不同穴盘规格和基质对夏季甘蓝漂浮育苗秧苗生长的影响

为选择夏季甘蓝漂浮育苗合适的穴盘规格和基质,开展了不同穴盘规格和基质对夏季甘蓝漂浮育苗秧苗生长的影响试验。结果表明,夏季甘蓝漂浮育苗优先选用孔数较少的穴盘,特别是在可能受茬口、天气等的影响,难以确保适时定植,优先选用50孔穴盘；苗龄25d,选择78孔穴盘可满足生产要求；基质以江苏鸿逸泰农艺科技开发有限公司生产的为佳。     

不同穴盘规格和苗龄对番茄幼苗质量的影响

试验以番茄＂红桔＂为供试品种,选取3种规格的穴盘在满足集约化育苗条件下的大棚进行育苗试验,研究不同处理番茄幼苗的生长发育,筛选出适合番茄育苗的穴盘规格和苗龄。结果表明：选用72孔穴盘35d苗龄的番茄幼苗表现最好;105孔穴盘30d苗龄的表现次之。     

不同规格穴盘和基质对夏季甘蓝漂浮育苗秧苗生长的影响

为筛选出适用于夏季甘蓝漂浮育苗的穴盘和基质,开展了不同规格穴盘和基质对夏季甘蓝漂浮育苗秧苗生长的影响试验。结果表明:夏季甘蓝漂浮育苗优先选用孔数较少的穴盘,特别是在可能受茬口、天气等的影响,难以确保适时定植时,优先选用50孔穴盘;苗龄25 d,选择78孔穴盘即可满足生产要求;育苗基质以江苏鸿逸泰农艺科技开发有限公司生产的为佳。     

不同播种量与穴盘对冬凌草种子育苗的影响

为推动济源冬凌草工厂化育苗，特开展不同播量、穴盘等对冬凌草种子育苗影响的试验研究。结果表明，冬凌草种子育苗，幼苗期首选128孔穴盘，105孔穴盘次之，播种量为25～30粒/穴，苗龄控制在25～35 d；假植苗期首选50孔穴盘，72孔穴盘次之，每穴一苗，苗龄控制在20～25 d。     

不同规格穴盘育苗对越冬茬番茄生长及产量的影响

为促进越冬茬育苗穴盘番茄生产,采用32、50、72孔规格穴盘育苗,进行越冬茬番茄栽培试验。结果表明:穴盘苗综合指标中72孔处理最弱,32与50孔处理差异不显著;番茄产量随着孔数的增加逐渐降低,32与50孔处理差异不显著;32孔667m~2育苗总成本高于50孔57.2%,相差68元。综上述各项指标,栽植越冬茬番茄,穴盘育苗以50孔规格为宜。     

穴盘孔数对早熟菜薹生长发育及产量的影响

为了满足人们一年四季对菜薹新鲜产品的需求,增加育苗企业的额外收入,笔者研究了不同孔数穴盘生产早熟菜薹,对其生长指标及单盘产量的影响。试验结果表明,品种、孔数及品种与孔数组合对菜薹株高、茎粗、开展度和最大叶面积均有显著影响,32孔和50孔的株高显著高于72孔,薹粗和开展度随着穴盘孔数的增加显著降低,32孔最大叶面积显著高于50孔和72孔。菜薹株高、茎粗、开展度、最大叶面积与单盘产量均呈负相关,品种和孔数与单盘产量呈正相关;穴盘孔数及品种与孔数组合对菜薹单盘产量的影响显著,随着穴盘孔数增多,种植密度增大,产量增高,尖叶45天72孔亩产量达2 394 kg。成本分析表明,利用32孔、50孔、72孔穴盘生产早熟菜薹,单盘成本接近;随着孔数增加,单盘产量增加,亩纯收入相应增加,72孔穴盘平均亩纯收入达11 783.0元。     

不同规格穴盘育苗对菜心幼苗生长的影响

为筛选最适的菜心工厂化育苗穴盘,以菜心为试材进行穴盘育苗,研究32穴(T1)、50穴(T2)、72穴(T3)以及128穴(T4)4种规格穴盘对菜心幼苗生长的影响。结果表明,不同规格穴盘幼苗的主要生长指标以及根系各形态指标差异随苗龄增加逐渐加大,在苗龄17 d时出现明显差异,T1、T2处理株高、茎粗明显大于T3、T4处理,T1、T2、T3处理地上部鲜质量与干物质积累速率远大于T4处理,总根尖数和根系分支数表现为T1T2T3T4,根系总长度、根系总表面积、根系总体积表现为T1、T2大于T3、T4,T1、T2、T3处理的N、P、Ca、Mg、S积累量显著高于T4处理,T2处理K的积累量明显高于T3、T4处理。幼苗的质量显著影响移栽后植株的生长。定植大田(苗龄17 d)后7 d,T1、T2处理株高和地上部鲜质量显著大于T3、T4处理,地上部干质量和干物质积累速度表现为T1T2T3、T4,N、P、K、Ca、Mg、S积累量T1处理显著高于T2处理,T2处理显著高于T3、T4处理。综上所述,菜心17 d以上苗龄移栽最好选用大孔穴盘,如32或50穴穴盘。     

育苗基质和穴盘规格对黄瓜幼苗生长的影响

[目的]为推动蔬菜穴盘育苗技术的标准化奠定基础。[方法]选用3种常用基质(中药渣、有机活性基质和营养土)和5种规格的穴盘进行黄瓜的穴盘育苗试验,研究不同基质处理对黄瓜出苗率的影响以及不同基质处理和不同规格穴盘对黄瓜幼苗生长发育的影响。[结果]播种5 d后,使用中药渣基质的黄瓜出苗率最高(95%),有机活性基质和营养土次之。在育苗前期和后期,基质对黄瓜幼苗生长发育的影响均较大,其中有机活性基质对黄瓜幼苗的生长发育最为有利,而中药渣和营养土的效果较差,且差异不显著。穴盘规格对黄瓜幼苗的生长发育影响不大。5种穴盘规格都适于黄瓜育苗,以50孔穴盘效果较好。[结论]在黄瓜工业化育苗中,宜选用50孔穴盘。     

西瓜穴盘基质标准化育苗

<正>1．材料准备。西瓜育苗一般采用48孔或50孔穴盘,苗龄25～30天。穴盘规格540毫米×280毫米×5．5毫米。有机基质可选用西瓜育苗专用有机基质。一袋基质50升,可装穴盘11～12盘。1000株西瓜苗需要90升基质。2．苗床准备。穴盘育苗苗床要选择地势较高、背风向阳、排灌方便     

不同规格穴盘对樱桃萝卜生长发育的影响

通过4种不同规格穴盘的种植比较,筛选适宜在阳台种植樱桃萝卜的穴盘规格。结果表明,32孔深盘樱桃萝卜长势显著优于其他穴盘,32孔浅盘与50孔深盘植株长势相当,适合樱桃萝卜种植,50孔浅盘长势最差;32孔穴盘种植成本高,50孔穴盘种植成本低;阳台栽植樱桃萝卜以50孔深盘为宜。     

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.