继代培养十年后玉米单倍性胚性细胞系的倍性和再生

本文观查了玉米单倍性胚性细胞无性系在继代培养十年中的分化再生能力,测定了十年后染色体的倍性,并用t测验和相关系数进行统计分析,结果表明,继代培养十年后,供试的二个单倍体细胞系和二个加倍单倍体细胞系的分化再生能力无显著变化,仍基本保持稳定。单倍体细胞和二倍体细胞的数量虽有所下降,但仍占优势。它们对细胞系的分化再生能力无明显影响,r为0.329,相关不显著。亚单倍体细胞尚未见到,但出现了一定数量的多倍体细胞。它们与非整倍体细胞所占的比例与细胞系分化率之间的相关系数为-O.786。呈弱负相关,即其数量的增加对细胞系的分化能力有一定影响。     

种子企业持久技术创新能力的构建与保持

结合多年的工作实践,探讨了如何构建和保持种业企业技术创新能力,进而形成企业持久核心竞争力,保障企业持续健康发展的方法。     

根瘤菌类菌体的繁殖能力 Ⅱ、在大豆Glycine max(L.)Merr.根瘤中

采用单个原生质体分离和微室培养技术对大豆根瘤类菌体繁殖能力作了研究。结果表明:(1)大豆根瘤原生质体由内含多个类菌体的小胞囊组成。从不同年龄的根瘤中可以区分出:未成熟的细长杆状类菌体,主要存在于幼小根瘤中,以及成熟的与培养体相似的杆状类菌体,主要存在于成熟根瘤之中。(2)采用微室培养技术,在显微镜下直接观察并用磁带录像记录到成熟的大豆根瘤类菌体的分裂和微菌落的形成。(3)类菌体的繁殖率,由二周的<0.01%逐渐增加到13周的60%。(4)分离和培养大豆根瘤类菌体的适宜基质是蒸馏水或矿质溶液(如PDB~-),培养基为BMM或YMA,pH为5.0-7.0。(5)渗透压保护并不是大豆根瘤类菌体繁殖的必要条件。Gresshoff等人推荐的PDB液和B~( m)培养基,非但无利,反而有害。(6)大豆根瘤或根的提取液能大大促进类菌体的繁殖。硫胺素等五种维生素和酵母汁均无此种刺激作用。根瘤提取液的生物活性在100℃下5分钟即部分破坏,而在12l℃下加热就完全遭到破坏。(7)类菌体每次分裂的世代时间随次数的增多而逐步缩短。一般经过第一次的延迟分裂之后,其分裂速度即与培养体根瘤菌相当。(8)荧光抗体试验证明根瘤中的类菌体及其分离菌株与供试菌在主要抗特征上的同一性。     

粳稻品种分蘖状的遗传研究

１７个粳稻代表性品种，经２年重复试验，结果表明：（１）分蘖力的遗传力及相对遗传进度均较高，且与分蘖速度和单株产量达极显著正相关，故可作为株形育种的一个重要指示性状。（２）对分蘖与单株产量等的相关及通径分析现有水稻品种，以选育分蘖早、快、多而角度较大为宜。     

喷雾施药靶标的红外线探测性能研究

[目的]研究红外线探测技术应用于对靶探测的性能、效果及影响因素,为实体植株的红外对靶探测提供理论依据和技术基础。[方法]以模拟靶标为试验对象,选用不同功率的红外发射管及光电开关放大灵敏度组合,针对不同反射物尺寸、光照强度和反射物反射率条件进行研究。[结果]"D36,F50"探头的探测距离和探测范围综合效果最佳,其最佳参数为:红外发射管功率为0.42 W,放大器灵敏度调节钮置为10档;探头"D20,F55"和"D36,F50"在探测距离上均有一段距离0点较大的空白值,且探测范围随探测距离的增大呈现先增后减的变化规律,并在接近探测距离中点处达到最大值;反射物(靶标)尺寸越大,光照强度越强,反射物表面反射率越高,探测效果越好。[结论]影响红外探测的3个要素为:反射物(靶标)尺寸、光照强度、反射物表面反射率。为获得较好的对靶探测效果,应选配合适的红外探测器。     

Stakeholder perception of wheat production constraints,capacity building needs,and research partnerships in developing countries

