玉米英语讲稿
玉米育种演讲稿范文三分钟(3篇)
第1篇大家好！今天，我非常荣幸能够站在这里，与大家分享关于玉米育种的一些心得和体会。
玉米，作为我国重要的粮食作物之一，其产量和品质的提升对于保障国家粮食安全、促进农业可持续发展具有重要意义。
接下来，我将从玉米育种的历史、现状、挑战以及未来发展趋势等方面进行阐述。
一、玉米育种的历史玉米育种的历史可以追溯到数千年前。
最早的人工选育玉米起源于墨西哥，经过长时间的培育和改良，逐渐形成了具有不同特征和特性的品种。
在我国，玉米种植历史悠久，早在公元前1000年左右，就已经开始种植玉米。
经过数千年的发展，我国玉米育种取得了举世瞩目的成就。
二、玉米育种的现状1. 玉米品种丰富：目前，我国玉米品种已超过5000个，涵盖了不同生态类型、不同用途和不同熟期。
这些品种在产量、抗病性、适应性等方面具有明显优势。
2. 育种技术先进：我国玉米育种技术已达到国际先进水平，如分子标记辅助选择、基因编辑、基因工程等技术在玉米育种中得到广泛应用。
3. 玉米产量稳步提高：近年来，我国玉米产量逐年攀升，已成为全球玉米产量最高的国家。
据统计，2019年我国玉米总产量达到2.64亿吨，占全球总产量的40%以上。
4. 玉米品质不断提升：通过品种改良和栽培技术改进，我国玉米品质得到显著提高。
如今，我国玉米品种在蛋白质、脂肪、淀粉等营养成分含量上均达到国际先进水平。
三、玉米育种面临的挑战1. 环境变化：全球气候变化导致极端天气事件频发，对玉米生产带来极大挑战。
玉米育种需要适应更加复杂多变的环境。
2. 资源约束：随着人口增长和耕地减少，玉米育种面临着资源约束的挑战。
如何提高单位面积产量和资源利用率成为育种工作的重要方向。
3. 病虫害问题：玉米病虫害严重影响产量和品质，给玉米育种带来巨大压力。
如何培育抗病虫害品种，提高玉米产量和品质成为育种工作的重点。
4. 市场需求变化：随着消费者对玉米品质要求的提高，玉米育种需要不断适应市场需求，培育出更多符合消费者需求的优质品种。
产品介绍英语演讲稿
产品介绍英语演讲稿篇一：产品介绍英语演讲稿公司及产品讲稿列位亲爱的家人（朋友或伙伴们）：大伙儿上午（下午）好！我是大漠紫光超级荣幸今天由我来介绍一下咱们公司及产品（打招呼表示感激）（塑造产品价值，突出产品独特卖点，引发强烈爱好）列位亲爱的伙伴们在进入主题之前我可不能够和大伙儿先做一下友好的互动（能够），请问大伙儿咱们每一个人都专门期望让自己变得更年轻长寿对不对（对），咱们每一个人都期望让自己远离疾病与痛楚是不是（是的），咱们每一个人都专门想吃到营养全面最健康的食物对吗（对的）！可是我想讲的是现代科技尽管如此发达，人们的生活水平取得了显著提高，可是现代人的死亡率却在慢慢呈现年轻化，普遍化的趋势。
咱们来看以下的一组数据：几乎99%的人都存在亚健康，50%以上的人患有前列腺疾病，30%以上的人视力有问题，死亡年轻化的具体表现就再于死神不只垂青于年老的，而正将魔爪伸向成功的年轻人，死亡的名单中即有没钱、贫困的、也有有钱的、出名的，有权的成功人士，咱们来一起的试探一下，什么缘故有如此的悲剧发生？什么缘故死亡会呈现愈来愈年轻化的趋势，而不是老年化呢？按理说，那些富有和成功的人，本来更应该有资格多享受人一辈子。
比一样人能够活的更长寿，更健康，因为他们能够消费的起高级化妆品，保养品，买得起高级滋补保健品，那么一个人什么缘故会生病呢？有钱人什么缘故寿命会越短，下面咱们来听听营养保健专家们的观点：针对那个问题，专家们做出了以下良好的建议：他们说一个人要想活的健康，远离疾病，就要做到，少抽烟，少饮酒，不吃或少吃油腻、膨化、烧烤、油炸类食物，要注意营养均衡，维持多运动，心怀踊跃心态，多吃新鲜蔬菜水果，生活维持有规律，工作有目标，维持少睡早起。
大伙儿说专家们总结的体会，对咱们有无帮忙，好不行？（专门好，太好了）。
答案固然是好了，简直太好了！可是咱们都明白，那个世界上，没有人是全能的，任何人都有他不能办到的事，专家也一样，大家说对吗？（对的）因此，单纯从理论上讲，专家们的观点理论，确实够权威专业，可是真正到咱们每一个人，开始实施它的时候，却又很难办取得，具体表此刻以下的客观缘故：咱们无法掌控，专家也无法掌控，那确实是现代社会，因为过度开发致使了人类生活的大环境，受到了严峻破坏，处处是摩天大楼，从而对地心造成了极大的压力，因此火山海啸，泥石流在全世界频繁出没，地下因为常年过度开采煤矿，将地心挖空，致使地球失去平稳力，丛林受到了过度的砍伐，从而致使生态被破坏，过度建筑从而造成尘埃污染，汽车尾气排放，工业烟囱向天空排放化学气体，致使天空空气造成污染、水污染、环境污染致使田地中的果蔬污染，食物为了延长保质期，为了好卖，从而人为的添加了化学剂，人工色素，防腐剂，甜蜜素，致使饮料营养流失减少，人们的居住环境，因为装修工，人为的以次充好，将有毒的油漆及涂料涂在室内的墙上，从而造成咱们赖以生存的环境空气污染，现代人，因为久居温室里，远离阳光，缺少晒太阳，从而致使躯体虚弱，抗击力下降，免疫力下降，常吹空调，长期在空调下生活工作，就会得空调病，食物污染的案例，真是太多了，在此举几个具代表性的例子供大伙儿检讨：像暖锅底料，商家为了盈利，在暖锅底料中加了化学剂，牛奶中加了三聚氰胺，主食馒头中加了漂白剂，大米中掺了增白剂，玉米中加了糖精，火腿肠中掺了致癌物，肉中加了瘦肉精，注了水，莲藕表面摸了漂白粉，豆腐中掺了米粉、石灰粉，扎啤中掺了化学剂，鱼吃了避孕药，鸡、鸭、鹅、猪、牛在大型圈养场，服用了大量生长激素。
英语课前5分钟的演讲稿大全6篇
英语课前5分钟的演讲稿大全6篇英语课前5分钟的演讲稿大全 (1) ladies and gentlemen, this is joe biden, i'm filling in for presidentobama, while he addresses the nato summit in wales.when the president and i took office in january of , this nation wasin the midst of the greatest economic crisis since the great depression.our economy had plummeted1 at a rate of 8% in a single quarter-part ofthe fastest economic decline any time in the last half century. millionsof families were falling underwater on their homes and threatened withforeclosure. the iconic american automobile2 industry was under siege.but yesterday's jobs report was another reminder3 of how far we'vecome. we've had 54 straight months