Exogenous Methyl Jasmonate Application Improved Physio-Biochemical Attributes, Yield, Quality, and Cadmium Tolerance in Fragrant Rice

Abstract

Cadmium (Cd) has detrimental effects on crop plants, whereas, jasmonates (JAs) play a vital role in abiotic stress tolerance in plants. The present study investigated the effects of exogenous application of methyl jasmonate (MeJa) on the physio-biochemical attributes, yield, and quality of two fragrant rice cultivars, i.e., Xiangyaxiangzhan and Meixiangzhan-2 under Cd stress. The experiment was comprised of four treatments, i.e., CK, control (normal conditions); Cd: 100 mg Cd kg–1 of soil; MeJa: exogenous application of MeJa at 20 mM; and Cd + MeJa: 100 mg Cd kg–1 of soil + exogenous MeJa application at 20 mM. Results depicted that Cd toxicity resulted in a substantial reduction of enzymatic activities and non-enzymatic antioxidants, chlorophyll contents, while enhanced oxidative damage in the terms of lipid peroxidation (higher malondialdehyde (MDA) contents), H2O2, and electrolyte leakage. Proline contents were found higher whereas protein and soluble sugars were lower under Cd stress as compared with Ck and Cd + MeJa. Exogenous MeJa application further improved the panicles per pot, spikelets per panicle, seed setting (%), 1,000 grain weight, and yield per pot under Cd stress conditions as compared with non-MeJa applied plant under Cd stress. In addition, exogenous MeJa application enhanced the accumulation of macro (N, P, K, Mg, and Ca) and micronutrients (Mn, Zn, Fe, and Cr) in both cultivars under Cd stress, while reduced the Cd contents in different plant parts. Overall, the contents of Cd in different plant organs were recorded as: root > stem > leaves > grains for all treatments. Comparing both cultivars, the grain Cd contents were higher in Meixiangzhan 2 than Xiangyaxianzhan under Cd contaminated conditions. Conclusively, Cd toxicity impaired growth in rice by affecting physio-biochemical attributes, however, Xiangyaxiangzhan performed better than Meixiangzhan-2 cultivar.

Riboflavin improves grain yield, 2‐acetyl‐1‐pyrroline accumulation, and antioxidative properties of fragrant rice

“…To date, numerous studies have demonstrated that the productivity of fragrant rice can be regulated through the application of various PGRs. For instance, Kanu et al 34 found that fragrant rice yield could be significantly increased by 13.4-17.6% for both experimental cultivars when uniformly sprayed with 20 mM L −1 MeJA at vegetative and reproductive stages. Jiang et al 35 also discovered that low levels of melatonin spraying could alleviate heavy metal toxicity and promote fragrant rice yield.…”

Biosynthesis of 2-Acetyl-1-pyrroline in Fragrant Rice: Recent Insights into Agro-management, Environmental Factors, and Functional Genomics

“… However, it has been found that foliar application of jasmonic acid, at the time of grain filling, on young seedlings of fragrant rice cultivars increased 2-AP and other volatiles . Similarly, the exogenous application of methyl jasmonate resulted in substantial improvements in yield and quality of fragrant rice under Cd toxicity . Paclobutrazol is widely recognized as an effective regulator of plant development, and the foliar application of paclobutrazol was proven efficient in improving the aroma of fragrant rice, grain quality, and yield .…”

“…83 Similarly, the exogenous application of methyl jasmonate resulted in substantial improvements in yield and quality of fragrant rice under Cd toxicity. 84 Paclobutrazol is widely recognized as an effective regulator of plant development, and the foliar application of paclobutrazol was proven efficient in improving the aroma of fragrant rice, grain quality, and yield. 85 Similarly, the foliar application of procyanidins (a polyphenolic compound with multiple properties), and epoxiconazole (a triazole compound) also enhanced the biosynthesis of 2-AP in aromatic rice.…”