TY - JOUR
T1 - Dormancy breakage and germination are tightly controlled by hypoxic submergence water on Echinochloa crus-galli seeds from an accession resistant to anaerobic germination
AU - Echeverry Holguín, Juliana
AU - Crepy, Mariá
AU - Striker, Gustavo G.
AU - Mollard, Federico P.O.
PY - 2020/12
Y1 - 2020/12
N2 - In wetlands, dormancy may be a key functional trait enabling seeds to avoid underwater germination, which could be lethal for seedling establishment. Our objectives were to find out (i) if shallow dormant (i.e. conditionally dormant) Echinochloa crus-galli seeds from an anaerobic germination resistant accession can break dormancy under hypoxic submergence and (ii) if underwater germination can be restored in scarified, non-dormant seeds. Shallow dormant E. crus-galli seeds perceived diurnally alternating temperatures (AT) and red light (R) pulses (i.e. dormancy-breaking cues) under hypoxic submergence; however, an inhibitory far-red light pulse given at the end of the 4-d inundation period demonstrated that most of the seeds (85%) were unable to break dormancy. Scarified E. crus-galli seeds, which did not express dormancy under drained conditions, were unable to germinate under hypoxic submergence, despite being exposed to dormancy-breaking cues (AT + R). Lastly, the temporal window for germination sensitivity to the inhibitory action of hypoxia, once dormancy-breaking signals have been applied, is progressively lost and bounded to approximately 18 h for half of the seed lot. These results highlight the importance of dormancy as a trait enabling E. crus-galli seeds to avoid underwater germination, a risky scenario for seedling emergence and establishment in this facultative hydrophyte.
AB - In wetlands, dormancy may be a key functional trait enabling seeds to avoid underwater germination, which could be lethal for seedling establishment. Our objectives were to find out (i) if shallow dormant (i.e. conditionally dormant) Echinochloa crus-galli seeds from an anaerobic germination resistant accession can break dormancy under hypoxic submergence and (ii) if underwater germination can be restored in scarified, non-dormant seeds. Shallow dormant E. crus-galli seeds perceived diurnally alternating temperatures (AT) and red light (R) pulses (i.e. dormancy-breaking cues) under hypoxic submergence; however, an inhibitory far-red light pulse given at the end of the 4-d inundation period demonstrated that most of the seeds (85%) were unable to break dormancy. Scarified E. crus-galli seeds, which did not express dormancy under drained conditions, were unable to germinate under hypoxic submergence, despite being exposed to dormancy-breaking cues (AT + R). Lastly, the temporal window for germination sensitivity to the inhibitory action of hypoxia, once dormancy-breaking signals have been applied, is progressively lost and bounded to approximately 18 h for half of the seed lot. These results highlight the importance of dormancy as a trait enabling E. crus-galli seeds to avoid underwater germination, a risky scenario for seedling emergence and establishment in this facultative hydrophyte.
KW - Barnyard grass
KW - diurnally alternating temperature
KW - flooding
KW - hypoxia
KW - phytochrome
KW - seed dormancy
KW - wetlands
UR - http://www.scopus.com/inward/record.url?scp=85083363620&partnerID=8YFLogxK
U2 - 10.1017/S0960258520000070
DO - 10.1017/S0960258520000070
M3 - Article
AN - SCOPUS:85083363620
SN - 0960-2585
VL - 30
SP - 262
EP - 267
JO - Seed Science Research
JF - Seed Science Research
IS - 4
ER -