荔枝矮化品种的相关机制研究

Dwarfing related mechanisms of dwarf cultivars in Litchi chinensis

为了揭示荔枝矮化品种的致矮机制,研究采用徒手切片法、组织离析法和石蜡切片法,观察了荔枝2个矮化品种和6个乔化品种的茎、叶解剖结构的差异;采用酶联免疫法和愈创木酚比色法,分别测定了8份供试材料的激素含量和过氧化物酶(POD)活性。结果表明,各供试材料的茎、叶解剖结构及叶片内源激素含量和POD活性均表现出一定的差异。其中,紫娘喜在解剖结构上表现出树皮率高、导管内径小、导管总面积/木质部面积的比值小,叶脉突起度小、气孔密度低和栅栏组织/海绵组织的比值大等,这些特征符合矮化树体的特征;而Ya1仅表现出叶片气孔密度低的一个矮化树体的解剖特征,但其低的IAA、GA含量和高的ABA、ZR含量,以及极高的POD活性是导致其矮化的主要因素;此外,Ya1和紫娘喜的IAA/ABA和ZR/ABA的比值均低于其他品种,而ABA/GA和ZR/GA的比值则均高于其他品种,这也是导致其矮化的重要因素。

In order to reveal the dwarfing related mechanisms of dwarf cultivars in litchi,the differences of stem and leaf anatomical structures among two dwarf cultivars and six arbor cultivars were observed by free hand section,tissue segregation procedure and paraffin,and leaf hormone contents and POD activity in eight accessions were determined by enzyme-linked immunosorbent assays and guaiacol colorimetry,respectively.The results showed that stem and leaf anatomical structures,leaf hormone content and POD activity among eight accessions had significant differences.Stem and leaf anatomical structures in Ziniangxi showed high bark rate and the ratio of palisade tissue/spongy tissue,low stomatal density,the ratio of total vessel area/xylem area and vein protuberant degree,and small vessel internal diameter,and the traits could explain its dwarfing character.Whereas Ya1 showed only one of several typic anatomical traits for dwarf cultivar,which was low stomatal density.The main factors causing dwarf in Ya1 were low IAA and GA contents,high ZR and ABA contents,and extremely high POD activity.In addition,the ratios of IAA/ABA and ZR/ABA in Ya1 and Ziniangxi were lower,whereas the ratio of ABA/GA and ZR/GA were higher than that of the other cultivars.,These indices were also important factors contributing to their dwarfing.