显性雄性不育硬粒小麦（Triticum durum）和二粒小麦（Triticum dicoccum）选育

用已育成的显性雄性不育六倍体小黑麦为母本分别与硬粒小麦、二粒小麦及黑麦杂交,并每代选不育株用原父本回交。结果表明,来源于太谷核不育小麦4D染色体上的Ms2（Tal）基因已易位到A或B染色体组的某一条染色体上。从而育成了显性核不育硬粒小麦和二粒小麦。     

显性雄性不育硬粒小麦（Triticum durum）和二粒小麦（Triticum di…

用已育成的显著性雄性不育六倍体小黑麦为母本分别与硬粒小麦、二粒小麦及黑麦杂交，并每代选不育株用原父本回交。结果表明，来源于太谷核不育小麦４Ｄ染色体上的Ｍｓ２基因已易位到Ａ或Ｂ染色体组的某一条染色体上。从而育成了显性核不育硬粒小麦和二粒小麦。     

矮败蓝标型小麦的选育

利用蓝粒太谷核不育硬粒小麦附加系89—2343(AABB 4D／4E)与普通小麦7739—3(2n=42)杂交、回交所产生的蓝粒可育株与白粒矮败材料杂交、回交，育成了一份矮败蓝粒小麦附加系(2n=43)。选用13份遗传背景不同的白粒普通小麦与之杂交、回交，育成了13份矮败蓝粒小麦。对13份矮败蓝粒后代的粒色和育性分离进行分析，蓝粒矮败不育株占22.1％，白粒非矮秆可育株占77．7％．可能表明蓝粒基因、Ms2和Rht10均位于附加染色体上，且连锁紧密；但不同轮回亲本，矮败蓝粒的传递率有差异。     

硬粒小麦4D单体附加系的选育与利用

太谷核不育小麦是一个十分有用的遗传改良工具,现在已广泛用于我国的小麦育种实践。它的显性不育基因位于4D染色体上的事实,似乎限制了这个基因在硬粒小麦、圆锥小麦和六倍体小黑麦中的应用。这些物种4D单体附加系的产生,有可能打开小麦显性不育基因应用于这些物种的大门。     

一个与高秆基因连锁的太谷核不育硬粒小麦的发现

用太谷核不育硬粒小麦与硬粒小麦品种吉拉多杂交并连续回交，在回交的Ｆ１群体中，我们发现不育株的株高明显高于不可育则可育株的株高近似于回交父本。对１９９６年的考种资料经统计分析及交换值的测定，初步确定此材料是太核不育基因Ｔａｌ与高秆基因连锁的材料。     

蓝标型矮败小麦的创制及利用

以蓝粒太谷核不育硬粒小麦附加系89-2343(AABB 4D/4E)与普通小麦7739-3(2n=42)杂交、回交所产生的蓝粒可育株与白粒矮败材料杂交、回交,育成了矮败蓝粒小麦附加系98-266.利用97-866为基础,转育成8份不同基因背景的新蓝标矮败小麦,并对这8个蓝标矮败小麦的粒色和育性分离及杂种优势进行了分析.结果表明,蓝粒不育株变幅为20.6%～23.8%,平均为22.3%;白粒非矮秆可育株占77.6%,其他类型仅占0.1%,表明蓝粒基因、Ms2和Rht10均位于附加染色体上,且连锁紧密;但不同轮回亲本,矮败蓝粒的传递率有差异;而同一轮回亲本在年份间的蓝粒不育株传递率差异不显著.同时,对蓝标型矮败小麦的杂种优势进行了探讨.     

科技情报单——学术·学人·理论

<正>1972年山西太谷高忠丽发现一株不育小麦,1979年经中国农科院邓景杨研究员鉴定出其不育性受一个显雄性核不育基因控制在小麦中第一次被发现的天然突变体.设计出染色体组合定位结合端体分析把该基因“定位于4D染色体短臂上距着丝粒31.16个交换单位.命名这株小麦为“太谷核不育小麦”,其不育基因符号为“TAl”1986年在国际小麦基因登记署入册,编号为ms2.此不育小麦败育早,属无花粉型,不育性稳定除用于单交、复交、回交、阶段杂交等外,首次成功地用于自花授粉小麦的轮回选择实现基因充分交流与重组、累加、高有益基因特别是微效基因的利用率,培育出遗传基础广、适应性强、丰产性好的25个品种,种植面积3634.57万亩,获纯收益的44.8亿元,解决耐旱、耐盐碱、抗赤霉病及多种病虫害等育种难题.使占我国耕地面积2/3的中低产田产量得到提高,增加困难地区农民的收益.在远缘杂交方面育成基因综合体及八倍体,六倍体核不育小黑麦及核不育硬粒小麦这些都是世界首例.发表论文160多篇出版论文集三本,其中一本英文版在荷兰发行、1990年获劳力士雄才伟略国际大奖荣誉奖,“1997年列中国十大科技新闻之一.1997年获农业部科技进步奖二等奖,1998年国家技术发明二等奖,得到评委的高度评价.     

