| Hydrangea macrophylla is an important ornamental flower in the summer garden landscape.In my country,the introduction of Hydrangea macrophylla is mainly based on cultivation and production.And there are few new varieties independently researched and developed.The domestic use of biotechnology breeding is relatively backward.In recent years,a few researchers have used embryo rescue to solve the problem of difficult survival of hybrid offspring,but there are shortcomings.Because there are few types of tissue culture materials used,the technology also has limitations.Therefore,the pollen grains and anthers were used as experimental materials to initially explore the morphological characteristics of In order to enter the technical field of Hydrangea macrophylla haploid species and provide ideal materials for genetic transformation,using pollen grains and anthers as test materials,the morphological characteristics of Hydrangea macrophylla pollen and anther culture in vitro were studied.The content of this study is divided into the following two parts:1.Morphological characteristics of pollen grains of Hydrangea macrophylla: Observe the characteristics of pollen grain shape,aspect ratio,germination groove,ornamentation,polar surface and other characteristics of 10 Hydrangea macrophylla through electron microscope scanning to analyze the differences between different Hydrangea varieties and pregnancy pollen grains sex.the results are as follows:(1)The pollen grains of the 10 varieties of Hydrangea are long spherical,with 3grooves splitting into the germination grooves of the poles.The pollen belongs to the N3P4C5 type,and the outer wall decoration is hole-shaped.(2)The fertile flower: The polar faces of pollen grains have different shapes,such as‘Endless Summer’,‘Otaksa’,‘Maman rose’,‘Head Flower’ and ‘First Love’ are trilobate circles,others are blunt triangles.The length of the germination groove of different varieties of pollen grains differs from the width of the ridge surface of the germination groove,as well as the size,shape and distribution characteristics of the holes(3)Infertile flowers: Only the ‘Endless Summer’ and ‘Otaksa’infertile flowers are super-long spheres,and the pollen grains of different fertility of ‘Maman rose’ is significant in germination groove and ridge width.However,there is no significant difference in the morphological characteristics of the outer wall decoration patterns of different pregnancy pollen grains of the same variety.The above indicated that the outer wall decoration of pollen grains is one of the basis for identification of Hydrangea macrophylla varieties,but it connot be used as the identification basis of pollen pregnancy.The classification of kinship from palynological studies needs to be further improved.2.Hydrangea macrophylla anther culture in vitro: The anthers of three Hydrangea macrophylla fertile flowers were used as materials to explore the effects of pollen development period,low temperature pretreatment time,hormone combination and genotype on the induction of anther callus.the result shows:(1)On the basis of the research on the development period of ‘Maman rose’microspores,the external characteristics of flower buds corresponding to different development stages of microspores were determined.The microspores are in the tetrad stage,and the buds of its infertile flowers are all green,and their length is 0.22-0.34 cm.The microspore is in the mid-single nucleus.Its infertile flower buds are green with purple streaks,and its length is 0.34-0.45 cm.The microspores are mononuclear,and the buds of its infertile flowers are all purple,and the length is 0.34-0.45 cm.(2)When ‘Maman rose’ was treated in a low temperature environment of 4℃ for 4days,the induction rate of anther callus was significantly higher than other treatments;(3)The induction rate of the anther callus of ‘Maman rose’ in the single-core marginal stage can reach up to 36.7%,in MS+6-BA2.0mg/L+NAA0.1mg/L+2,4-D0.2mg/L.The single-nuclear mid-phase anthers in MS+6-BA2.0mg/L+NAA0.1mg/L+2,4-D0.4mg/L medium have a maximum recovery rate of 25.3%(4)There are significant differences in callus induction rate and callus morphology among the three different genotypes,‘Otaksa’at MS+6-BA2mg/L+NAA0.2mg/L+2,4-D0.1mg/L.The highest recovery rate was reaching 49.3%,while the induction rate of‘Lanarth’with different hormone combinations was low.(5)The anther callus was not obtained through the in vitro culture of flower buds,but an adventitious bud differentiated from the incision at the bottom of the flower buds was obtained.(6)‘Lanarth’s callus can turn green in MS+6-BA2.0mg/L+ NAA1.0mg/L medium and continue to proliferate,and differentiate few adventitious roots.This experiment initially explored the technical system for obtaining callus by Hydrangea anther culture,but the differentiation of organs and the formation of complete plants are for further study. |
PDF Full Text Request