Seed priming is a physiological seed enhancement method.
Hydro- or osmotic priming can advance germination under adequate moisture
conditions. During direct seeding on well-drained paddy and upland fields, rice
seeds occasionally encounter low soil moisture conditions. Under these
conditions, rice seeds need to undergo rapid germination and secure
emergence through improved water absorption capacity and seed bioactive. This
study aims to clarify the effects of seed hydropriming on germination and
seedling vigor in rice under different soil moisture conditions. The study employed three
hydration conditions such as priming, soaking, and control. The seeds to be
primed and soaked were submerged in tap water at 30℃ for 12 h.
For priming, the seeds were subsequently dried to attain their initial seed
weight, but the seeds for soaking were not dried before sowing, and the control
seeds were untreated. In addition, different soil moisture conditions, such as
3%, 6%, 8%, 11%, 15%, and 20%, were set. Therefore, emergence time shortened
with seed priming at 3%-11% soil moisture contents. In particular, at 8% soil
moisture content, priming and soaking decreased emergence time by
26.8 h and 21.7 h, respectively compared with that of the control. At 8%-15% soil moisture
contents, shoot elongation rate obtained with the priming seeds increased
>1.2 times compared with that obtained with the control and soaking seeds.
At >8% soil moisture content, shoot dry weight obtained with the priming
seeds increased >1.3 times compared with that obtained with the soaking seeds.
Furthermore, at declining soil moisture conditions, the increase in
root dry weight is promoted by seed priming compared with that in the control
seeds. These results suggest that increased root growth affects plant water
absorption under low soil moisture conditions due to priming. This study
demonstrates that seed priming facilitates rapid emergence and seedling vigor,
unless extremely dry or flooded soil moisture conditions are present at
Seed size is a plastic trait of the plants that directly affect seed
germination and seedling recruitment. This study aimed to investigate the
relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four
hypotheses: 1) larger seeds have higher germination percentage; 2) smaller
seeds require less time to germinate and for initial development of the
seedlings; 3) larger seeds produce more vigorous seedlings and 4) seed size negatively
affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds
were randomly collected in the plant canopy. All these seeds were weighted and
placed in germination tray using vermiculite as substrate. Seed germinability and initial development of
seedlings were monitored daily until cotyledons fell. Small seeds have higher germination
percentage and germinate faster when compared to large seeds. Nonetheless,
seedlings originated from larger seeds have longer development times, resulting
in more vigorous seedlings. In addition, seedlings originating from small seeds
allocate proportionally greater amount of resources to roots when compared to
larger seeds. The fact that small seeds have higher germination
percentage and faster germination favors the colonization of transient
habitats. However, larger seeds produce more vigorous seedlings, favoring the
seedling establishment in more stable habitats. Thus, we argue that high
variability in seed size of C.
langsdorffii favors its widespread geographic distribution.