Nanoscale molybdenum oxide improves plant growth and increases nitrate utilisation in rice (Oryza sativa L.)

Abstract

Nanoscale molybdenum oxide (nano‐MoO3) is widely used in industrial and environmental fields and its release to the environment is increasing. However, the potential effect of nano‐MoO3 on rice (Oryza sativa L.) seedling growth is unclear. Herein, the different impacts of vaired concentrations (0, 50, 100, 200 and 300 μg Mo L–1) of Na2MoO4 and nano‐MoO3 on the growth and nitrate (NO3–) utilisation of rice were investigated using hydroponics. The Mo concentration in roots and shoots, N metabolism enzyme activity, root morphology, root redox ability and root exudates were then analysed to understand the potential mechanisms of the growth impacts. Results showed that the Mo concentration in rice roots increased incrementally as the amount of Mo application increased, whereas different Mo sources did not affect the Mo concentration in shoots. Both Na2MoO4 and nano‐MoO3 promoted the growth and NO3– utilisation of rice. The promotion effects of higher nano‐MoO3 dosages were better than those of Na2MoO4. Nano‐MoO3 application significantly affected the activity of nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (NADH‐GOGAT), which in turn promoted NO3– assimilation. Additionally, rice seedlings treated with nano‐MoO3 had a relatively high rice root volume, surface area, total absorption area, active absorption area, low‐molecular‐weight organic acids, root oxidation and reduction capacities. Based on these results, it is proposed that nano‐MoO3 facilitates rice growth and NO3– assimilation via the enhancement of nitrogen metabolism enzyme activity and the promotion of good root morphological and physiological characters with high root secretion concentration and redox ability. This study provides insights regarding the further application of nano‐MoO3 in agriculture enhancing N use efficiency and rice productivity.

Rhizosphere soil nitrification ability controls nitrogen‐use efficiency in rice growth period

“…Leaf samples (1.0 g) were ground in a chilled mortar containing 6 ml of extraction buffer. The crude supernatant was analyzed for NR and GS activity according to the methods as follows: NR activity was determined by a modification method reported by Zhang et al (2022), and GS activity was determined according to the method, which reported by Han et al (2017).…”

“…A good match between plant N preferences and soil mineral N forms (regulated by the characteristics of soil N transformations) can increase NUE and crop yield (Zhang et al, 1997). It is well known that rice prefers to take up ‐N (Zhang et al, 2022). Zhang et al (2016) demonstrated that in soils with low nitrification rates, ‐N‐preferring crops would take up more ‐N.…”

“…A good match between plant N preferences and soil mineral N forms (regulated by the characteristics of soil N transformations) can increase NUE and crop yield (Zhang et al, 1997). It is well known that rice prefers to take up NH + 4 -N (Zhang et al, 2022). Zhang et al (2016) demonstrated that in soils with low nitrification rates, NH + 4 -N-preferring crops would take up more NH + 4 -N. Many reports indicated that rice had higher NUE under mixed NH + 4 -N and NO − 3 -N supply than NH + 4 -N only supply in hydroponic experiments (Kronzucker et al, 1997).…”

Dynamic Transformation of Nano-MoS2 in a Soil–Plant System Empowers Its Multifunctionality on Soybean Growth

“…However, studies on using nanoscale Mo are still scarce. Nanoscale MoO 3 has been shown to increase nitrate utilization in rice . Positive effects, such as enhanced nutrient uptake and root area, were also reported in chickpeas after foliar treatment with biosynthesized Mo nanoparticles (composition not reported) .…”

Study and comparative evaluation of the toxicity of molybdenum (VI) oxide nanoparticles at a single oral exposure

“…В связи с этим изучается возможность применения НЧ МоО3 в сельском хозяйстве в качестве удобрения. В исследованиях на Oryza sativa L. (рис посевной) установлено, что НЧ МоО3 способствуют ассимиляции азота, усиливая активность нитратредуктазы, глутаминсинтетазы и глутаматсинтазы, а также увеличению объёма корня, площади поверхности, общей и активной площадей поглощения у экспонированных проростков [Zhang et al, 2022]. Применение НЧ МоО3 в качестве некорневой подкормки Phaseolus vulgaris L. (фасоль обыкновенная) приводит к повышению количества семян на ~80% и количества побегов на ~30% .…”