关键词: 桃叶珊瑚, 果实, 种子, 胚, 形态发育, 水热条件

Abstract: Using Aucuba chinensis from Badagong Mountain National Nature Reserve as a model, the regularity of fruit and seed development were elucidated basing on monthly observation on fruit/seed length, width, color and embryonic/endosperm morphology. On this basis of observation, the relationship between morphological developmental and ecological factors including annual average temperature and rainfall were analyzed. The results showed that: (1) The total development of fruit took 13 months, which means the process from fruit abscission to falling lasted from April to next April. (2) The variation of fruit length, width and peel thickness manifested a tendency which include four stages as “slow-fast-slow-fast”, and which just like a typical double “S” shaped curve. And the most obvious development of fruit shape index appeared in stage Ⅱ, whose value varied from 2.63 to 1.57. (3) In the developmental process, fruit color kept green in the early and lasted for a long time, and then turn red very quickly, which should attribute to the rapid value decreasing of blue and green color. (4) Embryo and endosperm growth were synchronized with fruit development, and growth stage Ⅰ was the critical stage for embryonic and endosperm development, in which the embryo length/width ratio increased from 1.83 to 2.56; the endosperm developed as a cellular phenotype without a typical pasty stage. (5) At 13 months after corolla drop, about 77% of the embryos were still torpedo shaped. (6) There were significant positive correlation in fruit shape index/embryo ratio and temperature/rainfall (P<0.05), but fruit shape index was more dependent on precipitation (P<0.01) and embryo rate was more dependent on annual average temperature. Based on the above, the fruit development of A. chinensis was characterized by the obvious phenomenon of simultaneous flowering and overlapping fruiting periods. And the limitation of hydrothermal conditions was probably the main reason for the slow development of fruit and seed and the impact on seedling establishment. At the same time, most of the seed embryos were not fully differentiated when the fruits were abscised, which meant that the seed development had to undergo after-ripening, and therefore the seeds were morphologically dormant.

Key words: Aucuba chinensis, seed, morphological development, hydrothermal conditions