of job creation. and that's the longeststreak4 of uninterrupted job growth in the united states' history.we've gone from losing 9 million jobs during the financial crisis tocreating 10 million jobs. we've reduced the unemployment rate from 10%in october of to 6.1% today. and for the first time since the 1990s,american manufacturing is steadily5 adding jobs-over 700,000 since . andsurveys of both american and foreign business leaders confirm that americaonce again is viewed as the best place in the world to build and invest.that's all good news.but an awful lot of middle class americans are still not feeling theeffects of this recovery. since the year , gross domestic product-our gdp- has risen by 25%. and productivity in america is up by 30%. but middleclass wages during that same time period have gone up by only fourteencents.folks, it's long past time to cut the middle class back into the deal,so they can benefit from the economic growth they helped create. folks, there used to be a bargain in this country supported by democrats6 and republicans, business and labor7. the bargain was simple. if an employee contributed to the growth and profitability of the company, they got to share in the profits and the benefits as well. that's what built the middle class. it's time to restore the bargain, to deal the middle class back in. because, folks, when the middle class does well, everybody does well-the wealthy get wealthier and the poor have a way up.you know, the middle class is not a number. it's a value set. it means being able to own your home; raise your children in a safe neighborhood; send them to a good school where if they do well they can qualify to go to college and if they get accepted you'd be able to find a way to be able to send them to college. and in the meantime, if your parents need help, being able to take care of them, and hope to put aside enough money so that your children will not have to take care of you.that's the american dream. that's what this country was built on. and that's what we'redetermined8 to restore.in order to do that, it's time to have a fair tax structure, one that values paychecks as much as unearned income and inherited wealth, to take some of the burden off of the middle class. it's time to close tax loopholes so we can reduce the deficit9, and invest in rebuilding america - our bridges, our ports, our highways, rails, providing good jobs.with corporate10 profits at near record highs, we should encourage corporations to invest more in research and development and the salaries of their employees. it's time for us to invest in educational opportunity to guarantee that we have the most highly skilledworkforce11 in the world, for 6 out of every 10 jobs in the near term is going to require some education beyond high school. folks, it's long past due to increase theminimum wage that will lift millions of hardworking families out ofpoverty target poverty and in the process produce a ripple12 effect thatboosts wages for the middle class