不同株龄日本落叶松插穗的内源激素含量与生根的关系

The Relation between Endogenous Hormone Contents and Rooting of Larix kaempferi Cuttings at Different Donor Ages

研究了日本落叶松母株年龄、插穗内源激素含量与生根之间的关系,以及外源IBA对插穗内源激素含量的影响及其对插穗生根的促进作用。结果表明:不同株龄插穗生根性状及插穗茎和叶中激素含量差异均达极显著水平,叶中激素含量对插穗生根力没有直接影响;插穗茎中生根抑制激素(ABA)含量随株龄增长而增加,生根促进激素与抑制激素的比值(IAA+GA+ZR)/ABA却随株龄的增长而递减,与生根力随株龄的变化趋势一致,且该比值与生根性状紧密相关,因此可作为评价母株(无性系)生根力的指标;插后13～32d是插穗愈伤组织形成和不定根诱导的关键期,此期生根促进激素消耗量大,茎中含量大幅度降低,进入根伸长生长阶段,含量上升;外源IBA促进插穗生根的机制在于通过外源激素的刺激,在不定根诱导期,插穗茎中ABA含量大幅度降低,从而有利于不定根的发生和发育。

The relations among donor ages, endogenous hormone contents and rooting, and the positive effects of exogenous IBA on hormone contents and rooting of Larix kaempferi cuttings were studied. The results showed that the differences between rooting indexes and hormone contents in stems and leaves of cuttings at different donor ages were significant. The effects of hormone contents in leaves were not involved with rooting. ABA content in stems increased with donor age, （IAA＋GA＋ZR）/ABA in stems decreased with donor age and the trend was similar to the change trend of rooting ability, the relationship between （IAA＋GA＋ZR）/ABA and rooting traits was significant, so （IAA＋GA＋ZR）/ABA could be used as an index of rooting ability. The crucial period of callus formation and adventitious root induction ranged from 13 d to 32 d, hormones which promoted cuttings rooting were consumed largely during this period and reduced greatly in stems, then increased at the stage of root elongation. The mechanism of exogenous IBA promoted cuttings rooting was that, under exogenous IBA stimulation, during adventitious root induction period, ABA contents in stems decreased greatly which was conducive to the occurrence and development of adventitious roots.