Starch‐based biodegradable hydrogel as seed coating for corn to improve early growth under water shortage

Abstract

In this work, the effect of a biodegradable hydrogel as a seed coating on the early growth of corn seed was studied. The hydrogel was a succinate‐modified potato starch, and it had an equilibrium water absorption capacity of 260 g distilled water (DW)/g hydrogel. To coat corn seeds, the seeds were slightly wetted with an aqueous adhesive solution and then, in a closed container, mixed with a dry mixture of the modified starch (MS), bentonite, and talc. The damp coated seeds were air‐dried at 40 °C for 24 h. The seed emergence and postemergence growth of coated and uncoated seeds were assessed with respect to: (1) the amount of MS on coated seeds, and (2) the available water supply. At a water supply of 77% field capacity (FC), the coated seeds showed a significantly higher rate of emergence than uncoated seeds—however, only a minor improvement was observed at higher and lower water supply levels (92, 82, and 65% FC, respectively). This indicates that, while poor water absorption by hydrogel at low water supply (65% FC) has limited benefit to seed water availability, the effect of good water retention by the hydrogel at high water supply (92, 82% FC) appears redundant in the presence high soil water availability. After 14 and 21 days of growth, the dry weights of the corn plants' roots and shoots did not significantly differ between coated and uncoated seeds, which indicate that, after seed emergence and root development, the contribution of the hydrogel coating to the plant's water requirements becomes negligible. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48523.

Study of the Preparation and Properties of TPS/PBSA/PLA Biodegradable Composites

“…MI/g•10 min (190 °C, 2.16 kg) 2.1 1.9 1.5 1.1 0.9 Density/g•cm 3 1.227 1.266 1.224 1.228 1.226 Figure 9 was the TGA spectrum for the TPS/PBSA/PLA composites in N2. As dis played in the TGA spectrum, there were four steps in the spectrum of the TPS/PBSA/PLA composites, and steps in the spectrum meant the degradation of composites.…”

“…Starch, the second largest natural polymer on earth, is widely synthesized by plants. Due to the renewable, biodegradable resource and low price, starch is widely used in the manufacturing industry for food, medicine, plastic and chemical packaging [1][2][3][4][5][6]. At present, the production of starch degradable plastics accounts for more than 60% of the total production of degradable plastics [7][8][9][10][11].…”

Superabsorbent Polymer Seed Coating Reduces Leaching of Fungicide but Does Not Alter Their Effectiveness in Suppressing Pathogen Infestation

“…Oksińska et al [ 47 ] identified two bacteria, Rhizobium radiobacter 28SG and Bacillus aryabhattai 31SG, isolated from the watered SAP, that were able to biodegrade up to 36% of the similar copolymer of acrylamide and potassium acrylate containing 5.28% of unpolymerized monomers in 30 days. Despite the expected biodegradability, there are efforts to replace synthetic SAPs with natural ones such as starch [ 21 ], cellulose [ 14 ], chitosan or alginate [ 22 ], or with synthetic-biopolymer hybrid SAPs that combine the desired chemical properties of synthetic polymers–such as mechanical strength, high water capacity, and stability, and lower cost and biological safety of natural polymers [ 48 ]. Proteins are also currently gaining a lot of attention as a replacement for synthetic SAPs because they are biodegradable and available from agricultural waste [ 49 , 50 ].…”

“…Moreover, this technology enables to minimize the amount of applied SAP compared to the addition as a soil supplement. In seed coating technology, synthetic polymers are commonly used [ 18 , 19 ] due to their suitable chemical properties, but natural polymers such as hydroxypropyl methylcellulose [ 20 ], starch [ 21 ], or chitosan with alginate [ 22 ] have also been tested. The application of SAPs as swelling hydrogels on the seed surface creates a direct line of available water for seeds and can help plants cope with water shortage during the germination and early growth phase.…”

Recent advances in biodegradable matrices for active ingredient release in crop protection: Towards attaining sustainability in agriculture

“…In an attempt to reduce the fossil fuel–based polymers and owing to the biodegradable nature, ease of availability, and generally low cost of the precursors, biodegradable polymers have been used in seed coating over the last two decades. Gelatin [ 25 ], gums [ 25 , 28 ], CS [ 24 , 29 ], cellulose and its derivatives [ 23 , 29 , 30 ], starch [ 26 , 31 ], and alginates [ 32 ] are some of the biopolymers that are used alone or in combination with other materials as seed coats for targeted delivery of AIs and enhanced growth and preservation of plants. However, most of the biopolymers have to be used with additional substances, that is, surfactants and film formers.…”