Yokoyama G, Ono S, Yasutake D, Hidaka K, Hirota T
Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, 819-0395 Fukuoka, Japan.
Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, 819-0395 Fukuoka, Japan.
Photosynthetica. 2023 Jan 25;61(1):1-12. doi: 10.32615/ps.2023.001. eCollection 2023.
The diurnal variations in the factors of photosynthesis reduction under well-watered greenhouse conditions remain poorly understood. We conducted diurnal measurements of gas exchange and chlorophyll fluorescence in strawberries ( Duch.) for three sunny days. Quantitative limitation analysis was also conducted to investigate the diurnal variations of photosynthetic limitations [stomatal ( ), mesophyll ( ), and biochemical limitation ( )]. Under well-watered greenhouse conditions, a photosynthesis reduction was observed, and the respective limitations exhibited different diurnal changes based on the environmental stress severity. The main limitation was , varying between 11.3 and 27.1% around midday, whereas and were in 4.3-14.2% and 1.7-8.5%, respectively, under relatively moderate conditions. However, both (11.2-34.2%) and (4.8-26.4%) predominantly limited photosynthesis under relatively severe conditions, suggesting that stomatal closure was the main limitation and that the decline in mesophyll conductance was not negligible under strong environmental stress, even under well-watered greenhouse conditions.
在水分充足的温室条件下，光合作用降低因素的日变化仍未得到充分理解。我们在三个晴天对草莓（品种）进行了气体交换和叶绿素荧光的日测量。还进行了定量限制分析，以研究光合限制（气孔限制、叶肉限制和生化限制）的日变化。在水分充足的温室条件下，观察到光合作用降低，并且根据环境胁迫的严重程度，各自的限制表现出不同的日变化。主要限制是气孔限制，中午前后在11.3%至27.1%之间变化，而在相对温和的条件下，叶肉限制和生化限制分别在4.3%至14.2%和1.7%至8.5%之间。然而，在相对严重的条件下，气孔限制（11.2%至34.2%）和叶肉限制（4.8%至26.4%）都主要限制光合作用，这表明气孔关闭是主要限制，并且即使在水分充足的温室条件下，在强烈的环境胁迫下叶肉导度的下降也不可忽略。
