共查询到20条相似文献,搜索用时 78 毫秒
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<正>一、空秆1.现状空秆是玉米拔节以后不抽雄或吐丝,到收获玉米时没有结果穗的现象,在玉米生产中较常见。据生产调查,空秆率一般为18%~22%,严重者高达35%以上(个别品种的空秆率高达50%~60%),致使玉米大幅度减产。2.形成原因在玉米生长期,由于矿物质营养失调,不能满足穗分化对养分的需求;种植密度过大,通风透光不良,造成田间郁闭,个体瘦弱,影响雌穗发育,光合作用减弱; 相似文献
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玉米果相是由茎针中上部叶服的腋芽分化而成。玉米的果穆数与品种的特性及栽培条件有关。栽培条件好,茎秆上有l-2个或更多的腋芽发育成果穗,若栽培条件不好,影响果稳分化和籽粒发育,就会形成空秆。1引起空秆的原因1.1果穗分化发育期间,营养物质供应不足,满足不了果稳分化期间的要求,形成空秆。1.2营养元素比例失调,重施氮肥,缺少磷肥,据分化速度迟缓,造成空秆。1.3孕稳期过分干旱,茎叶生长和果稳发育受阻而形成空秆。1.4开花授粉期,若遇高温门2-35℃)、干旱(3%相对湿度),花粉1-2小时就丧失活力,而且花丝也干枯,受精不良,而造成缺位或空秆。1.5种植密度过大。无论是平展型还是紧凑型五米都有其最适宜的栽培密度,而且适宜的密度还应根据当地的自然条件、土壤条件、施肥水平、栽培水平等确定。密度过大,通风送光不良,同化物质减少而形成空拜。1.6种子纯度、净度差,种子大小不整,出苗不整,田间整齐度差,大苗欺小苗,空秆增加。1.7土壤墒情差,播深不一致,出苗不齐,大小范共存,小苗易形成空秆。1.8间、定苗时间晚,小苗争夺肥、水矛盾突出,所形成的高脚苗、小老苗易形成空秆。1.9植株遭到病虫危害后,器官受到破坏,养分运输受阻或直... 相似文献
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夏玉米空秆的原因及对策 总被引:1,自引:0,他引:1
夏玉米空秆的原因及对策张银虎,张兰中(河北省衡水地区农业局053000)玉米空秆常年时有发生,主要是弱晚苗和自交苗,一般在6%左右。而1994年的玉米空秆比较普遍,也较严重,一般空秆率为25%,严重的达7o%以上。表现为穗小崎形,乃至有穗无粒或无穗。... 相似文献
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拔节期到抽穗期是玉米旺盛生长期,茎叶增长速度决、增长量大,雌雄幼穗不断分化形成,需水量很大。抽穗开花期是需水临界期,需水量达到高峰,对水分的反应最敏感。灌浆期需要水为介质运输营养物质,需水量也较大。从拔节到灌浆期干旱会扰乱植株的正常生理代谢过程,使光合作用受抑制,合成产物量减少,而呼吸作用增强,加速物质的分解,消耗大于积累,造成营养缺乏。干旱导致萎蔫也会造成正在分化的幼穗或正在灌浆的籽粒的水分流向茎,而使幼穗分化和籽粒灌浆过程受阻,小花分化数目少。影响雄穗的抽出和雌穗的吐丝,延缓授粉,严重时会造成花粉、花丝丧失生活力,果穗上籽粒的数量减少,造成穗小、缺粒,甚至幼穗分化停止,形成空秆。 相似文献
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介绍了运用冷冻干燥技术进行速溶蛋花汤的加工,研究了生产工艺、特点以及影响产品质量的主要因素。试验表明,采用冷冻干燥技术加工的速溶蛋花汤,具有营养丰富、风味独特、方便快捷等特点。 相似文献
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DENG Zhao-jing 《保鲜与加工》2005,(1):153-156
A new definition of inertia,i.e. the momentum is the measuring of inertia of matter, is proposed. The article through and etc., subjects, the correctness of the new notion of inertia:The monentum is the measuring of inertia has been demonstrated, and the unsolved contradictions of the traditional definition of inetia. And the mass is the measuring of inertia has been revealed. 相似文献
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香蕉是热带亚热带发展中国家重要的粮食作物和碳水化合物来源。但近年来,香蕉生产受到严重的病虫危害。大多数香蕉栽培品种是三倍体,生长周期长,而且不孕。由于没有种子,给繁殖和育种带来一定的困难。遗传转化技术的发展为香蕉品种的改良提供了一种有效的手段。香蕉的遗传转化方法有电激法、基因枪法、农杆菌介导法等。农杆菌介导法的应用是香蕉品种改良的一个重大突破。香蕉遗传转化的外植体也发展到多种,有原生质体,胚性细胞悬浮系,分生组织,以及横切薄片等。近几年,随着分子生物学的发展,出现了转化效率更高,重复性更好的香蕉遗传转化技术。如农杆菌和基因枪结合法,离心辅助农杆菌介导法、真空渗透技术等。这些新技术新方法的出现,必将推动香蕉产业高速发展。 相似文献
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基于RS与GIS技术,利用景观生态学理论及景观格局指数对布尔津县土地利用现状进行定量分析。结果显示为:(1)布尔津县以草地、林地为主要景观类型,镶嵌着耕地、水域等景观类型。(2)四个分区(即高山区、丘陵区、平原区、荒漠区)的林地资源组成差异明显,耕地、居民、交通及工矿用地集中分布在丘陵区和平原区(3)从各项指数来看,高山区的多样性指数较低;平原区是受人文因素最多的区域,景观优势度低,各种土地利用类型比例差异不大,有利于生态可持续发展,但要合理的开发利用;荒漠区生态环境相对脆弱,要加强生态环境的保护与改善。通过该研究对布尔津县的土地利用现状作一个了解,为该县乃至整个地区的景观规划和可持续发展战略提供科学依据。 相似文献
