Laminaria gametophyte clone culture and its application in sporeling cultivation   总被引：1，自引：0，他引：1  

Zhou Zhigang  Li Dapeng  Wu Chaoyuan  Liu Haihang 《海洋学报(英文版)》2000,19(2):89-95

IN~UCrIOXIn China, the total annual production of cultivated ham maria japonica reached half milliontons in dry weight these few years. All the sporelings used for artificial cultivation were culturedin greenhouses with controlled temperature. This technique was developed in the mid 1950s(Tseng et al., 1955). The key point of this method is to collect ~spores in summer instead Ofautumn. The garnetophytes and the resulting young sporophytes are cultured at 6 -- 10t generally with sufficient…  相似文献   

A LiDAR-based flood modelling approach for mapping rice cultivation areas in Apalit,Pampanga     

《Applied geography (Sevenoaks, England)》2017

Majority of rice cultivation areas in the Philippines are susceptible to excessive flooding owing to intense rainfall events. The study introduces the use of fine scale flood inundation modelling to map cultivation areas in Apalit, a rice-producing municipality located in the province of Pampanga in the Philippines. The study used a LiDAR-based digital elevation model (DEM), river discharge and rainfall data to generate flood inundation maps using LISFLOOD-FP. By applying spatial analysis, rice cultivation zone maps were derived and four cultivation zones are proposed. In areas where both depth and duration exceed threshold values set in this study, varieties tolerant to stagnant flooding and submergence are highly recommended in Zone 1, where flood conditions are least favorable for any existing traditional lowland irrigation varieties. The study emphasizes that a decline in yield is likely as increasing flood extents and longer submergence periods may cause cultivation areas for traditional irrigated lowland varieties to decrease over time. This decrease in yield may be prevented by using varieties most suitable to the flooding conditions as prescribed in the rice zone classification. The method introduced in this study could facilitate appropriate rice cultivation in flood-prone areas.  相似文献   

Subdivision and fragmentation of land holdings and their implication in desertification in the Thar Desert, India   总被引：1，自引：0，他引：1  

K. Anantha Ram  A. Tsunekawa  D. K. Saha  T. Miyazaki 《Journal of Arid Environments》1999,41(4):463

Analysis of data at the household level in Khabra Kalan village in the Thar desert of India revealed that the land holding size is halved every 20–30 years due to subdivision of land holdings. The subdivision is caused by the equal sharing among sons at the time of inheritance based on the succession laws, and attributed to the increase in the village population. The shrinking land holdings resulted in a shortfall of food on small farms; 12% in cereals and 42% in pulses, promoted continuous cultivation and the increase of monoculture, and deteriorated the land productivity through its effect on the soil fertility and land management.  相似文献   

半干旱地区沙地麻黄人工栽培技术研究     

邵永久  刘立成  于景树 《中国沙漠》1999,19(Z1):127-131

在深入研究麻黄野生生长特性的基础上,对在半干旱沙地开展麻黄人工栽培过程中的苗木繁育、栽培管理等相关的技术问题进行了较深入的研究。结果表明:①1%浓度的尿素溶液和糖液分别可使麻黄种子发芽率提高10%和26.3%,浓度≥3%时对种子发芽不利;②苗木栽植前应用水或50mg·kg^-1生根粉液浸根,浸根后可提高苗木成活率8%~10%;③栽植麻黄最好选择平坦沙壤地,以利麻黄的高产稳产,流动半流动沙地也可种植,但种植前应进行地面防沙处理;④栽植后应加强水肥管理,特别是要适量追施化肥,用量为尿素11.25g·m^-2加二铵11.25g·m^-2;⑤麻黄人工栽植可提高其有效成份麻黄碱含量,改善其品质。  相似文献   

中间球海胆人工育苗附着基改良及不同规格种苗养殖效果的比较     

冯纪虎  田德阳  袁廷柱  袁孟强  郭文剑  王晓娜  黄宝玉  魏磊  刘雅琼  张美溦  韩怡静  张学开  王晓通 《海洋通报》2023,(3):325-333

人工育苗是我国培育中间球海胆养殖业种苗的主要手段,然而传统的海胆附着基的人工育苗效果不尽如人意,尤其是在控制稚胆剥离损伤方面。目前,海上吊笼养殖是中间球海胆人工养殖最主要的养成方式之一,而随着室内工厂化养殖技术的更新和优化,海胆的室内工厂化养殖产业发展迅速并受到广泛关注。为探明以软质塑料膜作为中间球海胆附着基的育苗效果以及不同规格种苗养殖的效果,分别使用硬质波纹板和软质塑料膜作附着基进行中间球海胆人工育苗,并开展了大、小两种规格（壳径分别为0.5 cm和2.0 cm）的海胆种苗室内工厂化养殖和海区养殖研究,旨在明确软质塑料膜替代传统硬质波纹板作海胆育苗附着基的可行性以及中间球海胆室内工厂化养殖和海区养殖效果的优劣。实验结果表明：软质塑料膜在采苗效率方面与波纹板无异,但在促进稚胆生长和提高存活率方面优势显著（p<0.05）;在不同规格中间球海胆种苗的工厂化养殖和海上养成研究中,相同养殖条件下,养殖12月龄的大规格种苗相较于小规格种苗在生长和存活方面优势显著（p<0.05）,同时工厂化养殖能确保更高的养殖成活率和更优的生长性能（p<0.05）,然而中间球海胆的工厂化养殖在...  相似文献   

