Effect of auxin concentration on cell elongation ●●●●● ●●●● ●●0 ●●● ●●●● Stems Roots 10 10910-710-510-310 Auxin(Molar concentration Fic gure 35.5 Effect of auxin concentration on cell elongation Notice that a hormone concentration high enough to inhibit root growth is optimal for stimulating stem growth
Effect of auxin concentration on cell elongation
生长素抑制侧枝的生长 ●●●●● ●●●● ●●0 ●●● ●●●● Lateral buts Figure 39.10 Apcs dominance i an mportant tactor in determining the shoe of pant A tree demons a conin shape becaise the hgh Figure 39.9 concertato of auxin at the op inhibts lateral growth.The The tarnal buo of u soot moores a non, wrch tenos to miot notion decreases in proportion to ihe dstance from the to. so ower mos gow onger, The lower lmos have aiso been growng te uow d other duds reamy. Ths s apca commence
生长素抑制侧枝的生长
●●●●● ●●●● ●●0 ●●● ●●●● 证明顶端优势由生长 Plain 激素调控的实验 aolin-羊毛脂 FIGURE 36-6 Demonstration that api il dominance is mediated by auxin (Left) Removal of the apical bud permits growth of axillary buds, but if the apical meristem is replaced witht an auxin solu tion (right), the axillary buds are still AxilLary bu Axillary buds hinted from growing. (Winy is plain arow into branches lanolin applied to the plant on the left?)
证明顶端优势由生长 激素调控的实验 lanolin——羊毛脂
●●●●● ●●●● ●●0 ●●● ●●●● 4.生长素的作用原理 1)受体 2)信号转导|P3,DAG, Ca caM是生长素信号转导糸统的组成 3)细胞壁酸化可塑性增大细胞仲长 酸生长学说acid- growth theory 实验基础是生长素促使H分淤的速率和细胞仲长是同步的 生长素诱导的生长是通过细胞壁可塑性增加而实现的。 4)促进核酸、蛋白质的合成
4. 生长素的作用原理： 1) 受体 2) 信号转导 IP3 ，DAG， Ca CaM是生长素信号转导系统的组成 3）细胞壁酸化 可塑性增大 细胞伸长 酸生长学说（acid-growth theory) 实验基础是生长素促使H+分泌的速率和细胞伸长是同步的 生长素诱导的生长是通过细胞壁可塑性增加而实现的。 4) 促进核酸、蛋白质的合成
IAA的极性运输和酸生长假说 ●●●●● ●●●● Auxin ●●0 Increased ion fiux ●●●● at plasma membrane pressure from H Loosening of cell wall structure ADP+ Cytoplasm Elongation Figure 35.6 The acid-growth hypothesis. There is evidence that auxins initial effect on cell elongation is due to stimula tion of a proton pump, which causes acidification of the wall. According to the acid-growth hypothesis, acidifica. tion of the wall activates enzymes that break cross-links between microfibrils of the wall. This loosens the wall allowing elongaton of the cell owing to its turgor pressure 细胞壁环境酸化后,一些细胞壁中的酶被激活 igure 39.4 FI uxin acts on celis of a specific age in the growing tips of roots an在酸性环境中,对酸不稳定的键(H键)易新裂 stems. It induces proteins to pump H" ions into the cell wall, thu细胞壁多糖分子间交织点破裂,联糸松弛,细胞 oosening the wall structure. It induces pumping of K' ions into the壁可塑性增加。 entral vacuole; water follows osmotically, building up an internal pressure that forces the cel to elongate
IAA的极性运输和酸生长假说 细胞壁环境酸化后，一些细胞壁中的酶被激活 在酸性环境中，对酸不稳定的键（H键）易断裂 细胞壁多糖分子间交织点破裂，联系松弛，细胞 壁可塑性增加