Stimulatory Effect of Fe3O4 Nanoparticles on the Growth and Yield of Pseudostellaria heterophylla via Improved Photosynthetic Performance

Abstract

Nanomaterials have recently been used as growth stimulants to promote the production of crops in saline-alkali through root application. However, if applied through leaves, little is known about the effect of Fe3O4 nanoparticles (NPs) on the root growth and yield, especially for medicinal crops. To fill this gap, a single factor experiment was conducted to explore the effects of Fe3O4 NPs on growth, yield, the dry matter distribution, chlorophyll content, photosynthetic characteristics, chlorophyll fluorescence parameters, and polysaccharide content of Pseudostellaria heterophylla by foliar spraying under field conditions. Fe3O4 NPs (20–50 mg·L–1) significantly promoted growth, the dry matter distribution of root and root tuber yield per unit area. Fe3O4 NPs enhanced net photosynthetic rate (Pn) by increasing chlorophyll content. And Fe3O4 NPs increased the daily mean and peak value of Pn, and alleviated the phenomenon of “midday depression” by improving nonstomatal limitation. Chlorophyll fluorescence parameters indicating that Fe3O4 NPs promoted the photochemical activity of PSII and alleviated photoinhibition by enhancing the photochemical use of excess excitation energy. Gray correlation analysis showed that Fe3O4 NPs enhanced the adaptability of P. heterophylla photosynthesis to high temperatures and strong light. Of note, Fe3O4 NPs enhanced the polysaccharide content of the root tuber. Phytotoxic effect was recorded at high NPs (100 mg·L–1) doses. Collectively, Fe3O4 NPs could promote performance of P. heterophylla by improving photosynthetic performance, enhancing its adaptability to the environment, and increasing the distribution ratio of photosynthates to the underground part.

Impact of Magnetite Nanoparticles Coated with Aspartic Acid on the Growth, Antioxidant Enzymes Activity and Chlorophyll Content of Maize

“…The growth of barley seedlings was improved when exposed to 17 mg/L or up to 250 mg/L magnetite nanoparticles [36,49]. Magnetite nanoparticles (20 nm in size and concentrations between 20 and 50 mg/L) significantly promoted growth and increased chlorophyll content in Pseudostellaria heterophylla plants [50]. Enhanced growth, biomass and chlorophyll content were obtained for Cannabis sativa plants treated with 17 nm of magnetite nanoparticles at concentrations between 50 and 500 mg/L [51].…”

Engineered Nanomaterials Suppress the Soft Rot Disease (Rhizopus stolonifer) and Slow Down the Loss of Nutrient in Sweet Potato

“…The postharvest diseases in crops and fruit causing major losses are primarily controlled using fungicides [6,7]. However, in recent years, the resistance of Rhizopus stolonifer to conventional synthetic fungicides [8] has drastically increased because the fact that the widespread, long-term agricultural use of synthetic fungicides has caused some major postharvest pathogens to develop resistance [9].…”

Humic Acid-Coated Fe3O4 Nanoparticles Confer Resistance to Acremonium Wilt Disease and Improve Physiological and Morphological Attributes of Grain Sorghum

“…In fact, the higher concentration 80 mg L −1 caused a negative effect on the growth of all genotypes. Other studies reported similar results where they found out that the high concentrations of Fe 3 O 4 NPs had an inhibitory effect on growth due to accumulation in some cells, leading to stress effects [ 77 , 78 ]. The importance of HA cannot be ignored as many studies explored its beneficial application as biological amendments for maintaining plant growth [ 79 , 80 , 81 , 82 ].…”

“…Many investigators pointed out the significant effect of iron on the growth, yield and other biochemical parameters of many plants [ 75 , 76 ]. Along with this, Li et al demonstrated that foliar spraying with suitable concentrations (20–50 mg L −1 ) of iron oxide NPs could significantly promote the growth of P. heterophylla and increase the root yield per unit area under field conditions [ 77 ]. In fact, the higher concentration 80 mg L −1 caused a negative effect on the growth of all genotypes.…”

“…However, Haydar et al noted that the activities of all studied enzymes except peroxidase increased along with the plant growth [ 54 ]. The dissimilarities in published results might be due to the difference in NP size, culture condition or plant species used in the studies [ 77 ].…”