Germination in king palm (Archontophoenix alexandrea) as influenced by changes during seed development

Changes occurring during fruit and seed development are an important factor to determine the stage of maturity, which indirectly influences germination. Commonly, change in Jruit size and color is used as an indicator of seed maturity. This study was undertaken to observe the relationship between the physical parameters such as seed size and color with internal development in relation to germination. The development offruits beginning from anthesis was observed on a single inflorescence and sample was collected at two days interval until the fruits abscised. At each point oj sampling, seed was split open to study the internal development. Seed size, moisture content, dry weight and germination test was carried out for samples collected at one-week interval. There were three phases of development, the first beginning from anthesis until the fourth week characterized by active cell division and expansion without distinct organ development. A slight increase in fruit size was observed. The second phase began at four weeks and continued until eleven weeks. During this phase the seed started to take shape and the cavity within the seed was soon filled with reserve materials initially in the liquid form changing into a jelly like substance and finally solidified. The seed size and dry weight increased and embryo formation was observed beginning the eight-week after anthesis. Embryo development was complete at eleven weeks. The third phase was depicted by stabilization in seed dry weight, a decline in seed moisture content and change in fruit color from dark green to shades of red. The king palm seeds were not able to germinate until the eleventh week recording a high germination percentage of 82%. Following this stage in seed development as seeds are seen as mature by normal standards, germination declined. Seeds at fourteen weeks with a bright red color or the ripe stage had a low germination percentage of only 40%. Furthermore the duration for germination was shorter for seeds germinated at eleven weeks and longer for seeds germinated at fourteen weeks. It is suggested that for germination purpose especially for nurseries the use of palm seeds at the appropriate stage would result in higher germination percentage.