Zorica Jovanovic

Growth and proteomic analysis of tomato fruit under partial root-zone drying.

The effects of partial root-zone drying (PRD) on tomato fruit growth and proteome in the pericarp of cultivar Ailsa Craig were investigated. The PRD treatment was 70% of water applied to fully irrigated (FI) plants. PRD reduced the fruit number and slightly increased the fruit diameter, whereas the total fruit fresh weight (FW) and dry weight (DW) per plant did not change. Although the growth rate was higher in FI than in PRD fruits, the longer period of cell expansion resulted in bigger PRD fruits. Proteins were extracted from pericarp tissue at two fruit growth stages (15 and 30 days post-anthesis [dpa]), and submitted to proteomic analysis including two-dimensional gel electrophoresis and mass spectrometry for identification. Proteins related to carbon and amino acid metabolism indicated that slower metabolic flux in PRD fruits may be the cause of a slower growth rate compared to FI fruits. The increase in expression of the proteins related to cell wall, energy, and stress defense could allow PRD fruits to increase the duration of fruit growth compared to FI fruits. Upregulation of some of the antioxidative enzymes during the cell expansion phase of PRD fruits appears to be related to their role in protecting fruits against the mild stress induced by PRD.

DEFICIT IRRIGATION TECHNIQUE FOR REDUCING WATER USE OF TOMATO UNDER POLYTUNNEL CONDITIONS

The aim of paper was to asses the use of regulated deficit irrigation (RDI) for production of two tomato cultivars (Cedrico and Abellus) in polytunnels in Serbia. RDI plants received 60% of the water that was applied to FI plants and significant saving of water for irrigation and increased in irrigation water use efficiency (IWUE) were achieved. Yield data for Cedrico cultivar showed no differences between RDI and FI, while due to the bigger sensitivity to drought, yield of Abellus was reduced under RDI. In general, fruit quality (soluble solids, titrable acidity) was sustained or improved in both cultivars under RDI. Economic analyses showed that due to the current low prices of water and electricity in Serbia, the profit increase of Cedrico, similarly to the previously trialed cultivar Amati, was not high under RDI comparing to FI. Reduction of yield and consequent profit for Abellus, indicated that for future commercial growing of tomato under RDI should be used drought resistant cultivars.

Strategies for Improving Water Productivity and Quality of Agricultural Crops in an Era of Climate Change

Climate change is one of the most serious problems facing the world today. The recent Intergovernmental Panel on Climate Change reports confirmed that climate change will have a significant impact on global surface temperature. The projections of IPCC are that the rise of the mean temperature will be as high as 6.4oC by 2100, while the concentration of CO2 will be 1.3 times higher than it was 20 years ago. Furthermore, the number of extreme events, including heat waves, storms and flooding will increase (IPCC, 2007).

The Mutual Effect of Extracellular Ca2+, Abscisic Acid, and pH on the Rate of Stomatal Closure

Abstract: An analysis of the rate of stomatal closure in epidermal strips of Commelina communis L. induced by different calcium concentrations (10 nM to 1 mM) demonstrated a biphasic dependency, the initial process of closure being more calcium dependent. This dependency was more evident at pH 7 than pH 5 of the bathing medium. Addition of low concentrations of abscisic acid (10 nM) induced a broadening of the Ca2 dependency, while 10 μM abscisic acid increased the rate of stomatal closure in the whole Ca2+ range and to a large extent abolished the calcium‐induced effects. Such results indicate an interaction of external protons, Ca2+, and abscisic acid, and possible competition for the membrane associated binding sites of the mechanism(s) responsible for the regulation of stomatal closure.

Partial Root-Zone Drying Technique: from Water Saving to the Improvement of a Fruit Quality

Due to climate changes and increased demands of different water users (agriculture, industry, domestic) water becomes scarce resources worldwide. Since irrigated agriculture is the one of the largest consumer of these resources (so called blue water footprint), irrigation management must be shifted from maximal production per crop area to maximal production per unit of water used by crops. Among the strategies for reducing water footprints, changing the full irrigation to the reduced crop’s water supply (deficit irrigation techniques) is one of the options. In this mini-review we present the latest advances of partial root-zone drying (PRD) applications in different agricultural plants, with the special emphases on the PRD effects on increasing WUE, yield and yield quality. We describe two PRD practical approaches (alternate and fixed), background of PRD induced increase in yield and water use efficiency and improved understanding about nutrient use efficiency. The evidence of PRD effect on the increase in nutritional and health attributes of yield in different species is also presented. Because of limited available data, further research is needed to understand complex biosynthetic pathway and synthesis of nutritive and healthy related metabolites and antioxidants in PRD treated plants. Practical application and promotion of this knowledge will allow farmers in water scarce areas to adapt PRD not only as a strategy for saving water, improving nutrient use and increase/sustain yield, but also for producing food with enhanced nutritive and health characteristics.