现代水产种业硅谷建设的几点思考   总被引：3，自引：1，他引：2  

杨红生 《海洋科学》2018,42(10):1-7

"国以农为本,农以种为先",种业位于农业产业链的最前端,是国家战略性、基础性产业,也是决定现代农业发展的核心要素。我国是世界上12个生物多样性特别丰富的国家之一,水产种质资源分布极为广泛。近年来,我国水产种业发展迅速,但水产增养殖业的良种覆盖率仍然较低。因此,加快发展水产种业尤显迫切。该文论述了国内外水产种业发展现状,分析了我国水产种业存在的问题和发展趋势,提出了建设水产种业硅谷的设想,并对建设目标、建设内容、建设原则及其保障措施提出了几点建议,以期为我国水产种业健康发展起到积极的促进作用。  相似文献   

Soil seed bank composition and distribution on eroded slopes in the hill‐gully Loess Plateau region (China): influence on natural vegetation colonization     

Ning Wang  Ju‐Ying Jiao  Yan‐Feng Jia  Xiao‐an Zhang 《地球表面变化过程与地形》2011,36(13):1825-1835

On the Chinese Loess Plateau, serious slope and gully erosion have caused a decrease in soil water capacity and fertility, which has resulted in vegetation degradation and a reduction in agricultural productivity. Great efforts have been made to restore vegetation to control soil erosion, but the efficiency of artificial revegetation is not satisfactory. Natural revegetation is an alternative. However, while soil seed banks are an essential source for natural revegetation, their composition and distribution on eroded slopes remains unknown. In addition, whether or not seed loss during soil erosion limits vegetation colonization is also unknown. In this work, soil seed bank composition and distribution were studied in three situations. Specifically, three main microsites were selected as sampling plots: fish‐scale pits, as artificial deposited micro‐topography; under tussocks, as trap microsites; and open areas, as eroded areas. Soil samples were collected at depths of 0–2 cm, 2–5 cm and 5–10 cm. The soil seed bank was identified using germination experiments, and a total of 34 species were identified. The dominant species in the soil seed bank were annual/biennial herbs with an average proportion more than 90% and density reaching 19,000 seeds m^‐2. The pioneer species Artemisia scoparia was especially abundant. The dominant later successional species, such as Lespedeza davurica, Artemisia giraldii, Artemisia gmelinii, Stipa bungeana and Bothriochloa ischcemum, were present in the soil at a density that ranged from 38 to 1355 seeds m^‐2. Compared with the eroded open areas, the fish‐scale pits retained a higher density of seeds, and the tussocks retained a larger number of species. However, there was no serious reduction of the soil seed bank in the erosion areas. The present study indicates that, on these eroded slopes, the soil seed bank is not the key factor limiting the colonization of natural vegetation. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Influence of temperature and salinity on germination of eelgrass (Zostera marina L.) seeds     

Jinhua Pan  Xin Jiang  Xiaojie Li  Yizhou Cong  Zhuangzhi Zhang  Zhiling Li  Weili Zhou  Houwei Han  Shiju Luo  Guanpin Yang 《中国海洋大学学报(英文版)》2011,10(2):147-152

Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years. Seed broadcasting has been widely accepted as the most potentially useful method for seagrass restoration over large areas. We examined the influence of key environmental factors on seed germination to help promote eelgrass bed restoration. Under anoxic conditions, the influence of temperature and salinity on the germination rate of eelgrass (Zostera marina L.) seeds was examined at different combinations of four temperatures (4, 9, 14, and 24°C) and nine salinities (5 to 45, increment of 5). The effect of significant interaction of temperature and salinity on germination rate was observed (ANOVA) (P<0.001). The highest germination rate (83.3 ± 3.5)% was reached in 8 weeks at 14°C and salinity 5. Higher temperature significantly increased the germination rate at salinity 5 (P<0.001) during the whole observation period except for 24°C, while lower salinity significantly increased the germination rate at 14°C (P<0.001). Although significant interaction was found between temperature and salinity (P<0.001), the influence of salinity was stronger than that of temperature for the germination of eelgrass seeds. These results provide useful information for the propagation of artificial seedlings for seagrass restoration in China.  相似文献   

