Effect of exogenous GA 3 and its inhibitor paclobutrazol on floral formation, endogenous hormones, and flowering-associated genes in ‘Fuji’ apple ( Malus domestica Borkh.)

Identification, Classification, and Expression Analysis of GRAS Gene Family in Malus domestica

“…Previous studies have shown the exogenous treatments (GA, 6-BA, and sucrose) can alter flowering rates, among which GA always decreases the flowering rate, while 6-BA and sugar increase flowering rates (Xing et al, 2015; Li et al, 2016; Zhang et al, 2016). We used these kinds of treatments to further investigate the expression of the candidate MdGRAS genes during flowering.…”

“…The experiment was conducted from 30 to 70 days after full bloom (DAFB) in 2015. (1) GA 3 treatment was performed as described by Zhang et al (2016) with a slight modification: 700 mg L −1 GA 3 (Sigma, Deisenhofen, Germany) was sprayed once on a clear morning at 30 DAFB (May 9). (2) 300 mg L −1 6-BA (Sigma, Deisenhofen, Germany) was also sprayed on a clear morning at 30 DAFB (May 9).…”

“…All treatments were performed on the whole plant and were applied with a low-pressure hand-wand sprayer. Terminal buds on current-year spurs (<5 cm), which were chosen according to our previous studies (Xing et al, 2014, 2015; Li et al, 2016; Zhang et al, 2016), were collected into liquid nitrogen at 30, 40, 50, 60, and 70 DAFB, and then stored at −80°C for use in gene expression analyses.…”

“…Flower induction was affected by environmental and internal factors (Guitton et al, 2012; Xing et al, 2014, 2015; Fan et al, 2016). Sugar and hormones were involved in flower induction (Guitton et al, 2012; Xing et al, 2014, 2015; Fan et al, 2016; Li et al, 2016; Zhang et al, 2016). Among all kinds of hormones, including auxin, cytokinins, abscisic acid, GA and other hormones.…”

“…Among all kinds of hormones, including auxin, cytokinins, abscisic acid, GA and other hormones. GA was defined the most important hormones in regulating flower induction and GA pathway was recognized as one of the flowering pathways (Guitton et al, 2012; Porri et al, 2012; Li et al, 2016; Zhang et al, 2016). 6-BA and sucrose, which can promote flower bud differentiation, were also important and widely used (Xing et al, 2015; Li et al, 2016).…”