Effects of water vapor pressure difference on leaf gas exchange in potato and sorghum at ambient and elevated carbon dioxide under field conditions |
| |
| Institution: | 1. Metabolic Mechanism Research Group, Korea Food Research Institute, Seongnam, Republic of Korea;2. Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea;1. Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China;2. Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China;1. Department of Mechanical Engineering, Celal Bayar University, 45140, Manisa, Turkey;2. Department of Mechanical Engineering, Technology Faculty, Fırat University, 23119, Elazığ, Turkey |
| |
| Abstract: | High leaf to air water vapor pressure differences often substantially reduce rates of assimilation of carbon dioxide, especially in C3 species. Rising concentrations of carbon dioxide CO2] in the atmosphere could reduce the sensitivity of assimilation rate to partial stomatal closure caused by high vapor pressure difference by a variety of mechanisms. However, field data addressing this question are scarce. In this study, we examined day-to-day variation in midday gas exchange rates of upper canopy leaves of potato and sorghum grown at the current ambient CO2] and ambient+350 μmol mol−1 CO2] in field plots. Stomatal conductance and assimilation rate were negatively correlated with vapor pressure difference across days. Assimilation rate was not less sensitive to vapor pressure difference at elevated than at ambient CO2] in either species. For both potato and sorghum short-term increases in vapor pressure difference for individual leaves produced significantly smaller responses of leaf gas exchange than did the day-to-day variation in vapor pressure difference, again with no reduced sensitivity at elevated CO2]. The smaller response of gas exchange to short-term manipulations of vapor pressure difference than to day-to-day variation may indicate that much of the response to high vapor pressure difference apparent in the day-to-day variation resulted from leaf water deficits caused by exposure of the whole canopy to high vapor pressure difference, rather than from direct effects of high water vapor pressure difference. The lack of a CO2] effect on the sensitivity of assimilation rate to vapor pressure difference, and the substantial sensitivity of assimilation rate to vapor pressure difference in the C4 species both resulted from reductions in assimilation at a given internal CO2] at high vapor pressure difference. An implication of these results is that that high leaf to air water vapor pressure difference may continue to be a major limitation to assimilation rates in C3 and C4 crop species even at twice the current concentration of carbon dioxide in the atmosphere. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
