TY - JOUR
T1 - Deep simple morphophysiological dormancy in seeds of the basal taxad Cephalotaxus
AU - Yang, Chia Ju
AU - Chien, Ching Te
AU - Liao, Yue Ken
AU - Chen, Shun Ying
AU - Baskin, Jerry M.
AU - Baskin, Carol C.
AU - Kuo-Huang, Ling Long
PY - 2011/9
Y1 - 2011/9
N2 - Although mature seeds of the monogeneric conifer family Cephalotaxaceae sensu stricto have underdeveloped embryos, no definitive studies have been done to classify dormancy in this family. Our primary purpose was to determine the kind of dormancy in seeds of Cephalotaxus wilsoniana and to put the results into a broad phylogenetic context for gymnosperms. The species is of horticultural and medicinal value, and information is needed on how to propagate it efficiently from seeds. Embryo growth and germination were monitored for seeds at warm, cold and warm plus cold temperatures, and germination was monitored for seeds subjected to: (1) cold → warm → cold → warm; and (2) warm → cold → warm → cold → warm temperature sequences. The effects of gibberellic acids GA3 and GA4 were tested on radicle emergence in ungerminated seeds and on shoot emergence in root-emerged seeds. Germination was promoted by ≥ 36 weeks of warm stratification followed by ≥ 8 weeks of cold stratification, but only if seeds were returned to high temperatures. The underdeveloped embryo must increase in length by >120% before the radicle emerges. Neither GA3 nor GA4 was effective in promoting radicle emergence; however, both plant growth regulators increased rate (but not percentage) of shoot emergence in root-emerged seeds. We conclude that seeds of C. wilsoniana have the deep simple level of morphophysiological dormancy (MPD), C1b-C3-B1b; thus, warm stratification followed by cold stratification and then warm-temperature incubation are required for germination. In gymnosperms, MPD is known in cycads, Ginkgo and now in three families of conifers.
AB - Although mature seeds of the monogeneric conifer family Cephalotaxaceae sensu stricto have underdeveloped embryos, no definitive studies have been done to classify dormancy in this family. Our primary purpose was to determine the kind of dormancy in seeds of Cephalotaxus wilsoniana and to put the results into a broad phylogenetic context for gymnosperms. The species is of horticultural and medicinal value, and information is needed on how to propagate it efficiently from seeds. Embryo growth and germination were monitored for seeds at warm, cold and warm plus cold temperatures, and germination was monitored for seeds subjected to: (1) cold → warm → cold → warm; and (2) warm → cold → warm → cold → warm temperature sequences. The effects of gibberellic acids GA3 and GA4 were tested on radicle emergence in ungerminated seeds and on shoot emergence in root-emerged seeds. Germination was promoted by ≥ 36 weeks of warm stratification followed by ≥ 8 weeks of cold stratification, but only if seeds were returned to high temperatures. The underdeveloped embryo must increase in length by >120% before the radicle emerges. Neither GA3 nor GA4 was effective in promoting radicle emergence; however, both plant growth regulators increased rate (but not percentage) of shoot emergence in root-emerged seeds. We conclude that seeds of C. wilsoniana have the deep simple level of morphophysiological dormancy (MPD), C1b-C3-B1b; thus, warm stratification followed by cold stratification and then warm-temperature incubation are required for germination. In gymnosperms, MPD is known in cycads, Ginkgo and now in three families of conifers.
KW - Cephalotaxus
KW - cold stratification
KW - deep simple morphophysiological dormancy
KW - gibberellins
KW - seed germination
KW - underdeveloped embryo
KW - warm plus cold stratification
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U2 - 10.1017/S0960258511000134
DO - 10.1017/S0960258511000134
M3 - Article
AN - SCOPUS:80055069221
SN - 0960-2585
VL - 21
SP - 215
EP - 226
JO - Seed Science Research
JF - Seed Science Research
IS - 3
ER -