The resistance of the epidermis of the leaf to diffusion of water vapour can be measured most accurately in the field by closed diffusion porometers. It was possible to overcome the problems related to calibration and to dynamical use of a LiCl humidity sensor in the porometer. The dynamic behaviour could be represented by one calibration volume provided a special measuring scheme is applied. Presence or absence of device influence on the opening situation of the stomata is demonstrated. Measurements on corn leaves yielded permitted clamping times of 1½ to 2 minutes. All sunlit places of corn leaves, sampled throughout a dense crop on a moist soil, showed on the average a basic equality in resistance. Sampling shaded places separately this equality was also found in the average reaction of resistance to different light density levels.
|Qualification||Doctor of Philosophy|
|Award date||21 Nov 1974|
|Place of Publication||Wageningen|
|Publication status||Published - 1974|
- data collection
- water vapour
- Zea mays