Abstract
One of serious barriers to the breeding of lris plants is the poor rate of seed germina-tion. Aiming at analyzing this difficulty of germination and detecting an effective method to improve the germination, the present study was conducted using the mature seeds of an lris, Iris pseudacorus L. The material seeds were subjected to five sorts of experiments. In two of them, intact seeds were germinated under several different external conditions. In the other three, the testa (and partly also the inner seed coat) of seeds was removed, then the peeled seeds were treated (washed) with cleanser or xylen, and/or partially excised at endosperm prior to germination test. The effects of treatment were estimated by germination rates from 5 to 45 days aLter sowing. The results obtained are as follows: 1. Any external factors did not significantly affect the germination of intact seeds. 2. Removing of the testa resulted in apparent promotion of germination, but the highest possible germination rate was about 20%-3. The germination of the peeled seeds was strikingly promoted by treatment with cleanser, attaining a maximum rate of about 60%· Partial ecising of endosperm also showed the same degree of effect as the treatment with cleanser. 4. The effect of treatment with xylen showed the same degree as the treatrrLent with cleanser. The most powerful treatment was 6 minutes-washing by xylen, which brought about the germination rate over 80-5. No germination inhibitors were detected in xylen extracts from the surface of the peeled seeds.
