问题 解答题

如图所示是嫁接的一种方法,请回答:

(1)图中的[1]是______,[2]是______,嫁接成败的关键是使二者的______紧密结合在一起.

(2)这样的方法是______.

(3)嫁接这种生殖方式属于______.

答案

(1)嫁接是比较常见的营养繁殖方式,1是接上去的枝条,叫接穗;2是保留根系的植株,叫砧木.由于形成层细胞有分裂的功能,因此,嫁接能否成功的关键是让接穗与砧木的形成层密合在一起.

(2)图中所示的繁殖方法是嫁接中的枝接.

(3)嫁接用的接穗是枝条或芽,枝条、芽都属于营养器官,这种繁殖方式属于营养繁殖.嫁接过程中没有两性生殖细胞的结合过程,因而嫁接又属于无性生殖.

故答案为:

(1)接穗;砧木;形成层

(2)嫁接

(3)无性生殖(营养繁殖)

阅读理解

阅读理解

     The United Nations says more than 900 million people worldwide do not have enough to eat.Officials

say 100 million more could go hungry this year because of the food and financial crises.

     To deal with the situation, the UN World Food Program has started a project to help small farmers.

These farmers are mainly women.Many cannot produce enough food even to feed and support their own

families.

     The new effort is called Purchase for Progress, or P4P.It aims to connect local farmers with

dependable markets.That way, they could get a chance to sell their surplus (剩余) at competitive prices.

P4P will be tested in as many as 21 countries during the next five years.

     The biggest contributor to the project is Bill Gates, through the Bill and Melinda Gates Foundation.

Another donor (捐款者) is the Howard Buffett Foundation, led by a son of the American investor

Warren Buffett.The government of Belgium is also supporting the project in a former colony (殖民地),

now the Democratic Republic of Congo.

     Together these donors have provided more than 76 million dollars for projects in Africa and Central

America.

      Purchase for Progress will work with United Nations agencies, governments and nongovernmental

organizations to help increase crop production.The World Bank Group and other partners are to help

train farmers in better crop management and marketing skills.

      The World Food Program says it expects to buy 40,000 tons of food in the first year using methods

carried out by the project.That will be enough to feed 250,000 people.

     P4P is expected to develop food cooperatives and longterm agreements for buying corn, wheat and

other food crops.About 350,000 farmers could be assisted.

     Officials say the project will change the way the World Food Program buys food in developing

countries.  Executive Director Josette Sheeran says this is the first time her agency will buy a large

amount  of food from small farmers.The agency has traditionally bought most of its food from developing

countries, but through larger trading organizations.

1.  From the passage, we know that________.

A. in all 900 million people worldwide lack food

B. a project has been started to help women farmers

C. there are only two donors to help the project

D. some farmers still cannot support their families

2. According to the passage, ________will work hard to deal with the situation.

A. the United Nations

B. the combined efforts

C. some governments

D. some nongovernmental organizations

3. Which of the following will NOT be done to help small farmers?

A. To donate money.

B. To reform the way of food purchase.

C. To provide them with food.

D. To buy a large amount of food from them.

4. What's the best title for this passage?

A. Project to Help Small Farmers

B. Contribution to Small Farmers

C. Food Problems

D. P4P Is Being Carried Out

选择题