Soaking, Temperature, and Seed Placement Affect Seed Germination and Seedling Emergence of Litchi chinensis

Abstract

To find efficient ways to increase the percentage of seed germination and seedling emergence in litchi (Litchi chinensis Sonn.), we investigated the effects of soaking and high temperature on seed germination, as well as the influence of seed placement (orientation and burial depth) on seedling emergence. Seeds of most tested litchi cultivars soaked in water had a better germination performance than seeds without soaking. More than 90% germination of tested litchi seeds was obtained when the soaking times were 26–54 hours. During presprouting, short-term high temperatures (37–44 °C) exerted a negative effect on seed germination rate, but did not influence the germination percentage. In addition, high temperatures (>42 °C) compromised the further growth of sprouted litchi seeds. Burial depth and seed orientation both significantly influenced the seedling recruitment. There was a reduction in seedling emergence with an increase in burial depth. Seeds at the depth of 2 cm showed the best seedling emergence with an average percentage of 90%. Litchi seedling emergence was greatest and most rapid when seeds were sown 2 cm deep, positioned flat, on their sides, and with the radicle oriented downward.