and spurs economic growth for the unitedstates of america. economists13 acknowledge that if we do these and otherthings, wages will go up and we'll increase the gross domestic productof the united states.my fellow americans, we know how to do this. we've done it before.it's the way we used to do business and we can do it that way again. allthe middle class in this country want is a chance. no guarantee, just achance.americans want to work. and when given a fair shot, the american workerhas never, ever, ever, let his country down. folks, it's never a good betto bet against the american people.thanks for listening.英语课前5分钟的演讲稿大全 (2) My hometown is very beautiful, there are many beautiful places, butmy favorite is the banyan tree.Spring, the banyan tree branches out grow pale green leaves, the grassunder the tree leaned out of his head, as if to say: "the world is reallybig ah!" The flowers have opened smiling face, as if to say: "the worldis really beautiful! I want to hurry and grow up." A breeze blowing, thebanyan tree is say "hello" to us!In summer, the banyan tree branches more lush and green, like the jade.We often to the banyan tree shade and playing. Banyan tree zhefengdangyufor us, for we are blocking the sun's radiation. The banyan tree isblocking our view of the blue sky, looked from a distance, like a big greenumbrella, brings us a cool.Autumn, banyan tree leaves turn yellow, autumn mother-in-law deeplybreathed a sigh of relief. Banyan tree mother left their mother's arms,look! How sad they are! When I stepped on banyan tree after mother's baby,they will "sasha vujacic" to cry, don't they know it hurt? When I steppedon some hesitation, afraid to hurt it.Winter, snow flying, like white butterflies fluttering and dancing.Aunt wind blew breath deeply, banyan shivered with cold, good snow girldressed banyan tree in a sheepskin coat, banyan tree feel warm a lot of,is really fantastic!I love my hometown, love home banyan tree.英语课前5分钟的演讲稿大全 (3) My home village is a small one. It’s in Yuxian county of ShanxiProvince. Small as it is， it’s very beautiful.There are many hills around my home village and they are more beautifulthan some big mountains. In spring， we can fly kites which are made byourselves on the top of the hills. The kites fly very high.In summer，the trees are green and the grass is green， too. It is green everywhereon the hills. There are so many wild apple trees on the hills. The wildapples are nice to eat. In autumn， the corns under and around the hillsare ripe. So we eat them almost every day. In winter， when it snows，all the ground is covered with snow. We can play with snow and sometimeswe eat the clean snow with sugar. In my hometown the sky is blue， theair is clean， the water is sweet and the people are very friendly. I lovemy hometown!我的家乡是位于山西盂县的一个小村庄。
玉米种植讲稿（DOC）