小麦抗条锈新种质的创制－－I．外缘抗条锈基因的导人

通过普通小麦与六倍体小黑麦杂交、多元回交和花培纯合 ,将小黑麦抗条锈基因导入普通小麦 ,获得了 12个在成株期对小麦条锈病菌流行小种免疫的新种质 ,其中 8个新种质在苗期对流行小种高抗。研究普通小麦与六倍体小黑麦的杂交特性结果表明 ,六倍体小黑麦×普通小麦与普通小麦×六倍体小黑麦两种杂交方式都有较高的杂交结实率 ,但前者种子发育好 ,出苗率高 ,后者种子胚乳发育不良 ,出苗率低。用普通小麦进行回交 ,可获得一定的结实率 ,种子出苗率较好。     

小麦抗条锈新种质的创制Ⅰ.外缘抗条锈基因的导入

通过普通小麦与六倍体小黑麦杂交、多元回交和花培纯合,将小黑麦抗条锈基因导入普通小麦,获得了12个在成株期对小麦条锈病菌流行小种免疫的新种质,其中8个新种质在苗期对流行小种高抗.研究普通小麦与六倍体小黑麦的杂交特性结果表明,六倍体小黑麦×普通小麦与普通小麦×六倍体小黑麦两种杂交方式都有较高的杂交结实率,但前者种子发育好,出苗率高,后者种子胚乳发育不良,出苗率低.用普通小麦进行回交,可获得一定的结实率,种子出苗率较好.     

小麦核不育的遗传研究和雄性不育遗传模式的建立

综述了多年对小麦雄性不育研究的进展。太谷核不育小麦是显性雄性不育材料,它的显性不育基因Ms2位于4D染色体短臂上,距离着丝点31.16cM。以矮变1号小麦为标记性状供体,经大群体筛选和细胞学研究,研制出具有矮秆基因标记的显性核不育材料—矮败小麦。在矮败小麦中,矮秆基因Rht10与雄性不育基因Ms2在4D染色体短臂上连锁十分紧密,交换率仅为0.18%。该两基因的连锁片段已转移到中国春小麦ph1b突变体和八倍体小黑麦中。发现一套基因控制的雌雄性都不育的小麦遗传种质和双隐性基因控制的小麦核不育材料。综合分析已发现的核不育材料,提出植物基因互作型显性核不育材料起源假说;经遗传分析和数学推导,建立植物隐性核不育材料姊妹交后代育性遗传模式。     

穴盘规格和苗龄对塑料大棚菜豆性状及产量的影响

本试验以菜豆品种先行者为试材,采用32孔、50孔两种规格穴盘,设置10、15、20、25 d等4个苗龄段,通过研究不同穴盘规格和苗龄对菜豆性状及产量的影响,筛选出适合菜豆育苗的穴盘规格和适宜的苗龄。结果表明：穴盘育苗的营养面积增大,菜豆产量随之增加,25 d苗龄条件下,32孔穴盘的前期产量和总产量均显著高于50孔穴盘;随着苗龄的增长,菜豆的前期产量和总产量呈增加趋势,其中25 d苗龄的产量显著高于其他苗龄。综合上述各项指标,菜豆育苗阶段,10 d苗龄可选用32孔、50孔穴盘,15 d以上秧苗选用32孔穴盘为宜。     

不同基因型小麦苗期耐低氮性评价及筛选

氮素作为重要的营养元素,限制着小麦的生长发育和经济产量,筛选和培育耐低氮小麦品种是提高氮素利用率、降低生产成本的有效途径。以118份不同基因型小麦为材料,在低氮(0.1 mmol·L^-1)和正常氮(5 mmol·L^-1)条件下苗期水培,测定根干重、茎叶干重、根冠比、植株干重、最大根长、初生根数和二级初生根数等相关指标,采用模糊隶属函数法、主成分分析以及聚类分析法综合评价小麦品种的耐低氮性。结果表明,在低氮胁迫下小麦幼苗的根干重、根冠比和初生根数目显著提高,茎叶干重、植株干重和最大根长不同程度的降低,7个苗期性状指标在两个氮水平下均存在显著性差异。主成分分析提取3个主成分,贡献率分别为 43.575%、22.904%和17.873%,累积贡献率达 84.351%。以耐低氮性综合评价D值进行聚类分析,将118份小麦品种划分为强耐低氮型、耐低氮型、中间型、较敏感型和敏感型5类。筛选出3份耐低氮型小麦（齐大195、金丰7183和天民198）和2份强耐低氮型小麦（山农0917和鲁麦8号）。不同小麦品种的耐低氮机制不同,研究结果为小麦耐低氮品种的选育提供理论依据和材料基础。     

