1. | Darwin | 2. | Boysen Jenson |
3. | Paal | 4. | Went |
1. | When the apical bud is removed, the lowered IAA concentration allows the lateral buds to grow and produce new shoots, which compete to become the lead growth. |
2. | When the apical bud is removed, the increased IAA concentration allows the lateral buds to grow and produce new shoots, which compete to become the lead growth. |
3. | When the apical bud is removed, the lowered IAA concentration stops the growth of lateral buds and production of new shoots. |
4. | When the apical bud is removed, the increased IAA concentration stops the growth of lateral buds and production of new shoots. |
To promote stem elongation, gibberellins act in concert with:
1. Auxins | 2. Cytokinins |
3. Ethylene | 4. ABA |
I: | Auxin stimulates cell elongation by stimulating wall-loosening factors, such as expansins, to loosen cell walls. |
II: | When auxin and cytokinin are applied to callus, rooting can be generated with higher auxin to cytokinin ratios, shoot growth is induced by lower auxin to cytokinin ratios. |
III: | Auxin induces the formation and organization of phloem and xylem. |
IV: | In low concentrations, auxin can inhibit ethylene formation and transport of precursor in plants; however, high concentrations can induce the synthesis of ethylene. |