The Impact of Salinity Stress on Antioxidant Response and Bioactive Compounds of Nepeta cataria L.

Abstract

In this study, the ability of Nepeta cataria L. to grow and synthesize bioactive compounds on soil treated with different salt concentrations was tested to evaluate the opportunity of cultivating it in soils affected by salinization. N. cataria L. was grown in soil containing specific amounts of NaCl, Na2SO4, and their mixture. After harvesting, the plants were analyzed from the morphological and physiological point of view. Salinity stress inhibited the growth, with the highest decrease of the plant yield up to about 70% in the case of salt mixture, and smaller values for the separate salt treatments. In the same time, as a defense mechanism, there was an increase of granular trichomes’ density, as observed with the scanning electron microscope. For mild concentrations of salt, the amount of chlorophyll pigments was enhanced, while for stronger salinity stress, it decreased. The opposite behavior was evidenced for the polyphenol content, as antioxidant activity was used as a protective mechanism against reactive oxygen species produced under salinity stress. The antioxidant activity was considerably higher for separate NaCl and Na2SO4 treatments than for the salt mixture variants. The results showed that the species Nepeta cataria L. reacts well to high salinity levels, with an increased content of bioactive compounds and antioxidant activity even for the highest studied salinity conditions.

Photosynthesis and chlorophyll fluorescence of Iranian licorice (Glycyrrhiza glabra l.) accessions under salinity stress

“…The increase in trichome numbers and length means that more areas of the plant surface become physically covered by the trichomes for more efficient water conservation to relieve abiotic stress . It was observed that trichome density increased in response to salt stress in buffel grass (Cenchrus ciliaris L.) (Wasim et al, 2022), catnip (Nepeta cataria L.) (Lungoci et al, 2022), and smooth flatsedge (Cyperus laevigatus L.) (Mumtaz et al, 2021), which confirms the relevant results in the present study. It is now widely assumed that halotolerant PGPB has an inherent potential to assist in coping with high-saline conditions and to facilitate plant growth through different direct/indirect mechanisms that benefit plants (Sagar et al, 2022).…”

Successive harvests affect the aromatic and polyphenol profiles of novel catnip (Nepeta cataria L.) cultivars in a genotype-dependent manner

“…Previous research has identified that glandular trichomes of different chemotypes of N. cataria differ in their structure and morphology ( Kolalite, 1998 ), therefore, it is possible that part of the chemical contrast observed between cultivars CR3 and CR9 are correlated to differences in their glandular trichomes, a topic worthy of further research. Additionally, the density of glandular trichomes on the surface of N. cataria leaves is also known to be affected by environmental conditions such as saline stress ( Lungoci et al., 2022 ) and fertilization ( Paria et al., 2021 ). The investigation of trichome density and morphology in N. cataria and their correlation with agricultural practices and genotypes can be of fundamental importance for breeding programs as this is a trait directly associated with the productivity of compounds of interest in the species.…”

Salinity Stress Influences the Main Biochemical Parameters of Nepeta racemosa Lam.

“…Nepeta sp. belongs to the Laminaceae family and has approximately 300 species with high phenotypic plasticity and it originates from South-West Asia [ 21 , 22 , 23 ]. Nepeta racemosa Lam.…”

“…Nepeta racemosa Lam. is characterized by a high content of nepetalactone, which are secondary metabolites with a wide range of uses [ 21 , 22 , 23 , 24 ]. The beneficial effects can be divided into several categories depending on the bioactivity: the antiseptic, astringent, and antiasthma properties are used in medicine, the antibacterial and preservative properties are put to use in the food industry, the bio-herbicidal and pheromonal properties for aphides abilities are used in plant protection [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

“…Some researchers found that salt stress significantly reduces the germination and seeding growth in Nepeta persica exposed under laboratory conditions [ 29 , 30 ]. In our previous study, we found that salt stress can indeed lead to negative effects on Nepeta cataria L such as a decrease in yield and concentrations of photosynthetic pigments, but can also stimulate the production of bioactive compounds and antioxidant activity in some conditions; overall, the species react well to high salinity levels [ 21 ]. In this work, we aimed to test the influence of sodium chloride (NaCl) and sodium sulfate (Na 2 SO 4 ), the two most common salts in Romanian soils affected by salinity, on Nepeta racemosa Lam.…”