生物多样性 ›› 2007, Vol. 15 ›› Issue (5): 492-499.doi: 10.1360/biodiv.060238

所属专题: 三峡工程对生物多样性的影响

• 论文 • 上一篇    下一篇

濒危植物巴东木莲种子休眠与萌发特性的研究

陈发菊1, 2, 梁宏伟2, 王旭1, 何正权2, 李凤兰1*   

  1. 1 (北京林业大学生物科学与技术学院, 北京 100083)
    2 (三峡大学生物技术研究中心, 湖北宜昌 443002)
  • 出版日期:2007-09-20

Seed dormancy and germination characteristics of Manglietia patungen-sis, an endangered plant endemic to China

Faju Chen1, 2, Hongwei Liang2, Xu Wang1, Zhengquan He2, Fenglan Li1*   

  1. 1 School of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083
    2 Biotechnology Research Center, China Three Gorges University, Yichang, Hubei 443002
  • Online:2007-09-20

巴东木莲(Manglietia patungensis)为我国特有种, 属国家重点保护植物。为找出其生殖环节中的致危因素, 作者对巴东木莲种子休眠与后熟过程中的形态和萌发特性进行了研究。结果表明, 巴东木莲种胚发育不完全可能是种子休眠的主要原因, 在其后熟过程中胚不断分化、发育成熟; 种皮具有较好的透性, 与休眠的关系不大; 种子不同部位均存在萌发抑制物, 胚乳中高含量的萌发抑制物是影响胚萌发的重要因素。内源激素ABA和IAA在巴东木莲种子休眠与萌发过程中起着重要作用, ABA是引起休眠的关键因素, IAA有助于种子的萌发, IAA/ABA相对含量的变化对种子的休眠和萌发产生重要影响。巴东木莲种子的休眠是由种子本身的形态和生理特点引起的综合休眠, 在4℃低温保湿条件下才能完成其形态和生理后熟过程, 而自然条件下, 巴东木莲种子成熟时正值秋季少雨, 很容易失水而不能完成其后熟过程而失去生活力, 这可能是导致该物种自然更新困难的重要原因。

Manglietia patungensis, an endangered tree species endemic to China, is listed in National Key Protected Species. To explore the underlying mechanisms relevant to the impediment in its sexual reproduction, we studied the morphological and physiological characteristics of seeds during its dormancy and after-ripening process. The results showed that the incomplete development of embryos was the main reason for seed dormancy. The immature embryos continued differentiating and developing during the after-ripening process. As the seed coat was permeable, it would not induce seed dormancy. Germination inhibitors existed in different parts of seeds, especially in the endosperm, which was believed to be a major factor for the ger-mination delay. Endogenous hormone ABA and IAA played an important role in the dormancy and germina-tion of seeds. ABA was the key factor for seeds dormancy while IAA benefited germination. Therefore, the change of IAA/ABA ratio was crucial to seed dormancy and germination. Only at a temperature as low as 4°C and in a humid environment, could M. patungensis seeds complete the morphological and physiological after-ripening process. In fact, it was observed that the after-ripening process of M. patungensis seeds oc-curred in autumn, a season characterized by low rainfall and drought in this area. Evidently, viability loss of seeds caused by water deficit during the after-ripening period may explain the poor regeneration of this spe-cies.

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