问题 问答题 简答题

解释作物的温光反应特性,试述温光反应特性在农业生产上的应用。

答案

参考答案:

作物的温光反应特性:指作物必须经历一定的温度和光周期诱导后,才能从营养生长转为生殖生长,进行花芽分化或幼穗分化,进而才能开花结实。作物对温度和光周期诱导反应的特性,称为作物的温光反应特性。在农业生产上的应用:在引种上的应用:纬度和海拔相近的地区相互引种、南北相互引种、海拔高低不同的地方相互引种在栽培上的应用:作物品种的使用;作物播种期的安排等在育种上的应用:在杂交育种时,应用温光反应特性解决两亲本花期相遇问题。

单项选择题
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●The first double hand transplant patient in the US has left a hospital after medicine cleared up

small red spots on his skin that signaled he might be rejecting his new hands. Jeff Kepner, a 58-year-old former chief cook in a restaurant, lost his hands and feet a decade ago to a bacteria infection. The donor was a 23-year-old man.

●A second major storm in less than a week was blowing yesterday toward the Washington area, where federal government offices were closed for a second day and workers struggled to restore power knocked out by a weekend heavy snowstorm. The storm could leave as much as 20 inches (50 centimeters) of new snow in Washington and nearly as much near Philadelphia –a Northeast travel-hub by tonight.

●British Prime Minister Gordon Brown will give evidence to a public inquiry into the Iraq War in early March, officials for the inquiry said yesterday. Brown’s appearance, just weeks before an election expected in May, could hit the ruling Labour Patry’s attempts to catch up in the polls (民意调查)behind the opposition party Conservatives. Brown, who will be questioned about his time as prime minister, will be a witness in the highest position at the inquiry since former Prime Minister Tony Blair’s appearance last month.

●The head of the UN agency aiding Palestine refugees (难民)is warning a funding shortfall and appealing for another $100 million. Filippo Grandi says the money is necessary for education, health and social services for 4.7 million Palestinian refugees scattered across Jordan, Syria, Lebanon, the West Bank and the Gaza Strip. The agency’s 2010 budget is $620 million, and it expects a shortfall of $140 million. The agency says $100 million is necessary for basic services.

64.The passage is most probably adapted from        .

A.new items in a newspaper       B.descriptions of the world situation

C.discussions on foreign affairs  D.statements of a government report

65.It can be inferred from the passage that        .

A.the man lost his hands for an unknown reason

B.the result of the transplant operation seems satisfying

C.another storm will hit Washington area in less than a week

D.the electricity supply was cut off in Philadelphia a week ago

66.According to the passage, Gordon Brown          .

A.is the leader of the ruling Labour Party in Britain

B.will send army to the Iraq War in March this year

C.will compete with former Prime Minister Tony Blair

D.is now gaining more support from voters than others

67.Which of the following statements is TRUE according to the fourth news?

A.$100 million should be needed for the survival of the refugees.

B.At least $100 million is to be raised for Palestinian refugees.

C.The refugees mentioned in the passage are in the Middle Africa.

D.It is a tough job for the UN agency to get money for the refugees.