A System for Measuring Single Leaf Photosynthesis and Related Factors Simultaneously under Field Conditions

[摘要] The following system was devised to meet the requirement to measure carbon exchange rate (CER) and the related factors of single rice leaves in situ efficiently. 1. A small leaf chamber (100 × 23 × 8 mm) which is connected with two differential type IRGAs (one is for CO2 and the other for H2O), is attached to a central part of a leaf blade and CER and transpiration rate are measured (Fig. 2). 2. Leaf temperature is measured with two thermocouples simultaneously with CER and transpiration rate. Based on the transpiration rate, absolute humidity of the surrounding air of the leaf and leaf temperature, "stomatal conductance" (gs, CO2 diffusion conductance for the path from the surrounding air to the intercellular space of leaf) is evaluated. 3. The time required to measure CER and gs of a single leaf is about 1.5 min. The gs value evaluated in such a way is considered to be that corresponding to stomatal aperture just before attaching the leaf chamber. It was proved that repeated attachment of the chamber to leaves has little aftereffect on gs and CER of the same leaves. 4. Light intensity, temperature and CO2 concentration inside the leaf chamber are similar to those outside the chamber. 5. From the above mentioned, this system is considered to be suitable for measuring CER of many single leaves in situ to examine its dependence on related factors, especially on gs under field conditions.

[学科分类] 农业科学（综合）