Seed dormancy and dormancy‐breaking methods in Leymus chinensis (Trin.) Tzvel. (Poaceae)

Abstract

Leymus chinensis (Trin.) Tzvel. is a perennial grass with high productivity and forage value; however, poor stand establishment, often due to seed dormancy, limits its widespread use for forage production. To investigate the mechanism of seed dormancy and to develop effective methods of improving germination, the contribution of each part of the caryopsis to dormancy was investigated, and a number of single or combined dormancy-breaking pre-treatments were conducted using three seed lots. The palea, lemma, pericarp/testa, and endosperm all contributed to seed dormancy. The contribution of each part to dormancy was 23Á4%, lemma; 6Á2%, palea; 28Á4%, pericarp/testa; and 42Á0%, endosperm. Hull (palea and lemma) removal, pericarp/testa piercing, and soaking in distilled water or 30% sodium hydroxide (NaOH) significantly decreased the percentage of dormant seeds (i.e. increased germination). Treating hull-removed and pericarp/testa-pierced seeds with gibberellic acid (GA 3 ) also significantly decreased the percentage of dormant seeds. Compared with each of the single pre-treatments, the combined pre-treatment of pre-soaking in water for 1 d, then 30% NaOH for 60 min and treating with 300 lM GA 3 resulted in the highest germination (89%); and seed viability was 91%.

bHLH92from sheepgrass acts as a negative regulator of anthocyanin/proanthocyandin accumulation and influences seed dormancy

“…However, the low germination rate (10–20%) with deep dormancy affects rapid and uniform seed germination in sheepgrass production and further blocks its wide application and the attainment of its expected value (Ma et al , 2010 b ). Approaches such as fluctuating temperature or the application of plant hormones, removal of the hull (palea and lemma), and mechanical resistance have been used in dormancy breaking and germination (Ma et al , 2010 a ; Hu et al , 2012; He et al , 2016). Although our understanding of seed dormancy and germination is well advanced in some model plants and important crops (Himi et al , 2011; Jia et al , 2012), little is known about the molecular mechanism of seed dormancy in sheepgrass, and it will be important to select genes related to germination or dormancy for molecular breeding.…”

A Combined Analysis of the Transcriptome and Metabolome Revealed the Molecular Mechanism by which GA3 Disrupts Dormancy in Leymus Chinensis Seeds

“…Seed hulls are one of the key factors that restrict seed germination, and the mechanical properties of seed hulls may have a certain obstacle-like effect on the exchange of gas and water [28]. He et al [29] mentioned in their study on seed dormancy of L. chinensis that seed hulls accounted for 28.4% of the causes of dormancy induction, and hulled seeds treated with GA 3 also exhibited a signi cantly reduced percentage of seed dormancy. Therefore, in this study, the main metabolic pathways involved in the treatment of hulls after GA 3 treatment and the main differentially abundant metabolites involved were explored.…”

Germination characteristics among different sheepgrass (Leymus chinensis) germplasm during the seed development and after-ripening stages

“…Previous studies on the seed dormancy and germination of sheepgrass have mostly focused on dormancy-breaking methods and the environmental and hormonal effects on germination (He et al, 2016; Zhang et al, 2006). The mechanical restriction of the lemma is considered to be the major cause of sheepgrass seed dormancy because removing the lemma can significantly increase germination (Ma et al, 2008).…”

“…The mechanical restriction of the lemma is considered to be the major cause of sheepgrass seed dormancy because removing the lemma can significantly increase germination (Ma et al, 2008). Furthermore, it was reported that the seed dormancy of sheepgrass was significantly affected by the lemma, palea, pericarp/testa, and endosperm of the seed, and their average contribution to seed dormancy was 23.4%, 6.2%, 28.4%, and 42.0%, respectively (He et al, 2016). However, the ecological and physiological role of the lemma was revealed; it plays important roles in water uptake, dehydration and salt tolerance during germination (Lin et al, 2016a).…”

“…In studies, the dormancy-breaking methods for sheepgrass seed have varied from low temperature treatments to chemical agents, including PEG and GA3 (Gu, Yi & Holubowiecz, 2005; Liu, Wang & Li, 2002; Zhang et al, 2006). Multiple methods to break seed dormancy have been developed; for instance, a combination of seed soaking treatments, which was to presoak the seed in distilled water for 1 day and then soak it in 30% NaOH for 1 h, followed by treatment with 300 μM GA3, was recently reported as an optimum dormancy-breaking method (He et al, 2016). Temperature and plant hormones are considered crucial factors in the regulation of the germination of sheepgrass.…”