Geographical variation on cone and seed production of natural Pinus halepensis Mill. forests in Tunisia     

A. Ayari  D. MoyaM.N. Rejeb  A. Ben MansouraA. Albouchi  J. De Las HerasT. Fezzani  B. Henchi 《Journal of Arid Environments》2011,75(5):403-410

Aleppo pine (Pinus halepensis Mill.) is found in discontinuous bands along the Mediterranean Basin, usually at low elevations and in dry climates. This study was conducted to relate bioclimatic zones and geographic distribution with representative individual tree of populations for cone number and weight from the driest to the wettest Aleppo pine forest zones. Epidometric values were recorded in all sample stands in the monitoring plots set in 79 native populations from the Algerian border to the eastern coast of Tunisia, representing a wide range from each region in northern Africa. Simple and multiple regressions were performed on the data. Results showed that the canopy seed bank increased according to elevation, latitudinal and longitudinal gradients. The simple regression analysis showed a latitudinal effect positively relating increasing latitude to greater cone crop. Similarly, longitudinal and elevation variations were related to significant differences in cone dimensions. Higher average seed mass was related to populations located westwards or at higher elevation. The multiple regression analysis indicated that the longitudinal variations were the most determinant geo-positional factors in Aleppo pine cone dimensions and average seed mass in natural Aleppo pine forests in Tunisia.  相似文献   

荒漠植物苦豆子和苦马豆种子硬实特性与活力关系研究     

王进  罗光宏  颜霞  陈叶  白生文 《中国沙漠》2011,30(4):974-980

 以荒漠边缘采集的苦豆子和苦马豆种子为材料,研究其硬实特性及其与活力的关系。结果表明,每日内吸胀的种子数量随时间推移,以一定比列下降,苦豆子非硬实种子吸胀速率较缓慢,第10天后吸胀率降到1%,苦马豆非硬实种子第3天后下降到1%,第13—16天突然上升后又下降到1%。两种豆类种子都显示出硬实种子发芽率、发芽指数、活力指数、脱氢酶、呼吸速率、超氧化物歧化酶(SOD)均高于非硬实种子,而电导率、浸出液可溶性糖和丙二醛(MDA)低于非硬实种子,缓慢吸胀的硬实种子活力指标高于快速吸胀的硬实种子,这表明硬实种子吸胀过程中存在吸胀损伤。而在非硬实种子中,根据以上活力指标判断,晚吸胀的种子比早吸胀的种子活力高。  相似文献   

The convection cooling system of the Yakutsk permafrost seed repository     

Vladimir N. Panin  Georgii P. Kuzmin 《寒旱区科学》2014,6(4):0309-0313

Temperature is critical to maintaining seed viability under long-term storage conditions. It has been common practice to use refrigeration systems to maintain required storage temperatures. A seed repository constructed in permafrost in Yakutsk, Russia is the first seed storage facility that relies solely on natural cold. This paper describes the design and performance of the cooling system of the repository. An innovative aspect of the cooling system is that it utilizes the patterns of temperature wave propagation in permafrost. Predicted and measured ground temperatures for the first year of operation are presented and analyzed. Results indicate that convection air cooling systems can be used to control the temperature regime in underground facilities in permafrost.  相似文献   

Effects of the grazing systems on germinable soil seed bank of desert steppe   总被引：1，自引：0，他引：1  

RuiRui Yan  ZhiJun Wei  XiaoPing Xin  HongMei Liu  Jing Yang  Qiqige Wuren 《寒旱区科学》2012,4(1):0040-0045

