论文部分内容阅读
以四川盆地北部低山区湿地松Pinus elliottii幼林为研究对象,对冠层顶部不同年龄针叶光合作用、叶片温度以及冠层顶部空气温度和相对湿度、光照强度和二氧化碳摩尔分数的日变化进行测定,并测定针叶叶绿素质量分数。结果表明:1年生针叶和当年生针叶净光合速率随光照强度增强而增大,均未出现光合午休现象;叶片温度除了在12:00~14:00略高于气温外,其他时间均低于气温;气孔导度与蒸腾速率随时间变化规律相同,最大值出现在14:00;空气相对湿度呈“U”型变化;二氧化碳摩尔分数在8:00~16:00逐渐减小,并在18:00开始回升。1年生针叶净光合速率始终低于当年生针叶,而前者叶绿素质量分数低于后者。相关性分析表明,叶片温度、空气相对湿度、光照强度和气孔导度是引起湿地松光合日变化的主要因素。图3表1参17
Taking the Pinus elliotttii wetland in northern low mountainous area of northern Sichuan Basin as the research object, diurnal variations of photosynthesis, leaf temperature and air temperature and relative humidity, light intensity and carbon dioxide mole fraction at the top of canopy were measured. The conifer chlorophyll content was measured. The results showed that the net photosynthetic rate of conifer needles and annual needles increased with increasing light intensity, and no midday depression occurred. The leaf temperature was higher than that at 12: 00-14: 00, The results showed that the stomatal conductance and transpiration rate varied with time, the maximum value appeared at 14:00, the relative humidity of air showed “U” type change, and the mole fraction of carbon dioxide decreased gradually from 8:00 to 16:00 Pick up at 18:00. The annual net photosynthetic rate of needles was always lower than that of annual needles, while the former had lower chlorophyll content than the latter. Correlation analysis showed that leaf temperature, air relative humidity, light intensity and stomatal conductance were the main factors causing the diurnal variation of photosynthesis of Pinus elliottii. Figure 3 Table 1 Reference 17