Short-term (during minutes) changes in the composition of weed leaves exposed to abiotic stress

Abstract

Exposure to abiotic stress can lead to various physiological, biochemical, and molecular changes in plants. In 2025, a field experiment was conducted to study the rapid (within the first 15-30 minutes) response of two weeds, dandelion and couch grass, to mechanical damage (sequential cutting of leaf pieces). Raman spectroscopy was used to analyze the plant samples. The focus was on organic compounds such as aliphatic compounds, aromatic rings, carotenoids, pectin, phenylpropanoids, and starch. Several other organic compounds and complexes have also been identified that could potentially play an important role in plant resistance to stress factors. The concentration of different organic compounds in control and damaged plant leaves varied with time. These changes differed in the morning and afternoon. This might be caused by differences in external environmental factors and also short-term circadian variations of the plant's physiological activity. The temporal fluctuations of most organic compounds in the leaves of dandelion and couch grass were different. Furthermore, the plants responded differently to abiotic stress. This may be due to the fact that couch grass is a monocot, while dandelion is a dicot. The physiological and biochemical processes in these plants can differ significantly. The response of plants to leaf cutting was very rapid. The concentration of organic compounds could vary up to three times compared to the control. However, in many cases, plants recovered from mechanical impact within a short period of time, 30 minutes.