Growth and biomass partitioning of young loquat plants under water deficit

Abstract

Water scarcity in the Mediterranean areas is very common and understanding responses to drought is important for loquat management and production. The objective of this study was to evaluate the effect of water deficit on growth and biomass partitioning of loquat. Ninety 1-year-old plants of 'Marchetto' loquat (Eriobotrya japonica Lindl.) grafted on quince were grown in the greenhouse in 12-liter pots and three water regimes were imposed starting on 11 May and until 27 July, 2013. One-third of the plants was irrigated to reintegrate 100% of the water consumed (CTR); a second group of plants was irrigated with 66% of the water consumed by CTR plants (MD); a third group was irrigated with 33% of the water consumed by CTR plants (SD). Minimum water potential levels of -2.0 MPa were reached by SD plants at the end of May. Photosynthetic rates were slightly reduced according to water supply (CTR>MD>SD), especially during the morning hours. By the end of the experiment, plant total dry weight was also reduced according to water supply, and with reductions of 22 and 25% in MD and SD, respectively. Dry weights of all plant components were reduced by water deficit, with leaf dry weights being the most affected. Water deficit slightly reduced shoot:root ratios only in SD. Dry matter partitioning was generally unaffected, with minor decreases of partitioning to leaves of SD, and slight increases of partitioning to MD and SD stems. Loquat behaved as a moderately tolerant species to water deficit (minor WPstem and growth reductions) and allocation patterns remained unmodified after one long drought cycle.