Effect of Methanol Spraying on Seed Yield and Mucilage of Flixweed (Descurainia sophia L.)

Descurainia sophia L. is one of the most valuable medicinal plants in the pharmaceutical industry because its seeds are used for the production of mucilages. Methanol spraying, as a biological stimulant on three carbonaceous plants, can increase carbon dioxide stability and reduce respiration, resulting in more dry matter in these plants.

This experiment was carried out to investigate the effect of methanol spraying on seed yield and mucilage variation of D. sophia based on randomized complete block design with five treatments and three replications in a field experiment in Khoy, Iran. The treatments consisted of the control treatment (distilled water without methanol application) with 4 concentrations of methanol spraying (containing 10, 20, 30 and 40%) carried out during the growing season three times at intervals of 12 days (36, 48, 60 days after planting). After the last spraying at the time of full maturity, the plants in each plot were taken individually. The measured morphophysiological characteristics included plant height, plant leaf number, plant stem number, plant dry weight, number of pods per plant, number of seeds per pod, 1000 seed weight and seed yield. Also, the measured phytochemical traits included seed ash content, mucilage percentage and yield, and inflation index.

Results showed that foliar application of different concentrations of methanol had a significant effect on number of plant stems, number of plant leaves, plant dry weight, number of pods per plant, number of seeds per pod, grain yield, seed mucilage yield, seed ash, seed inflation index (p ≤ 0.01), plant height and 1000 seed weight (p ≤ 0.05). Foliar application of different concentrations of methanol had a significant effect on all morphological and functional components. To be more precise, methanol spray had a significant effect on plant height, number of stems, plant leaf number, shoot dry weight, number of pods per plant, number of seeds per pod, 1000 seed weight and seed yield, but the effect of year on none of the measured traits was meaningful. Also, the interaction between the year and methanol spraying on the traits of plant leaf number, number of seeds per pod and 1000 seed weight had a significant effect, but the remaining traits were not affected considerably. Combined analysis of variance showed that the year effect had no noticeable effect on seed ash. While methanol concentration had a significant effect (p≤ 0.01) on the seed ash content, the interaction of methanol in different years of experiment was not significant on this characteristic.

Regular methanol spraying, as an active bioavailable and a new method in the production of medicinal plants, improved seed yield and mucilage of Descurainia sophia seed. Generally, the highest values for the evaluated properties were obtained in the induction of 40% volumetric methanol solution.