Effect of Excision on Leaf Water Potential
| Autor: | Alfred Cass, Michael J. Savage, Herman H. Wiebe |
|---|---|
| Rok vydání: | 1984 |
| Předmět: | |
| Zdroj: | Journal of Experimental Botany. 35:204-208 |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/35.2.204 |
| Popis: | Improvements of thermocouple hygrometrie techniques for in situ leaf water potential measurement in the field now allows for continuous monitoring of water potential in response to an external perturbation, such as leaf excision. Using Citrus jambhiri plants, measured leaf water potentials of completely excised leaf portions immediately increased when the petiole was excised or incisions were made either transverse or parallel to the midrib. Incisions parallel to the midrib were on the side nearest the hygrometer or opposite it if preceded by a petiole excision. Midrib incisions were 100-150 mm long with the nearest cut edge being 20-50 mm from the hygrometer cavity. All excisions were such that leaf tissue was removed from the leaf with water potential on one of the leaf portions being measured continuously prior to and after excising. The peak increase in measured water potential of the excised leaf portions ranged between 20 kPa and 80 kPa but averaged 50 kPa. In uncovered leaves, particularly under field conditions with the associated high evaporative demand, measured leaf water potential declined rapidly after the initial increase. The increase in measured water potential immediately following various types of excision was confirmed for dark and light conditions (laboratory and field respectively) using both psychrometric and dewpoint modes and occurred for secondary excisions, but to a lesser extent. Discovery of this phenomenon implies that water potential measured on detached leaves may not always represent accurately in situ leaf water potential. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|