Yang T., Davies P. J., Reid J. B.
Section of Plant Biology, Plant Science Building, Cornell University, Ithaca, New York 14853 (T.Y., P.J.D.).
Plant Physiol. 1996 Mar;110(3):1029-1034. doi: 10.1104/pp.110.3.1029.
Exogenous gibberellin (GA) and auxin (indoleacetic acid [IAA]) strongly stimulated stem elongation in dwarf GA1-deficient le mutants of light-grown pea (Pisum sativum L.): IAA elicited a sharp increase in growth rate after 20 min followed by a slow decline; the GA response had a longer lag (3 h) and growth increased gradually with time. These responses were additive. The effect of GA was mainly in internodes less than 25% expanded, whereas that of IAA was in the older, elongating internodes. IAA stimulated growth by cell extension; GA stimulated growth by an increase in cell length and cell number. Dwarf lkb GA-response-mutant plants elongated poorly in response to GA (accounted for by an increase in cell number) but were very responsive to IAA. GA produced a substantial elongation in lkb plants only in the presence of IAA. Because lkb plants contain low levels of IAA, growth suppression in dwarf lkb mutants seems to be due to a deficiency in endogenous auxin. GA may enhance the auxin induction of cell elongation but cannot promote elongation in the absence of auxin. The effect of GA may, in part, be mediated by auxin. Auxin and GA control separate processes that together contribute to stem elongation. A deficiency in either leads to a dwarfed phenotype.
外源赤霉素（GA）和生长素（吲哚乙酸[IAA]）强烈刺激了光照下生长的豌豆（Pisum sativum L.）GA1缺陷型矮化le突变体的茎伸长：IAA在20分钟后引起生长速率急剧增加，随后缓慢下降；GA反应有较长的延迟（3小时），生长随时间逐渐增加。这些反应是相加的。GA的作用主要在小于25%伸长的节间，而IAA的作用在较老的、正在伸长的节间。IAA通过细胞伸长刺激生长；GA通过增加细胞长度和细胞数量刺激生长。矮化lkb GA反应突变体植株对GA的伸长反应较差（由细胞数量增加所致），但对IAA反应非常敏感。GA仅在IAA存在时才使lkb植株产生显著伸长。由于lkb植株含有低水平的IAA，矮化lkb突变体中的生长抑制似乎是由于内源生长素缺乏。GA可能增强生长素对细胞伸长的诱导作用，但在没有生长素的情况下不能促进伸长。GA的作用可能部分由生长素介导。生长素和GA控制着各自独立的过程，共同促进茎的伸长。其中任何一种缺乏都会导致矮化表型。
