J Plant Ecol ›› 2024, Vol. 17 ›› Issue (3): rtae035.DOI: 10.1093/jpe/rtae035

• Research Articles •    

Phenotypic plasticity variations in Phragmites australis under different plant-plant interactions influenced by salinity

Huijia Song1,2, Xiao Guo3,*, Jingcheng Yan1, Lele Liu2, Mingyan Li3, Jingfeng Wang2, Weihua Guo2,*   

  1. 1National Natural History Museum of China, Beijing 100050, China;
    2Key Laboratory of Ecological Prewarning, Protection, and Restoration of Bohai Sea, Ministry of Natural Resources, School of Life Sciences, Shandong University, Qingdao 266237, China;
    3College of Landscape Architecture and Forestry, Qingdao Agricultural University, Qingdao 266109, China

盐分介导下芦苇对不同邻体植物的表型可塑性响应

Abstract: Coastal wetland ecosystems are increasingly threatened by escalating salinity levels, subjecting plants to salinity stress coupled with interactions in the community. Abiotic factors can disrupt the balance between competition and facilitation among plant species. Investigating the effects of different neighboring species and trait plasticity could extend the stress gradient hypothesis and enhance understanding of vegetation distribution and diversity in salt marshes. We conducted a greenhouse experiment and investigated the plastic response of wetland grass Phragmites australis to seven neighboring plants of three functional types (conspecifics, graminoids and forbs) under soil salinity (0 and 10 g/L). Plant height, base diameter, density, leaf thickness, specific leaf area and total and part biomasses were measured. Additionally, the relative interaction index (based on biomass) and the relative distance plasticity index (RDPI) were calculated. Salinity significantly reduced the biomass, height, density and diameter of P. australis. The functional types of neighboring plants also significantly affected these growth parameters. The influence of graminoids on P. australis was negative under 0 g/L, but this negative effect shifted to positive facilitation under 10 g/L. The facilitation effect of forbs was amplified under salinity, both supporting the stress gradient hypothesis. The growth traits of P. australis had a plastic response to salinity and competition, such as increasing belowground biomass to obtain more water and resources. The RDPI was higher under salt conditions than in competitive conditions. The plant-plant interaction response to stress varies with plant functional types and trait plasticity.

Key words: functional type, interaction, phenotypic plasticity, salt tolerance, stress gradient hypothesis

摘要:
随着滨海湿地生态系统盐胁迫增加,群落中的植物同时受到盐胁迫和植物相互作用的影响。非生物因素干扰植物之间竞争和促进效应的稳定,使植物产生复杂的表型可塑性响应。探讨不同的邻体物种及对性状可塑性的影响将会扩展胁迫梯度假说,深入理解盐沼湿地的物种分布特征。本研究开展温室控制实验,探究盐胁迫下(0和10 g/L)芦苇(Phragmites australis)对3种功能类型7种邻体植物(同种植物、禾草类植物和杂草类植物)的表型可塑性响应。实验测量了株高、基径、密度、叶厚度、比叶面积、总生物量和各部分生物量等性状,计算了邻体效应指数(基于生物量)和相对表型可塑性指数。结果表明,盐分显著降低了芦苇的生物量、株高、密度和基径。邻体植物的功能类型显著影响芦苇的生长性状。盐分为0 g/L时,禾草类植物对芦苇形成负的竞争效应,但在10 g/L盐分下,这种负效应转变为正的促进作用。芦苇的生长性状对盐分和竞争具有可塑性反应,如增加地下生物量以获得更多的水分和资源,可塑性指数在盐分条件下比竞争条件下更高。总之,植物-植物相互作用对胁迫的响应随植物功能类型和性状可塑性而异。

关键词: 功能性状, 表型可塑性, 相互作用, 耐盐性, 胁迫梯度假说