Evaluation of allelopathic potential of safflower genotypes (Carthamus tinctorius L.)

Abstract

Forty safflower genotypes were grown under normal irrigation and drought stress. In the first experiment, the allelopathic potential of shoot residues was evaluated using the sandwich method. Each genotype residue (0.4 g) was placed in a sterile Petri dish and two layers of agar were poured on that. Radish seeds were placed on agar medium. The radish seeds were cultivated without safflower residues as the controls. The length of the radicle, hypocotyl, and fresh biomass weight and seed germination percentages were measured. A pot experiment was also done on two genotypes with the highest and two with the lowest allelopathic activity selected after screening genotypes in the first experiment. Before entering the reproductive phase, irrigation treatments (normal irrigation and drought stress) were applied. Shoots were harvested, dried, milled and mixed with the topsoil of new pots and then radish seeds were sown. The pots with safflower genotypes were used to evaluate the effect of root residue allelopathy. The shoot length, fresh biomass weight, and germination percentage were measured. Different safflower genotypes showed varied allelopathic potential. The results of the first experiment showed that Egypt and Iran-Khorasan genotypes caused maximum inhibitory responses and Australia and Iran-Kerman genotypes resulted in minimum inhibitory responses on radish seedling growth. Fresh biomass weight had the most sensitivity to safflower residues. The results of the pot experiment were consistent with the results of in vitro experiments. Residues produced under drought stress had more inhibitory effects on the measured traits. Safflower root residue may have a higher level of allelochemicals or different allelochemicals than shoot residue.

A review of significance of allelopathy in anticipating negative climate change effects

“…To our knowledge, there is currently insufficient evidence regarding the impact of reduced precipitation or prolonged drought on the overall allelopathic potential of invasive and indigenous species. Although a limited number of studies have proposed that plants tend to limit the release of allelochemicals under unfavourable water-limited conditions (Didyk et al, 2021;Hashoum et al, 2021), the prevailing majority of research emphasises the positive correlation between drought stress and intensification of allelopathy in invasive species (Motamedi et al, 2016;Rositska, 2020;Wu et al, 2012). Aimed to estimate the differences in the allelopathy between invasive woody species (Rhus typhina L.) and indigenous woody species (Sapindus mukorossi Gaerten) under drought stress, Zhong et al ( 2023) demonstrated that drought stress reinforced the allelopathy of both the invasive (>14.59%) and indigenous (>54.17%) species.…”

Allelopathic effect of Carthamus tinctorius on weeds and crops

“…Forty genotypes were randomly selected, cultivated and their potential was evaluated in a previous study (Motamedi et al, 2016). These genotypes were grown at the research farm of the Isfahan University of Technology located at Lavark, Najaf-Abad, Iran (40 km south-west of Isfahan, 32 o 32'N 51 o 23'E).…”

Allelopathic Potential of Quinoa (Chenopodium Quinoa Willd.) Genotypes on the Germination and Initial Development of Some Weeds and Crops

“…Some studies found a higher allelopathic activity of the plant grown under water stress conditions as compared to well watered soils (Kong et al, 2002 andZuo et al, 2010). It is complicated to measure the allelopathy in the field, where it is difficult to separate resource competition (Motamedi et al, 2016), therefore the allelopathic properties are screened under laboratory conditions.…”