小麦水浸提液对节节麦种子萌发和幼苗生长的影响

为阐明小麦Triticum sestivum对入侵植物节节麦Aegilops tauschii的化感作用机制，采用培养皿生物测定法，依据萌发率、苗高、根长及超氧化物歧化酶（SOD）、丙二醛（MDA）等生理生化指标的变化，研究了小麦茎叶和根系水浸提液对节节麦种子萌发和幼苗生长的影响。结果表明:小麦茎叶和根系水浸提液对节节麦种子萌发、幼苗苗高和根长均表现出“低促高抑”的化感作用。生理生化指标结果显示，小麦不同部位水浸提液对节节麦幼苗生长表现出质量浓度效应的化感胁迫作用，随浸提液质量浓度的增加，节节麦幼苗相对电导率不断增加，叶绿素质量分数逐渐下降，当浸提液质量浓度达100 g·L-1时，与对照差异均达显著水平（P < 0.05）。此外，SOD活性、脯氨酸质量分数及丙二醛质量摩尔浓度均呈逐渐增加变化，其中，前期（0~5 g·L-1）丙二醛质量摩尔浓度较对照增加差异不显著（P>0.05），可能与节节麦自身调节有关，之后增加迅速，且较对照增加均达到差异显著水平（P < 0.05），表明节节麦幼苗生长受到小麦水浸提液化感胁迫作用的加剧。综合化感效应值显示，浸提液质量浓度为25~100 g·L-1时，小麦对节节麦幼苗化感抑制作用强弱为茎叶≥根系。

Seed germination and seedling growth of Aegilops tauschii with wheat extracts

To clarify allelopathic potential and the preliminary mechanism of Triticum sestivum (wheat) on Aegilops tauschii, the effect of concentrations of T. sestivum extracts from stems, leaves, and roots on seed germination and seedling growth of A. tauschii were studied using Petri dish bioassays. Effects were based on physiological and ecological indexes, such as seed germination rate, seedling height, root length, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and other physiological and ecological index. Results showed that the aqueous extract increased membrane penetrability of A. tauschii, and enlarged the relative electrical conductivity, but decreased the chlorophyll mass fraction, reaching significance at 100 g·L-1 (P < 0.05). Also, water extracts increased SOD activities as well as proline and MDA content. At low concentrations (5 g·L-1), MDA increase was not significant (P>0.05), but with higher concentrations, MDA increased significantly (P < 0.05). According to the inhibition synthesis effect, the allelopathic inhibition of wheat stems and leaves was stronger than roots in the range of 25-100 g·L-1. Thus, seed germination along with seedling and root growth of A. tauschii were promoted at low concentrations of T. sestivum extracts and inhibited at high concentrations.