以苜蓿(M ed icag o sa tiva)为原材料,添加乳酸菌复合系A l2调制青贮苜蓿,并以不添加接种剂的苜蓿作为对照,分析苜蓿青贮过程中微生物区系变化及接菌的改善效果。通过提取青贮料中细菌的总DNA,通过聚合酶链式反应(PCR)扩增其16S rDNA ...
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以苜蓿(M ed icag o sa tiva)为原材料,添加乳酸菌复合系A l2调制青贮苜蓿,并以不添加接种剂的苜蓿作为对照,分析苜蓿青贮过程中微生物区系变化及接菌的改善效果。通过提取青贮料中细菌的总DNA,通过聚合酶链式反应(PCR)扩增其16S rDNA V 3区域,利用变性梯度凝胶电泳法(D enaturing G rad ien t G e l E lectrophores is,DGGE)分析青贮料中细菌的区系变化,并结合平板计数法对青贮料中的乳酸菌、一般细菌、霉菌进行动态分析。DGGE图谱结果显示自然青贮苜蓿的优势菌是戊糖片球菌(P ed iococcus p entosaceus)。在接菌A l2的青贮料中,以植物乳杆菌(L actabacillus p lantarum)为主的A l2的成员菌迅速控制发酵过程,并且在发酵过程中稳定存在。与对照相比,添加乳酸菌剂能够提高乳酸菌的数量,在第2 d将青贮料的pH值降低到4.2,最后稳定到4.1,显著提高了乳酸生成量,降低了氨态氮的产生,明显改善了青贮饲料的发酵品质。
Maize （Zea raays L.） is one of the most important crops because of the remarkable properties of its hybrid, which is responsible for the high commercial value of hybrid maize. The genetic basis of heterosis （hybrid...
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Maize （Zea raays L.） is one of the most important crops because of the remarkable properties of its hybrid, which is responsible for the high commercial value of hybrid maize. The genetic basis of heterosis （hybrid vigor） is not well understood. A differential display technique was performed to identify genes with differential expression across twelve maize inbred lines and thirty-three hybrids during ear development. An incomplete diallel design was used to investigate the relationship between the global framework of differential gene expression and heterosis. It was found that the genes belonging to MONO pattern （i.e., genes expressed in both parental lines and in hybrid） was the highest in percentage among the total five patterns and illustrated that the properties of differentially expressed genes are not entirely responsible for heterosis. Furthermore,a larger number of differentially expressed genes in hybrid, which serves as a major reservoir for generating novel phenotypes that exhibit heterosis of certain agronomic traits during early development and differentiation of maize ear. Moreover, there were some silent genesin hybrids that are responsible for the arrest or abortion of spikelets and for the increase in kernels weight.
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