【摘要】 三种不同生长型芦苇（大型芦苇、中型芦苇、小型芦苇）在一天中最大的光合速率和呼吸速率基本相同，但全天的平均值完全不同，光合速率的平均值是大芦苇最高，中芦苇次之，小芦苇最低，而呼吸速率的平均值则是小芦苇最高，大芦苇次之，中芦苇最低。三种芦苇在中午时均出现明显的光合午休现象，以小芦苇光合午休最为严重，大芦苇最轻。在光合午休期间，小芦苇的气孔导度明显下降且伴随着细胞间隙ＣＯ＿２浓度的降低及气孔限制值的增加，说明小芦苇光合午休的限制因素是气孔因素。大芦苇的气孔导度在中午呈上升趋势，细胞间隙ＣＯ＿２浓度及气孔限制值全天无明显变化，说明大芦苇光合午休的限制因素是非气孔因素。三种芦苇的呼吸速率中午都达到一天中的最高值。更多还原

【Abstract】 he maxinum rate of photosynthesis and respiration in reed leaves of 3 different growth froms（high reed,middle reed and small reed）during a day approximated same,but the average rates of a whole day were quite different.The average rate of pholosynthes in high reed was the highest,the rate in small reed was the lowest among 3 growth forms.Nevertheless,the average rate of respiration in small reed was the highest,while in middle reed is the lowest。At midday the respiration in leaves of 3 growth forms got their maximum rate,but the photosynthetic rate in all 3 growth froms de-creased sabstantialy. The extent of the depression of photosynthesis in small reed was the highest while in high reed was the lowest.During the time of midday depression of photosynthesis,the stomatal conductance in small reed also decreased substalltialy,the internal leaf CO₂ pressure in creased and the stomatal limitation decreased at the same time,which indicated that the stomatal conductance was the liminmg factor of midday depression of photosynthesis in small reed.Nevertheless,the stomatal conductance in high reed increased at midday,which indicated that the nonstomatal factor was the dominant factor of midday depression of photosynthesis in high reed.更多还原