Cytological Studies On Floral Primordtum Of Amygdalus Ledebouriana Schleche And Amygdalus Communis L. In Xinjiang

This paper took Amygdalus ledebouriana Schleche and Amygdalus communis L. as the researchobjects. using the paraffin sectioning method and microscopic observation, taking pictures andmeasurements, The floral primordium between A. ledebouriana Schleche and A. communis L. beforeoverwintering and after overwintering were observed on anatomy and cytology, in order to analyze thedifferences of cold resistance of species and varieties. And by varying degrees of low temperature(4°C,-15°C,-20°C,-25°C,-30°C,-35°C), slicing to observe the changes of A. ledebouriana Schleche and A.communis L.cv. floral primordium in cell morphology, exploring the relationship between floralprimordium anatomical structures and the cold resistance of almond, in order to provide theoretical basis interms of cytology for revealing almond mechanism of cold resistance. The main conclusions were asfollows:1. Before overwintering, there were some significant difference in anatomical structure of floralprimordium between A. ledebouriana Schleche and A. communis L. The cellular vertical diameter andtransverse diameter of floral primordium of A. ledebouriana Schleche with strong colder-resistance wassmall. The cell arrangement tightness was closely, and the intercellular space was also small. The cellularvertical diameter and cellular transverse diameter of floral primordium of A. communis L. with weakcolder-resistance was large. The cell arrangement tightness was loose, and the intercellular space was alsolarge.2. Before overwintering and after overwintering with low temperature stress step down and A.ledebouriana Schleche and its anther and ovule primordiun are extremely significant less than the differentcultivation almond varieties in thickness, cell size and intercellular space. Under low temperature stressbefore overwintering and after overwintering, the cell size order was: Zhipi>Shuangruan>Thompson>Nonpareil>Amygdalus ledebouriana Schleche. It was comparisons that the intercellular space and thicknessof anther and ovule primordium of A.ledebouriana Schleche and A. communis L.cv., Luren was themaximum, A. ledebouriana Schleche was the minimum.With the temperature reduced, the cells of the anthers and ovule primordium of all varieties wereincreasingly big, the cell arrangement were increasingly loose, the intercellular space were more and morelarge, so the cells affected heavier by chilling injury, cold resistance was gradually reduced, but the coldresistance of A. ledebouriana Schleche was significantly stronger than Nonpareil、Thompson、Luren、Shuangruan.3. By browing and recovery growth study found:The lethal temperature of dormancy branches ofA.ledebouriana Schleche was-35℃to-38℃.-38℃was regarded as critical lethal temperature ofdormancy flower buds of A.ledebouriana Schleche; the effecting of flower buds living and flowering rateof A.ledebouriana Schleche was-30℃t o-38℃.4. After overwintering, the sepal primordium, petal primordium, anther promordium and stylepromordium of A. ledebouriana Schleche and A. communis L. before overwintering showed significantdifference. The cellular vertical diameter, transverse diameter and intercellular space were smaller than A.communis L., the cell arrangement tightness was more closely than A. communis L., and the size andthickness of the floral organ primordium were thicker than almond cultivars.5. It was preliminary obtained from cytology that the smaller floral primordium cell size andintercellular space, and the more closely on cell arrangement tightness, the stronger colder-resisted onvarieties of almond. So, the cell size, the tightness extent of cell arrangement and intercellular space couldbe used to evaluate cold resistance of almond on anatomy indexes.