Dormancy breaking in Teramnus labialis (L.f.) Spreng seeds through liquid nitrogen exposure is based on the modification of the hilar region, cuticle, and macrosclereid

• Published in: Acta physiologiae plantarum 2020-09, Vol.42 (9), Article 144
• Main Authors: Acosta, Yanier, Pérez, Lianny, Escalante, Doris, Nápoles, Lelurlis, Concepción, Oscar, Pérez, Aurora, Pérez, Lázara Sara, Martínez-Montero, Marcos Edel, Fontes, Dayamí, Sershen, Lorenzo, José Carlos
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agriculture; Animal feed; Biomedical and Life Sciences; Biomedical materials; Cracks; Cryopreservation; Cuticles; Dormancy; Exposure; Feeds; Germination; Imbibition; Legumes; Life Sciences; Light microscopy; Liquid nitrogen; Microscopy; Nitrogen; Optical microscopy; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Revegetation; Scanning electron microscopy; Seed coats; Seedlings; Seeds; Short Communication; Statistical analysis; Teramnus labialis
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-020-03134-9

Teramnus labialis (L.f.) Spreng is a legume that plays an important role in mixed agroecosystems, due to its use as animal feed and its role in restoring soil nitrogen levels. However, its wide-scale use in agriculture and revegetation efforts is limited due to its physically dormant seeds. In our previous study on the effects of seed cryopreservation on seedling vigor in this species, our preliminary findings (using scanning electron microscopy) indicated that liquid nitrogen (LN) disrupted the seed coat in this species and led to improved seedling emergence. In our present study, we use light microscopy to investigate whether LN exposure influences the structure/integrity of the hilar region, cuticle, and macrosclereid in relation to seed imbibitional rate and germination. In terms of thickness, statistically significant differences between treated and control seeds were not observed in the cuticle, macrosclereid, osteosclereid or the counter-packed cell layer. Contrastingly, the percentage of seeds with the hilar region open reached 45% in seeds treated with LN but only 10% in the control seeds. Additionally, 85% of seeds immersed in LN showed cracks and breaks in the cuticle and macrosclereid, which were not present in the control. Seed exposure to LN improved seed imbibition rate and germination significantly relative to control seeds/seedlings. Cryo-stored seeds showed a 5.6 fold-increase in imbibition rate, and 2.6 fold-increase in germination. The results validate the use of LN exposure for breaking physical dormancy in seeds of other legumes that display seed anatomy similar to T. labialis .