高山植物花形态特征对花温度积累的影响

Effects of floral morphology on flower temperature increment in alpine plants

关键词:  花温度积累, 花对称性, 花颜色, 花大小, 高山环境

Key words:  flower temperature increment, flower symmetry, flower color, flower size, alpine environment

摘要:

高山生态系统的低温环境不利于植物繁殖器官的发育和传粉过程,因此能改善花内或花序温度的结构对植物繁殖具有积极意义。该研究利用红外测温仪测量了高寒草甸中64种植物的花温度和叶温度以计算花温度积累,并检测了系统发育、花大小、花对称方式和花大小对花温度积累的影响。结果表明:所测量的64种植物种类,花部温度均高于叶部温度。花温度积累的系统发育信号较弱,表明物种间花温度积累的差异可能主要与不同物种对温度的需求有关。花温度积累与花大小存在显著的正相关关系,且两侧对称花的温度积累比辐射对称花更为迅速,但花对称方式和花颜色对花温度积累并没有显著的影响。该研究结果表明花温度积累在不同植物间存在很大的差异,但这些差异对植物繁殖的实际贡献和意义仍需要进一步验证。

Abstract:

Low temperature of alpine environment would limits the development of reproductive organs and pollination process, and thus flower structures that increase the temperatures within flowers and inflorescence will protect anthers and ovules from the low temperature and then increase the reproductive success. In this study, we investigated the flower and leaf temperature of 64 alpine plants with an infrared camera equipped with a macro-lens, and then calculated the flower temperature increment(FTI)by subtracting the leaf temperature from the temperature of the reproductive organs. Based on these data, we examined the effects of phylogeny, flowers size, symmetry and color on the FTI. Our result showed that the phylogenetic signal of FTI among different species was weak, indicating that FTI among different species might result from the various demands to temperature, independent of phylogenetic relationship. Furthermore, FTI increased with the increase of flower size, and FTI increased more quickly in zygomorphic flower than in actinomorphic flowers, but the effects of symmetry and color on the averaged FTI were minor across all species. Our results suggest that the differences in FTI are great among different species, but the contribution of FTI on plant reproductive success need to be clarified in future researches.