问题 单项选择题

下列药材组织中,具有异型维管束的是

A.沉香

B.大血藤

C.木香

D.鸡血藤

E.降香

答案

参考答案:D

解析:

鸡血藤【显微鉴别 】茎藤横切面:木栓细胞数列至数十列,微木化至木化,有的含棕色物。栓内层为2-4列细胞,内含棕色物。皮层窄,细胞10余列,含黄棕色物;石细胞众多,成群散在,层纹、孔沟明显,胞腔内充满红棕色物,少数含草酸钙方晶,其周围有的薄壁细胞含草酸钙方晶,含晶细胞壁木化增厚;分泌细胞少数,散在。维管束异型,由韧皮部与木质部相间排列成数个偏心性环。每轮韧皮部最外侧为石细胞与纤维组成的厚壁组织环带,环带内外两侧细胞有时含草酸钙方晶;韧皮部分泌细胞常数个至10多个切向排列成层,含黄棕色、红棕色或金黄色分泌物;纤维束众多,散在,其周围细胞含草酸钙方晶形成晶纤维;石细胞少数,散在;射线宽l-4列细胞,弯曲,多被挤压。形成层明显。木质部导管多单个或2个并列散在,直径约400μm,有的内壁附有棕色块状物,多呈新月形;木薄壁细胞多围绕导管,壁稍厚,多含棕色物,其间散布分泌细胞;木纤维亦均形成晶纤维,几呈层状排列;木质部射线细胞纹孔明显,有的含棕色物。髓小,偏心,环髓分泌细胞多数。

阅读理解

阅读理解。

    People in the United States honor their parents with two special days: Mother's Day, on the second Sunday

in May, and Father's Day, on the third Sunday in June. These days are set aside to show love and respect for

parents. They raise their children and educate them to be responsible citizens. They give love and care. These

two days make us think about the changing roles of mothers and fathers. More mothers now work outside the

home. More fathers must help with child care. 

    These two special days are celebrated in many different ways. On Mother's Day people wear carnations

which have two colors. A red one symbolizes (象征) a living mother. A white one shows that the mother is

dead. Many people attend religious services to honor parents. It is also a day when people whose parents are

dead visit the cemetery. On these two days families get together to have parties at home, as well as in

restaurants. These are days of fun and good feelings and memories.

    Another tradition is to give cards and gifts. Children make them in school. Many people make their own

presents. These are valued (珍爱) more than the ones bought in stores. It is not the value of the gift that is

important, but it is "the thought that counts". Greeting card stores, florists, candy makers, bakeries, telephone

companies, and other stores do a lot of business during these holidays.

1. Which of the following is NOT a reason for children to show love and respect for parents?

A. Parents bring children

B. Parents give love and care to children

C. Parents educate children to be good persons.

D. Parents pass away before children grow up

2. What do you know from the passage?

A. Mother's Day and Father's Day are both in May.

B. Fewer women worked outside the home in the past

C. Not all the children respect their parents

D. Fathers are not as important as mothers at home

3. Which do you think is right about "carnation"?

A. It has only two kinds of colors.

B. It refers to the special clothes people wear on Mother's Day or Father's Day.

C. It's a kind of flower showing love and best wishes.

D. People can wear carnations only on the second Sunday in May.

4. What do you think "florists" do?

A. They sell flowers

B. They made bread or pastry

C. They offer enough room for having family parties.

D. They sell special clothes for Mother's Day and Father's Day.

填空题