Plant growth regulation by seed coating with films of alginate and auxin-intercalated layered double hydroxides

Abstract

Auxins are a class of organic substances known as plant-growth regulators, which act on plant physiology, promoting its full development. However, due to the great instability of these substances among the diversity of crops and cultivation environments, it is necessary to seek more efficient modes of application, which lead to a homogeneous distribution and promote a sustained release according to the plants demand. Seed coating, using films containing a biodegradable polymer and auxins intercalated into layered compounds, emerges as a very promising approach to a new form of growth regulator application. Thus, the presented work had three aims: (i) the synthesis and characterization of an organic–inorganic hybrid material containing a layered double hydroxide (LDH) of zinc and aluminum and the synthetic auxin 1-naphthalenoacetic acid (ZnAl-NAA-LDH), (ii) the coating of bean seeds (Phaseolus vulgaris L.) with composite films produced from mixtures of alginate polymer and ZnAl-NAA-LDH, and (iii) the evaluation of the plant response by bioassays. The hybrid ZnAl-NAA-LDH was characterized by a set of analytical techniques, including powder X-ray diffraction, thermogravimetric analysis coupled to differential scanning calorimetry and mass spectrometry, specific surface area measurement, and scanning electron microscopy. Bioassays were performed with the seeds coated with the composite film to assess the germination rate and germination speed index of the seeds, as well as biometric analyses including measurements of root area, root fresh matter, and shoot length of the plants. The bioassay performed in soil pots showed that the alginate film containing ZnAl-NAA-LDH yields an enhancement regarding root area, fresh root matter and shoot length of plants. Thus, films produced from a mixture of alginate and the hybrid material containing the growth regulator intercalated into LDH can be a viable alternative to enhance plant development, which can be included in seed management.

Application of Data Modeling, Instrument Engineering and Nanomaterials in Selected Medid the Scientific Recinal Plant Tissue Culture

“…To promote the growth of plant tissue culture materials, we need to find a more efficient application model to ensure an even distribution of plant growth regulators in plant tissues. At the same time, we also need to supply plant growth regulators according to the needs of the plant tissue to achieve the rapid accumulation of plant tissue biomass [ 117 ]. Nano-carriers have great prospects for the application of plant growth regulators such as layered double hydroxide (LDH) [ 15 ] and chitosan nanoparticles [ 16 ].…”

“…Yanfang Liu et al [ 123 ] used the ion exchange method to insert sodium naphthalene acetate (NAA, a plant growth regulator) into layered double hydroxide Mg/Al-LDH, so that NAA showed a significant release effect. Vander A. de Castro et al [ 117 ] used an alginate polymer (a substance with good biodegradability) to encapsulate zinc-aluminum LDH and NAA to act on plant seeds. The results showed that the alginate film containing ZnAl–NAA–LDH enhanced the root area, fresh root material, and shoot length of the plants.…”

Recent advances in seed coating technologies: transitioning toward sustainable agriculture

“…4k and l). 71 Although the intercalation of the auxins within the LDH can facilitate their slow release and reduce the amount of AI required, the inhibited germination of coated seeds can be a drawback due to potential reduction in crop yield. Recently researchers have also explored the use of quaternary ammonium alginate salts as seed coatings.…”

Enhanced white rot control in garlic bulbil using organic–inorganic hybrid materials as coating membranes

“…7,8 The use of polymeric membranes in the coating of bean seeds (Phaseolus vulgaris L.), from organic-inorganic hybrid materials, incorporating 1-naphthaleneacetic acid (NAA), is an example of how these materials have shown good results in the physiological characteristics of the plant, improving its development. 9 Another example has been the use of organicinorganic hybrid materials in the coating of sugarcane microstalks, to reduce the percentage of stalks used in the crop planting process. 10 From this perspective, this study focused on preparing organic-inorganic hybrid materials to coat garlic bulbils as a preplanting treatment.…”