问题 实验题

下图是桃花的结构示意图,请据图回答下列问题。(图例:[ 7 ]卵细胞

(1)该图除了表示桃花的主要结构外,还可表示桃花的     过程。花谢以后要结桃子,还要经历的另一个重要生理过程是             

(2)图中序号1、2所示结构共同组成         

(3)我们平时所吃的桃子,其食用部分是由图中的[   ]       发育而来的。

(4)亟需改良桃树品种,而且能够短时间内取得效益,采取最合理的办法是       

答案

(1)传粉;受精

(2)雄蕊

(3)3子房壁

(4)嫁接

题目分析:图中1是花药,2花丝,3子房壁,4柱头,5花柱,6花瓣,7卵细胞.

(1)该图中1花药中的花粉散落到4柱头上,这个过程成为传粉,此后花粉生出花粉管,花粉管穿过花柱,进入子房,一直到达胚珠的珠孔.将精子输送到胚珠与卵细胞在胚珠中结合,形成受精卵.这过程就叫受精.而后受精卵发育成种植的胚;胚珠发育成种子;子房发育成果实.

(2)让我们观察实物图我们可以看出雌蕊包括柱头、花柱和子房;雄蕊包括花药和花丝

(3)我们平时所吃的桃子,其食用部分是果皮,受精完成后子房发育为果实,子房壁发育为果皮,胚珠发育为种子,受精卵发育为胚.因此桃子的食用部分是果皮是由子房壁发育而来的。

(4)嫁接是指把一个植物体的芽或枝,接在另一个植物体上,使结合在一起的两部分长成一个完整的植物体。嫁接时,接上去的芽或枝叫接穗,被接的植物叫砧木,嫁接时应当使接穗和砧木的形成层紧密结合,以确保成活,因为形成层具有很强的分裂能力,能不断分裂产生新细胞,使得接穗和砧木长在一起,易于成活。因此,欲改良桃园中的桃树品种,应采取嫁接的方式。

阅读理解

阅读下面短文,简要回答所给问题。

                                              Thumbs Down to Texting 屈指发短信

     Do you have a mobile phone? Do you send text messages to your friends and family?

    Text messaging or "texting" is becoming very popular. But, scientists have discovered that texting can

  give us problems with our hands. Be careful! Too much texting can cause swelling (肿胀) in our

 thumbs.  Our thumbs were not made for pushing small buttons, over and over.  Scientists call this problem

  RSI.  We spoke to a doctor called Harriet Wilson, who treats many sick people with RSI. She says we

 need to see how much time we are spending in typing text messages.  If we are spending more than 10-15

  minutes at once, we could have problems in the future.

     As mobile phones develop, they are getting smaller with buttons closer together. Texting with a smaller

  phone is worse than using a larger phone with bigger buttons.Using a computer keyboard and playing

 video games can cause the same problem.  So more and more people could find themselves with RSL 

 Among them, most are university students and teenagers, as they do not know the risks of spending so

 much time using computer, video games and mobile phones. If we don't do something about this, too

 many young people could grow up in terrible pain.

    Note: RSI abbr .肢体重复性劳损 (repetitive strain injury).

1. What is becoming very popular now according to the passage?

    ______________________________.

2. Does the word "once" mean "one time" in the second passage?

    ______________________________.

3. What kind of people are easier to have the problem of RSI?

    ______________________________.

4. What can also cause RSI besides texting?

    ______________________________.

5. Which is easier to cause the problem of RSI,  using smaller mobile phones or larger ones?

    ______________________________.