Light and water treatment during the early grain filling stage regulates yield and aroma formation in aromatic rice

Abstract

The effect of light and water on aromatic rice remain largely unclear. A pot experiment was conducted to investigate the influences of light-water treatments (CK: natural light and well-watered conditions, WS: natural light and water-stressed conditions, LL: low light and well-watered conditions, LL-WS: low light and water-stressed treatment) on yield and 2-acetyl-1-pyrroline (2AP) formation in aromatic rice. Compared with CK, the light-water treatments decreased grain yield (10.32–39.19%) due to reductions in the filled grain percentage and total dry weight, in the regulation of biomass distribution, and in the attributes of gas exchange and antioxidant response parameters. The 2AP content in grains increased in the LL treatment (5.08–16.32%) but decreased in the WS treatment compared with that in CK. The changes in 2AP were associated with changes in 2AP formation-related traits and element content. Low light and water stress led to yield declines in aromatic rice, but low light alleviated the decrease in 2AP content caused by water stress.

Effects of Light Quality Treatments during the Grain Filling Period on Yield, Quality, and Fragrance in Fragrant Rice

“…Previous studies have reported that there may be a 'light quality' effect on the fragrance accumulated in other plants such as strawberry and coriander leaves [33,34]. A previous study has shown that low light-induced 2AP accumulation in fragrant rice [19,20]. As expected, reductions of the 2AP content were detected for all the light quality treatments by 16.67-32.82%.…”

“…Moreover, the crop management or breeding of fragrant rice varieties with different light quality responses in yield and fragrant balance is possible. From the results of previous studies, the 2AP content in grain showed a strong relationship with P5C content [20] and GABA content [19]. In this study, the strong relationships between the 2AP content in grains at MS and the P5C content in grains at 15 d AT (r 2 = 0.6714, p < 0.05), the P5C content in grains at MS (r 2 = 0.7846, p < 0.01), and the GABA content in grains at 15 d AT (r 2 = 0.5222, p < 0.05) were detected ( Figure 6).…”

“…For fragrant rice, shading during the grain filling period could lead to yield reduction but improved fragrance, regulating the grain quality [19]. Further, Li et al [20] reported shading and water stress during the early grain filling stage effect on the grain yield and fragrance of fragrant rice. Therefore, it is generally agreed that low light benefits fragrance accumulation but not grain yield.…”

Creation of aromatic maize by CRISPR/Cas

“…At the heading stage, foliar application of zinc promotes the activity of P5CS, proline dehydrogenase, and diamine oxidase enzymes, resulting in increased 2AP contents of aromatic rice grains (Luo et al, 2019). Low light treatment also increases 2AP concentration in mature grains of the aromatic rice cultivars Xiangyaxiangzhan and Yuxiangyouzhan, but drought stress lowers their 2AP content (Li et al, 2020). Cadmium stress causes various inhibitory effects in rice, such as reducing nitrogen assimilation and 2AP contents.…”

Post-genomics revolution in the design of premium quality rice in a high-yielding background to meet consumer demands in the 21st century

“…Approximately 300 volatiles have been detected in rice to date, but 2-AP is regarded as the primary aromatic component, and most studies have therefore focused on its genetic regulation. However, the intensity of the aroma conferred by 2-AP is markedly affected by both genetics and the environment ( Okpala et al., 2019 ; Li et al., 2020 ; Luo et al., 2021b ). In fact, the same variety of rice grown under the same conditions may still differ in 2-AP content because of differences in harvest duration and processes.…”