Seed anatomy and water uptake and their relation to seed dormancy of Ormosia paraensis Ducke

Abstract

Ormosia paraensis Ducke has ornamental seeds widely used in the manufacture of bio-jewels and wood used in the furniture industry. For seedling production, the information on its seed physiology is scarce. Thus, the aim of this study was to assess methods for breaking dormancy and relate them to integument structure and water uptake by O. paraensis seeds. Seed dormancy-breaking was performed by mechanical scarification and soaking in sulfuric acid for 0, 15, 30, 60, 120, and 240 minutes. Dormancy‐broken seeds were compared with intact seeds. Seed integument is formed by a cuticle (hydrophobic substances), epidermis (macroesclereids of the palisade layer,), hypodermis (osteosclereids), and parenchyma cells. Intact seeds did not absorb water after 72 hours of soaking. The highest percentages and rates of seed germination were observed in treatments with mechanical scarification and soaking in sulfuric acid for 60 or 120 minutes. Seed soaking in sulfuric acid (H2SO4 p.a. 98.08%) for 60 or 120 minutes or mechanical scarification are adequate to overcome physical dormancy associated with O. paraensis seed integument impermeability to water or gases.

Induction of seed coat water impermeability during maturation of Erythrina speciosa seeds

“…Chai et al (2016) observed a relationship between the light line, together with the cuticle, and the onset of SCWI. Unlike that observation, as well as the observation made by Silva et al (2018) for Ormosia paraenses, the measurements observed in the cuticle present above the layer of palisade cells in the seeds of E. speciosa in the present study did not show significant changes related to the onset of dormancy or to induction from drying. All the treatments in the two years of collection had a visible cuticle (Figures 3 and 4); therefore, the presence of the cuticle and light line for this species is not related to dormancy.…”

“…There were no changes in the layer of the palisade cells in the seeds of the immature stages before and after drying (Figures 3,4,5a,and 5b). Therefore, changes in this cell layer also appear not to be related to the onset of SCWI, unlike that observed by Silva et al (2018) in Ormosia paraenses. In Desmanthus virgatus changes were found in the measurements of the palisade cells according to the year and location of collection (Richard et al, 2018).…”

“…Figures 3 and 4 show the layers of the palisade cells (PC) and the presence of the light line (*) in the upper part of the cells near the cuticle (arrow). The cuticle and PC in Ormosia paraenses Ducke, for example, were considered to be associated with SCWI (Silva et al, 2018). The seed coat of E. speciosa also had hourglass cells (HC), a layer of parenchymal cells (Pa), and collapsed parenchyma cells (PaC).…”

Exploring the Applicability of Calorespirometry to Assess Seed Metabolic Stability Upon Temperature Stress Conditions—Pisum sativum L. Used as a Case Study

“…where UP is the percentage of WU by seeds, Mf is the fresh seed mass after soaking, and Pi is the dry seed mass before soaking ( Silva et al, 2018 ).…”

“…The agronomically acceptable minimum (aam) germination is 70% for pea seeds ( Miguel, 1983 ). The percentage of seeds germinated per day ( PG ) was determined ( Silva et al, 2018 ) according to the equation:…”