Roles of Hardened Husks and Membranes Surrounding Brachypodium hybridum Grains on Germination and Seedling Growth

Abstract

Several studies have assessed the function and significance of the presence of dead, hardened husks on germination and seedling growth in several grass species and reached to inconsistent results. Here, we assess the roles of husks (dead lemma and palea) and an inner membrane surrounding the grains on germination behaviour and seedling growth of Brachypodium hybridum, one of three species of the genetic model B. distachyon complex, in an arid mountain of Arabia. The interactive effects between temperature and the incubation light were assessed on germination of husked and dehusked-demembraned grains. Germination and seedling growth were assessed for different combinations of grain treatments (soaked and non-soaked husked, dehusked-membraned and dehusked-demembraned). Dehusked-demembraned grains were also germinated in different dormancy regulating compounds (DRCs) and light qualities (light, dark and different red: far red [R: FR] ratios). The results indicated an insignificant difference between husked and dehusked-membraned grains on final germination and the germination rate index (GRI), with the former producing significantly bigger seedlings. Removal of the inner-membrane resulted in a significant reduction in all traits. Soaking grains in water resulted in significant enhancements in germination and seedling growth of only husked grains. Husked-membraned and demembraned grains germinated more significantly and faster at lower rather than higher temperatures. None of different concentrations of several DRCs succeeded in enhancing final germination of dehusked-demembraned grains. Red-rich light significantly enhanced germination of dehusked-membraned grains in comparison to other light qualities. It could be concluded that the role of husks is to mainly enhance seedling growth, while the major role of the membrane is to increase final germination. The ability of red-rich light in enhancing the germination of dehusked-membraned but not dehusked-demembraned grains suggest a role for the inner membrane in regulating dormancy through differential filtering of light properties.

Dead but Not Dead End: Multifunctional Role of Dead Organs Enclosing Embryos in Seed Biology

“…Also, germination assays performed on red sandy soil of winter wild oat and wild emmer wheat showed faster, greater, and more uniform germination from the intact DUs or the intact florets than germination from naked caryopses [19]. Likewise, hydrated husked grains of Brachypodium hybridum displayed enhanced germination under optimal light and temperature conditions compared to de-husked grains [20] and the hairy bracts of winterfat (Eurotia lanata) dispersal unit were shown to contribute profoundly to seedling establishment and vigor [17]. Presently, the mechanism(s) by which the husks promote and synchronize germination is not clear.…”

“…Some work demonstrated that intact dispersal units improve the seedling establishment compared to naked seeds [16][17][18][19]. In a recent study, El-Keblawy et al [20] examined the importance of the husks of Brachypodium hybridum DU to germination and seedling growth. They found that the husks, particularly soaked husks, significantly improved all examined parameters including final germination and the germination rate index as well as seedling growth.…”

Maternal environment alters dead pericarp biochemical properties of the desert annual plant Anastatica hierochuntica L.

“…Other reports showed that the intact dispersal units improved the seedling establishment compared to naked seeds [ 9 , 14 , 15 ]. In a recent study, El-Keblawy et al [ 16 ] examined the importance of husks (dead lemma and palea) and of the membranes surrounding Brachypodium hybridum caryopsis on germination and seedling growth. They found that the husks, particularly soaked husks significantly improved all examined parameters including final germination, germination rate index as well as seedling growth, concluding that it would be beneficial for farmers growing B .…”

RETRACTED ARTICLE: The role of seed appendage in improving the adaptation of a species in definite seasons: a case study of Atriplex centralasiatica

“…Seedlings derived from intact diaspores had longer and more lateral roots than that derived from naked seeds [24, 32]. El-Keblawy et al [33] assessed the roles of husks (dead lemma and palea) surrounding the grains of Brachypodium hybridum on germination behaviour and seedling growth and concluded that husks did not affect final germination or germination rate, but significantly enhanced seedling growth.…”