| Sweet cherry is one of the earliest fruit tree species among the deciduous fruit trees in northern of China.At present,both the planting area and the yield of sweet cherry rank the first in the world.The choice of sweet cherry rootstock largely determines the success or failure of sweet cherry cultivation,rootstock not only affect the yield and quality of sweet cherry,but also affect its adaptability and stress resistance.Compared with apple and other fruit trees,the genetic transformation of sweet cherry rootstock is difficult and the transformation efficiency is extremely low.So far,there is little research on the regeneration system of sweet cherry rootstock explants,it is urgent to establish efficient and stable regeneration and transformation system.In this experiment,stem segments and leaves of the triploid sweet cherry dwarf rootstock "Gisela 6" and the new variety tetraploid "Aijie" were used as explants to investigate the effects of different types and concentrations of auxin and cytokinin on the regeneration of sweet cherry rootstock.（1）Auxin IBA,2,4-D and cytokinin ZT,6-BA were used in pairwise combination（IBA+ZT;IBA+ 6-BA;2,4-D+ ZT;2,4-D+ 6-BA）.The concentrations used here were 0 mg/L,0.1mg/L,0.5 mg/L,1.0 mg/L and 2.0 mg/L.The results showed that the organ regeneration ability of "Aijie" was stronger than "Gisela 6".When the stem segments were used as explants,the callus regeneration ability and rooting ability were stronger,the best rooting hormone combination was 0.5 mg/L IBA+ 2.0 mg/L ZT IBA and the frequency of rooting was 94%.Among them,the callus regeneration frequency of "Aijie" stem segments induced by 2.0mg/L 2,4-D+ 0.5 mg/L 6-BA was highest,and the callus quality was better and the browning frequency was lower;2.0 mg/L IBA+ 2.0 mg/L 6-BA induced the leaves of “Aijie” to produce the best quality of form the A type Ⅱ callus;2.0 mg/L IBA+ 0.5 mg/L ZT induced the leaves of “Aijie” to produce the best quality of the form A type Ⅱ callus.（2）Three kinds of callus with different morphology could be induced from stem segments and leaves of “Aijie” and “Gisela 6” by different hormone treatment.There were named as type I,type Ⅱ and type Ⅲ callus.Type I callus had a dense structure with hard surface and dark green or black,lighter stained by Sudan red.Type Ⅱ callus was loose and fragile with neatly arranged cells in which cytoplasm was thick,the color was yellow or light yellow,and orange red after Sudan red stained.Type Ⅲ callus was soft with disordered cells and a lot of gaps in which the cytoplasm was thin or the disorganized surface was watery,the color was light yellow transparent or translucent,and Sudan red was not easy to stain.The results of stereoscopy and tissue section showed that the form A type Ⅱ callus grew evenly along the cutting edge,the form B type Ⅱ callus mainly grew in clusters at the blade of veins.The genes related to embryogenesis of callus were detected.The results showed that the expression levels of embryogenic marker genes Pa LEC2 and Pa SECK in type Ⅱ callus were much higher than those in other callus,so it was speculated that type Ⅱ callus was probably embryogenic.In conclusion,this research studied the effects of different concentrations and types of auxin IBA,2,4-D and cytokinin on the in vitro regeneration of sweet cherry rootstock "Aijie" and "Gisela 6",which plays a role in the subsequent factory mass propagation of high-quality dwarf rootstock seedlings and virus-free seedlings.It also provides a theoretical basis for the genetic transformation of sweet cherry rootstock. |
PDF Full Text Request