Growth and mycorrhizal colonization of maize plants treated with aqueous extracts from nonmycorrhizal weeds

Abstract: The objective of this work was to evaluate the influence of aqueous extracts of nonmycorrhizal weedy species on dry matter accumulation and assimilate partitioning of maize plants, with or without Cetraspora pellucida inoculation. The experiment was carried out in pots, in a completely randomized design, in a 5x2 factorial arrangement consisting of four plant extracts (purple nutsedge, guinea-hen weed, slender amaranth, and knotweed), a control irrigated with water, and two conditions (mycorrhizal and nonmycorrhizal maize plants), with four replicates of each treatment. Plants were irrigated with aqueous extracts diluted at 15%. Root colonization (RC), shoot dry matter (SDM), root dry matter (RDM), and RDM/SDM were evaluated. Root colonization was not influenced by the extracts, and ranged from 41.5 to 65.2%. Shoot dry matter of mycorrhizal (AM) and nonmycorrhizal (NM) plants was not influenced by the extracts; however RDM showed varying responses. Mycorrhization favored the production of RDM, and increased plant sensitiveness to the extracts. Guinea-hen weed extract increased RDM of AM plants, while the other extracts inhibited it. In NM plants, the production of RDM was benefited by slender amaranth extract, to the detriment of SDM. Mycorrhizal and nonmycorrhizal maize plants respond differently to aqueous extracts of nonmycorrhizal weeds.

摘要：本研究旨在评估非菌根杂草物种（nonmycorrhizal weedy species）的水提物对接种或未接种透明囊霉（Cetraspora pellucida）的玉米植株干物质积累（dry matter accumulation）与同化物分配（assimilate partitioning）的影响。本试验采用盆栽完全随机设计，设置5×2因子处理组合：4种杂草水提物（紫香附子、鸡眼草、细叶苋、虎杖）、1个清水灌溉对照组，以及2个接种条件（菌根化与非菌根化玉米植株），每个处理设置4次生物学重复。所有供试植株均以15%稀释比例的水提液进行灌溉。试验测定指标包括根系定殖率（root colonization, RC）、地上部干物质重量（shoot dry matter, SDM）、根系干物质重量（root dry matter, RDM）以及RDM与SDM的比值。数据分析结果显示，杂草水提物对玉米根系定殖率无显著影响，其根系定殖率介于41.5%至65.2%之间。杂草水提物对菌根化（arbuscular mycorrhizal, AM）与非菌根化（nonmycorrhizal, NM）玉米植株的地上部干物质重量均无显著调控作用，但对根系干物质重量的调控效应存在显著差异。菌根化处理可显著促进根系干物质的积累，并增强植株对杂草水提物的响应敏感性。具体而言，鸡眼草水提物可提升菌根化玉米植株的根系干物质重量，其余三种提取液则对其产生抑制效果；而在非菌根化植株中，细叶苋水提物可促进其根系干物质积累，但会降低地上部干物质重量。综上，菌根化与非菌根化玉米植株对非菌根杂草水提物的响应模式存在显著差异。