楊紹榮 李國權 張武男
Physiological Studies of the Sex Expression of Mango
Yang, S. R., K. C. Lee and W. N. Chang
The mango panicle consists of male, hermaphrodite and imperfect flowers. Air temperature greatly affected the percentage of hermaphrodite flowers emerging from the shoots in different months. The optimum temperatures for the formation of hermaphrodites were between 18℃ and 25℃. Temperature below 18℃ or above 25℃ was found to have inhibitory effects. The amount of hermaphrodites in flowers varied with the months of the year and the cultivars of the plant. December was the month which showed the lowest ;occurrence rate and Keitt was the cultivar which had the highest occurrence frequency (49.8%) followed by cvs. Irwin (34.1%), Haden (18.9%), Native (17.6%) and White (49.8%). Higher hermaphrodite rates were observed on the top (41.3%) and in the southern part (45.2%) of the canopy as opposed to 26.0 and 20.7% in the western and northern sides, respectively. Age of plant plays a part in sex ration as well. One-year-old Irwin was found to contain 71% hermaphrodite flowers, on the other hand, 7-year-old and 20-year-old plants has only 51 and 46% of this kind of flowers, respectively. Shading plants with black nylon net (40~65% shading) helped the suppress of the phenomenon. The shaded plants was proved to bear 15.1~23.6% less hermaphrodite flowers than the unshaded ones. When concentrations of mineral nutrients, soluble carbohydrate, starch and total phenolic compounds of the middle leaves of the first internode below panicles were analyzed for their relationship to sex ration. No clear picture emerges. Further investigations are needed to clear those points of interest.
Accepted for publication: October 8, 1990.