Effects of tissue support and aeration on the germination and growth of Aralia cordata somatic embryos

The effects of supporting materials and aeration treatment on the germinati on and growth of somatic embryos induced from suspension cells of Aralia co rdata 'Aichi-bozu' were examined. 1. Germination and growth of somatic embryos differed depending on the kind s of supporting materials, e.g. the germination rate after a 4-week culture period was 75.0% for polyester, 56.3% for vermiculite, and 37.5% for agar. Fresh and dry weights of tops of plantlets after a 4-week culture period t he polyester support was heavier than these on the others. 2. Seventy percent of the embryos of plot A, which were naturally aerated f or the entire 5-week period germinated, whereas 69% of those in plot B, whi ch were exposed to natural aeration for 2 weeks and forced aeration for ano ther 3 weeks, germinated; only 58% of the embryos germinated in plot C whic h were only forced aerated for 5 weeks. All somatic embryos which germinate d developed into plantlets. The increment of plant height, fresh and dry we ights of plantlets after a 5-week culture period was greater in plot A and B than that in plot C. All plantlets became swollen in plot A but not those in plot B and C. Nevertheless, many normal plantlets developed in plot B. Hence, we found that for the efficient production of the plantlets, polyest er was the superior plant support and that high humidity in the first half of a culture period and low humidity in the second half yielded optimum res ults.