叶片的解剖结构 epiderme Palisade mesophyll Sioma Guard Vein Guaro FIGURE 344.31 A leaf in cross-section. T ransection of a leaf showing the arrangement of palisade and spongy mesophyll, a vascular bundle or vein, and the epidermis with paired guard cells flanking the stoma
叶片的解剖结构
气孔器的结构 Epidermal cell Epidermal cel Guard cell Thickened inner wall of guard cell Guard Nucleus cell Stoma Chloroplast Stoma FIGURE 34.30 A stoma.(a) Surface view (b) View in cross-section 如何调节促c02吸饭和水外蒸发之间的平衡?
气孔器的结构 如何调节促进CO2吸收和水分蒸发之间的平衡？
2、Co2的吸收与水分散失的调节 气孔开关的机制与调节 影响气孔开关的因素 ①水量水量充足,气孔开,干旱缺水,气孔闭。 ②CO2的浓度浓度高,闭;浓度低,开 ③保卫细胞中K十的浓度 ④保卫细胞中淀粉水解的机制
2、CO2的吸收与水分散失的调节 气孔开关的机制与调节 影响气孔开关的因素 ① 水量 水量充足，气孔开，干旱缺水，气孔闭。 ② CO2的浓度 浓度高，闭；浓度低，开； ③ 保卫细胞中K +的浓度 ④ 保卫细胞中淀粉水解的机制
气孔开闭的机制 气孔的开闭影响光合作用的 效率并控制蒸腾作用的进行 OPEN (turgid) CLOSED (flaccid) Figure 32.9 Control of stomatal aperture. Guard cells of a dicot and a grass are shown in their flaccid and turgid states. Guard ceils respond to a complex set of signals, in- cluding environmental factors and cues within the plant itself, The uptake or loss of water causes the guard cells to change their shape and widen or narrow the gap between them, a response that affects the rate of photosynthesis and controls 调节气孔的开放和气孔的 ubsidiary cell 开闭可达到捕获CO2和防 止水分散失之间的巧妙平 衡
气孔的开闭影响光合作用的 效率并控制蒸腾作用的进行 调节气孔的开放和气孔的 开闭可达到捕获CO2和防 止水分散失之间的巧妙平 衡 气孔开闭的机制
气孔开闭的调节——水量的影响 Guard cell Chloroplasts Epidermal ca Thickened Stoma open Stoma closed Solute potental is hig Solute potential is low water moves into guard water moves out of FIGURE 35.8 How a stoma opens and closes. (a) When potassum ions from surrounding cells are pumped into guard cells, the guard cell turgot pressure increases as water enters by osmosis. (b)T he increased turer pressure causes the guard cells to bulge, with the thick walls on the inner side of each guard cell bowing outward, thereby opening the stoma. (ey When the potassium ions leave the guard tells and their solute potential becomes low, they lose water and turgor and the stoma closes
气孔开闭的调节——水量的影响