Effect of nutrient and soil moisture of maternal environment on quality and biochemical characteristics of Dragon’s head (Lallemantia iberica) seed

Lallemnatia ibercia (Dragon’s head) is an annual herb, which belongs to the Lamiaceae family. Nowadays, its seed is widely used in food and pharmaceutical industries due to its high mucilage and oil content. Soil moisture, nutrition, light, and temperature of the maternal environment play an important role in plant growth. However, the effect of soil moisture on yield and seed quality indices is greater during seed development. The positive effects of maternal plant nutrition with mycorrhizal inoculation can influence the quality improvement of the seeds developed under water deficit conditions. The reason for the quality improvement of the seeds developed under mycorrhizal inoculation condition is reported to be their water balance under water deficit conditions and as a result, more absorption of water and nutrients. Nutrient uptake by the maternal plant can play an important role in improving the germination and quality characteristics of the seeds developed under drought stress.

A field experiment was conducted in a completely randomized design with three replications at the Seed Science and Technology Laboratory of the College of Agriculture, Shahed University during f 2018-19 and 2019-20 years. Experimental treatments included irrigation regime (30, 60 and 90% of depletion of available soil water (ASW)) and mycorrhizal inoculation (non-inoculation and inoculation).

The results showed that a reduction in soil moisture in the maternal environment decreased germination percentage and seed quality.  Germination percentage (51.20%) germination rate (7%), seed vigor index (27.70%), seedling length (28.3%), seedling dry weight (34.80%), seed mucilage (75.40%), as well as seed nutrients (27.30%), seed oil (14.60%) and catalase (35.25%) and ascorbate peroxidase (25.70%) enzymes activities enhanced in the seeds developed under 60% depletion of available soil water and application of mycorrhizal compared to control (30% depletion of available soil water and without mycorrhizal). Compared with the 30% depletion of available soil water and without mycorrhizal, mean germination time (17%) and lipid peroxidation (41.10%) increased under the 90% depletion of available soil water and without fertilizer mycorrhizal.

According to the results of this study, the irrigation regime of 60% available soil water depletion of maternal plants leads to the reduction of seed quality. However, the nutrition of maternal plants by mycorrhizal inoculation effectively improved the quality of seeds developed under water deficit due to the absorption of water and nutrients.

Germination and seedling growth indices, quality and biochemical characteristics of the Lallemantia iberica seeds developed under different conditions of irrigation regime were investigated.
 The effect of mycorrhiza on nutrient uptake, oil content, and antioxidant enzyme activity of the seeds developed under different irrigation regimes was investigated.
The extent of damage to the lipid structures of cells in the seeds developed under different irrigation regimes and mycorrhiza fertilizer was investigated.