几种木本植物插穗生根与内源IAA,ABA的关系

迄今为止,传统的插条繁殖仍是林业和园林工作者获得良种无性系和培育苗木的重要途径。在影响插穗不定根形成内外因素中,植物内源激素水平和生长调节剂应用占有重要地位。已知第一个根原基细胞的分裂依赖于内源生长素或外源的生长调节剂(Hartmann 1983,Haissig 1974),低浓度的ABA(1.26～20μg/ml)能促进

Relationship Between Adventitious Root Formation and Endogenous IAA and ABA of Several Tree Species

A comparative study on the rooting capacity of hardwood cuttings of 2 poplars, rooting-reluctent Populus tomentosa and rooting-prompt P. beijingensis, was carried out for three successive years. Monthly tests showed that both poplars had the seasonal changes in rooting capacity. For P. tomentosa, rooting capacity of hardwood cuttings decreases in September and is lowest from October to December. It increased gradually from January to April and remained on high level from June to August. However, it is lower than the rooting capacity of shoot cuttings during the same period. ABA levels in bark and buds were analysed at the same time as the rooting tests. Statistic analysis showed an inverse correlation between the rooting capacity and the ABA level. The same was found in P. beijingensis. The authors suggest to use IAA/ABA ratio as a criterion to judge the rooting capacity of the tree species. The experimental results with some species in Cupressaceac showed that the IAA/ABA ratios in Sabina vulgaris and Platycladus orentalis were quite high, and their shoot cuttings were easy to form adventitious roots, and the former even did not need NAA treatment, the IAA/ABA ratio of S. chinensis was low and remained unchanged from June to August. This species did not root well during the growing season, unless it was treated with a higher concentration of NAA. In addition, funiperus rigida was difficult to form roots, and its IAA/ABA was very low. The authors found that NAAtreatment, especially NAA BA treatment, significantly increased the endogenous IAA level and decreased the endogenous ABA level. It stimulated the root formation of cuttings and increased its rooting rate. The endogenous IAA/ABA ratio in cuttings treated with NAA or NAA BA increased during rooting processes, while the ratio in control cuttings had no significant changes.