Effects of Salinity on Tagetes Growth, Physiology, and Shelf Life of Edible Flowers Stored in Passive Modified Atmosphere Packaging or Treated With Ethanol

Abstract

Irrigation with saline water causes significant crop yield loss. However, short-term saline application might cause less negative effects on yield yet at the same time improve quality aspects of edible products. Tagetes (Tagetes patula L.) plants were subjected to salinity (0, 50, and 100 mM NaCl) and harvested flowers were stored up to 14 days in passive modified atmosphere packaging (with or without ethanol application). Salinity of 100 mM NaCl decreased plant biomass and plant size (i.e., height) and had a negative effect on physiological processes such as stomatal closure and chlorophylls content decrease. Salinity increased flower polyphenols, antioxidant activities, and total carotenoids but decreased anthocyanins, and greater impacts were found at salinity of 100 mM NaCl, providing higher antioxidant value of the edible flowers. Short-term saline exposure of tagetes plants activated metabolic processes and as a result there was an accumulation of minerals such as N, P, Na, and Zn on edible flowers. During storage, salinity maintained but ethanol application increased the flower CO2 production. Ethanol application decreased the decay of flowers subjected to 100 mM NaCl. Flower weight losses and marketability accelerated at salinity of 100 mM NaCl after 14 days of storage. Tagetes flowers demonstrated induction in both non-enzymatic (i.e., proline content) and enzymatic mechanisms (catalase) to overcome stress caused by salinity during harvest stage and/or ethanol at storage. Our results have shown that short-term exposure to salinity and/or ethanol is able to achieve higher carotenoids and anthocyanins levels and these compounds can be considered as a new source of nutraceuticals.

The Impact of Salt Stress on Plant Growth, Mineral Composition, and Antioxidant Activity in Tetragonia decumbens Mill.: An Underutilized Edible Halophyte in South Africa

“…Conversely, the FRAP capacity was positively influenced by salt stress with the strongest antioxidant capacity obtained at 50 mM NaCl. A similar trend was reported earlier by [16] in edible flowers, where the application of salinity enhanced antioxidant activities.…”

“…Contrary to the increase in phenolic content, the antioxidant activity (ABTS) in the leaves of T. decumbens exposed to various salinity concentrations showed a much weaker antioxidant capacity compared to the control. This contradicts the findings of [16] on edible flowers, where three antioxidant assays (FRAP, DPPH, and ABTS) increased with the application of salinity, with a more pronounced impact at a salinity of 100 mM NaCl. Furthermore, these results also substantiate that of [72] on a traditional Chinese herb, where a much weaker antioxidant capacity was found with increasing NaCl concentrations at 50 mM and 100 mM, respectively, compared to the control.…”

“…To overcome salt-mediated oxidative stress, plants detoxify ROS by up-regulating antioxidative enzymes, which includes the superoxide dismutase (SOD) found in various cell compartments [15]. This enzyme catalyzes a conversion from two O 2 radicals to H 2 O 2 and O 2 [16]. In alternative ways, several antioxidant enzymes can also eliminate the H 2 O 2 , such as catalases (CAT) and peroxidases (POX), by converting it to water [17].…”

Phytonutritional Content and Aroma Profile Changes During Postharvest Storage of Edible Flowers

“…Within the Asteraceae family, discrepancies were observed; the morphology of A. houstonianum flowers strongly compromised the storage due to dehydration and color change. By contrast, T. lemmonii showed limited signs of dehydration, similarly, as observed in T. patula after 7 postharvest days (Chrysargyris et al, 2018). The broad Salvia genus highlighted differences between single species; S. dorisiana showed limited weight loss and discoloration, while in other Salvia species, divergent behavior was observed (Landi et al, 2015(Landi et al, , 2017.…”

Current Advances in Plant Growth Promoting Bacteria Alleviating Salt Stress for Sustainable Agriculture

“…Interestingly, 50 mM NaCl salinity generated Ca in flowers approximately three times relative to the control of crops not treated with salt [87]. In addition, phonological findings of bud flowering and forming were found in plants handled with high amounts of NaCl occurred in contrast to control plants [88]. For instance, in [89], with rising salinity rates, days to flowing were expanded, however, in rapeseed rice varieties days to maturation were reduced.…”