Carter Carol E, Partis Michael D, Thomas Brian
1 Department of Botany, School of Plant Sciences, University of Reading, Whiteknights, Reading RG6 6AS, UK.
New Phytol. 1999 Sep;143(3):461-470. doi: 10.1046/j.1469-8137.1999.00484.x.
The tissue-specific and developmental expression of histone 2A was studied in onion (Allium cepa'Robusta'), using northern blots. Histone 2A expression was enriched in basal tissues, particularly in the inner, meristematically active parts of bulbs. The expression was assessed during a time course of bulb development, dormancy onset and post-harvest sprouting in field-grown material. During bulb development histone 2A expression in the inner bulb declined rapidly during bulb ripening, reaching a minimum with the onset of dormancy. During post-harvest storage, expression increased slowly, reaching a peak in the spring, coinciding with the first observed sprout emergence. It was concluded that in onion, as in other plant systems, histone 2A expression is linked to cell division and dormancy level, the peak in expression during post-harvest storage indicating the time of dormancy breakage. In cultivars where post-harvest sprouting occurred much earlier or much later than in 'Robusta', this expression peak occurred at about the same time of year, regardless of sprouting time. It was concluded that differences in storage longevity between cultivars were not due to differing times of dormancy breakage. Factors controlling the rate of sprout emergence post-dormancy are likely to be major determinants of storage capacity.
利用Northern印迹法，研究了洋葱（‘Robusta’葱）中组蛋白2A的组织特异性和发育表达情况。组蛋白2A的表达在基部组织中富集，尤其是在鳞茎内部具有分生活性的部分。在田间种植材料的鳞茎发育、休眠开始和采后发芽的时间进程中评估了其表达。在鳞茎发育过程中，鳞茎内部的组蛋白2A表达在鳞茎成熟期间迅速下降，随着休眠开始达到最低水平。在采后储存期间，表达缓慢增加，在春季达到峰值，与首次观察到的芽出现时间一致。得出的结论是，在洋葱中，与其他植物系统一样，组蛋白2A的表达与细胞分裂和休眠水平相关，采后储存期间的表达峰值表明休眠打破的时间。在采后发芽比‘Robusta’早得多或晚得多的品种中，这个表达峰值在每年大致相同的时间出现，与发芽时间无关。得出的结论是，品种间储存寿命的差异不是由于休眠打破时间不同。控制休眠后芽出现速率的因素可能是储存能力的主要决定因素。
