Physiological and biochemical parameters controlling waterlogging stress tolerance in Prunus before and after drainage

Abstract

Waterlogging is associated with poor soil drainage. As a consequence oxygen levels decrease in the root environment inducing root asphyxia and affecting plant growth. Some plants can survive under these conditions triggering complex anatomical and biochemical adaptations, mostly in the roots. Long- and short-term responses to waterlogging stress were compared in two trials using a set of two myrobalans (Prunus cerasifera Erhr), 'P.2175' and 'P.2980', as tolerant rootstocks and two almond × peach [Prunus amygdalus Batsch ×Prunus persica (L.) Batsch] interspecific hybrids, 'Garnem' and 'Felinem', as sensitive ones in two consecutive years. Stomatal conductance and chlorophyll content were measured in the long-term trials to assess survival performance, while the enzyme activities of superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (POD, EC 1.11.1.7), and catalase (CAT, EC 1.11.1.6) were measured in the short-term trials to study early antioxidant response. The incidence of the stress in the root environment was different as a result of the different plant development at the moment of the treatment, as a consequence of different environmental conditions both before and during the treatment between the 2 years. The activity of the different enzymes was higher in the sensitive genotype 'Felinem' than in the tolerant 'P.2175'. This result shows an activation of the antioxidant system and has been observed to depend of the different nature of the roots between the 2 years. As the antioxidant enzymes seem to work more efficiently when roots are more aerated, we cannot conclude that they are responsible for the higher tolerance observed in the myrobalan plums.

Plant water stress: Associations between ethylene and abscisic acid response

“…Excess water reduces oxygen (O 2 ) availability in plant roots, causing a barrier for gas diffusion into plant cells, inhibiting free gas exchange for photosynthesis and respiration and inducing changes in plant water relations (SanchezBlanco et al, 1994;Drew, 1997;Amador et al, 2012). Several anatomical, physiological and molecular changes due to flooding have been described, including: epinasty, wilting leaves (Kawase, 1981;Sanchez-Blanco et al, 1994;Dennis et al, 2000), premature leaf senescence, stem deformation, shoot length alteration and leaf area reduction (Aloni and Rosenshtein, 1982;Schaffer et al, 1992;Robbani et al, 2006).…”

Rootstock breeding in Prunus species: Ongoing efforts and new challenges

“…In nature it is common that plants under a flooding condition is first subjected to an hypoxic condition where oxygen decreases gradually to reach the condition of anoxia, which gives time to the plants to generate defense responses before the environmental condition becomes lethal (Drew, 1997). Response of sensitive rootstocks to water logging, such as the peach-almond hybrids 'Felinem' and 'Garnem' exhibit increased activity of defense enzymes against oxidative damage as compared to tolerant Myrobalan plum rootstocks (Amador et al, 2012). They found that it was not possible to establish a direct relationship among the activity of the enzymes: peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), and tolerance to water logging conditions.…”

“…Webb × Prunus persica [L.] Batsch) (Martinazzo et al, 2011), apricot (P. armeniaca) (Domingo et al, 2002;Nicolás et al, 2005), peach (Insausti and Gorjón, 2013), in peach-almond interspecific crosses and Prunus cerasifera Ehrh. (Xiloyannis et al, 2002), and the peach-almond hybrids 'Felinem' and 'Garnem' rootstocks (Amador et al, 2012).…”

“…Subsequently, in Prunus, by prolonging the time of flooding many physiological anomalies can be observed or detected, the most common being lower chlorophyll content and less development (Amador et al, 2012;Insausti and Gorjón, 2013), increased defoliation (Ranney, 1994;Jacobs and Johnson, 1996), lower weight and root necrosis (Jacobs and Johnson, 1996), lower leaf water potential (Domingo et al, 2002;Nicolás et al, 2005;Insausti and Gorjón, 2013), less sap flow (Domingo et al, 2002;Nicolás et al, 2005), reduced turgor and leaf epinasty (Domingo et al, 2002), redness, and subsequent necrosis of leaf senescence and damage on vascular bundles (Iacona et al, 2013), all as symptoms of medium and long term appearance. In flooded peach (highly sensitive species) Insausti and Gorjón (2013) observed that fruit size was smaller and that harvested fruits produced ethylene earlier, advancing the climacteric ripening and softening of the fruit, seriously affecting fruit production.…”

“…In flooded peach (highly sensitive species) Insausti and Gorjón (2013) observed that fruit size was smaller and that harvested fruits produced ethylene earlier, advancing the climacteric ripening and softening of the fruit, seriously affecting fruit production. In most of these studies differences between sensitive and resistant plants of Prunus have been described in relation to the delay period to visualize first symptoms, degree of sensitivity, rate of recovery and survival of plants (Amador et al, 2012). Several of these indicators could be used in the selection of rootstocks for assessing tolerance to flooding conditions in Prunus.…”