⽟⽶种植讲稿（DOC）⽟⽶种植培训班讲稿（教案）⼀、⽟⽶的整地与播种（⼀）整地1、⽟⽶整地的好处，如何进⾏整地（⼆）播2、⽟⽶发芽与出苗过程，影响⽟⽶发芽的主要环境条件3、提⾼播种质量对⽟⽶⾼产有什么重要意义，如何提⾼播种质量4、播种前为什么要进⾏种⼦精选和发芽试验，怎样进⾏5、为什么播种前要进⾏种⼦处理，如何进⾏6、⽟⽶适时早播为何能增产，早播的⽅法有哪些7、⽟⽶有哪⼏种播种⽅法，各有什么特点⼆、⽟⽶的合理密植（⼀）⽟⽶合理密植的重要性8、⽟⽶为什么要适当增加种植密度9、合理密植增产的原因（⼆）⽟⽶密植的原则与技术10、确定适宜种植密度应掌握哪些原则11、紧凑型品种适宜密植的原因12、合理密植技术有哪些13、怎样确定⽟⽶的适宜株距三、⽟⽶的施肥（⼀）⽟⽶的需肥特点14、⽟⽶的需肥量是多少15、⽟⽶不同⽣育期对氮、磷、钾的吸收（⼆）⽟⽶的施肥原则与技术16、施⽤化肥的增产效果如何，受哪些因素影响17、如何确定⽟⽶的施肥量18、合理施肥应掌握的原则19、⽟⽶正确的施肥⽅法20、⽟⽶需要多少微量元素，如何施⽤微肥四、⽟⽶灌溉（⼀）⽟⽶的需⽔特点21、⽟⽶产量与需⽔量的关系22、⽟⽶需⽔量与⽣长环境的关系23、⽟⽶不同⽣育阶段的需⽔特点24、如何通过栽培措施实现⽟⽶少需⽔多打粮（⼆）灌溉与节⽔25、⽟⽶什么时期最需要浇⽔26、⽟⽶节⽔灌溉的⽅法和优点五、⽥间管理及化学除草（⼀）⽥间管理27、间苗、定苗应注意的问题28、中耕松⼟的作⽤和应掌握的原则29、培⼟的作⽤、时间和⽅法30、⽟⽶去雄穗和⼈⼯辅助授粉的作⽤，如何进⾏（⼆）化学除草31、化学除草的意义和作⽤原理32、使⽤化学除草剂必须注意哪些原则33、常⽤⽟⽶除草剂的使⽤要求34、混配型除草剂有哪些优点六、⽟⽶栽培新技术（⼀）地膜覆盖35、盖膜⽟⽶的增产效果如何，增产的原因36、盖膜⽟⽶如何选⽤地膜和计算⽤量37、盖膜⽟⽶对品种、⼟壤和肥料的要求38、盖膜⽟⽶的种植要点39、怎样进⾏盖膜⽟⽶的播种和⽥间管理（⼆）种⼦包⾐和化学调控40、何为种⾐剂，使⽤种⾐剂的优点41、⽟⽶的种⾐剂有⼏种，如何进⾏⼈⼯包⾐42、⽟⽶应⽤的⽣长调节剂有哪些，如何使⽤七.⽟⽶抗旱播种技术⼲旱地区或⼲旱年份常采⽤（1）抢墒播种（2）提墒播种（3）深开沟浅覆⼟播种（4）明沟深种（5）开沟等⾬（6）催芽坐⽔等抗旱播种法2.夏⽟⽶贴茬免耕播种技术（1）浇好麦黄⽔（2）贴茬机播（3）播种后出苗前喷施化学除草剂（4）⼿提苗（5）加强⽥间管理3.夏⽟⽶⾼产栽培的施肥要点⽟⽶⼀⽣需要的营养元素很多，以氮、磷、钾需求量最⼤，要通过施肥补⾜，⾼产栽培中基肥施⽤量占70%，追肥占30%，磷肥全部底施于上季作物上，氮肥施⽤原则供秆肥占总追肥量的60－70%，攻穗肥占30－40%，攻粒肥于吐丝前施⽤，不超过10%，钾肥底施。
玉米PPT讲稿
呕吐毒素 (DON)
赭曲霉毒素A (OA)
T2-毒素
限量（ppb）
50
500
1000
100
1000
备注
GB130782001
GB13078.22006
猪配合料
GB13078.32006
GB13078.22006
猪配合料
GB216932008
小结
• 1、粉质玉米优于硬质玉米（教乳料中）； • 2、注意玉米陈化：脂肪酸值； • 3、吉林烘干玉米质优稳定； • 4、国家标准中：生霉粒≤2.0，水分≤14.0；
3、玉米种类
按种皮颜色分为
黄玉米：95%以上黄色，或略带红色：目前主流 白玉米：95%以上白色，或略带淡黄或略带粉红 混合玉米：不符合以上两者
按性状特点分为
粉质玉米：直链淀粉，用于教乳料，容重低 胶质玉米
陈化玉米
粉质玉米与胶质玉米区别
品种 粉质玉米
胶质玉米
形状 淀粉 结构 产地
马齿状
直链淀 粉高
3、价值评定
品种
描述
水分，%
CP，%
DE，
ME，
NE，
kcal/kg kcal/kg kcal/kg
玉米 2级,中国2010版
14
7.8
3390
3200
2640
玉米
普通，NRC2012
11.69 8.24
3451
3395
2672
水分对玉米价值的估算
水分含量
猪消谢能 消谢能差异 相当油脂量 价值差异(元/
涩
涩
收缩 凹陷
不动 光滑 弱
收缩 凹陷 轻微掐痕 光滑 弱 无 凹陷 有微响 光滑 有
中石油职称英语课文讲稿1-60第01课 (33)
34.Super Athlete of the Sangamon[桑格蒙郡].超级运动员1. Two wrestlers[(wrestler):n.摔角选手] stood in a circle of shouting onlookers[(onlooker):n.旁观者] and sized up each other. One was of medium height, sturdily[(sturdy):a.结实的] built and strong as an ox. He was stripped[脱光衣服]to the waist[n.腰,腰部], revealing[(reveal):v.露出] a huge chest[n.胸部]overlaid[覆盖]with hard muscle. His arms were like the limbs[树枝] of a tree. The other man towered[高于] over him, six feet and four inches tall and slender[a.苗条的],his long arms dangling[(dangle):vt.摇摆]from his shoulders. His muscles were long and smooth[a.光滑的], like those of a panther[n.豹]. The muscle man was Jack Armstrong. His tall opponent[n.对手] was 22-year-old Abraham Lincoln.1、两个摔跤手站在一圈嚣叫的旁观者中心，互相打量着对方。
一个是中等身材，肌肉结实，体壮如牛。
他光着上身，露出宽大、厚实、满是肌肉的胸部，胳膊像树干一样粗。
另一个人远远高出对手，6英尺4英寸高，身材细长，他的长胳膊摇晃着从肩膀垂下来。
美食英语三分钟演讲稿10篇
美食英语三分钟演讲稿10篇美食英语三分钟演讲稿 (1) we know the nature of impeachment. we've been talking about it awhilenow. it is chiefly designed for the president and his high ministers tosomehow be called into account. it is designed to "bridle" the executiveif he engages in excesses. "it is designed as a method of national inquestinto the conduct of public men."