Carol Baskin Reports
|Alani (Melicope knudsenii)|
January 20, 2004
I used 10 seeds to do some studies on imbibition of water. I placed the seeds on wet filter paper in separate Petri dishes and weighed each seed individually on a highly accurate analytical balance for a total of 20 days. After 4 days, there was a 9-17% increase in weight, depending on the individual seed, but little or no additional increase in weight occurred during the remainder of the 20-day period. On day 10, I cut a small hole in five of the seeds but documented only an additional 2-4% increase in weight in the scarified seeds by the end of day 20.
None of the 10 seeds had germinated during the 20-day period; however, I concluded that lack of germination could not be attributed to failure of the seeds to imbibe water. Interestingly, the scarified seeds not only failed to germinate, but they were attacked by fungi and died.
The five nonscarfied seeds still have not germinated. On 9 September 2003, I placed nine seeds on moist, white quartz sand in each of 9 Petri dishes. Three dishes each were placed in light (14 hour daily photoperiod) at 15(day)/6(night) C, 20/10 C, and 25/15 C. The seeds have been checked for germination at 2-week intervals. The first seedling was recorded at 15/6 C on week 14, and the first seedling at both 20/10 C and 25/15 C was recorded on week 8.
After 18 weeks, 3 seedlings have been recorded at 15/6 C, 9 seedlings at 20/10 C, and 3 seedlings at 25/15 C. I conclude that the seeds have physiological dormancy, i.e., the embryo has very low growth potential. With sufficient time, however, the embryo slowly changes, and seeds germinate. I have five of the seedlings growing in a mixture of sand, soil, and humus in an incubator at set 20(day)/15 (night) C; I poured boiling water over the potting mixture before I transplanted the seedlings. The seedlings are growing slowly, and three of them have expanded cotyledons. In a few weeks, I will put the seedlings in the greenhouse. I have other seedlings on sand in a large Petri dish at 20/10 C, and after they have grown some I will transplant them into soil.