htt/www.cucdecom.cn中国高校课件下载中心 rgy and fixes it into carbon compounds. Net assimilation is the difference between photosynthetic assimilation and losses due to respiration. Therefore, not assimilation will negative in the dark and will increase with increasing PAR. The intensity of PAR at which the gain in photosynthesis equals the losses is known as the compensation point 光合作用的测量 光合作用速率是总速率的测量,即植物捕获的辐射能,并把它固定到碳的化合物中。光合作 用净同化是同化量的呼吸的丢失量之差。因此,净同化在黑暗中是负值,并随PRA增加而 增长。在光合作用的同化量等于呼吸消耗量时的PRA强度,称为补偿点( compensation point) 植物的光补偿点示意图( Emberlin,1983) 光补偿点( compensation point光饱和点( (saturate point) 光合作用强度和呼吸作用强度相当处的光强度为光补偿点;当光照强度达到一定水平后,光 合产物不再增加或增加得很少,该处的光强度即为光饱和点 Changes in the intensity of radiation Plants rarely achieve their full photosynthetic potential, due to water shortage and to variation in the intensity of radiation. The systematic variations in light intensity are spatial and tem poral of plar radiation. Less systematic variations in light intensity are caused by the positioning of leaves in relation to each other 辐射强度的变化 植物很难获得它们完全的光合作用潜能,是由于水短缺和辐射强度的改变。光强度的系统变 化是太阳辐射的空间和时间的差异。光强度中极少部分的系统变化是因叶子彼此的相对位置 引起 太阳高度角不同,射程不同,太阳辐射强度不同 C3 and C4 plants A major difference in the photosynthetic capacity of plants is that between C3and C4 plants. C4 plants are able to capture CO2 with greater water use efficiency than C3 plants, but this advantage comes at an energy cost. In C4 plants the rate of photosynthesis increases with light intensity, whilst photosynthesis tails off with increasing light intensity in C3 plants C3和C4植物 植物光合能力中的主要差别是在C3和C4植物之间。C4植物能捕获CO2,伴随着水的 利用效率比C3植物更大,而这优点需要消耗能量。在C4植物中,光合作用率随光强度而 增加,而C3植物随光强度增加光合作用渐渐减小。 Strategic and tactical response of plants to radiation A major strategic difference between plant species in their response to the intensity of radiation is exhibited by sun speciesand shade species, which possess a range of adaptations to high and low light levels, respectively, Also, plants may grow leaves which develop differently under clearly seen in the formation of sun leaves and shade leaves within a leaf canopy of single plan different light conditions as part of a tactical response to the light environment This is m 植物对辐射的战略和战术响应 植物种间对辐射强度反应的主要战略差异显示为“阳地种”和“阴地种”,它们分别具有适应 高的和低的光辐射范围。同样,植物能够在不同光条件下生长不同的叶子,作为对光环境的 部分战术反应。这一点最清楚地在单株植物叶冠内的阳叶和阴叶的结构上看到。 1)阳地植物/阳生植物在强光照下才能正常生长、发育,而在隐蔽条件和弱光条件下生长 不良的植物。如松、杉、杨、柳、麻栎、栓皮栎、桦、槐等。 2)阴地植物/阴生植物:在弱光照下比在强光照下生长良好的植物。如人参、三七、红豆杉、http://www.cucdc.com.cn 中国高校课件下载中心 energy and fixes it into carbon compounds. Net assimilation is the difference between photosynthetic assimilation and losses due to respiration. Therefore, not assimilation will be negative in the dark and will increase with increasing PAR. The intensity of PAR at which the gain in photosynthesis equals the losses is known as the compensation point. 光合作用的测量 光合作用速率是总速率的测量，即植物捕获的辐射能，并把它固定到碳的化合物中。光合作 用净同化是同化量的呼吸的丢失量之差。因此，净同化在黑暗中是负值，并随 PRA 增加而 增长。在光合作用的同化量等于呼吸消耗量时的 PRA 强度，称为补偿点（compensation point） 植物的光补偿点示意图(Emberlin,1983) 光补偿点 (compensation point)光饱和点(saturate point) 光合作用强度和呼吸作用强度相当处的光强度为光补偿点；当光照强度达到一定水平后，光 合产物不再增加或增加得很少，该处的光强度即为光饱和点。 Changes in the intensity of radiation Plants rarely achieve their full photosynthetic potential, due to water shortage and to variation in the intensity of radiation. The systematic variations in light intensity are spatial and temporal of solar radiation. Less systematic variations in light intensity are caused by the positioning of leaves in relation to each other. 辐射强度的变化 植物很难获得它们完全的光合作用潜能，是由于水短缺和辐射强度的改变。光强度的系统变 化是太阳辐射的空间和时间的差异。光强度中极少部分的系统变化是因叶子彼此的相对位置 引起。 太阳高度角不同，射程不同，太阳辐射强度不同 C3 and C4 plants A major difference in the photosynthetic capacity of plants is that between C3and C4 plants. C4 plants are able to capture CO2 with greater water use efficiency than C3 plants, but this advantage comes at an energy cost. In C4 plants the rate of photosynthesis increases with light intensity, whilst photosynthesis tails off with increasing light intensity in C3 plants. C3 和 C4 植物 植物光合能力中的主要差别是在 C3 和 C4 植物之间。C4 植物能捕获 CO2 ，伴随着水的 利用效率比 C3 植物更大，而这优点需要消耗能量。在 C4 植物中，光合作用率随光强度而 增加，而 C3 植物随光强度增加光合作用渐渐减小。 Strategic and tactical response of plants to radiation A major strategic difference between plant species in their response to the intensity of radiation is exhibited by ‘sun species’ and ‘shade species’, which possess a range of adaptations to high and low light levels, respectively, Also, plants may grow leaves which develop differently under different light conditions as part of a tactical response to the light environment. This is most clearly seen in the formation of sun leaves and shade leaves within a leaf canopy of single plant. 植物对辐射的战略和战术响应 植物种间对辐射强度反应的主要战略差异显示为“阳地种”和“阴地种”，它们分别具有适应于 高的和低的光辐射范围。同样，植物能够在不同光条件下生长不同的叶子，作为对光环境的 部分战术反应。这一点最清楚地在单株植物叶冠内的阳叶和阴叶的结构上看到。 1）阳地植物/阳生植物:在强光照下才能正常生长、发育，而在隐蔽条件和弱光条件下生长 不良的植物。如松、杉、杨、柳、麻栎、栓皮栎、桦、槐等。 2）阴地植物/阴生植物:在弱光照下比在强光照下生长良好的植物。如人参、三七、红豆杉