[Stimulatory effects of low temperature treatment of germinating seeds on flower-bud differentiation in broccoli].
The effects of low temperature treatment (0-2 degrees C) of germinating seeds in accelerating process of flower-bud differentiation in broccoli (Brassica oleracea var. italica) were studied. The results indicated that low temperature treatment of germinating seeds for 10 d in broccoli (T(10)) lowered 0.86 nodes and advanced 5 d for the critical stage of flower-bud differentiation, stage of primary furcation scape primordium differentiation and stage of secondary and tertiary furcation scape primordium differentiation; Low temperature treatment of germinating seeds for 20 d in broccoli (T(20)) lowered 1.03 nodes and advanced 6 d for the critical stage of flower-bud differentiation , stage of primary furcation scape primordium differentiation and stage of secondary and tertiary furcation scape primordium differentiation. The node number at which flower-bud differentiation started under T(10) and T(20) was significantly lower than that of control while there was no significant difference between T(10) and T(20). In addition, the flower-bud differentiation was accompanied by increase in GA(3) contents, soluble protein contents, POD activities and invertase activities. GA(3) contents, soluble protein contents, POD activities and invertase activities started to increase significantly when plants entered the critical stage of flower-bud differentiation; POD activities, invertase activities and GA(3) contents emerge high apex value when plants entered stage of primary furcation scape primordium differentiation and stage of secondary and tertiary furcation scape primordium differentiation. Curve change trend of these physiological and biochemical indexes under T(10) and T(20) were accord with CK while advent of each high apex value was earlier about a week than CK during flower-bud differentiation. In a word, synthesization of GA(3) was induced firstly after germinating seeds were treated under low temperature, consequently POD activities and invertase activities were increased which took advantage of flower-bud differentiation.
Jiang
Xin-Mei
XM
College of Horticulture, Northeast Agricultural University, Harbin 150030, China.
Yu
Xi-Hong
XH
D001937:Brassica / Q000254:growth & development* / Q000378:metabolism; D035264:Flowers / Q000254:growth & development*; D018525:Germination; D010544:Peroxidases / Q000032:analysis; D018515:Plant Leaves / Q000201:enzymology; D010940:Plant Proteins / Q000032:analysis; D012639:Seeds / Q000254:growth & development*; D013696:Temperature
D010940:Plant Proteins; D010544:Peroxidases