一串红N、P、K、Ca、Mg、Fe缺素症状研究

以‘展望红’为材料,研究N、P、K、Ca、Mg、Fe缺乏对其生长发育的影响,并总结缺素症状,研究结果表明:N缺乏时植株矮小,叶发黄;P缺乏时叶色暗绿,且影响开花;K缺乏时基部叶枯黄,并易落叶;缺Fe症状较为明显,但能正常开花;Ca、Mg未表现出缺素症状,且各项指标要优于全素处理;N、P显著影响一串红的生长发育,K对开花品质的影响较大。     

Segregation of form, color, movement, and depth: anatomy, physiology, and perception

Anatomical and physiological observations in monkeys indicate that the primate visual system consists of several separate and independent subdivisions that analyze different aspects of the same retinal image: cells in cortical visual areas 1 and 2 and higher visual areas are segregated into three interdigitating subdivisions that differ in their selectivity for color, stereopsis, movement, and orientation. The pathways selective for form and color seem to be derived mainly from the parvocellular geniculate subdivisions, the depth- and movement-selective components from the magnocellular. At lower levels, in the retina and in the geniculate, cells in these two subdivisions differ in their color selectivity, contrast sensitivity, temporal properties, and spatial resolution. These major differences in the properties of cells at lower levels in each of the subdivisions led to the prediction that different visual functions, such as color, depth, movement, and form perception, should exhibit corresponding differences. Human perceptual experiments are remarkably consistent with these predictions. Moreover, perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties.     

ICP-OES法同时测定果蔬中铅、砷、镉、铬、铜、锡含量

果蔬样品经混酸消化后,控制一定的酸度,定容后应用等离子体发射光谱法(ICP-OES)对果蔬中铅、砷、镉、铬、铜、锡六种有害重金属进行测定,研究了分析测定条件,方法简单快速。测定结果表明,五种元素的加标平均回收率在91.0%~107%之间。其RSD均小于3.5%。按该方法进行处理及测定铅、砷、镉、铬、铜、锡,在选择的测定条件下最低检出限分别为0.0006 mg/kg、0.0003 mg/kg、0.00003 mg/kg、0.00005 mg/kg、0.00003 mg/kg、0.0006 mg/kg。     

Space, stars, c60, and soot

Although carbon has been subjected to far more study than all other elements put together, the buckminsterfullerene hollow-cage structure, recently proposed to account for the exceptional stability of the C(60) cluster, has shed a totally new and revealing light on several important aspects of carbon's chemical and physical properties that were quite unsuspected and others that were not previously well understood. Most significant is the discovery that C(60) appears to form spontaneously, and this has particularly important implications for particle formation in combustion and in space as well as for the chemistry of polyaromatic compounds. The intriguing revelation that 12 pentagonal "defects" convert a planar hexagonal array of any size into a quasi-icosahedral cage explains why some intrinsically planar materials form quasi-crystalline particles, as appears to occur in the case of soot. Although the novel structural proposal has still to be unequivocally confirmed, this article pays particular attention to the way in which it provides convincing explanations of puzzling observations in several fields, so lending credence to the structure proposed for C(60).     

Strategic command, control, communications, and intelligence

Command, control, communications, and intelligence (C(3)l) for nuclear forces are essential elements in the deterrence of nuclear war. The present C(3)l) system has vulnerabilities associated with its reliability, survivability, and endurance under attack, thereby weakening deterrence by increasing the ambiguity in our capabilities. Development of a reliable and enduring C(3)l) system would reduce this ambiguity. Its reliable, positive control of nuclear forces would give the national leadership more time to assess situations, ensure discriminate retaliation, and improve our ability to manage crises in general. These capabilities could help to stop a war rapidly should one start. A reliable and enduring C(3)1) system will be needed for a long time to come, even if a freeze on strategic nuclear forces is accomplished or other arms control successes achieved. Indeed, C(3)l) may be the best source today of confidence-building measures to reduce tensions and the threat of nuclear catastrophe.