² the framers confided in the congressthe power if need be, to remove the president in order to strike a delicatebalance between a president swollen with power and grown tyrannical, andpreservation of the independence of the executive.the nature of impeachment: a narrowly channeled exception to theseparation-of-powers maxim. the federal convention of 1787 said that. itlimited impeachment to high crimes and misdemeanors and discounted andopposed the term "maladministration." "it is to be used only for great misdemeanors," so it was said in the north carolina ratificationconvention. and in the virginia ratification convention: "we do not trustour liberty to a particular branch. we need one branch to check the other.""no one need be afraid" -- the north carolina ratification convention-- "no one need be afraid that officers who commit oppression will passwith immunity." "prosecutions of impeachments will seldom fail to agitatethe passions of the whole community," said hamilton in the federalistpapers, number 65. "we divide into parties more or less friendly orinimical to the accused."³ i do not mean political parties in that sense.the drawing of political lines goes to the motivation behindimpeachment; but impeachment must proceed within the confines of theconstitutional term "high crime[s] and misdemeanors." of the impeachmentprocess, it was woodrow wilson who said that "nothing short of the grossestoffenses against the plain law of the land will suffice to give them speedand effectiveness. indignation so great as to overgrow party interest maysecure a conviction; but nothing else can."common sense would be revolted if we engaged upon this process forpetty reasons. congress has a lot to do: appropriations, tax reform,health insurance, campaign finance reform, housing, environmentalprotection, energy sufficiency, mass transportation. pettiness cannot beallowed to stand in the face of such overwhelming problems. so today weare not being petty. we are trying to be big, because the task we havebefore us is a big one.美食英语三分钟演讲稿 (2) "You are what you eat."Nutrition experts often use this saying topromotebetter eating habits.What we put in our mouths does become a partof us.But wecan look at this statement another way.What we eat reflectswho we are--aspeople and as a culture.Do you want to understand anotherculture?Then you oughtto find out about its food.Learning about Americanfood can give us a real tasteof American culture."你吃什么就成为什么样子"营养专家经常使用这句话来倡导更好的饮食习惯，入嘴的东西确实成为我们的一部分.但我们也可以从另一个角度来看这句话，我们所吃的反映出我们自己--不论就人或文化而言.你想了解另一种文化吗?那么你应该去认识他们的食物.认识美国食物可以让我们得知美国文化的精髓。
三分钟英语故事
三分钟英语故事篇一：英语三分钟故事Monkeys fishing month One day, a little monkey is playing by the well. He went to in the well look,shouted: “oh! My god! The moon has fallen into a well!” A big monkey runsover, takes a look, and says: “my god! The moon is really in the water.” Oldmonkey is also running over. He was surprised, cried out: “bad, the moon isreally in the water.” A group of monkeys run to the well, they see the moon inthe well, shout: “the moon is really in the water! Come on! Let’s pick it out！”Say, old monkey hangs upside down in the big tree, took the big monkey feet,the other monkeys follow, they join each other one by one until the well. Theyjust want to touch the moon, the moon is looking up old monkey found hangingin heaven towards them laugh! It excited to shout loudly: “look, the moon isstill a good hanging in the sky!猴子捞月一天,有只小猴子在井边玩儿。
