title: "On-off" thermoresponsive coating agent containing salicylic acid applied to maize seeds for chilling tolerance.
abstract: Chilling stress is an important constraint for maize seed establishment in the field. In this study, a type of "on-off" thermoresponsive coating agent containing poly (N-isopropylacrylamide-co-butylmethacrylate) (Abbr. P(NIPAm-co-BMA)) hydrogel was developed to improve the chilling tolerance of coated maize seed. The P(NIPAm-co-BMA) hydrogel was synthesized by free-radical polymerization of N-isopropylacrylamide (NIPAm) and butylmethacrylate (BMA). Salicylic acid (SA) was loaded in the hydrogel as the chilling resistance agent. SA-loaded P(NIPAm-co-BMA) was used for seed film-coating of two maize varieties, Huang C (HC, chilling-tolerant) and Mo17 (chilling-sensitive), to investigate the coated seed germination and seedling growth status under chilling stress. The results showed that the hydrogel obtained a phase transition temperature near 12°C with a NIPAM to MBA weight ratio of 1: 0.1988 (w/w). The temperature of 12°C was considered the "on-off" temperature for chilling-resistant agent release; the SA was released from the hydrogel more rapidly at external temperatures below 12°C than above 12°C. In addition, when seedlings of both maize varieties suffered a short chilling stress (5°C), higher concentrations of SA-loaded hydrogel resulted in increased germination energy, germination percentage, germination index, root length, shoot height, dry weight of roots and shoots and protective enzyme activities and a decreased malondialdehyde content in coated maize seeds compared to single SA treatments. The majority of these physiological and biochemical parameters achieved significant levels compared with the control. Therefore, SA-loaded P(NIPAm-co-BMA), a nontoxic thermoresponsive hydrogel, can be used as an effective material for chilling tolerance in film-coated maize seeds.
authors: Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors: Yajing
authors: Y
authors: Guan
authors: Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors: Zhan
authors: Z
authors: Li
authors: Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors: Fei
authors: F
authors: He
authors: Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors: Yutao
authors: Y
authors: Huang
authors: Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors: Wenjian
authors: W
authors: Song
authors: Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, P.R. China.
authors: Jin
authors: J
authors: Hu
mesh_terms: D000178:Acrylamides / Q000494:pharmacology; D001669:Biochemical Phenomena / Q000187:drug effects; D003080:Cold Temperature; D018525:Germination / Q000187:drug effects* / Q000502:physiology; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology; D008315:Malondialdehyde / Q000494:pharmacology; D010829:Physiological Phenomena / Q000187:drug effects / Q000502:physiology; D020156:Salicylic Acid / Q000494:pharmacology*; D036226:Seedlings / Q000187:drug effects* / Q000502:physiology; D012639:Seeds / Q000187:drug effects* / Q000502:physiology; D013312:Stress, Physiological / Q000187:drug effects*; D003313:Zea mays / Q000187:drug effects* / Q000502:physiology*
chemical_list: D000178:Acrylamides; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008315:Malondialdehyde; C067295:N-isopropylacrylamide; D020156:Salicylic Acid