The University of Queensland, School of Agriculture and Food Sciences, The Centre for Native Floriculture, Gatton, Qld 4343, Australia.
Ann Bot. 2011 Jul;108(1):215-20. doi: 10.1093/aob/mcr116. Epub 2011 May 17.
The time at which plants are transferred to floral inductive conditions affects the onset of flowering and plant morphology, due to juvenility. Plants of Brunonia australis and Calandrinia sp. were used to investigate whether Australian native ephemeral species show a distinct juvenile phase that can be extended to increase vegetative growth and flowering.
The juvenile phase was quantified by transferring seedlings from less inductive (short day and 30/20°C) to inductive (vernalization or long day) conditions at six different plant ages ranging from 4 to 35 d after seed germination. An increase in days to first visible floral bud and leaf number were used to signify the end of juvenility.
Brunonia australis was receptive to floral inductive long day conditions about 18-22 d after seed germination, whereas plants aged 4-35 d appeared vernalization sensitive. Overall, transferring plants of B. australis from short to long day conditions reduced the time to anthesis compared with vernalization or constant short day conditions. Calandrinia sp. showed a facultative requirement for vernalization and an insensitive phase was not detected. Floral bud and branch production increased favourably as plant age at time of transfer to inductive conditions increased. Younger plants showed the shortest crop production time.
Both species can perceive the vernalization floral stimulus from a very young age, whereas the photoperiodic stimulus is perceived by B. australis after a period of vegetative growth. However, extending the juvenile phase can promote foliage development and enhance flower production of both species.
由于幼年期的存在，植物转入成花诱导条件的时间会影响其开花时间和植株形态。本研究使用 Brunonia australis 和 Calandrinia sp. 两种植物来研究澳大利亚本土短命植物是否存在明显的幼年期，可以通过延长该阶段来增加营养生长和开花。
通过将幼苗从较弱的成花诱导条件（短日照和 30/20°C）转移到成花诱导条件（春化或长日照），在种子萌发后 4 到 35 天的六个不同的植物年龄中量化幼年期。首次可见花芽和叶片数量的增加表示幼年期结束。
Brunonia australis 在种子萌发后 18-22 天对成花诱导的长日照条件具有接受能力，而 4-35 天的植物对春化敏感。总体而言，与春化或恒定短日照条件相比，将 B. australis 植物从短日照条件转移到长日照条件可以缩短开花时间。Calandrinia sp. 表现出对春化的兼性需求，并且没有检测到不敏感阶段。随着转入成花诱导条件时的植物年龄增加，花芽和枝条的产生增加有利。年轻的植物表现出最短的作物生产时间。
两个物种都可以在非常年幼的时候感知春化的花刺激，而 B. australis 则在一段时间的营养生长后感知光周期刺激。然而，延长幼年期可以促进两种植物的叶片发育并增加花的产量。