介绍美食的英语演讲稿2020
介绍美食的英语演讲稿2020美食带来的是一种情怀，一段回忆，一片乡愁，一种人生。
一起来看看介绍美食的英语演讲稿2020，欢迎查阅!介绍美食的英语演讲稿1Food Culture in Western CountriesIn England, people always have some bread and milk for breakfast on weekday which is always in a hurry. But on weekends, breakfast is a big feast with bacon, porridge, coffee, eggs, toasts, cakes, and so on.在英国，人们总是在工作日的时候匆匆忙忙的吃一些面包和牛奶来当午餐。
但在周末，早餐是非常丰富的，有培根，鸡蛋，粥，咖啡，面包，蛋糕等等。
As for lunch, it's always so simple. People usually have a sandwich or a hot dog. Some people also eat in a fast-food restaurant nearby. This meal won’t last very long.至于午餐，却总是那么简单。
人们通常吃一个三明治或热狗。
有些人在附近的快餐店吃。
这顿饭不会持续很长时间。
Dinner is the biggest meal with potato, beef, chicken, soup, and some desserts. At this meal, people usually sit around the table and talk about their daily events. This is the best time for family gathering.晚餐是最丰富的有土豆，牛肉，鸡肉，汤，和一些甜点。
保护动物的英语演讲稿学生(精选15篇)
保护动物的英语演讲稿学生（精选15篇）保护动物的英语演讲稿学生篇1动物是人类的好朋友，人们应该善待它们，但现在，中国和世界上的许多人为赚钱而捕杀动物。
众所周知，中国有许多珍稀动物，如熊猫、金丝猴等。
一些人捕杀它们是为了用它们的皮毛制衣制鞋，或是为了食用它们的肉。
结果大量的珍稀动物死亡了，真可惜呀!目前，我国政府已制定出有关严惩不法分子的法律;近来又建起了一些自然公园;人们：也捐款来支持保护动物的活动，如，有些学生通过义演或用其它方式为保护珍稀动物积极筹款。
我们有义务保护野生动物，因为自然就像一个大家庭，人类和动物必须和平共处：我们必须保持生态平稳。
如果人类能这么做，这个世界就会越来越好。
Animals are our good friends. People should be friendly to them. Butnow,many people in China as well as in the world kill animals in order to get money.It's well known that there are many kinds of rare animals in China, such aspandas, golden monkeys and so on. Some people catch or kill them. They use theirfurs and skins to make clothes and shoes or eat their meat. As a result, a lotof rare animals have disappeared.What a pity!At present, our government have made some plans to punish thesepeople.Recently, some nature parks have been built. Lots of money collected forprotecting them. For example, some students put on perfom ances or have otherkinds of activities to collect money for rare animals.It's our duty to protect wild animals. As nature is like a big family, manand animals must live together in it peacefully. We must keep the balance ofnature. If we do like this, our world will become better and better.保护动物的英语演讲稿学生篇2Many animals are in danger of dying out. As is shown in the chart, we cansee the number of animal species decreases faster and faster and this trend willcontinue. From 1980 to 20__, at least 1 million animal species have disappeared.Worse still, more and more wild animals are in great danger. It is nota pieceof sensational news; it is a fact, a harsh reality. Unfortunately, we may notsee these animals in the near future.From the second picture, we can find some reasons. Why is the number ofanimal species declining year by year? Apparently animals have become victims offashion industry. Animal skin has been used to make fashionable clothes andthese clothes