Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, 35 Stirling Highway Crawley 6009, Western Australia, Australia.
J Exp Bot. 2011 Jan;62(3):1037-47. doi: 10.1093/jxb/erq334. Epub 2010 Oct 25.
Seed dormancy in wild Lolium rigidum Gaud (annual ryegrass) populations is highly variable and not well characterized at the biochemical level. To identify some of the determinants of dormancy level in these seeds, the proteomes of subpopulations selected for low and high levels of primary dormancy were compared by two-dimensional polyacrylamide gel electrophoresis of extracts from mature, dry seeds. High-dormancy seeds showed higher expression of small heat shock proteins, enolase, and glyoxalase I than the low-dormancy seeds. The functional relevance of these differences in protein expression was confirmed by the fact that high-dormancy seeds were more tolerant to high temperatures imposed at imbibition and had consistently higher glyoxalase I activity over 0-42 d dark stratification. Higher expression of a putative glutathione peroxidase in low-dormancy seeds was not accompanied by higher activity, but these seeds had a slightly more oxidized glutathione pool and higher total peroxidase activity. Overall, these biochemical and physiological differences suggest that L. rigidum seeds selected for low dormancy are more prepared for rapid germination via peroxidase-mediated cell wall weakening, whilst seeds selected for high dormancy are constitutively prepared to survive environmental stresses, even in the absence of stress during seed development.
野生硬羊茅（一年生黑麦草）种群的种子休眠具有高度可变性，在生化水平上尚未得到很好的描述。为了确定这些种子休眠水平的一些决定因素，通过对成熟干燥种子提取物进行二维聚丙烯酰胺凝胶电泳，比较了选择低休眠和高休眠水平的亚种群的蛋白质组。高休眠种子的小热休克蛋白、烯醇酶和甘油醛酶 I 的表达水平高于低休眠种子。这些蛋白质表达差异的功能相关性得到了证实，即高休眠种子在吸水时对高温更耐受，并且在 0-42d 黑暗分层过程中始终具有更高的甘油醛酶 I 活性。低休眠种子中一种假定的谷胱甘肽过氧化物酶的高表达并不伴随着更高的活性，但这些种子具有稍微氧化的谷胱甘肽池和更高的总过氧化物酶活性。总的来说，这些生化和生理差异表明，选择低休眠的硬羊茅种子通过过氧化物酶介导的细胞壁弱化，为快速萌发做好了更充分的准备，而选择高休眠的种子则在没有种子发育期间的压力的情况下，就已经做好了应对环境压力的准备。
