scholarly journals Effects of CEPA and 1-MCP on flower bud differentiation of apple cv. ‘Nagafu No.2’ grafted on different rootstocks

2018 ◽  
Author(s):  
Wenfang Li ◽  
Baihong Chen ◽  
Juan Mao ◽  
Xinwen Li ◽  
Jing Su ◽  
...  

AbstractThe apple (Malus domestica Borkh.) has a relatively long juvenile period which prevent the fruit breeding. The understanding of the flowering system is important to improve breeding efficiency in the apple. In this context, 2-year-old “Fuji” apple cv. “Nagafu No.2” trees that were grafted on dwarf self-rooted rootstock M.26, vigorous rootstock M. sieversii and interstock M.26/M. sieversii, respectively. Spraying with clean water (as controls), 800 mg·L−1 2-Chloroethylphosphonic acid (CEPA) and 2 μL·L−1 1-methylcyclopropene (1-MCP). The results showed that CEPA significantly repressed the vegetative growth attributed to the increase of the ABA and ZT synthesis, and the decrease of IAA synthesis in leaves and buds. However, there was no significant difference or significant inverse effect between 1-MCP and control. Furthermore, CEPA promoted flower formation, increased the flowering rate and advanced the blossom period for 2 days compared with the control, which accompanied by the accumulation of soluble sugar, glucose and sucrose, and the increase of α-amylase (α-AMY) and sucrose phosphate synthase (SPS) activities, and the decrease of the starch contents and sucrose synthase (SS) activities in leaves and buds. However, the blossom period was delayed for 2 days after spraying with 1-MCP. Finally, the expression of TFL1 was significantly repressed while the AP1 was significantly promoted in buds from M.26 and M.26/M. sieversii after spraying with CEPA, while the effect was not significant from M. sieversii. However, the expression levels of TFL1 and AP1 were not significantly different from the control after the application of 1-MCP. In spite of this, CEPA was more susceptible to easy-flowering M26, followed by M26/M. sieversii, and still less susceptible to difficult-flowering rootstock M. sieversii.Abbreviations1-MCP1-methylcyclopropeneα-amylase(α-AMY)ABAabscisic acidCEPA2-Chloroethylphosphonic acidCTKcytokininsETHethyleneGAgibberellinSPSsucrose phosphate synthaseSSsucrose synthaseZTzeatin.

1994 ◽  
Vol 21 (3) ◽  
pp. 255 ◽  
Author(s):  
IF Wardlaw ◽  
J Willenbrink

Wheat plants grown under non-stress conditions at a dayhight temperature of 18/13�C under glasshouse conditions from head emergence to maturity showed a maximum accumulation of water-soluble, non-structural carbohydrates 20-25 days after anthesis. This storage was largely as fructans with the timing and amount of storage and mobilisation varying between cultivars, although the maximum concentration (fructose equivalents per unit stem fresh weight) was similar in all cultivars. The main storage in the culm was located in the lower part of the peduncle enclosed by the flag leaf sheath, in the penultimate internode and for one cultivar also in the flag leaf sheath. 14CO2 pulse-chase studies showed that there was a considerable delay in the incorporation of flag leaf assimilates into stem fructans, a delay probably associated with transfer and metabolic processes in the stem itself. At anthesis, when soluble carbohydrates were rapidly accumulating in the culm, the level of activity of sucrose synthase (SS) in the penultimate internode was much greater than that of sucrose phosphate synthase (SPS). The activity of SS declined rapidly as active storage ceased. This pattern was the reverse of that found in the leaf where SPS, rather than SS, was initially high and declined towards maturity. These changes are discussed in relation to the possible role of sucrose synthesising enzymes, particularly SS, in the accumulation and mobilisation of stem reserves in wheat.


2000 ◽  
Vol 27 (1) ◽  
pp. 81 ◽  
Author(s):  
Frederik C. Botha ◽  
Kevin G. Black

Sucrose accumulation rates, sucrose-phosphate synthase (SPS, EC 2.4.1.14) and soluble sucrose synthase (SuSy, EC 2.4.1.13) activities were measured in internodal tissue from a sugarcane (Saccharum species hybrids) variety N19. The sucrose accumulation rate sharply increases between internodes 3 to 11. In the older internodes SPS activity was at least three times higher than the SuSy activity. A highly significant positive correlation was found between SPS activity and sucrose content. In contrast, no significant correlation was observed between SuSy and sucrose content. In agreement, when radiolabelled glucose was fed to internodes with a high sucrose accumulation rate, label was equally distributed in the hexose moieties of sucrose. This clearly indicates that SPS is the major sucrose synthesis activity in the culm of sugarcane. Different kinetic forms of SPS apparently exist in the internodal tissue at different stages of development.


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