Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains.

	Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains.
	Peng, Deli; Chen, Zhe; Hu, Xiaojian; Li, Zhimin; Song, Bo; Sun, Hang
	2017
发表期刊	Plant diversity
ISSN	2468-2659
卷号	39 期号:4 页码:180-186
摘要	Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species (Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy, fresh seeds of the two species (one population each) were incubated in light at 25/15 and 15/5°C, and then dry after-ripening (DAR) seeds were incubated on water agar substrate with or without GA3. To determine the effect of temperature and light on germination, DAR seeds of the two species (two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature (Tb) and thermal times for 50% germination (theta50) were calculated. DAR released physiological dormancy (PD), increasing final germination at 15/5°C and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species (two populations each). Seeds of the two species germinated significantly better (>80%) at medium temperatures (10-25°C) than at extreme low (5°C) or high (35°C) temperatures. Alternating temperatures (25/15 and 15/5°C) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5°C. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tb values were 1 and 0.9°C, respectively, in two Rh. nobile populations; 4 and 4.1°C, respectively, in two Rh. alexandrae populations; theta50 (thermal time) were 100 and 125°Cd, respectively in two Rh. nobile populations; 76.92 and 83.33°Cd, respectively in two Rh. alexandrae populations. The dormancy type, and germination responses to temperature and light condition does not explain why the two Rheum species are distributed in contrasting habitats. However, these findings reflect an advantageous germination strategy of these two Rheum species to adapt to the same alpine environments.
文献类型	期刊论文
条目标识符	http://ir.kib.ac.cn/handle/151853/64838
专题	植物化学与西部植物资源持续利用国家重点实验室
推荐引用方式 GB/T 7714	Peng, Deli,Chen, Zhe,Hu, Xiaojian,et al. Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains.[J]. Plant diversity,2017,39(4):180-186.
APA	Peng, Deli,Chen, Zhe,Hu, Xiaojian,Li, Zhimin,Song, Bo,&Sun, Hang.(2017).Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains..Plant diversity,39(4),180-186.
MLA	Peng, Deli,et al."Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains.".Plant diversity 39.4(2017):180-186.