{"title":"Integrated above and below-ground responses of the gypsum specialist Helianthemum squamatum (L.). to drought","authors":"","doi":"10.1016/j.envexpbot.2024.106006","DOIUrl":null,"url":null,"abstract":"<div><div>Gypsum endemics (i.e. gypsophiles) have adapted to live in gypsum-rich soils where nutrient unbalance and drought can be extreme. Despite their relevance as plants adapted to extreme conditions, a complete analysis of the physiological responses of gypsophiles to drought is still lacking. <em>Helianthemum squamatum</em> (L.) Dum. Cours. is a conspicuous Iberian gypsophile that has been reported to use gypsum crystallization water during the driest period, but the mechanisms behind this process are unknown. To characterize gypsophile responses to drought and unravel the mechanisms underlying gypsum crystalline water use, <em>H. squamatum</em> plants were grown in pots with natural gypsum soil and gypsum soil with deuterium-labelled crystalline water. After three years, a drought experiment was carried out and whole-plant responses were investigated. Unexpectedly, the labelling treatment affected soil physicochemical characteristics and reduced microbial biomass and organic matter content, decreasing plant aerial biomass. <em>H. squamatum</em> plants did not use gypsum crystallization water during simulated drought neither in the labelled soil, nor in the natural one. Drought reduced plant transpiration, stomatal conductance, water use, photosynthetic rate and the foliar concentration of most elements except P and N, which were higher in the drought stressed plants. We detected increased root exudation of choline, an osmoprotector, by drought stressed plants. The drought treatment also affected the structure of microbial communities but did not reduce the relative abundance of functional microbial groups, highly adapted to the natural drought pulses. Our results highlight an integrated water-saving strategy of <em>H. squamatum</em> plants in the short-term, where responses at the leaf level are combined with belowground processes, like altered root exudation. Our findings also underline the remarkable resistance to drought of microbial communities present in gypsum soils.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":null,"pages":null},"PeriodicalIF":4.5000,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Environmental and Experimental Botany","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0098847224003642","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Gypsum endemics (i.e. gypsophiles) have adapted to live in gypsum-rich soils where nutrient unbalance and drought can be extreme. Despite their relevance as plants adapted to extreme conditions, a complete analysis of the physiological responses of gypsophiles to drought is still lacking. Helianthemum squamatum (L.) Dum. Cours. is a conspicuous Iberian gypsophile that has been reported to use gypsum crystallization water during the driest period, but the mechanisms behind this process are unknown. To characterize gypsophile responses to drought and unravel the mechanisms underlying gypsum crystalline water use, H. squamatum plants were grown in pots with natural gypsum soil and gypsum soil with deuterium-labelled crystalline water. After three years, a drought experiment was carried out and whole-plant responses were investigated. Unexpectedly, the labelling treatment affected soil physicochemical characteristics and reduced microbial biomass and organic matter content, decreasing plant aerial biomass. H. squamatum plants did not use gypsum crystallization water during simulated drought neither in the labelled soil, nor in the natural one. Drought reduced plant transpiration, stomatal conductance, water use, photosynthetic rate and the foliar concentration of most elements except P and N, which were higher in the drought stressed plants. We detected increased root exudation of choline, an osmoprotector, by drought stressed plants. The drought treatment also affected the structure of microbial communities but did not reduce the relative abundance of functional microbial groups, highly adapted to the natural drought pulses. Our results highlight an integrated water-saving strategy of H. squamatum plants in the short-term, where responses at the leaf level are combined with belowground processes, like altered root exudation. Our findings also underline the remarkable resistance to drought of microbial communities present in gypsum soils.
石膏特有植物(即嗜石膏植物)已经适应了在富含石膏的土壤中生活,在这种土壤中,养分失衡和干旱的情况可能非常严重。尽管它们是适应极端条件的植物,但目前仍缺乏对嗜石膏植物对干旱的生理反应的全面分析。Helianthemum squamatum (L.) Dum.Cours.是伊比利亚一种明显的嗜石膏植物,有报道称它会在最干旱的时期利用石膏结晶水,但这一过程背后的机制尚不清楚。为了描述嗜石膏植物对干旱的反应,并揭示石膏结晶水利用的内在机制,我们在盆栽中种植了 H. squamatum 植物,其中有天然石膏土壤,也有含氘标记结晶水的石膏土壤。三年后,进行了干旱实验,并调查了植物的整体反应。出乎意料的是,标记处理影响了土壤理化特性,降低了微生物生物量和有机质含量,减少了植物的气生生物量。在模拟干旱期间,无论是在贴标土壤中还是在天然土壤中,H. squamatum 植物都没有使用石膏结晶水。干旱降低了植物的蒸腾作用、气孔导度、水分利用率、光合速率和大多数元素的叶片浓度,但 P 和 N 元素除外,干旱胁迫植物的 P 和 N 元素浓度更高。我们发现干旱胁迫植物根部渗出的胆碱(一种渗透保护剂)有所增加。干旱处理也影响了微生物群落的结构,但并没有降低高度适应自然干旱脉冲的功能微生物群的相对丰度。我们的研究结果突显了 H. squamatum 植物在短期内的综合节水策略,即叶片层面的反应与地下过程相结合,如改变根系渗出。我们的研究结果还强调了石膏土壤中微生物群落对干旱的显著抵抗力。
期刊介绍:
Environmental and Experimental Botany (EEB) publishes research papers on the physical, chemical, biological, molecular mechanisms and processes involved in the responses of plants to their environment.
In addition to research papers, the journal includes review articles. Submission is in agreement with the Editors-in-Chief.
The Journal also publishes special issues which are built by invited guest editors and are related to the main themes of EEB.
The areas covered by the Journal include:
(1) Responses of plants to heavy metals and pollutants
(2) Plant/water interactions (salinity, drought, flooding)
(3) Responses of plants to radiations ranging from UV-B to infrared
(4) Plant/atmosphere relations (ozone, CO2 , temperature)
(5) Global change impacts on plant ecophysiology
(6) Biotic interactions involving environmental factors.