沙芦草种子发芽抑制物的初步探究

沙芦草又称蒙古冰草，具有抗旱、抗寒、抗病、耐盐碱等优良性状，是荒漠草原和典型草原地带沙地主要植被之一。沙芦草种子存在发芽率低、发芽持续时间长等野生特性，这对沙芦草人工种子繁育和生产利用造成一定程度的影响。为探究沙芦草种子休眠机制，试验分别用石油醚、乙醚、乙酸乙酯、甲醇、丙酮等5种有机溶剂和纯水对沙芦草种子稃壳进行浸提，利用白菜种子发芽试验测定各提取相的抑制性，通过气相色谱-质谱联用仪（GC-MS）对5种有机溶剂浸提液进行分离鉴定，确定浸提物质的种类和性质。结果表明：沙芦草种子稃壳的各相浸提液对白菜种子的发芽率、根长及苗高均有不同程度的抑制作用，其中抑制作用最强的是水相，其次是乙酸乙酯相和甲醇相；通过GC-MS检测，发现沙芦草种子稃壳中存在烷类、醇类、酯类、酮类、苯类、酰胺、缩醛、酸类和酚类等9类32种有机化合物，其中醇类、酮类和烷类物质的含量相对较高，且大部分为水溶性物质。因此，沙芦草种子稃壳中存在的醇类、酮类和烷类等可溶性物质是引起沙芦草种子休眠的主要原因之一，该研究可为寻找沙芦草种子休眠破除方法提供理论依据。

A preliminary study on substances that inhibit germination in the seeds of Agropyron mongolicum

Agropyron mongolicum， commonly known as Mongolian wheatgrass， is one of the main plants in desert steppe and typical steppe vegetation in sandy land. It has excellent characteristics of resistance to drought， cold， disease， salt， and alkali. However， the seeds of A. mongolicum retain some wild characteristics such as a low germination rate and a long duration of germination. This affects the artificial seed reproduction， production， and utilization of A. mongolicum. To explore the dormancy mechanism of A. mongolicum seeds， the seed husks were extracted with five different solvents （petroleum ether， ether， ethyl acetate， methanol， acetone， and pure water） and the inhibitory effects of the extracts on seed germination of Brassica pekinensis （cabbage） were evaluated. In addition， gas chromatography-mass spectrometry （GC-MS） analyses were conducted to determine the types of compounds in the extracts. The five extracts from the husks of A. mongolicum seeds inhibited the germination rate， root length， and seedling height of cabbage to different degrees. Among the five types of extracts， the water extract had the strongest inhibitory effect， followed by the ethyl acetate extract and then the methanol extract. In the GC-MS analyses， 32 kinds of organic substances in nine classes （alkanes， alcohols， esters， ketones， benzenes， amides， acetals， acids， and phenols） were detected in the extracts of A. mongolicum. Most of those substances were water soluble， and the most abundant substances were alcohols， ketones and alkanes. Therefore， one of the main reasons for the dormancy of A. mongolicum seeds is the presence of inhibitors such as alcohols， ketones， and alkanes in the husks. The results of this study will be useful for developing methods to break the dormancy of A. mongolicum seeds.