第二节 植物的休眠——植物生理学课件PPT

--by 2000, 2 species still alive
• lotus seeds carbon dated as 1500-3000 years old have germinated
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休眠的类型
1.生理休眠（physiological dormancy）亦称深休眠 在深休眠的中期阶段，植物的生长活动接近最低点，含 水量极低，这时即使给予适应的外界环境条件，也不生 长
Four classes of seed dormancy
1. Physiological dormancy 生理休眠
2. Morphological dormancy 形态休眠
3. Physical dormancy 物理休眠
4. binational dormancy 组合休眠
种子休眠的原因
2.强迫休眠（imposed dormancy）又叫相对休眠 当植物遇到不良环境条件 时，出现生长缓慢或停止状 态，给予适应的条件又开始 萌发生长。
植物的休眠器官
✓种子休眠 ✓芽休眠 ✓变态地下器官休眠
种子休眠 seed dormancy
种子休眠是具有正常活力的种子在适 宜的环境条件下仍不能萌发的现象
Enforced dormancy（强迫休眠） seed
germinate readily upon removal of the environmental limitation.
New Terminology
•Endodormancy: a period of quiescence caused by conditions or factor within the plant or organ itself. (For example the winter rest ) •Paradormancy: Dormancy imposed by physiological factor external to the embryo. Example: inhibitors in testa or pericarp •Ectodormancy: ( also Ecodormancy，exogenous or external dormancy ) a period of quiescence caused directly by adverse conditions, and lasting only while they prevail.
Primary dormancy (初生休眠)occurs during seed
maturation, and the seed does not germinate readily upon being shed.
Secondary dormancy（次生休眠） and
enforced dormancy occur after the seed is shed and may be caused by adverse environmental factors such as high or low temperature, absence of ogen or light, low soil moisture, and presence of chemical inhibitors. Seeds with secondary dormancy will not germinate spontaneously when environmental conditions improve, and need additional environmental stimuli.
第 二 节 植 物 的 休 眠
Plant Dormancy
植物休眠的定义
指在不良环境或特定季节来临时，植物的某些 器官或整株处于生长极为缓慢或者暂停的状态， 并出现保护性结构或形成贮藏器官，即使在适 宜条件下也不恢复生长，以利抵抗和适应恶劣 的外界环境条件的现象。
Dormancy is a state of low metabolic activity that occurs during the yearly cycle in plants or seeds when no outwardly visible growth takes place. It is a physical or physiological condition that suspends or prevents growth or germination even in the presence of otherwise favourable conditions.
初生休眠 primary dormancy 或先天性休眠
innate dorman 收获时即已具有的休眠现象
次生休眠或二次休眠secondary dormancy
原来不休眠或解除休眠后的种子由于高湿、低氧、 高二氧化碳、低水势或缺乏光照等不适宜环境条 件的影响诱发的休眠
Three types of seed dormancy
“an innate seed property that defines the ቤተ መጻሕፍቲ ባይዱnvironmental conditions in which the seed is able to germinate”
(Finch-Savage and Leubner-Metzger, 2006).
种子休眠的分类
How long can seeds remain dormant?
William James Beal
• 1879: 20 bottles of seeds buried
--dug up at 5-10 year intervals and tested
--after 10 years, most still viable
种壳休眠 Seed coat-imposed dormancy 物理性种壳休眠(physical dormancy) 机械性种壳休眠(mechnical dormancy) 化学性种壳休眠(chemical dormancy) 胚休眠 embryonic dormancy 形态学胚休眠（Morphological dormancy) 生理学胚休眠（Physiological dormancy, 种子后