In order to update the available information on the main current and future constraints on wheat production and human capacity development, a survey covering nineteen developing countries, including major wheat producers, was conducted prior to the 2006 International Symposium on Increasing Wheat Yield Potential in Ciudad Obregon, Mexico. The results emphasize the substantial yield losses associated with a number of critical abiotic, biotic and socioeconomic constraints, and indicate their global prevalence. The most important constraints on wheat production are heat (affecting up to 57% of the entire wheat area in surveyed countries), competition with weeds, and diseases (both affecting up to 55% of wheat area). Of the socioeconomic constraints listed and evaluated by respondents, access to mechanization and availability of credit were the most often highlighted. The most-reported infrastructural constraints were insufficient resources for field station operations. When evaluating the importance of research partnerships to achieve national wheat program goals, respondents from all 19 countries assigned the highest importance to partnerships with international agricultural research centers. The most desired outputs from these include development and exchange of germplasm and assistance in capacity building and knowledge sharing. These findings confirm the anticipated constraints and needs over the next 10–20 years and affirm the importance of international agricultural research centers in providing support to address them.     

上海转基因生物安全管理技术支撑体系与能力建设浅析

从转基因生物安全管理技术支撑体系与能力建设的意义及必要性、建设单位技术基础、建设内容、监管程序和检测技术流程、效益分析与风险评估等方面论述了在上海进行转基因生物安全管理技术支撑体系与能力建设的可行性。     

大白菜-辣椒轮作中土壤养分限制因子及平衡状况研究

采用肥料定位试验与土壤养分系统研究法相结合的方法,探讨北方裸菜地主要种植方式大白菜—辣椒轮作中土壤自然供氮、磷、钾、锌、硼能力,土壤氮、磷、钾的收支平衡及相应土壤养分的消长状况。主要结果:大白菜—辣椒轮作中:全肥处理(NPKZnB)大白菜和辣椒的年均产量分别为111.6,23.7 t/hm2,-N、-P、-K的相对产量分别为全肥的56.7%,63.6%,84.7%;辣椒上-N-、P-、K、-Zn-、B的相对产量分别为全肥的45.8%,45.9%,67.7%,88.0%,84.9%,差异均达到显著水平。大白菜限制产量的因子为:N>P>K,辣椒为:N,P>K>Zn,B。P2O5用量180kg/hm2,K2O用量300 kg/hm2的处理,土壤磷和钾养分分别盈余70.3%和2.0%,土壤有效磷(Olsen-P)、有效钾分别年均增加3.3和37.2 mg/kg,积累的土壤有效磷和有效钾分别占土壤磷和钾积累量的7.1%和28.3%。大白菜茬口N,P2O5,K2O推荐用量为225,90,150 kg/hm2,辣椒茬口分别为337.5,213,337.5 kg/hm2并配合施用一定的锌和硼肥。     

Ecological sustainability and the use of chemicals: Is ecotoxicological risk assessment doing its job properly? An introduction to chemical time bombs

Ten million chemical substances are registered scientifically, but only 1 per cent, 100000, are known to be traded internationally, and only a fraction of these are assessed to establish (eco)toxicological risks through international and national authorities. Only a few of the substances are natural or systemic; most are xenobiotic and poorly evaluated with respect to their environmental effects. It is not only the chemical accidents that make newspaper headlines, but the creeping accumulation of pollutants in soils, sediments and groundwater which degrade the environment for future generations. Ecotoxicological risk assessment still neglects this ‘hidden pollution’, as it usually deals only with the bioavailable fractions of chemicals in the environment. the ‘lost’ (residue) fractions, however, can have non-linear and time-delayed effects (chemical time bombs). As governments need to protect their natural resources (soils, sediments, groundwaters) against negative impacts from chemicals, an ecosystem approach May, help them to overcome the shortsightedness of current ‘acute’ ecotoxico-logical risk assessments. the Netherlands' risk philosophy on chemicals in the environment is discussed as an example. the National Environmental Policy Plan-2 (1994) stresses the chain of events associated with a chemical from the raw material, The side effects of its transport, production, use and disposal, to its final effects in the ecosystem, including the time-delayed responses of pollution. a revised ecotoxicological assessment policy under the new NEPP will have to take account of such chemical time bombs.