Sandberg G, Ericsson A
Department of Forest Genetics and Plant Physiology, The Swedish University of Agricultural Sciences, S-901 83 Umeå, Sweden.
Tree Physiol. 1987 Jun;3(2):173-83. doi: 10.1093/treephys/3.2.173.
Seasonal changes in the concentration of indole-3-acetic acid (IAA) in the leading shoot and in the live tissue external to the xylem (living bark) of 2-3 m tall Scots pine (Pinus sylvestris L.) trees were observed over a period of three years. Both the leading shoot and the living bark showed a consistent pattern of seasonal variation in IAA content, with maxima of about 150 and 350 ng g(-1) (fresh weight), respectively. The IAA concentration in both tissues increased in late June at the time of shoot growth termination, decreased from late August, and by October reached a low value, which was maintained throughout the winter. Excision of current year shoots on the upper branches decreased the annual stem diameter increment without affecting the concentration of IAA in the living bark. However, excising the leading shoot, or girdling the mainstem beneath the leading shoot, caused a substantial reduction in the IAA content of the living stem bark.
在三年时间里，对2 - 3米高的苏格兰松（Pinus sylvestris L.）树木的顶梢以及木质部外部的活组织（活树皮）中吲哚 - 3 - 乙酸（IAA）浓度的季节性变化进行了观察。顶梢和活树皮中的IAA含量均呈现出一致的季节性变化模式，最大值分别约为150和350 ng g(-1)（鲜重）。两种组织中的IAA浓度在6月下旬枝条生长停止时增加，从8月下旬开始下降，到10月达到低值，并在整个冬季保持该值。切除上部枝条上的当年生枝条会降低茎干直径的年增长量，但不影响活树皮中IAA的浓度。然而，切除顶梢或在顶梢下方环剥主干会导致活茎皮中IAA含量大幅降低。
