第一章 植物的水分代谢

第一章植物的水分代谢

一填空题

1 淀粉磷酸化酶在pH值降低时催化________转变为________，在光下由于光合作用的进行，保卫细胞中的________减少，pH值上升。

2 典型植物细胞的水势是由________组成的，细胞间水分子移动的方向决定于________，即水势________的细胞向水势________的细胞方向流动。

3 植物根系吸水的动力是________和________，其中________较为重要。

4 将已发生质壁分离的细胞放入清水中，细胞的水势变化趋势是________，细胞的渗透势________，压力势________。当________时，细胞停止吸水。

5 水分在植物细胞内以________和________状态存在，________比值大时，代谢旺盛；________比值小时，代谢降低。

6 在相同________下，一个系统中一偏摩尔容积的________与一偏摩尔容积的________之间的________，叫作水势。

7 ________和________现象可以证明根压的存在。

8 当相邻两个植物细胞连在一起时，水分移动方向决定于两端细胞的________。

9 植物对蒸腾的调节方式有________、________和________。

10 植物根部吸水能力最强的部位为________，因为________________。

二是非题

1 Leave is always the source and root is always the sink in the source-sink relationship.

（）

2 Osmotic adjustment is an active process in reducing the plant osmotic potential during water deficiency. （）

3 小麦从灌浆期倒乳熟末期是它的第二水分临界期。（）

4 伤流速度主要取决于木质部溶液与外界溶液的水势差。（）

5 深秋的早晨，树木花草叶面上有许多水滴，这种现象称为吐水。（）

6 落叶乔木在春天芽刚萌动时主要依靠根压吸收水分。（）

7 植物的蒸腾比率越大，说明其越抗旱。（）

8 土壤中水分越多，对植物吸收越有利。（）

9 植物蒸腾系数大，说明其利用水效率低。（）

10 蒸腾效率高的植物，一定是蒸腾量小的植物。（）

11 具液泡的细胞，其衬质势数值很小，通常忽略不计。（）

12 细胞水势在根部距离导管越远，则越高。（）

三选择题

1 The direction of water movement between adjacent cells is determined by the _______ gradient of the cells.

A. water potential

B. osmotic potential

C. pressure potential

D. matric potential

2 The loss of water from plants is called ____ and typically occurs through the ____.

A. evaporation, leaves

B. transpiration, leaves

C. transpiration, stem

D. osmosis, roots

3 Through which part of the leaf does water transpire?

A. stomata

B. epidermis

C. xylem

D. chloroplast

4 When the guard cells have a ___ water pressure, they become ____ and close the stoma.

A. low, turgid

B. low, flaccid

C. high, turgid

D. high, flaccid

5 Which of the following systems functions to absorb water and minerals?

A. leaf

B. stem

C. root

D. flower

6 A cell that is hypertonic...

A. will experience a net movement of water into the cell from the surrounding environment.

B. has a lower concentration of solutes than the surrounding environment.

C. will experience a net movement of water out of the cell into the surround environment.

D. is in danger of plasmolysis.

7 What is the term for a situation in which water osmoses out of a cell and into the surrounding environment?

A. lysis

B. plasmolysis

C. hemolysis

D. hydrostatic pressure increase

8 Which types of molecules usually will not pass through the membrane's lipid core?

A. permeable

B. nonpolar

C. small

D. polar

9 During the two procedures from lab, what was the indicator that cell membranes were damaged?

A. Betacyanin leaked from the tonoplast and the plasma membrane, turning the water red.

B. Betacyanin was absorbed from the water turning the tonoplasts red.

C. Tonoplasts were produced.

D. The cell membrane pulled away from the cell wall.

10 吐水时由于高温高湿环境下

A. 蒸腾拉力引起的

B. 根系生理活动的结果

C. 土壤中水分太多的缘故

D.空气中水分多的缘故

11 把植物组织放在高渗溶液中，植物组织是________

A. 吸水

B. 失水

C. 水分动态平衡

D. 水分不动

12 水分沿导管或管胞上升的主要动力是________

A. 吐水

B. 内聚力