Exogenous S-Methylmethionine Alleviates Salinity Stress by Modulation of Physiological Processes in Canola (Brassica napus)

Abstract

Canola is a moderately salt tolerant plant, high salinity inhibits germination of seeds, vegetative growth of young plantlets, and reduces biomass production. This study investigated the effects of priming with 1 mM S-methylmethionine (SMM) on germination, leaf gas exchange, induced chlorophyll fluorescence, photosynthetic pigment content and membrane damage through lipid peroxidation by exposing canola (Brassica napus L. cv. Cindi) plants to moderate and severe salt stress (induced by 60 mM and 120 mM NaCl) for different periods. Priming with SMM alleviated the reduction of net photosynthetic rate, the effective quantum efficiency and efficiency of excitation energy capture by open photosystem II reaction centers, chlorophylls to carotenoids ratio, enhanced water use efficiency and contributed to reduction of oxidative membrane damage in fully developed young leaves. Delay and inhibition of seed germination by salt stress were significantly reduced by SMM, as well as the non-photochemical quenching of the singlet excited state of chlorophyll a, suggesting a more efficient protection against hyperosmotic stress, ionic toxicity and associated oxidative stress in primed plants exposed to high salinity. This first assay of SMM as a priming agent for canola plants under high salinity contributes to a better understanding of the mode of action of this natural, plant-derived bioactive compound and the optimization of canola cultivation under the adverse growth conditions caused by salt stress. © 2021 Friends Science Publishers

S-Methylmethionine Effectively Alleviates Stress in Szarvasi-1 Energy Grass by Reducing Root-to-Shoot Cadmium Translocation

“…However, stomatal conductance was found to be unaffected by SMM priming ( Figure 1 B), which may refer to the fact that SMM did not reach, directly, the autonomous guard cells, or the metabolic shift caused by SMM was not in relation with their functioning. Our results are in line with similar studies performed under NaCl stress with Brassica napus and Cucumis sativus plants, in which SMM had no stimulatory effect on stomatal conductance and transpiration rate [ 91 , 92 ].…”

Influence of triacontanol and salt stress on the growth and metabolism of spinach

“…Similar results were reported for wheat, in which case the saline medium caused a signifi cant reduction in several attributes of leaf gas exchange, while the application of ascorbic acid as a bioactive compound increased the carbon assimilation rate in both stressed and non-stressed plants [2]. Vitamin U was also found to alleviate the negative effects of short-term salt stress on the net carbon dioxide assimilation of canola leaves [6]. Also, in young leaves of cucumber seedlings, the net photosynthetic carbon dioxide assimilation rate was reduced by high salt concentration, but this reduction was alleviated by putrescine used as a hardening agent [23].…”

“…In this case, application of 10 mM putrescine (a bioregulator from the group of polyamines) signifi cantly alleviated this undesirable effect of salt stress. Similar results were reported when S-methylmethionine (vitamin U) was used as a priming agent to enhance the salinity tolerance of canola [6]. Infl uence of triacontanol and salt stress on the growth and metabolism……”

“…Seeds sterilized with 3% (w/v) sodium hypochlorite were pre-hydrated for 12 hrs with distilled water and germinated in Linhard vessels. After one week, plantlets with similar size -fi ve for every experimental variantwere planted one by one in pots with perlite, watered regularly with Hoagland's mineral nutrient solution (to avoid any nutrient defi ciency) and kept for two weeks in a growth chamber (Sanyo MLR-351H) under a photosynthetically active photon fl ux density of 330 μmol m -2 s -1 for a daily photoperiod of 12 hrs, at 20 °C in the light period and 17 °C during the dark period, the relative air humidity being maintained constantly at 65% [3,6]. The different treatments were applied on three-week-old plantlets and lasted for 15 days, being repeated once in three days.…”

“…In some cases, e.g. in maize cultivars exposed for 35 days to 100 mM NaCl, an enhancement of chlorophyll content was reported in salt-stressed plants [13], while in lettuce, canola, and wheat leaves a pronounced salt stress resulted in a signifi cant reduction of the chlorophyll content [5,6,16]. Carotenoids, as the other type of photosynthetic pigments associated to chlorophylls, not only have a complementary role in the absorption of photo synthetically active blue light, but they also act as effi cient protective agents against oxidative stress conditions related to the excessive formation of singlet oxygen and of alkylhydroxyl radicals [8].…”