sell at a high price. So some greedy people begin to kill animalsin a large quantity. This irresponsible behavior not only breaks the balance ofnature but also endangers the living environment of human beings.As far as I am concerned, something must be done to stop this illegalaction. We believe "no buying, no killing". First, we must make concerning lawsto protect these animals in danger. Second, we must take some measures toprotect animals effectively. Animals are our friends and part of ourenvironment. Third, we should raise people's awareness to protect animals andour environment. In this way, we can build a harmonious society and ensure asustainable development.许多动物都在逐渐消失的危险。
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Effect of water stress on maizeAbstract: Water stress is one of the main restricting factors for maize production. [1] Water stress on various physiological processes of maize have a certain influence, including photosynthesis, respiration, nitrogen metabolism and growth.。
In addition, the influence of different moisture content of corn leaf area, stem diameter , root-shoot ratio and other growth indicators.[2] Thus affecting the yield of maize. The result of maize experiment with water stress in different growing stage showed that soil drought stress in many growing stage could lead to yield decreasing. Under water affect of seeding stage is faintish comparatively.[3]Key words: Maize; Water stress; YieldMaize as the 3rd largest food crops in China, occupies an important position in the national economy. Maize production losses caused by natural disasters in other agricultural production in the first place.[4] And the water stress is the most important factor in maize production constraints. Therefore, the study of water on the yield of corn is very important.1、Water stress on physiological processes of maizeThe relationship between photosynthesis and water potential of maize is very close. Water deficit of maize leaf green protein degradation, destruction of chlorophyll, reducing the absorption of light energy. At the same time, chlorophyll protein is composed of membrane composition, leaf green protein degradation, the structure of the membrane damage, thus affecting the electron transport, inhibition of photosynthetic phosphorylation, so that the driving force for CO2 assimilation and NDPH2 ATP production decreased. Photosynthesis is inhibited, production decline.According to Boyer.JS (1970) Study: When leaf water potential below-0.3Mpa, the rapid increase in respiration of maize; when the leaf water potential below-0.7Mpa, the decrease in water content, respiration rate and decrease. Serious water shortage P \ O values decreased oxidative phosphorylation coupling resolve, respiration was inhibited.The water stress on nitrogen metabolism is the process of protein synthesis weakened; growth and development process of cell division and the squadron have a significant increase of inhibition.