Methane and nitrous oxide emissions from three paddy rice based cultivation systems in Southwest China   总被引：4，自引：0，他引：4  

江长胜  王跃思  郑循华  朱波  黄耀  郝庆菊 《大气科学进展》2006,23(3):415-424

To understand methane (CH4) and nitrous oxide (N2O) emissions from permanently flooded rice paddy fields and to develop mitigation options, a field experiment was conducted in situ for two years (from late 2002 to early 2005) in three rice-based cultivation systems, which are a permanently flooded rice field cultivated with a single time and followed by a non-rice season (PF), a rice-wheat rotation system (RW) and a rice-rapeseed rotation system (RR) in a hilly area in Southwest China. The results showed that the total CH4 emissions from PF were 646.3±52.1 and 215.0±45.4 kg CH4 hm-2 during the rice-growing period and non-rice period, respectively. Both values were much lower than many previous reports from similar regions in Southwest China. The CH4 emissions in the rice-growing season were more intensive in PF, as compared to RW and RR. Only 33% of the total annual CH4 emission in PF occurred in the non-rice season, though the duration of this season is two times longer than the rice season. The annual mean N2O flux in PF was 4.5±0.6 kg N2O hm-2 yr-1. The N2O emission in the rice-growing season was also more intensive than in the non-rice season, with only 16% of the total annual emission occurring in the non-rice season. The amounts of N2O emission in PF were ignorable compared to the CH4 emission in terms of the global warming potential (GWP). Changing PF to RW or RR not only eliminated CH4 emissions in the non-rice season, but also substantially reduced the CH4 emission during the following rice-growing period (ca. 58%, P<0.05). However, this change in cultivation system substantially increased N2O emissions, especially in the non-rice season, by a factor of 3.7 to 4.5. On the 100-year horizon, the integrated GWP of total annual CH4 and N2O emissions satisfies PF>>RR≈RW. The GWP of PF is higher than that of RW and RR by a factor of 2.6 and 2.7, respectively. Of the total GWP of CH4 and N2O emissions, CH4 emission contributed to 93%, 65% and 59% in PF, RW and RR, respectively. These results suggest that changing PF to RW and RR can substantially reduce not only CH4 emission but also the total GWP of the CH4 and N2O emissions.  相似文献   

猕猴桃栽培的生态气候适应性研究   总被引：8，自引：2，他引：6  

吴战平  谷晓平  徐丹丹  吴登秀 《气象科技》2008,36(6):782-786

对贵州与新西兰主要猕猴桃种植地的生态气候条件进行了相似分析,得出贵州适宜猕猴桃生长发育的初步结论.通过试验和考察,分析了猕猴桃对生态环境的总体要求及主要生育期所需的农业气象指标.遵循农业气候相似理论,确定了分区依据和指标.并综合考虑猕猴桃栽培的生态气候适应性以及地形、地势、海拔等地理因素进行适当的调整,将贵州划分适宜区、次适宜区、不适宜区,并对各区的生态气候条件进行了评述.  相似文献   

中国经济头足类增养殖现状及展望   总被引：1，自引：1，他引：0  

宋旻鹏  汪金海  郑小东 《海洋科学》2018,42(3):149-156

头足类(Cephalopods)是软体动物门的重要组成部分,在中国海洋渔业中占有重要的经济地位。开展头足类增养殖,对于保护中国种质资源、提高头足类产量具有重要意义。本文就目前中国主要的经济头足类,包括金乌贼(Sepia esculenta)、拟目乌贼(S.lycidas)、虎斑乌贼(S.pharaonis)、无针乌贼(Sepiella japonica)、长蛸(Octopus minor)、真蛸(O.vulgaris)以及短蛸(Amphioctopus fangsiao)的繁殖习性、幼体培育、成体养成等各阶段生活史的研究进展和存在问题进行阐述,并对其发展前景进行展望,旨在为中国头足类养殖产业提供借鉴。  相似文献   

基于翻转课堂的三本院校应用型课程教学改革模式的研究     

陈兰兰  肖海平 《测绘通报》2019,(10):142-145

笔者所在院校为地处赣南老区的三本学校，教学中存在师资缺乏、软硬件设施不足、资源共享滞后等问题，严重制约了学院人才培养和专业发展。随着MOOC教学的不断深入和发展，为学院的教学改革、人才培养和师资队伍建设提供了一个新的教学方向。为进一步提高笔者所在院校人才培养质量，培养出适应于社会发展所需的应用型专业技术人才，笔者根据多年的教学工作经验，从学生、教师和学校3个层面，分析并指出了三本院校学生及教师教学中存在的一些问题，设计了基于MOOC平台的教学改革设计方案，提出了教学改革的研究方法和内容，以期为三本院校及应用型本科院校人才培养和课程教学改革提供新思路和新方法。  相似文献   

大型海藻无性系微球体构建和反应器培养研究   总被引：2，自引：0，他引：2       下载免费PDF全文

王金霞  李爱芬  周百成 《海洋科学》2011,35(2):17-21

利用大型海藻细胞的全能性获得了蜈蚣藻(Grateloupia filicina)、多管藻(Polysiphonia urceolata)和孔石莼(Ulva pertusa Kjellm)的无性系材料,在此基础上分别构建了绒球状微球体、网状微球体和簇生状微球体3种微球体形式,这种微球体形式适合于大型海藻的生物反应器高密度...  相似文献