Hawkesbury Institute for the Environment, Western Sydney University , Penrith, Australia.
Plant Signal Behav. 2020 Sep 1;15(9):1789320. doi: 10.1080/15592324.2020.1789320. Epub 2020 Jul 7.
Environmental factors such as photoperiod, temperature, phytohormones, sugars, and soil nutrients can affect the development of axillary meristems and emergence of shoot branches in plants. We investigated how an extended period of cold exposure to plants before and after inflorescence meristem differentiation would affect plant growth and shoot branching. The number of rosette leaves and shoot branches increased when wild type (WT) juvenile seedlings, but not adult plants, were subjected to a prolonged cold exposure (10/7°C day/night cycle). As the duration of cold exposure to WT juvenile seedlings increased, so too did the rosette area, number of leaves, and rosette branches revealing an extended period of vegetative growth. The prolonged cold treatment also increased the primary inflorescence stem height and number of cauline branches in WT plants revealing a delay in reproductive development that could be altered by early () and late () flowering mutants. The axillary buds/leaf and rosette branches/leaf ratios declined significantly in WT, yet were enhanced in the loss-of-function of () and () hyper-branched mutants. This indicated that axillary meristem differentiation continued during the cold exposure, which did not directly impact axillary bud formation or shoot branching. We conclude that a prolonged cold exposure to juvenile seedlings prior to inflorescence meristem development extended vegetative growth and delayed the reproductive phase to allow additional leaf primordia and axillary meristems to differentiate that enhanced the number of shoot branches in .
环境因素如光照周期、温度、植物激素、糖和土壤养分等都可以影响植物腋芽分生组织的发育和侧枝的萌发。我们研究了在花序分生组织分化前后，延长植物的冷暴露时间会如何影响植物的生长和侧枝分枝。当野生型（WT）幼龄幼苗经历长时间的冷暴露（10/7°C 昼夜周期）时，其莲座叶和侧枝的数量会增加，但成年植株则不会。随着 WT 幼龄幼苗冷暴露时间的延长，莲座叶面积、叶片数量和莲座叶分枝也随之增加，表现出延长的营养生长时期。长时间的冷处理还增加了 WT 植株的主花序茎高度和茎生枝数量，表明生殖发育延迟，这可以通过早期（）和晚期（）开花突变体来改变。WT 植株的侧芽/叶和莲座叶分枝/叶比值显著下降，而功能丧失的（）和（）超分枝突变体的比值则增强。这表明在冷暴露期间，腋芽分生组织继续分化，但这并不直接影响侧芽形成或侧枝分枝。我们得出结论，在花序分生组织发育之前，对幼龄幼苗进行长时间的冷暴露可以延长营养生长阶段，延迟生殖阶段，从而允许更多的叶原基和侧芽分生组织分化，从而增加 的侧枝数量。
