Effect of Three Irrigation Frequencies on Physiological-Biological Aspects of Young Olive Trees (Olea europaea L. cvs ‘Koroneiki’ and ‘Picholine’): Vegetative Growth, Leaf Turgor Pressure, and Fluorescence

Abstract

In arid and semi-arid areas, farmers are experiencing unprecedented water scarcity, which is likely to increase by the perspective of global warming. The purpose of this study was to evaluate the effect of three irrigation frequencies on vegetative growth, leaf turgor pressure, and photosynthesis of young olive trees (Olea europaea L. cvs 'Koroneiki' and 'Picholine'). We found that throughout the experiment and for all irrigation treatments, Picholine cultivar showed a higher rate of vegetative growth. In addition, the leaf turgor pressure for this cultivar showed fewer signs of stress overall as it recorded less Pp curve inversions during summer. However, during this season the photochemical efficiency in Picholine for the frequencies T1 and T2 were lower than Koroneiki by 9.53% and 10.63%, respectively. Which implied that the non-stomatal limitation of photosynthesis has an impact on Picholine photosynthetic production, which in turn indicates that this cultivar is more sensitive to high temperature. Moreover, irrigation frequency has little effect on the Koroneiki cultivar.

Antioxidant Adjustments of Olive Trees (Olea Europaea) under Field Stress Conditions

“…Olive trees have evolved morpho-physiological adaptive mechanisms to cope with the Mediterranean climate [ 10 ]. These include an efficient ability to control leaf transpiration (e.g., thick cuticle, high density of foliar tissue, and trichome layers), and to regulate stomata aperture, osmotic adjustment, and extract water from soils with low water potential [ 4 ].…”

“…Thus, understanding the changes in these metabolites’ profiles under extreme climate change conditions will support the selection of more adapted cultivars and contribute to ensuring olive productivity and olive/oil quality in the following decades. Most studies on young olive plants used single [ 11 , 14 ] or combined (drought and heat) stressful conditions [ 5 , 10 ] imposed in a controlled environment, which is easier to manipulate but does not mimic the complex environmental conditions of the field. Moreover, the source–sink relationships, determinant for photosynthetic acclimation process, in young potted plants are completely distinct from adult field-grown trees.…”

Continuous Plant-Based and Remote Sensing for Determination of Fruit Tree Water Status

“…In olive, they have been extensively tested with excellent results, indicating great reliability of the sensors for both ecophysiological studies and irrigation scheduling. Sghaier et al [71] utilized these probes to study the effect of three irrigation levels on the water relations of young 'Koroneiki' and 'Picholine' olive trees, demonstrating the suitability of the sensors to monitor plant physiological and biological mechanisms The sensor output (P p ) varies with the distance between the two magnets and is inversely proportional to the turgor pressure (P c ). For example, as the P c decreases in response to daytime stomatal opening, the P p gradually increases.…”