问题 问答题 论述题

论述植物组织培养技术的操作过程?

答案

参考答案:

①预备阶段:包括选择合适的外植体,除去病原菌及杂菌,配制适宜的培养基;

②诱导去分化阶段:诱导产生愈伤组织、原球茎、顶芽和腋芽、不定芽、体细胞胚状体等

③继代增殖阶段:将初代培养的产物切割、分离转接到新鲜的培养基上培养。以增加培养物的数量;④生根培养阶段:愈伤组织经过重新分化形成胚状物,继而生成小植株;

⑤移栽成活阶段:移栽室外,保证适度的光、温、湿条件下以利生长。

阅读理解

Before you make friends, you have to decide who you want to be your friends. Most people like to have friends who like to do the same kind of things they do.

The quickest way to make a friend is to smile. When you smile, people think you are friendly and easy to talk to. It may not be easy at first to smile, but remember most people will stay away from a scared or angry looking face.

One easy way to start a conversation with someone is to say something nice about him. Think about how great you feel when someone says something nice to you. Doesn’t it make you want to keep talking to that person?

Ask your new friends questions about themselves. Who’s their favorite singer, where do they live, what do they do after school are all good questions to start a conversation. Make sure you have something to add to the conversation, too. When someone asks you a question, do have an answer for them. There’s nothing that will stop a conversation quicker than a shrug (耸肩) for an answer.

Kids who show an interest in other kids and who are kind and friendly make good friends. Remember, everyone wants to be around people who like to do similar things and people who are nice to them.

小题1:This passage gives us some advice on _________.

A.how to make friends

B.what kind of person you can make friends with

C.how to start a conversation

D.the importance of smile小题2:Most people like to make friends with those______.

A.who are sad every day.

B.who share the same interest

C.who are fond of talking

D.who say bad things to them小题3:According to the third paragraph, most people enjoy talking to one _______.

A.who is always smiling

B.who seems to be friendly

C.who praises them

D.who points out their shortcomings.小题4:The underlined (划线的)part in this passage means “_______”.

A.being very proud

B.making no answer

C.knowing nothing

D.not hoping to answer

单项选择题