TY - JOUR
T1 - Morphophysiological dormancy synchronizes timing of seed germination of two alpine species of Meconopsis on the Tibetan Plateau to beginning of growing season
AU - Wang, Guoyan
AU - Baskin, Carol C.
AU - Baskin, Jerry M.
AU - Yang, Xuejun
AU - Liu, Guofang
AU - Ye, Xuehua
AU - Huang, Zhenying
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/7
Y1 - 2021/7
N2 - Timing of seed germination is critical for seedling establishment and growth of the plant to maturity. Theoretically, then, germination of alpine species should be restricted to a period that ensures seedlings will reach a critical size during the short growing season for overwinter survival. We hypothesized that seeds of two alpine monocarpic perennials of Meconopsis germinate only at the beginning of the growing season in early spring and that dormancy synchronizes the timing of germination to this period. We tested the effects of light, temperature, cold stratification and GA3 on germination of Meconopsis integrifolia and M. racemosa in the laboratory and germination responses to temperature during two 2-year periods of seed buried at 4450 m a.s.l. on the Tibetan Plateau. Most fresh seeds of both species were dormant, and the embryo underdeveloped, indicating morphophysiological dormancy (MPD). GA3 promoted embryo growth and germination of seeds. Buried seeds exhibited an annual dormancy cycle. The physiological component of MPD was released gradually in the field during autumn and winter, resulting in embryo growth (release of morphological component of MPD) and germination just after snowmelt in spring. Embryos in seeds that did not germinate the first year remained underdeveloped until the second spring. Delay of seed burial from October until January (simulating a delay in time of seed dispersal) delayed germination for 1 year but did not change the germination season. Thus, our hypothesis that MPD restricts germination to the beginning of the growing season is supported.
AB - Timing of seed germination is critical for seedling establishment and growth of the plant to maturity. Theoretically, then, germination of alpine species should be restricted to a period that ensures seedlings will reach a critical size during the short growing season for overwinter survival. We hypothesized that seeds of two alpine monocarpic perennials of Meconopsis germinate only at the beginning of the growing season in early spring and that dormancy synchronizes the timing of germination to this period. We tested the effects of light, temperature, cold stratification and GA3 on germination of Meconopsis integrifolia and M. racemosa in the laboratory and germination responses to temperature during two 2-year periods of seed buried at 4450 m a.s.l. on the Tibetan Plateau. Most fresh seeds of both species were dormant, and the embryo underdeveloped, indicating morphophysiological dormancy (MPD). GA3 promoted embryo growth and germination of seeds. Buried seeds exhibited an annual dormancy cycle. The physiological component of MPD was released gradually in the field during autumn and winter, resulting in embryo growth (release of morphological component of MPD) and germination just after snowmelt in spring. Embryos in seeds that did not germinate the first year remained underdeveloped until the second spring. Delay of seed burial from October until January (simulating a delay in time of seed dispersal) delayed germination for 1 year but did not change the germination season. Thus, our hypothesis that MPD restricts germination to the beginning of the growing season is supported.
KW - Buried seeds
KW - Dispersal time
KW - Dormancy cycling
KW - Meconopsis
KW - Secondary dormancy
KW - Underdeveloped embryo
UR - http://www.scopus.com/inward/record.url?scp=85105831021&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85105831021&partnerID=8YFLogxK
U2 - 10.1016/j.envexpbot.2021.104473
DO - 10.1016/j.envexpbot.2021.104473
M3 - Article
AN - SCOPUS:85105831021
SN - 0098-8472
VL - 187
JO - Environmental and Experimental Botany
JF - Environmental and Experimental Botany
M1 - 104473
ER -