Appropriate time interval of PPFD measurement to estimate daily photosynthetic gain
Appropriate time interval of PPFD measurement to estimate daily photosynthetic gain
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PPFD测量的适当时间间隔可估算每日光合增益
DOI：
10.1071/fp20323
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发表时间：
2021
影响因子：
3
通讯作者：
Jishi Tomohiro
中科院分区：
文献类型：
--
作者：
Murakami Keach;Jishi Tomohiro
光合作用模式有时包含通常以10分钟或1小时的时间间隔记录的气象要素。由于这些数据是通过对瞬时值随时间的平均值计算的，因此掩盖了可能影响模式输出的短期环境波动。为了评估测量光合光子通量密度（PPFD）的适当时间间隔，以便在开阔场地条件下准确估计光合增益，我们使用考虑或不考虑诱导动力学的光合模型模拟了响应PPFD变化的日积分净光合增益。与使用忽略诱导动力学的稳态模型（即基线增益）从60分钟间隔PPFD数据计算的日增益相比，使用更高分辨率PPFD数据（10-s， 1分钟和10分钟间隔）和使用考虑慢诱导动力学的动态模型模拟的增益都小了约2%。使用10 s间隔PPFD数据的慢动态模型估计的增益比基线增益小5%以上，概率为66%。因此，使用低分辨率的PPFD数据会导致对露地每日光合增益的高估。PPFD测量的适当时间间隔为1分钟或更短，以确保估计的准确性。
Photosynthetic models sometimes incorporate meteorological elements typically recorded at a time interval of 10 min or 1 h. Because these data are calculated by averaging instantaneous values over time, short-term environmental fluctuations are concealed, which may affect outputs of the model. To assess an appropriate time interval of photosynthetic photon flux density (PPFD) measurement for accurate estimation of photosynthetic gain under open field conditions, we simulated the daily integral net photosynthetic gain using photosynthetic models with or without considering induction kinetics in response to changes in PPFD. Compared with the daily gain calculated from 60-min-interval PPFD data using a steady-state model that ignored the induction kinetics (i.e. a baseline gain), the gains simulated using higher-resolution PPFD data (10-s, 1-min, and 10-min intervals) and using a dynamic model that considered slow induction kinetics were both smaller by ~2%. The gain estimated by the slow dynamic model with 10-s-interval PPFD data was smaller than the baseline gain by more than 5% with a probability of 66%. Thus, the use of low-resolution PPFD data causes overestimation of daily photosynthetic gain in open fields. An appropriate time interval for PPFD measurement is 1 min or shorter to ensure accuracy of the estimates.