不同生境对蝴蝶花花部与果实特征的影响

通过对毛竹林(Bamboo forest,BF)与林缘旷地(Open area of forest edge,OAFE)两类生境蝴蝶花自然种群花部与果实(种子)特征及降雨干扰影响的研究,探讨不同生境中蝴蝶花花部特征适应性及有性各组分的差异。结果表明:(1)竹林生境相对于林缘旷地生境,蝴蝶花单花花冠的长、宽较大,子房、花部(除花柄)及单花总生物量较小,比花柄长较大;两类生境蝴蝶花花柄生物量与子房生物量呈正相关(P0.05),协方差分析表明,两类生境该直线回归的总体斜率间(F=18.420,P0.001)及总体截距间(F=3791.7,P0.001)均具有显著差异,竹林生境花柄生物量随子房生物量增大而增大的程度更强。竹林生境的蝴蝶花侧花花冠长与宽最高,竹林生境顶花次之,林缘旷地顶花与林缘旷地侧花最低;花部(除花柄)与全花重都表现为林缘旷地侧花最高,林缘旷地顶花次之,竹林侧花与竹林顶花最低。比花柄长随竹林侧花与竹林顶花-林缘旷地侧花-林缘旷地顶花依次降低;竹林顶花的花柄比率最高,竹林侧花与林缘旷地侧花最低。(2)林缘旷地生境中蝴蝶花的每花序花数、花序结果百分率、单花结果百分率、每结果花序果实数、每结果花序果实重与种子重及花期内每花序掉落花数都高于竹林生境。(3)林缘旷地生境大雨干扰的4个时段花朵掉落数显著高于竹林环境(P0.01)。不同生境花部形态结构特征表明其自身的生境适应性,林缘旷地生境蝴蝶花为抵御干扰及为获得有性繁殖成功,有性组分的投入更高。

Effect of different habitats on floral, fruit and seed traits of Iris japonica Thunb.

We investigated the flower, fruit and seed traits of Iris japonica and the effects of rainfall disturbance on those traits in two different habitats (OAFE-Open area of forest edge, BF-Bamboo forest) on Jinyun Mountain, Chongqing, China, and discussed the adaptability of flower traits and the differences in sexual reproduction components of this species in different habitats. The results showed that the corolla length, corolla width and specific pedicel length of I. japonica flowers were larger in BF than in OAFE, whereas ovary biomass, flower biomass (excluding pedicel) and whole-flower biomass (including pedicel) were smaller in BF than those in OAFE. There was a positive correlation between pedicel biomass and ovary biomass (P<0.05) in both BF and OAFE. Covariance analysis showed that the slope (F=18.4, P<0.001) and the intercept (F=3791, P<0.001) of the linear regressions were significantly larger in BF than in OAFE, which mean that the increase in pedicel biomass with increasing ovary biomass was stronger in BF than in OAFE. Corolla length and corolla width of the lateral flowers in BF were the largest, and those of the apical flowers and the lateral flowers in OAFE were the smallest. The lateral flowers in OAFE had the largest biomass, whilst the apical flowers in OAFE and the lateral flowers in BF had the lowest biomass. The pedicel ratio of the apical flowers in BF was the highest, and those of the lateral flowers in OAFE and BF were the lowest. The number of flowers per inflorescence, fruit percentage per inflorescence, fruit percentage per flower, the number of fruits per inflorescence, the number of dropped fruits per inflorescence and biomass of fruit and seed per inflorescence of I. japonica were significantly larger in OAFE than those in BF. In addition, the number of dropped flowers in four rainy periods was significantly higher in OAFE than that in BF (P<0.05). In conclusion, flowers of I. japonica with different morphological and structural traits can adapt themselves to the different habitats. In OAFE, the flower traits reflected themselves to endurance of strong disturbance caused by the wind and rain, and greater biomass investment in their sexual parts assisting, which will promote their reproductive success.