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The effect of three levels of salinity on physio-biochemical traits in 10 Alcea rosea (hollyhock) varieties were evaluated. It was observed that salt stress increased both the total phenolic content (TPC) and total flavonoid content (TFC) in some varieties and decreased them in others. The greatest increases in both TPC and TFC were recorded in the Saman variety (104% and 62%, respectively) when cultivated under severe salt stress, indicating that this is the most salt-tolerant variety amongst those tested. The most abundant phenolic compound recorded was ellagic acid, and the phenolic compounds that showed the greatest increases in concentration due to salt stress were p-coumaric acid (87% in the Isfahan variety) and chlorogenic acid (142% in the Mahallat variety). Salt stress was also shown to decrease the production of diphenyl-2-picrylhydrazyl (DPPH) in all varieties. The highest concentration of DPPH (133%) was recorded in the Shiraz 1 variety, grown under conditions of severe salt stress. Salt stress also increased the mucilage content present in the petals, leaves, and seeds of some of the selected varieties. These data suggest that the selection of salt-tolerant varieties of hollyhock for direct cultivation or for use in future breeding programs is feasible. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the allelopathic effect of essential oil (EO) extracted from five Foeniculum vulgare Mill. cultivars against two weed species, Portulaca oleracea L. and Amaranthus retroflexus L. Various EO concentrations (0, 100, 200, 400, 600, and 800 mgL−1) were used to determine their effects on germination and seedling growth of P. oleracea and A. retroflexus. Radicle length, plumule length, radicle wet weight, plumule wet weight, plumule dry weight, and germination percentage of the target plants were measured. GC-MS analysis revealed the presence of different compounds in studied F. vulgare cultivars. Cultivars containing α-pinene possessed strong inhibitory potential towards weeds growth. On the contrary, cultivars containing fenchone showed poor inhibitory potential on both weeds. Moreover, the results indicate that with increasing EO concentration of F. vulgare, radicle length, plumule length, radicle wet weight, plumule wet weight, plumule dry weight, and germination percentage of both weed species decreased. The highest inhibitory effects were observed at 600 and 800 mg L−1 concentrations. Boushehr F. vulgare cultivar showed the highest inhibitory effect, while Esfahan and Yazd cultivars were identified as least inhibitory against the two weeds. Both P. oleracea and A. retroflexus showed similar sensitivities to F. vulgare EO. [ABSTRACT FROM AUTHOR]

Water stress may affect the growth, physiology, morphology, biochemistry, and productivity of Nigella sativa (black cumin), a medicinal and aromatic plant. Measuring these parameters under various irrigation regimes could provide useful information for successful genotype selection and breeding. Therefore, these agronomically significant features were evaluated in ten black cumin genotypes (Afghanistan, Pakistan, Syria, India, Arak, Isfahan, Semirom, Shahreza, Shahrekord, and Mashhad) under three irrigation regimes (40% (I1), 60% (I2), and 80% (I3) of permissible moisture discharge) during the 2017 to 2018 growing seasons. Water stress was shown to increase the levels of carotenoids (Cars), proline, total soluble carbohydrates (TSC), malondialdehyde (MDA), hydrogen peroxide (H2O2), catalase (CAT), and ascorbate peroxidase (APX) activities but reduced the relative water content (RWC) and chlorophyll content. The highest increases in Cars, TSC, proline, CAT, and APX were noted in the Arak, Isfahan, Semirom, Shahreza, Shahrekord, and Mashhad genotypes under the I3 water regime, respectively. At the same time, the lowest decrease was observed in chlorophyll, H2O2, and relative water content (RWC) in Semirom. According to the stress susceptibility index, the most resistant genotypes were Shahrekord under I2 and Semirom under I3. These data demonstrate that the irrigation regimes affected the physiological, biochemical, and morphological features of black cumin both qualitatively and quantitatively, although the impact varied depending upon the genotype, irrigation regime, and traits. As such, the results presented represent valuable information with which to inform future selection and breeding programs for drought-tolerant black cumin. This is of particular significance considering global climate change. [ABSTRACT FROM AUTHOR]