To investigate the possible involvement of endogenous plant hormones in heterosis of Liriodendron interspecific hybrid, growth traits and contents of endogenous GA1/3(gibberellin A1, A3), IAA (indole 3 acetic acid) and iPA (isopentenyl adenine) of tulip tree （L. chinense (Hemsl.) Sarg.）,yellow poplar (L. tulipifera L.) and their interspecific hybrid (L. chinense×L. tulipifera) were examined. Results showed that: (1) the heterosis in height growth trait of the interspecific hybrid was mainly caused by the reletively greater elongation of internodes. Although the uppermost three internodes had the potential of elongation, the first one, which had the greatest elongation amount, contributed to the heterosis of the height growth trait; (2) the contents of endogenous GA1/3, IAA and iPA were greatly different among tulip tree, yellow poplar and their interspecific hybrid. All of the three interspecific hybrid families studied significantly contained higher amount of endogenous GA1/3 and iPA in the uppermost first internode than their parental species. And thus, a correlation between the contents of endogenous GA1/3 and iPA, and hybrid vigor for height growth trait in Liriodendron was observed; (3) the rankings of endogenous GA1/3 and iPA contents in the uppermost first internode of three hybrid families studied were not similar to the ranking for height of 3 year old trees. Therefore, the contents of endogenous GA 1/3 and iPA in the uppermost first internode could not be used in predicting hybrid vigor among hybrid families.
鹅掌楸属种间杂种优势与内源植物激素的关系
李周岐1 王章荣2*
（1. 西北农林科技大学林学院，陕西杨凌712100；2. 南京林业大学森林资源与环境学院，南京210037）
摘要: 研究了鹅掌楸属（Liriodendron)种间F 1杂种（杂种马褂木L.Cchinense×L.tulipifera)及其亲本种（中国马褂木L.chinense (Hemsl.)Sarg. 和北美鹅掌楸L.tulipifera L.)在生长性状和内源GA1／3，IAA和iPA含量上的差异性。结果表明：（1）杂种马褂木高生长性状杂种优势主要是由节间的相对伸长造成的，鹅掌楸属节间伸长区位于顶芽下第1－3节间，其中第1节间伸长量最大，是产生杂种优势的主要节间；（2）中国马褂木，北美鹅掌楸和杂种马褂木内源GA 1／3，IAA和iPA含量差异很大，顶芽下第1节间GA 1／3和iPA含量杂种家系分别为两个亲本种中含量相对较高的的中国马褂木的133．585－284．17％和396．64％－1264．28％。杂种马褂木顶芽下第1节间中GA 1／3和iPA含量的大量增加可能与高生长性状杂种优势有关；（3）杂种家系3年生时其苗高生长量排序与顶芽下第1节间中GA 1／3和iPA含量排序并不一致，不能以第1节间GA 1／3和iPA含量的高低作为预测杂种家系间杂种优势大小的依据。
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