Effects of low temperature storage before transplanting on the inner morphology of rice nursling seedlings

Storage of rice nursling seedlings before transplanting is thought to be a cost-saving technique in rice culture. The objective of this study is to cl arify the morphological changes of inner structures of stored rice seedling s under low temperatures (5.0, 10.0 and 12.5 degreesC) by means of observin g every serial cross-section through the stem with a light microscope. Comp ared with the nursling seedlings just after raising at 5.0 degreesC storage temperature, the stored seedlings showed a thinner leaf sheath and a decre ase in the number and size of the 2nd nodal tiller, but an increase in the number of crown root primordia. In the storage temperatures of 10.0 and 12. 5 degreesC, no changes occurred on the stem length and size, on the size an d number of nodal tillers, and on the inner structures of leaf sheath and s tem compared with the nursling seedlings just after raising, however, the n umber of crown root primordia increased. After transplanting, the crown roo t primordia that had increased during storage emerged. These results indica te that in comparison with the nursling seedlings just after raising, the s torage under low temperature before transplanting increases the number of c rown root primordia of seedlings without morphological changes of stem, lea f sheath, or tillers. Storage under 10.0 or 12.5 degreesC before transplant ing is available for rooting and growth after transplanting for rice nursli ng seedlings.