Cuscuta campestris is a holoparasitic plant that depends on the host for water, nutrients, and photosynthetic substances. The purpose of this research was to evaluate the effects of the host species on the content of bioactive and health-promoting substances in the Cuscuta seeds to test the following hypothesis: these substances are more induced if the hosts are herbs. The studied hosts were herbs (thyme, basil, and onion) and non-herbs (alfalfa and tomato). The results showed that the carotenoid accumulation in seeds developed on basil and thyme was the maximum. The extracts of seeds grown on thyme and onion had significantly more galactitol, total polysaccharide, and antioxidant activity than other hosts. Quercetin, kaempferol, and total flavonoids were higher in the seeds set on onion. The highest content of bergenin was recorded on thyme with no significant difference with onion. The extract of seeds grown on thyme had more total phenolics, followed by tomato and basil. Analysis of the phytosterol content of the seeds showed that campesterol was the minimum in seeds grown on alfalfa and stigmasterol was lowest in seeds grown on tomato than other hosts. Additionally, β-sitosterol increased in seeds developed on basil, onion, and thyme, and Δ⁷-avenasterol increased in seeds set on thyme and basil. Overall, the content of total phytosterols was higher in seeds developed on basil, onion, and thyme. The results were suggestive of the proper health-promoting levels of dodder seeds developed on medicinal plants such as onion and thyme for pharmaceutical and food applications.

Fenugreek (Trigonella foenum-graecum) is an annual plant belonging to the family Fabaceae and has fodder, medicinal and spice uses, and is also used as an organic fertilizer. A total of 18 treatments including the combination of two light environments (with and without supplementary blue light), three concentrations of potassium iodate (0, 2 and 4 mg L⁻¹) and four concentrations of sodium selenate (0, 2 and 4 mg L⁻¹) were organized in a three-way factorial experiment to evaluate the growth characteristics, pigments, trigonelline and seed yield of fenugreek in a greenhouse. The application of 4 mg L⁻¹ of Se resulted in the highest carotenoid, anthocyanin, plant length, fresh weight, chlorophyll and relative water content. The fresh and dry weight of the shoot and the anthocyanin increased with the 2 h supplementation of sunlight with a blue spectrum; however, the fresh root decreased. The interaction of blue light with 0 mg L⁻¹ of Se significantly reduced the plant length. The content of trigonelline was significantly improved with the application of blue light supplementation without negatively affecting the seed yield. In general, 2 h supplementing of sunlight with blue light and feeding with 4 mg L⁻¹ of selenium and iodine are recommended to improve various traits, including trigonelline content.

A water deficit can significantly limit the sustainable production of plants, resulting in reduced growth, development, and flowering. The use of biostimulants improves plant stability and promotes growth under low-irrigation conditions. This study evaluated the effects of biostimulators on the growth, development, and flowering of tuberose (Polianthes tuberosa L.) under water-deficit conditions. This experiment was conducted using a completely randomized design with three replications in pots and eight treatments: four irrigation regimes (100%, 80%, 60%, and 40%), and four biostimulant treatments (foliar application of seaweed extract (SE) at concentrations of 500, 1000, and 2000 ppm; humic acid (HA) application at concentrations of 150, 300, and 600 ppm; inoculation of the bed with mycorrhiza; a control treatment without biostimulators). We measured the length, diameter, and fresh and dry weight of the flower pedicel; the number of leaves per plant; the fresh and dry weight of the leaves, stem, and root of each plant; and the content of photosynthetic pigments, phenol, proline, carbohydrates, and flavonoids. The results of this study showed that the growth and development of tuberoses were positively affected by different irrigation levels and biostimulants. The highest morphological characteristics were observed in plants irrigated at 100% field capacity. In contrast, the irrigation regime treatment of 40% of the field capacity combined with 600 mg/l of HA had the most detrimental effect on plant growth indicators. Findings suggest that application of 2000 ppm of SE biostimulant contributes to the mitigation of the negative effects of water deficit in tuberose production under greenhouse conditions as an irrigation water conservation strategy that can be exploited to maintain high yields.