Response of Wheat and Barley during Germination to Seed Osmopriming at Different Water Potential

Abstract

Pre-sowing osmotic seed treatments were evaluated as a means of improving water uptake and germination performance of wheat {Triticum durum L. cv. Hourani-27) and barley {Hordeum vulgare L. cv. ACSAD 176) under four levels of water potetitial (0, -0.4, -0.8 and -1.2 MPa) created by using polyethylene glycoi 8000. Seeds were osmoprimed in aerated solutions of 0.0, 0.2, 0.4 or 0.6 M KCl at 24 + 2"C overnight and then rmsed and dried. Rate of water uptake by seeds was higher in osmoprimed than untreated seeds of both crops regardless of the water potential level. Decreasing water potential (more stress) adversely affected rate of water uptake in seeds of both crops. Seeds osmopriming increased germination percentage and decreased time to 50% germination at high water potentials (low stress), whereas the germination at low water potentials (more stress) was not affected by osmopriming treatments. The effect of osmopriming on rate of water uptake, germination percentage, and time to 50 Vo germination was more pronounced in wheat than in barley. Reduction in the lag time of imbibition may be accounted for in part by some germination rate enhancement in the osmopriming treatments. Fresh weight and length of shoots (plumules) and roots (radicles) were enhanced in osmoprimed seeds in comparison to untreated seeds, in both crops at high water potentials (0 and -0.4 MPa). As water potential in the medium decreased, these traits were inversely affected regardless of osmopriming treatment. Longer roots in wheat compared to barley were noted in the positive osmopriming treatments at high water potentials (0 and -0.4). These results might indicate that wheat is more responsive than barley at relatively high water potentials to osmopriming through rapid penetrating root system.

Enhancing the Performance of Direct Seeded Fine Rice by Seed Priming

“…Osmopriming with KCl has been found effective for improving germination rate and germination percentage in wheat and barley (Al -Karaki, 1998). These data substantiate the practicability of the KCl, CaCl 2 and ascorbate as effective seed priming tools.…”

Developing a Screening Tool for Osmotic Stress Tolerance Classification of Rice Cultivars Based on In Vitro Seed Germination

“…Dry soil conditions during sowing may cause delayed and nonuniform seed germination that can be further aggravated by the low temperature conditions. The PEG 8000 has been extensively used to study osmotic and seed germination assays in many crops: oat (Avena sativa L.) (Willenborg et al, 2005), switchgrass (Panicum virgatum L.) (Seepaul et al, 2012), wheat (Triticum aestivum L.) (Lafond and Baker, 1986;Al-Karaki, 1998), and barley (Hordeum vulgare L.) (Al-Karaki, 1998). An in vitro experiment was conducted to study the impact of osmotic stress using polyethylene glycol on seed germination traits of 15 rice cultivars commonly grown in the US Mid-South production system.…”

“…The higher concentration of NaCl not only affects seed germination but also impacts other processes, such as radicle cell damage, and is therefore less effective than PEG to induce osmotic stress (Liu et al, 2007). The PEG 8000 has been extensively used to study osmotic and seed germination assays in many crops: oat (Avena sativa L.) (Willenborg et al, 2005), switchgrass (Panicum virgatum L.) (Seepaul et al, 2012), wheat (Triticum aestivum L.) (Lafond and Baker, 1986;Al-Karaki, 1998), and barley (Hordeum vulgare L.) (Al-Karaki, 1998). These studies have proved PEG 8000 to be an effective osmotic media for conducting in vitro seed germination tests in response to drought stress.…”

The Allelopathic Potential of Hairy Vetch (Vicia villosa Roth.) Mulch

“…Nevertheless, after accounting for the osmotic effect of extracts in this study, radicle elongation still remained a more sensitive measure of allelopathic potential than germination. Although the range of osmotic potential among extracts was relatively narrow, the observed osmotic potentials were hypertonic enough to affect the rate of water uptake by seed [38]. Our study showed that it is imperative to include osmotic controls to account for osmotic potential of extracts in allelopathy studies.…”

“…Our study showed that it is imperative to include osmotic controls to account for osmotic potential of extracts in allelopathy studies. Al-Kahari, (1998) [38] found germination and radicle elongation of wheat, after eleven days, to be greatly affected when germinated in 0 to −1.4 MPa solutions of polyethylene glycol 8000, where a decrease in germination (99% to 7%) and root length (15 cm to 0.2 cm) was correlated with an increase in solute concentration. In another study, time to reach 10% germination of wheat increased from 44 h to 124.7 h when germinated in NaCl, Na 2 SO 4 , KCl, K 2 SO 4 , MgCl 2 , MgSO 4 , or polyethylene glycol 8000 solutions ranging from −0.3 MPa to −1.8 MPa [39].…”