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Based on the relation between the incipient yield pressure and the limit of yielding in cylinder according to the elastic disabled rule, a laboratorial method of determining limit of yielding of material is designed and a set of experimental data were gained by the method. The incipient yield pressure of the cylinder is gained by analyzing the experimental data, and then the limit of yielding is gained. The laboratorial method has a good reliability as the experimental value has a little error to the theory value. It has a definite engineering signification and theory value to research the mechanical capability of material and the disabled rule of high pressure vessel. 相似文献
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南瓜降糖功能及其系列食品加工技术 总被引:3,自引:0,他引:3
阐述了南瓜在糖尿病辅助治疗方面的功能特性,介绍了南瓜降糖主要制品南瓜全粉、南瓜脆片、南瓜果酱和南瓜肉汁的工艺流程和操作要点。 相似文献
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母猪繁殖障碍成因分析 总被引:3,自引:0,他引:3
繁殖障碍是导致母猪淘汰的最主要因素,直接造成母猪非生产天数延长,繁殖猪群生产效率降低,严重影响猪场的经济效益。本文作者对引起母猪繁殖障碍的多方面因素,包括营养因素(如饲养水平、饲料品质、断奶日龄)、环境因素(如温度、湿度、通风、光照)、疫病因素、生产技术及管理因素进行了详细阐述。 相似文献
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Efficiency of water use of early plantings of sunflower 总被引:4,自引:0,他引:4
M. Auxiliadora Soriano Francisco Orgaz Francisco J. Villalobos Elías Fereres 《European Journal of Agronomy》2004,21(4):465-476
Rain fed crop production in Mediterranean environments depends to a large extent on strategies that avoid the intense summer drought. Early plantings of sunflower have given consistently higher yields in such environments, but the basis for such yield increases has not been explored. We conducted two field experiments at Cordoba (Spain) to investigate the effects of an early and a late planting date on the components of water-limited crop productivity; namely, water use (T), water use efficiency (TE) and harvest index (HI) of sunflower. The results were generalized by simulating rain fed sunflower yields, under early (1 January) and late (15 March) plantings, for a 25-year period with the aid of a simulation model of the Ceres type (OILCROP-SUN) which has been validated in Cordoba. Experimental seed yields of early plantings in 1989 and 1996 were 2.0 and 3.0 t ha−1, while late plantings yields were 1.3 and 2.4 t ha−1, for the 2 years. Average simulated yields were 2.7 ± 1.1 and 1.9 ± 0.7 t ha−1 for early and late plantings, respectively. For the 2 years, T of early plantings was higher than that of late plantings, but the response of TE and HI to planting date was not the same in the two experiments. In the simulation exercise, T and TE of early plantings were consistently higher than those of late plantings, while there were no differences in the HI for the two planting dates. We conclude that early plantings of sunflower increase rain fed yields by increasing both T and TE, while the impact of planting date on HI very much depends on the crop water stress pattern, which is quite variable from year to year even in the predictable Mediterranean environment. 相似文献