Effects of Fruit Drop and Polyembryony of Ardisia pusilla as Influenced by Calcite, Promalin, and 2,4-DP

摘要

Experiments were initiated with Ardisia pusilla to screen an efficient plant bioregulator (PER) for preventing fruit drop by foliar-spray with aminoethoxyvinylglycine (AVG), CaCO_3 (calcite), promalin, and 2,4-dichlorophenoxypropionic acid trienthanolamine (2,4-DP), and to examine parthenocarpy and polyembryony as influenced by these PBRs. Plant growth and fruit set of 1-year-old rooted cuttings foliar-sprayed with four PBRs on May 14, 2004 were examined on November 10, 2004. Comparing fruit set of the control (23.4%), the plants treated with 2,4-DP showed the highest fruit set (37.5%) at 180 days after treatments than those treated with calcite (36.7%), followed by promalin (34.7%) and AVG (19.3%). The difference among three PBRs except AVG was notsignificant in fruit set. Although 2,4-DP improved fruit set in a concentration-dependent manner, calcite at 9,500 mg-L~(-1) showed the highest fruit set (45.1%) among all applications. Plants treated with all PBRs except AVG grew normally compared withthe control. However, AVG at higher than 100 mg-L~(-1) induced chemical injuries such as terminal shoot death and foliar discoloration. Concerning fruit development, plants treated with all PBRs except AVG produced the more and the larger first fruits than the control plants. Plants treated with 2,4-DP, calcite, promalin, or control did not produce any seedless fruit related to parthenocarpy. Seed germination percentages were significantly different among PBRs. Especially, seeds collected from plants treated with promalin regardless of its concentration, showed the highest germination as 80.0% at 45 days after sowing. A. pusilla fruit consisted of one seed coat and endosperm, but each seed contained about two viable embryos as an average. Thus, it wasconcluded that the seed of A. pusilla is polyembryonic. Moreover, seeds collected from promalin application produced the highest number of seedlings among PBRs.