Recently, the innovation team of vegetable cultivation and physiology of the Institute of Vegetables and Flowers (IVF) of the Chinese Academy of Agricultural Sciences (CAAS) published a research paper entitled "Enhancing iron content and growth of cucumber seedlings with MgFe-LDHs under low-temperature stress" in the journal Journal of Nanobiotechnology (IF=10.2, Q1). This research marks the first application of MgFe-LDHs to plant nutrition, demonstrating their ability to promote the growth of cucumber seedlings and enhance iron absorption, paving the way for LDHs nano-fertilizer development.

In soils and growing media, insoluble iron forms are hard for plants to use, leading to widespread iron deficiency affecting ~2 billion people, especially among the poor. Chelated iron helps, but is costly and can harm the environment & crop growth. There's a need for better iron fertilizers to tackle "hidden hunger." Layered double hydroxides (LDHs), a type of two-dimensional nanomaterial, are used in life sciences & medicine, and show promise in plant research, but their potential as nano-fertilizers to enhance plant nutrition hasn't been explored, offering a new avenue for future research.

Figure 1 TOC graphics

In this study, MgFe-LDHs nanomaterials were synthesized and characterized. Through seed germination and water absorption experiments, a concentration of 10 mg/L was identified as having the most significant effect on the germination of cucumber seeds. Subsequently, pre-germinated cucumber seeds were sown in a solar greenhouse and irrigated with the identified concentration, with only water supplemented during the cultivation period. After ten days, a notable improvement in the emergence rate and growth of the cucumber seedlings was observed. Analysis of temperature control data and ultra-thin section results indicated that the cucumber seedlings were subjected to low-temperature stress. Simulated experiments at low and normal temperatures in an artificial climate chamber confirmed that MgFe-LDHs could promote the emergence rate and growth of cucumber under low-temperature stress. Furthermore, this study employed SEM, TEM, FTIR, and ICP-OES techniques to investigate the cellular fate of MgFe-LDHs within cucumber seedlings. The findings indicated that MgFe-LDHs can adsorb onto the surface of mature root hairs, thereby improving the absorption of nutrients such as Fe, N, K, S, and increasing the accumulation of these elements in the seedlings. Integrating plant physiology, molecular biology experiments, and transcriptomics validation, the study revealed the potential molecular mechanisms by which MgFe-LDHs promote seed emergence, resist low-temperature stress, and enhance nutrient uptake. Specifically, MgFe-LDHs were found to significantly increase SA content, enhancing the expression of the CsFAD3 gene, increase GA₃ content, promoting nitrogen metabolism and protein synthesis, and reduce ABA and JA hormone content, thereby alleviating inhibition on seed germination and seedling growth.

This work was funded by the National Key Research and Development Program, and the National Key Vegetable Industry Technology System of China.

More information can be found through the link:

https://jnanobiotechnology.biomedcentral.com/articles/10.1186/s12951-024-02545-x

By Hongyang Wu(wuhongyang@caas.cn)