Coleoptile Emergence in Rice Seedlings in Different Oxygen Environments

Coleoptile emergence precedes primary root emergence in riceseeds germinated under stagnant or continuously-aerated wateror in normal air. This pattern of rice seed germination in oxygen-pooras well as in normal oxygen environments differs from previousdescriptions in the literature that the primary root emergesfirst when germination occurs on a well-drained substratum whereasthe coleoptile emerges first during germination under water.Evidence is presented here that the rice coleoptile providesa primary morphological region for oxygen entry into germinatingrice seeds.