TY - JOUR
T1 - Seed coat structure and oxygen availability control lowtemperature germination of melon (Cucumis melo) seeds
AU - Edelstein, Menahem
AU - Corbineau, Francoise
AU - Kigel, Jaime
AU - Nerson, Haim
PY - 1995/4
Y1 - 1995/4
N2 - The involvement of the seed coat in low‐temperature germination of melon seeds was examined in two accessions differing in their ability to germinate at 14°C: Noy Yizre'el (a cold‐sensitive cultivar) and Persia 202 (a cold‐tolerant breeding line). Decoating resulted in full germination of Noy Yizre'el at 14°C, but splitting the coat increased germination only partially. Thus, the inhibition of Noy Yizre'el germination at 14°C is not due to physical constraint on radicle protrusion. At 25°C, seeds of both accessions submerged in water or agar germinated fully as long as the hilum aperture remained uncovered. Submerging the whole seed, or covering the hilum with lanolin, strongly depressed germination of Noy Yizre'el but not of Persia 202. Accessions differed in germination response to decreasing O2 concentration, with Noy Yizre'el showing higher sensitivity to hypoxia. These differences were correlated with differences in seed coat structure as well as in embryo sensitivity to hypoxia. Intercellular spaces in the outer layer of the seed coat were evident in the more tolerant Persia 202, while in the sensitive Noy Yizre'el this layer was completely sealed. Sensitivity to hypoxia increased at 15°C as compared with 25°C, the increase being greater in Noy Yizre'el. It is proposed that the seed coat‐imposed dormancy at low temperature in Noy Yizre'el is the combined result of more restricted oxygen diffusion through the seed coat and a greater embryo sensitivity to hypoxia, rather than to physical constraints of radicle break‐through or impairment of imbibition.
AB - The involvement of the seed coat in low‐temperature germination of melon seeds was examined in two accessions differing in their ability to germinate at 14°C: Noy Yizre'el (a cold‐sensitive cultivar) and Persia 202 (a cold‐tolerant breeding line). Decoating resulted in full germination of Noy Yizre'el at 14°C, but splitting the coat increased germination only partially. Thus, the inhibition of Noy Yizre'el germination at 14°C is not due to physical constraint on radicle protrusion. At 25°C, seeds of both accessions submerged in water or agar germinated fully as long as the hilum aperture remained uncovered. Submerging the whole seed, or covering the hilum with lanolin, strongly depressed germination of Noy Yizre'el but not of Persia 202. Accessions differed in germination response to decreasing O2 concentration, with Noy Yizre'el showing higher sensitivity to hypoxia. These differences were correlated with differences in seed coat structure as well as in embryo sensitivity to hypoxia. Intercellular spaces in the outer layer of the seed coat were evident in the more tolerant Persia 202, while in the sensitive Noy Yizre'el this layer was completely sealed. Sensitivity to hypoxia increased at 15°C as compared with 25°C, the increase being greater in Noy Yizre'el. It is proposed that the seed coat‐imposed dormancy at low temperature in Noy Yizre'el is the combined result of more restricted oxygen diffusion through the seed coat and a greater embryo sensitivity to hypoxia, rather than to physical constraints of radicle break‐through or impairment of imbibition.
KW - Cucumis melo
KW - germination
KW - hypoxia
KW - melon
KW - oxygen
KW - seed coat
UR - http://www.scopus.com/inward/record.url?scp=0029132464&partnerID=8YFLogxK
U2 - 10.1111/j.1399-3054.1995.tb06842.x
DO - 10.1111/j.1399-3054.1995.tb06842.x
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AN - SCOPUS:0029132464
SN - 0031-9317
VL - 93
SP - 451
EP - 456
JO - Physiologia Plantarum
JF - Physiologia Plantarum
IS - 3
ER -