Effect of low temperature stratification on breaking dormancy of seeds and embryos in 'Campbell Early' grape [Vitis]
2003
Liu, J.S. (Osaka Prefectural Univ., Sakai (Japan). Coll. of Agriculture) | Mochioka, R. | Horiuchi, S. | Ogata, T. | Shiozaki, S.
The mechanism of breaking dormancy with low temperature stratification in the seeds and embryos of 'Campbell Early' grape was examined. The seeds kept at 25 deg C after the stratification at 1 deg C for 13 weeks germinated, but the embryos excised immediately after the stratification and cultured at 25 deg C did not germinate. On the other hand, it was germinated that 20 and 80% of the embryos excised from the seeds which had been kept at 25 deg C for 12 and 24 hours respectively after the stratification. None of the embryos excised from the seeds cultured for O, 12 and 24 hours without prior the stratification germinated. The germination of all embryos excised from the seeds cultured at 25 deg C for 24 hours after the stratification was inhibited completely when the surface of the seeds had completely been covered with paraffin after the stratification. The beak of the seed coat, the chalaza, the suture and the endosperm of most of the stratified seeds were stained after submersion in an iodine solution for 48 hours, but only the beak was stained in the seeds without the stratification. These findings indicate that the stratification at 1 deg C is effective for breaking dormancy of grape seeds. Although the stratification does not directly break the dormancy of the embryo, it increased the substance permeability of the seed coat, and thus the dormancy of the embryo may be broken by the action of the endosperm during the 24-hour culture at 25 deg C .
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