Beveridge C. A., Ross J. J., Murfet I. C.
Depertment of Plant Science, University of Tasmania, GPO Box 252C, Hobart, Tasmania 7001, Australia.
Plant Physiol. 1994 Mar;104(3):953-959. doi: 10.1104/pp.104.3.953.
Isogenic lines of pea (Pisum sativum L.) were used to determine the physiological site of action of the Rms-2 gene, which maintains apical dominance, and its effect on endogenous free indole-3-acetic acid (IAA) levels. In mutant rms-2 scions, which normally produce lateral branches below node 3 and above node 7, apical dominance was almost fully restored by grafting to Rms-2 (wild-type) stocks. In the reciprocal grafts, rms-2 stocks did not promote branching in wild-type shoots. Together, these results suggest that the Rms-2 gene inhibits branching in the shoot of pea by controlling the synthesis of a translocatable (hormone-like) substance that is produced in the roots and/or cotyledons and in the shoot. At all stages, including the stage at which aerial lateral buds commence outgrowth, the level of IAA in rms-2 shoots was elevated (up to 5-fold) in comparison with that in wild-type shoots. The internode length of rms-2 plants was 40% less than in wild-type plants, and the mutant plants allocated significantly more dry weight to the shoot than to the root in comparison with wild-type plants. Grafting to wild-type stocks did not normalize IAA levels or internode length in rms-2 scions, even though it inhibited branching, suggesting that the involvement of Rms-2 in the control of IAA level and internode length may be confined to processes in the shoot.
利用豌豆（Pisum sativum L.）的同基因系来确定保持顶端优势的Rms - 2基因的生理作用位点及其对内源游离吲哚 - 3 - 乙酸（IAA）水平的影响。在突变体rms - 2接穗中，其通常在第3节以下和第7节以上产生侧枝，通过嫁接到Rms - 2（野生型）砧木上，顶端优势几乎完全恢复。在反向嫁接中，rms - 2砧木不会促进野生型枝条的分枝。这些结果共同表明，Rms - 2基因通过控制一种可转运的（类激素）物质的合成来抑制豌豆枝条的分枝，这种物质在根和/或子叶以及枝条中产生。在所有阶段，包括气生侧芽开始生长的阶段，与野生型枝条相比，rms - 2枝条中的IAA水平升高（高达5倍）。rms - 2植株的节间长度比野生型植株短40%，与野生型植株相比，突变植株分配到地上部分的干重显著多于根。嫁接到野生型砧木上并没有使rms - 2接穗中的IAA水平或节间长度恢复正常，尽管它抑制了分枝，这表明Rms - 2参与IAA水平和节间长度的控制可能仅限于枝条中的过程。
