Slow Release of GA3 Hormone from Polymer Coating Overcomes Seed Dormancy and Improves Germination

Alexandra J S Larson; Maureen M Cartwright; Whitney D Jones; Katrina Luce; Mei-Yu Chen; Kate Petersen; Shannon V Nelson; David J Michaelis; Matthew D Madsen

doi:10.3390/plants12244139

Slow Release of GA₃ Hormone from Polymer Coating Overcomes Seed Dormancy and Improves Germination

Plants (Basel). 2023 Dec 12;12(24):4139. doi: 10.3390/plants12244139.

Authors

Alexandra J S Larson¹, Maureen M Cartwright¹, Whitney D Jones¹, Katrina Luce¹, Mei-Yu Chen¹, Kate Petersen², Shannon V Nelson¹, David J Michaelis², Matthew D Madsen¹

Affiliations

¹ Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA.
² Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.

Abstract

Seed dormancy often hinders direct seeding efforts that are attempting to restore degraded landscapes. Gibberellic acid (GA₃) can be applied to physiologically dormant seeds to induce germination, but this hormone is rarely effective, as it can degrade or be leached from the seed. We tested different polymer matrixes (polylactic acid, polyvinylpyrrolidone, and ethylcellulose) to apply and slowly release GA₃ to the seed. These polymers were tested as seed coatings in either a powder, liquid, or a combination of powder and liquid forms. We found that a liquid ethylcellulose/GA₃ coating generally outperformed the other polymers and applications methods using our test species Penstemon palmeri. With this top-performing treatment, seed germination was 3.0- and 3.9-fold higher at 15 °C and 25 °C, respectively. We also evaluated the liquid ethylcellulose/GA₃ coating on P. comharrenus, P. strictus, P. pachyphyllus, and P. eatonii. Again, the coating had a strong treatment response, with the degree of difference related to the relative level of dormancy of the species. Growth studies were also performed in pots to ensure that the side effects of GA₃ overdosing were not present. Here, we found minimal differences in root length, shoot length, or biomass between plants grown from untreated and GA₃-coated seeds.

Keywords: gibberellic acid; penstemon; physiological dormancy; restoration; seed coating.

Grants and funding

This research was funded by Rio Tinto Kennecott, the Utah Division of Wildlife Resources, Brigham Young University, and the Simmons Research Endowment.