Flotation techniques to improve viability of Juniperus polycarpos seed lots

Abstract

The germination of freshly collected Juniperus polycarpos (K. Koch) seeds is very low and attributed to the large proportion of nonviable seeds in the seed lots. Thus, the aim of this study was to improve seed lot quality by removing nonviable seeds using two flotation techniques: incubation-drying-separation (IDS) and modified specific gravity (MSG) separation. We examined different IDS conditions (the specific incubation time, subsequent drying time and sorting media) for effectively sorting out nonviable seeds; and tested the feasibility of modified SG separation, which involved soaking seeds in water for a certain period before sorting in different concentrations of sucrose solution. Viable seeds were expected to absorb and metabolically bind more water during soaking than dead seeds could, and hence be sorted effectively depending on the viscosity of the sucrose solution. The viability of the seeds that floated or sank was determined in a topographical tetrazolium chloride (TTC) test. For the IDS trial, 7 days incubation followed by 9 h of drying and sedimentation in pure water or 200 gÁL -1 sucrose solution identified, respectively, 75 and 82 % of the seeds as viable (sunken) seeds. For the MSG trail, 77 % viable seeds were recovered in the sunken fraction when seeds were soaked for 48 h then immediately sorted in 600 gÁL -1 sucrose solution. In both cases, the loss of viable seeds in the discarded floating fraction was only 4 %. The results demonstrate that both IDS and MSG separation techniques substantially improved seed lot viability, but MSG separation is simple and needs no modern seed handling facility, and its efficacy relies on seed mass (due to the initial soaking) and the specific density and viscosity of the flotation medium.

Impact of Mother Plant Saline Stress on the Agronomical Quality of Pepper Seeds

“…Seed quality has been an important factor in achieving high germination and uniform growth rates in agricultural crops (Hussain et al 2018). Seed quality depends on many factors including seed physiology and chemical composition (Copeland and McDonald 2001). In particular, germination and vigor are largely determined by the amount of mineral nutrients, carbohydrates, proteins, and lipids in seeds (Andreasen et al 2014).…”

Effect of Variegated Forest Soil Amendments on the Germination and Early Growth of Irvingia gabonensis (O Rorke, Baill)

“…Five hundred and fifty (550) ripe fruits of Irvingia gabonensis procured from the Department of Forestry of Anambra State Ministry of Environment were de-pulped manually with knife to scrap off the mesocarp. The obtained seeds were subjected to viability test by flotation method [22] and five hundred and forty three (543) that passed the test were sun dried at the screen house temperature of 25-30°C for 24 hours. Seventy (70) seeds were then sown in seven open wooden germination beds measuring 2.5 m x 1.5 m x 0.3 m filled with the 6 different soil amendments and the control of unamended top soil.…”

Seed viability changes during fruit ripening of Juniperus polycarpos: Implications for seed collection

“…Rugemalila et al (2017) found that 33% of A. tortilis and 61% of A. robusta seeds was infested in 2014, which can severely affect natural regeneration of these species. In this regard, Daneshvar et al (2017) found that 75 to 82% of J. polycarpos seeds was empty and insect-infested, but they didn't go deep in the case.…”