Defining biological thresholds associated to plant water status for monitoring water restriction effects: Stomatal conductance and photosynthesis recovery as key indicators in potato

Drought stress affects physiological parameters but not tuber yield in three Andean potato (Solanum tuberosum L.) cultivars

“…3A). A fast, full recovery of photosynthesis after re-watering has been reported in potato after irrigation deficit (Van Loon, 1981;Vos and Groenwold, 1989;Ramírez et al, 2016). It also was found that some drought stress-tolerant cultivars showed an increase in WUEi (Gago et al, 2014).…”

“…Cultivars can differ in their sensitivity to water deficit, being classified as tolerant or sensitive (Cabello et al, 2013;Obidiegwu et al, 2015). A few studies have been conducted on the physiological characterization of potato cultivars that are currently cultivated in the Andean region, under either irrigated or water deficit conditions (Tourneux et al, 2003a, b;Ramírez et al, 2014;Rolando et al, 2015;Ramírez et al, 2016). Neither is information available about the physiological effects of short periods of water deficit on potato.…”

“…Decreases in stomatal conductance (g s ) reduce water loss through transpiration, but it also decrease carbon dioxide uptake, reducing the production of photoassimilates and, therefore, plant growth (Lahlou et al, 2003;Tourneux et al, 2003a). This decrease in the photosynthetic rate under water deficit conditions has been reported in plants such as potato (Solamun tuberosum L.) (Moorby et al, 1975Schapendonk et al, 1989Ierna and Mauromicale, 2006;Liu et al, 2006;Ramírez et al, 2016). With severe water stress, in addition to the stomatal limitation of photosynthesis, the presence of non-stomatal limitations related to damage to the photosynthetic apparatus has been reported (Sanda et al, 2011;Noctor et al, 2014).…”

Extreme salinity as a challenge to grow potatoes under Mars-like soil conditions: targeting promising genotypes

“…1), which has been identified as an appropriate indicator for optimum irrigation and where plants are under optimum conditions (Flexas et al 2004). On the other hand, plants growing under Mars-like soil and even after water pulses showed g s_max < 50 mmol H 2 O m −2 s −1 , which is defined as a physiological severity threshold in potato (Ramírez et al 2016) where plants are likely submitted to irreversible physiological (oxidative) damage Medrano et al (2002). This last result and the low tuber yield in relation to the control (Fig.…”

“…Physiological performance of plants under Mars-like condition in relation to the control was assessed through the midExtreme salinity as a challenge to grow potatoes under Mars-like soil conditions 19 morning (taken from 8 to 10 am) or maximum light saturated (fixing 1200 µmol m −1 s −1 of PAR) stomatal conductance (g s_max ; see details in Ramírez et al 2016) after and before two water pulses. For this purpose, four genotypes were chosen based on following criteria: (i) contrasted leaf chlorophyll concentration values in relation to the control plants (see formula (1)) assuming that plants with greener leaves in relation to the control were more affected by stress condition imposed by Mars-like soil (see Rolando et al 2015); and (ii) plants with appropriate leaf size to be assessed in the cuvette of a portable photosynthesis system (LI-6400 TX, LICOR, Nebraska, USA).…”