Effect Of Water Availability On Physiological Performance And Lettuce Crop Yield (Lactuca Sativa)

Cien. Inv. Agr. 38(1):65-74. 2011 www.rcia.uc.cl
crop production

Effect of water availability on physiological performance and lettuce crop yield (Lactuca sativa)
Marco A. Molina-Montenegro1, Andrés Zurita-Silva2, and Rómulo Oses3
1

research note

Centro de Estudios Avanzados en Zonas Áridas (CEAZA); Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo #1281,Coquimbo, Chile. 2 Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad de La Serena, Av. Raúl Bitrán s/n, PO Box 554, La Serena, Chile 3 Instituto de Investigaciones Agropecuarias (INIA), Centro Regional Intihuasi, La Serena, Chile.

Abstract M.A. Molina-Montenegro, A. Zurita-Silva, and R. Oses. 2011. Effect of water availability on physiological performance and lettuce crop yield (Lactucasativa). Cien. Inv. Agr. 38(1): 65-74. Water is essential for plants, affecting the majority of the physiological processes related to growth and productivity. Water shortage is one of the most common factors that limit crop productivity worldwide. Many cultivars have elevated water requirements, nevertheless in some countries due to global climate change effects, the availability of water forirrigation is becoming limited. In fact, current models of climate changes predict that central Chile will be a sensitive zone where precipitation will drastically decrease. In this study, the variation of gas exchange and production of fresh biomass in a lettuce cultivar, grown under different water availability regimes, was evaluated. Additionally, the concentration of total soluble sugar andwater use efficiency (WUE) as mechanisms related to water shortage responses were also evaluated. Overall, individuals with the lowest water availability (50%) showed lower gas exchange and fresh biomass values than their conspecifics grown in optimal irrigated conditions. On the other hand, those individuals with moderate water shortage showed the highest concentration of total soluble sugars andWUE. Our results suggested that cultures exposed to extensive or intense drought events, could be negatively affected in both physiological performance and productivity. Nevertheless, slight decreases in water availability can enable lettuce plants to exhibit a high WUE, maintaining high levels of physiological performance and productivity. Key words: Soluble sugars, water use efficiency, watershortage, lettuce, photosynthetic rate.

Introduction Physiological responses to environmental fluctuations are one of the principal determinants of the distribution and productivity of most plant species worldwide (Bazzaz, 1996; Gurevitch et al., 2002). Water is an essential element for
Received January 25, 2010. Accepted January 27, 2011. Corresponding author: mam-m@ceaza.cl

plants, affectingmost physiological processes involved in growth and productivity (Nakayama and Bucks, 1986; Nobel, 2005). Water shortage is one of the most common factors of stress that may affect and limit agricultural productivity at world level (Gallardo et al., 1996; Sánchez, 2000; Hamdy et al., 2003; Pessarakli, 2007; Acar et al., 2008). Several crops have high water demands that must be supplemented withadditional irrigation; however, available water for irrigation becomes restricted in many countries

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as a result of global climate changes (Hamdy et al., 2003; Flexas et al., 2006). In fact, the current models of global climate changes identify Central Chile as one of the zones where there will be a clear evidence of decreased precipitations (IPCC, 2007),exposing the species inhabiting this zone to the negative effects of water shortage (Dirven and Rodríguez, 2008). Several efforts have been made to evaluate responses from different crops in the presence of water stress, as they ultimately limit the system productivity (Matthews and Anderson 1988; Jackson et al., 1994; Wheeler et al., 1994; Gallardo et al., 1996; Karam et al., 2002; Acar et al.,...