carbohydrates was low, probably because of high respiratory losses under the snow. This short-term study suggests that lingonberry, which occupies a wide range of microhabitats in the present climate, may thrive even if the overwintering conditions change as a result of climatic warming.  相似文献   

可追溯的水产品流通体系建设问题探讨     

潘澜澜  高天一  慕光宇  薛冬娟 《广东海洋大学学报》2010,30(5)

中国建立可追溯的水产品流通体系非常迫切,批发市场的流通主导地位,其本身设备及监管的局限性制约着可追溯的水产品流通体系的建设。提出应用One-up-one-down可追溯原则建立可追溯的水产品流通体系。通过建立可追溯监管法规约束水产品流通主体,并从标签的规定、信息的记录和追溯凭证方面实施可追溯的水产品流通体系。  相似文献   

Studies on photoprotective mechanism of desert plant Reaumuria soongorica under progressive soil drying     

YuBing Liu  MeiLing Liu  HuiJuan Tan  Jin Wang  ShengHui Zhou 《寒旱区科学》2010,2(3):0235-0240

Reaumuria soongorica (pall.) Maxim, a perennial desert semi-shrub, is widely found in semi-arid areas of China. It shows strong tolerance to drought, high temperature and intense radiation in its natural habitat. In the present study, photoprotective mechanism of R. soongorica was investigated by analyzing diurnal variations of gas exchange and chlorophyll fluorecence parameters during progressive soil drying. The results show that leaf water potential of R. soongorica decreased when the soil water content dropped. Diurnal patterns of net photosynthetic rate (Pn) changed from "two peaks" to "one peak" under drought stress, and the leaf water use efficiency (WUE) increased under moderate drought and declined under severe drought. Pn , the primary maximum photochemical efficiency of PSII (Fv/Fm) and the quantum efficiency of non-cyclic electron transport of PSII (ΦPSII) decreased obviously at noon, and showed a photoinhibition phenomenon. But, the non-photochemical quenching of fluorescence (NPQ) soon reached its maximum in the day and then remained almost at the high level until 17:00, indicating that the xanthophylls cycle-dependent thermal energy dissipation played an important role. Diurnal variations of the original chlorophyll fluorescence (Fo) increased at first and then decreased. The increased value of F o under drought stress indicates that there was a reversible inactivation of PSII reaction center. These results indicate that the photoprotective mechanism in R. soongorica was the photoinhibition by using both the xanthophylls cycle-dependent thermal energy dissipation and the reversible inactivation of PSII reaction center under drought stress.  相似文献