Non-deep physiological dormancy and the effect of temperature on the germination of Dipteronia dyeriana seed.

摘要

Dipteronia dyeriana Henry (Aceraceae), a plant native to southwest China, is being grown extensively in home gardens and along roadsides for its high ornamental value. However, in the field it is an endangered species due to low rates of seedling establishment. We found that the seed coat was water-permeable, and that pre-treatment with concentrated H₂SO₄ or hot water, or the partial or total removal of the seed coat, could effectively increase the frequency of seed germination. In particular, total removal of the seed coat enhanced the percentage germination to 97% at 15 degrees C/4 degrees C (light/dark) with a 12-h photoperiod. Cold stratification (at 4 degrees C) for 3 months, or a 3-month out-of-doors stratification (ODS) at 3 degrees C-17 degrees C significantly accelerated the release from dormancy. Among the various germination temperatures tested, 15 degrees C/4 degrees C (dayight) was optimum (97% germination), followed by 10 degrees C (day and night). Seedling emergence in this species increased gradually to 47% in an outdoor experiment. Thus, D. dyeriana seeds have non-deep physiological dormancy (PD) that can be broken in Winter, allowing seeds to germinate in the following Spring.