Liu Hongjiu, Wen Yanbin, Cui Mingming, Qi Xiaofang, Deng Rui, Gao Jingcao, Cheng Zhihui
College of Horticulture, Northwest A&F University, Yangling 712100, China.
Plants (Basel). 2020 Jul 31;9(8):970. doi: 10.3390/plants9080970.
The number of cloves in a garlic bulb is controlled by axillary meristem differentiation, which directly determines the propagation efficiency. Our previous study showed that injecting garlic plants with gibberellins (GA) solution significantly increased clove number per bulb. However, the physiological and molecular mechanism of GA-induced axillary bud formation is still unknown. Herein, dynamic changes in histology, phytohormones, sugars and related genes expression at 2, 4, 8, 16 and 32 days after treatment (DAT) were investigated. Histological results indicated two stages (axillary meristem initiation and dormancy) were in the period of 0-30 days after GA treatment. Application of GA caused a significant increase of GA and GA, and the downregulation of expression. Furthermore, the change trends in zeatin riboside (ZR) and soluble sugar were the same, in which a high level of ZR at 2 DAT and high content of soluble sugar, glucose and fructose at 4 DAT were recorded, and a low level of ZR and soluble sugar arose at 16 and 32 DAT. Overall, injection of GA firstly caused the downregulation of , a significant increase in the level of ZR and abscisic acid (ABA), and the upregulation of and to activate axillary meristem initiation. Low level of ZR and soluble sugar and a high level of sucrose maintained axillary meristem dormancy.
大蒜鳞茎中的蒜瓣数量由腋生分生组织分化控制，这直接决定了繁殖效率。我们之前的研究表明，向大蒜植株注射赤霉素（GA）溶液可显著增加每鳞茎的蒜瓣数量。然而，GA诱导腋芽形成的生理和分子机制仍不清楚。在此，我们研究了处理后2、4、8、16和32天（DAT）组织学、植物激素、糖类及相关基因表达的动态变化。组织学结果表明，GA处理后0 - 30天内存在两个阶段（腋生分生组织起始和休眠）。GA的施用导致GA和GA显著增加，以及表达下调。此外，玉米素核苷（ZR）和可溶性糖的变化趋势相同，其中在2 DAT时ZR水平较高，在4 DAT时可溶性糖、葡萄糖和果糖含量较高，而在16和32 DAT时ZR和可溶性糖水平较低。总体而言，注射GA首先导致下调，ZR和脱落酸（ABA）水平显著增加，以及和上调以激活腋生分生组织起始。低水平的ZR和可溶性糖以及高水平的蔗糖维持腋生分生组织休眠。
