Photosynthesis performance and leaf water potential impairments of Lime Tahiti affected by Wood pocket

Abstract

The progressive death of Tahiti lime trees in productive stage was evidenced in the production region of north-central Tolima in 2012, which led to significant detriment in fruit production of 79.98% in relation to the year 2011. Tree deterioration caused by progressive death of tissue or wood was attributed to the presence of the physiopathy known worldwide as Wood pocket (WP) because its damage was not associated with the presence of a pathogen in diagnostic tests in the laboratory. The presence and level of damage caused by WP has been associated with dry warm climate conditions related mainly to high temperatures, a condition similar to that which occurs in this producing area. The effect of WP on the photosynthetic parameters and leaf water potential was determined in an experimental trial in a commercial plantation of Lima Tahiti located in Flandes. In this area, hydrodynamic properties and the moisture content of the soil were characterized, and monitoring of climate conditions was also carried out. Our results indicated that the hydrodynamic properties, low availability of water in this soil and climatic conditions are favorable for the development of WP. The values in photosynthetic parameters and leaf water potential even in healthy plants are lower than those reported for this species, indicating that the plants are in constant condition of water stress that can be increased by the high average temperature. The presence of WP decreases in greater proportion the photosynthesis efficiency and water potential in leaf tissue. We hypothesized that the constant water deficit and high temperatures cause rupture of tracheids and cavitation in the xylem deteriorating the vascular system causing the death of wood or WP.