[4],2008年2、Water stress influence maize plant growth indexDry conditions, corn stem diameter was significantly thicker.[2]，44页，2009年Water stress produce high specific leaf weight, severe water stress is area reduction and even leaves to die. Occur water stress, maize can be hairy leaves reduced by leaf area, in order to enhance water diffusion resistance, and make accepting sunshine of leaf area decline.In addition, occurred in water stress, carbohydrate more assigned to the root, increase the root-shoot ratio, reduce the ground photosynthesis production accumulation.3、Water stress in different growth stages of maize influence名称正常供水（CK）苗期胁迫（MH) 拔节期胁迫（BH）抽雄吐丝期胁迫（TH）常量（g\株）生物产量（g\株）常量（g\株）生物产量（g\株）常量（g\株）生物产量（g\株）常量（g\株）生物产量（g\株）农大108 172.55 357.68 155.75 316.57 155.22 327.96 115.85 283.93 京科308 174.82 335.87 168.85 312.52 174.89 345.04 151.56 299.46 吉单261 187.64 342.55 172.54 329.52 132.64 270.61 89.04 228.66 中单808 198.67 366.88 177.39 337.00 187.98 353.63 119.25 275.46 丹玉39 212.61 409.54 191.16 379.73 176.72 350.06 114.30 273.79 郑单958 222.67 367.11 175.07 287.92 178.20 292.85 104.27 204.97 平均值194.83 363.27 173.46 327.21 167.61 323.36 115.71 261.04[3],99页，2009年Maize yield results show that different childbearing period of water stress which can lead to corn grain yield decreased, no significant difference between varieties, significant difference between treatment. Tasseling in silking stage water stress reduction is the most serious, jointing stage next, seedling cut the minimum, with contrast differences significant yield and in silking stage, tasseling of photographic comparative differences extremely significant. Water stress also enable maize biological yield decreased, tasseling in silking stage the greatest reduction, next is jointing stage, seedling minimum.Experience different growth stages of corn water stress will undoubtedly lead to plant dwarf, growth delay, deterioration of ear characteristics, so that biological and economic yield droppedsignificantly and so the impact of maize under water stress level, because of drought severity, duration, and birth process The differences vary, the more severe drought, the longer the duration, is affected by the more even.References[1] 《春玉米不同品种抗旱性及水分利用效率研究》（程明、周继华、王克武、张娜）（《玉米雨养旱作科技示范工程论文集》（79页，2009年）赵久然宋慧欣杨国航编）[2] 《模拟不同降水年型对玉米生长和水分利用的影响》（周继华、王克武、张娜）（《玉米雨养旱作科技示范工程论文集》（41页，2009年）赵久然宋慧欣杨国航编）[3] 《Effect of Water Stress on Maize Yield During Different Growing Stages》（BAI Xiang-li1,SUN Shi-xian2,Y ANG Guo-hang3,LIU Ming1,ZHANG Zhen-ping1,QI Hua1）（《玉米雨养旱作科技示范工程论文集》（97页，2009年）赵久然宋慧欣杨国航编）[4] 《Response of DifferentMaize Varieties to Drought Stress》（2008年）(HAN Miaom iao, ZHANG Renhe, ZHU Yongbo, BUL ingduo, XUE Jiquan)[5] 《玉米生育和产量模型》（166页—168页，1997年）（佟屏亚程延年著）[6] 《Effects of soil water stress on morphological development and yield of maize》（2004年）（BAI Li-Ping, SUI Fang-Gong, SUN Zhao-Hui, GE Ti-Da, LU Yin-Yan, ZHOU Guang-Sheng）[7]《Effect of Water Stress on Maize Kernel Yield and Ear Characterist ics During T asselling Stage》（2002年）（ZHAO Tian hong, SHEN Xiu ying, Y ANG De guang）。