Development of flower buds in the Japanese pear (Pyrus pyrifolia) from late autumn to early spring
Development of flower buds in the Japanese pear (Pyrus pyrifolia) from late autumn to early spring
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DOI：
10.1093/treephys/tpv043
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发表时间：
2015-06-01
期刊：
影响因子：
4
通讯作者：
Moriguchi, Takaya
中科院分区：
文献类型：
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作者：
Saito, Takanori;Pham Anh Tuan;Moriguchi, Takaya
我们使用磁共振成像定期研究“Kosui”梨（Pyrus perifolia Nakai）一年生芽的侧花芽形态的休眠进展情况。内休眠期间花芽的大小没有显着变化，但在生态休眠阶段末期发生快速膨大。为了深入了解这一时期的生理状态，我们分析了与细胞周期、细胞扩张和水通道相关的基因的表达，即细胞周期蛋白（CYC）、扩张蛋白（EXPA）、液泡膜内在蛋白（TIP）和质膜内在蛋白（PIP）。在从内休眠到生态休眠的过渡阶段，观察到梨细胞周期蛋白基因（PpCYCD3s）的恒定但低表达。 PpCYCD3s 的表达水平与花芽大小的少量变化一致，但在萌芽阶段之前表达量上调。相反，梨扩张蛋白和水通道相关基因（PpEXPA2、PpPIP2A、PpPIP2B、PpI delta TIP1A和PpI delta TIP1B）的表达较低，直到花芽快速膨大阶段开始。然而，随着花芽花原基中游离水含量的逐渐增加，这些基因的表达在发芽过程中迅速增加。综上所述，这些结果表明花芽大小往往保持恒定，直到休眠相转变。三月份观察到的花芽迅速增大部分是由于细胞周期的增强。然后，随着细胞膨胀和自由水运动的增加，发芽发生。
We periodically investigated the lateral flower bud morphology of 1-year shoots of 'Kosui' pears (Pyrus pyrifolia Nakai) in terms of dormancy progression, using magnetic resonance imaging. The size of flower buds did not change significantly during endodormancy, but rapid enlargement took place at the end of the ecodormancy stage. To gain insight into the physiological status during this period, we analyzed gene expression related to cell cycle-, cell expansion-and water channel-related genes, namely cyclin (CYC), expansin (EXPA), tonoplast intrinsic proteins (TIP) and plasma membrane intrinsic proteins (PIP). Constant but low expression of pear cyclin genes (PpCYCD3s) was observed in the transition phase from endodormancy to ecodormancy. The expression levels of PpCYCD3s were consistent with few changes in flower bud size, but up-regulated before the sprouting stage. In contrast, the expression of pear expansin and water channel-related genes (PpEXPA2, PpPIP2A, PpPIP2B, PpI delta TIP1A and PpI delta TIP1B) were low until onset of the rapid enlargement stage of flower buds. However, expression of these genes rapidly increased during sprouting along with a gradual increase of free water content in the floral primordia of buds. Taken together, these results suggest that flower bud size tends to stay constant until the endodormancy phase transition. Rapid enlargement of flower buds observed in March is partly due to the enhancement of the cell cycle. Then, sprouting takes place concomitant with the increase in cell expansion and free water movement.