Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Esch/Alzette, Luxembourg.
The Birchall Centre, Lennard-Jones Laboratories, Keele University, Stoke-on-Trent, UK.
J Trace Elem Med Biol. 2018 May;47:45-52. doi: 10.1016/j.jtemb.2018.01.015. Epub 2018 Jan 31.
Horsetail (Equisetum arvense) plants grew healthily for 10 weeks under both Si-deficient and Si-replete conditions. After 10 weeks, plants grown under Si-deficient conditions succumbed to fungal infection. We have used NanoSIMS and fluorescence microscopy to investigate silica deposition in the tissues of these plants. Horsetail grown under Si-deficient conditions did not deposit identifiable amounts of silica in their tissues. Plants grown under Si-replete conditions accumulated silica throughout their tissues and especially in the epidermis of the outer side of the leaf and the furrow region of the stem where it was continuous and often, as a double layer suggestive of a barrier function. We have previously shown, both in vivo (in horsetail and thale cress) and in vitro (using an undersaturated solution of Si(OH)), that callose is a "catalyst" of plant silica deposition. Here we support this finding by comparing the deposition of silica to that of callose and by showing that they are co-localized. We propose the existence of a synergistic mechanical protection by callose and silica against pathogens in horsetail, whereby the induction of callose synthesis and deposition is the first, biochemical line of defence and callose-induced precipitation of silica is the second, adventitious mechanical barrier.
在硅缺乏和硅充足的条件下，马尾草（Equisetum arvense）植物都健康地生长了 10 周。10 周后，在硅缺乏条件下生长的植物因真菌感染而死亡。我们使用 NanoSIMS 和荧光显微镜研究了这些植物组织中的硅沉积。在硅缺乏条件下生长的马尾草没有在其组织中沉积可识别量的硅。在硅充足条件下生长的植物在其组织中积累了硅，特别是在叶片外侧的表皮和茎的凹槽区域，硅是连续的，通常呈双层状，暗示其具有屏障功能。我们之前已经证明，无论是在体内（在马尾草和拟南芥中）还是在体外（使用未饱和的硅（OH）溶液），海藻糖都是植物硅沉积的“催化剂”。在这里，我们通过比较硅和海藻糖的沉积来支持这一发现，并表明它们是共定位的。我们提出了马尾草中海藻糖和硅协同机械保护病原体的存在，其中海藻糖合成和沉积的诱导是第一道生化防线，而海藻糖诱导的硅沉淀是第二道非特有的机械屏障。
