Physiological, biochemical and molecular responses in four Prunus rootstocks submitted to drought stress

Abstract

An understanding of the mechanisms that determine plant response to reduced water availability is essential to improve water-use efficiency (WUE) of stone fruit crops. The physiological, biochemical and molecular drought responses of four Prunus rootstocks (GF 677, Cadaman, ROOTPAC 20 and ROOTPAC(®) R) budded with 'Catherina' peach cultivar were studied. Trees were grown in 15-l containers and subjected to a progressive water stress for 26 days, monitoring soil moisture content by time domain reflectometry. Photosynthetic and gas exchange parameters were determined. Root and leaf soluble sugars and proline content were also measured. At the end of the experiment, stressed plants showed lower net photosynthesis rate, stomatal conductance and transpiration rate, and higher intrinsic leaf WUE (AN/gs). Soluble sugars and proline concentration changes were observed, in both root and leaf tissues, especially in an advanced state of stress. The accumulation of proline in roots and leaves with drought stress was related to the decrease in osmotic potential and increase in WUE, whereas the accumulation of sorbitol in leaves, raffinose in roots and proline in both tissues was related only to the increase in the WUE. Owing to the putative role of raffinose and proline as antioxidants and their low concentration, they could be ameliorating deleterious effects of drought-induced oxidative stress by protecting membranes and enzymes rather than acting as active osmolytes. Higher expression of P5SC gene in roots was also consistent with proline accumulation in the tolerant genotype GF 677. These results indicate that accumulation of sorbitol, raffinose and proline in different tissues and/or the increase in P5SC expression could be used as markers of drought tolerance in peach cultivars grafted on Prunus rootstocks.

Eco-physiological evaluation of different scion-rootstock combinations of almond grown in Mediterranean conditions

“…'Rootpac-20' illustrated the dwarfing effect through the significant slow growth of the trunk. Similarly, recent findings reported significantly lower performance of 'Rootpac-20' than 'Garnem' and 'Rootpac-40', based on different vigor parameters, with 40−50% less vigor than 'GF677' [3].…”

“…It has been demonstrated that trees grafted on invigorating rootstocks have consistently presented higher Ψ stem than trees grafted on dwarfing rootstocks as reported for cherry [22,23], peach [3,18] and apple [24]. This phenomenon is likely to be related to the lower water absorption capability of the root system of dwarfing rootstocks to fulfill the transpiration demand of the canopy.…”

“…have demonstrated that the rootstock type may affect the performance of the grafted scion cultivar [2]. Rootstock may provide improved fruit quality and water use efficiency by altering stomata size, transpiration, water potential and vegetative growth [3,4]. Selecting the right scion-rootstock association is important for optimizing the chemical characteristics of fruit, especially sugar profile [5], yield, vigor and plant blooming [6].…”

Rootstock breeding in Prunus species: Ongoing efforts and new challenges

“…Working under water stress conditions, rootstocks 'Cadaman', 'GF-677', 'ROOTPAC 20' (P. besseyi × P. cerasifera) and 'ROOTPAC R' (P. cerasifera × P. dulcis) grafted with 'Catherina' peach, increased the production of proline in roots and leaves, sorbitol in leaves and raffinose in roots, related to an increase in water use efficiency. A high expression of P5SC gene on 'GF-677' (tolerant) were associated with the high content of proline (Jiménez et al, 2013).…”

Plant respiration under low oxygen

“…Likewise, root respiration can be altered by a variety of factors such as temperature (Rachmilevitch et al, 2006), salinity (Bernstein et al, 2013), heavy metals (Moyen and Roblin, 2013), drought (Jiménez et al, 2013), waterlogging and flooding (Liao and Lin, 2001); however, the availability of O 2 is what most affects root respiration ). This factor is key in respiration metabolism, because oxygen is the final electron acceptor in OXPHOS (Moller, 2001).…”