We studied a soil seed bank in the Stipa breviflora desert steppe under three grassland management systems, namely continuous grazing, rotational grazing, and no grazing, from 1999 until 2007. The germinable seed bank species in rotational, continuous and no grazing were 11, 9 and 8 species, respectively. Rotational grazing increased the number of seed bank plant species and perennial grasses. The density of germinal soil seed bank was significantly higher in the enclosed area (19,533.33 seeds/m²) than those in rotational (3,233.33 seeds/m²) and continuous grazing areas (2,553.60 seeds/m²). The vertical distribution of the soil seed bank had a similar trend: 75.06%–83.19% of the seeds are distributed in the top 0–5 cm soil layer, 14.16%–21.68% in the 5–10 cm layer, and 2.65%–4.95% in the 10–15 cm layer, which varied between the grazing treatments. Density of the soil seed bank was significantly higher in the enclosed area, and there was no significant difference between rotational and continuous grazing. The Margalef and Shannon-Wiener indices for the soil seed bank were higher for rotational grazing treatment than for continuous grazing. The Sorensen’s similarity index for the soil seed bank between the enclosed and rotational grazing areas reached 0.857.  相似文献   

不同衬底材料上外延金刚石的研究     

满卫东  吕继磊  吴宇琼  陈朋  朱金凤  董维  汪建华 《地质科学译丛》2010,(4):6-11

利用自制的5kW微波等离子体化学气相沉积（MPCVD）装置对在不同衬底材料上外延生长的CVD金刚石进行了研究。利用HPHT金刚石、CVD异质形核生长的金刚石及Ia型天然金刚石样品作为籽晶,分析了不同CH4浓度与基片温度对外延CVD金刚石的影响以及通过扫描电子显微镜表征了CVD金刚石外延面的表面形貌。结果发现,HPHT金刚石为籽晶,由于其自身缺陷导致外延效果不佳;CVD异质形核生长的衬底因形核阶段的晶面生长难以控制而使其外延面较粗糙;经打磨的Ia型天然金刚石才是理想的籽晶。当CH4浓度约为10%、基片温度为1020℃时,CVD金刚石的外延生长速率可达到70.0μm/h。  相似文献   

Factors Influencing Species Composition in Canopy Gaps: The Importance of Edge Proximity in Hueston Woods,Ohio     

《The Professional geographer》2013,65(2):165-178

In this research, we attempt to quantify the factors structuring woody species composition within forest gaps in the interior of Hueston Woods Nature Preserve, Ohio. Our results indicate that composition is related not only to factors commonly cited in other studies, including disturbance history, topographic position, and environmental factors (e.g., gap age, soil pH, slope, and aspect), but also to the proximity of forest edge communities. Partitioning of species variation to environmental factors, spatial factors, and spatially structured environmental factors reinforces the importance of both environment and edge proximity in explaining gap composition. These findings underscore the need for a more complete understanding of the potential impacts of edge effects in fragmented landscapes.  相似文献   

Plant Seeds as Model Vectors for the Transfer of Life Through Space   总被引：1，自引：0，他引：1  

David Tepfer  Sydney Leach 《Astrophysics and Space Science》2006,306(1-2):69-75

We consider plant seeds as terrestrial models for a vectored life form that could protect biological information in space. Seeds consist of maternal tissue surrounding and protecting an embryo. Some seeds resist deleterious conditions found in space: ultra low vacuum, extreme temperatures and radiation, including intense UV light. In a receptive environment, seeds could liberate a viable embryo, viable higher cells or a viable free-living organism (an endosymbiont or endophyte). Even if viability is lost, seeds still contain functional macro and small molecules (DNA, RNA, proteins, amino acids, lipids, etc.) that could provide the chemical basis for starting or modifying life. The possible release of endophytes or endosymbionts from a seed-like space traveler suggests that multiple domains of life, defined in DNA sequence phylogenies, could be disseminated simultaneously from Earth. We consider the possibility of exospermia, the outward transfer of life, as well as introspermia, the inward transfer of life–both as a contemporary and ancient events.  相似文献