在群体、个体和单花水平上对白花丹科(Plumbaginaceae)二型植物蓝花丹(Plumbago auriculata Lam.)的开花物候期及开花特征进行了观察和比较。观察结果显示:蓝花丹每年开花1 次,花期一般从每年6 月初到11 月初。在群体水平上,长花柱型(L 型)群体的始花、盛花和终花日期分别为6 月15 日、8 月9 日和10 月24 日, 而短花柱型(S 型)群体的始花、盛花和终花日期分别为6 月9 日、9 月4 日和11 月3 日,二者的开花持续时间分别为148 和132 d,显示L 型和S 型群体的开花物候期差异明显。在个体水平上,L 型个体的始花、盛花和终花日期分别为6 月5 日、8 月5 日和10 月3 日, 而S 型个体的始花、盛花和终花日期分别为6 月2 日、8 月28 日和10 月27 日,二者的开花持续时间分别为61. 7 和71. 6 d,差异极显著;L 型和S 型个体的开花振幅分别为5. 39 和3. 43、开花总量分别为332. 1 和241. 9 朵、盛花期日产花数分别为7 和5 朵,也有明显差异;L 型和S 型个体相对开花强度的平均值分别为0. 39 和0. 35,其中,约有50%的S 型个体相对开花强度在0. 4 左右,而L 型以相对开花强度0. 2 ~0. 4 的个体为主;L 型和S 型个体开花同步指数的平均值分别为0. 70 和0. 69,表明二者的开花同步性均较低。在单花水平上,L 型和S 型植株的平均单花开花持续时间为5. 3 和4. 2 d,差异显著;虽然其分布频率有一定差异,但二者的单花开花持续时间集中约为5 d。由此可见,蓝花丹二型植株的生殖资源分配存在明显的时空差异,花期长但开花同步性较低,较长的花期可以减少非法花粉的干扰、保持其种群基因多样性,这是二型植物维持种群存活、优化生殖模式的生态对策之一。

Flowering phenophase and flowering characteristics of two type plant of Plumbago auriculata Lam. in Plumbaginaceae were observed and compared on levels of population, individual and single flower. The results show that this species flowers once a year, its flowering period is normally from early June to early November. On the population level, dates of early-flowering, full-flowering and late-flowering for long style. type (L-type) population are June 15, August 9 and October 24, respectively, while those of short style. type ( S-type) population are June 9, September 4 and November 3,respectively, and their flowering duration time is 148 and 132 d, respectively, meaning that there is obvious difference in flowering phenophase between populations of L-type and S-type. On the individual level, dates of early-flowering, full-flowering and late-flowering of L-type individual are June 5, August 5 and October 3, respectively, while those of S-type individual are June 2, August 28 and October 27, respectively, and their flowering duration time is 61. 7 and 71. 6 d, respectively with the extremely significant difference. Flowering amplitude of L-type and S-type individuals is 5. 39 and 3. 43, their total number of flower is 332. 1 and 241. 9, their daily flower number in full-flowering stage is 7 and 5, respectively, there also are obvious differences for two type individuals. Average of relative flowering intensity for L-type and S-type individuals is 0. 39 and 0. 35, respectively, in which, that of about 50% of S-type individual is about 0. 4, while that of mainly L-type individual is 0. 2 -0. 4. Average of flowering synchrony index of L-type and S-type individual is 0. 70 and 0. 69, respectively, meaning that both of their flowering synchronization are lower. On the single flower level, average flowering duration time of single flower for L-type and S-type plant is 5. 3 and 4. 2 d, respectively, the difference is remarkable. Though distribution frequency of flowering duration time of single flower between two type plants are different, but both of their flowering duration time of single flower are approximately 5 d. It is suggested that there are obviously temporal and spatial differences in allocation of reproductive resources between two type individuals of P. auriculata, with longer flowering period and lower flowering synchronization, while longer flowering period can reduce interference of illegal pollen and maintain gene diversity of population, which is one of the ecological countermeasures of two type plants to maintain population survival and optimize reproduction model.