Water relations, gas exchange, and yield of processing tomato under reduced irrigation

Partial root zone drying is a reduced irrigation technology to save water. The objective of this research was on measurement of hitherto unreported values of root water potential along with of processing tomato (Solanum lycopersicum L.) under reduced irrigation. Four irrigation treatments were applied, treatment 1, daily full irrigation as control, where both sides of the root system were well watered, treatment 2, daily irrigation on one side of the root system with half the volume of water given to daily full irrigation, treatment 3, full irrigation every other day of both sides of the root system (deficit irrigation), and treatment 4, irrigation on one side of the root system every other day with half the volume of water given to daily full irrigation. Root water potential was the same for both sides of root system in the treatments 2 and 4. Leaf water potential of treatment 2 was the same as that of treatment 1. Partial stomatal closure and lower transpiration and photosynthetic rates were observed in treatment 2 plants compared of treatment 1. Dry mass of fruit was higher in treatments 1 and 2, than in 3 and 4 treatments. It is concluded that any alteration in the physiological parameters of treatment 2 could have resulted from root signals because leaf water potential was the same in the treatments 1 and 2.El riego parcial de la raí­z (RPR) es una tecnologí­a de riego reducido para el ahorro de agua. El objetivo de esta investigación; además de otros parámetros relacionados, fue medir valores del potencial hí­drico de la raí­z (Ψraí­z) que hasta ahora no han sido publicados en tomate para proceso (Solanum lycopersicum L.), bajo el régimen de riego reducido. Se aplicaron cuatro tratamientos de riego: tratamiento 1, riego completo diario como testigo, donde ambos lados del sistema radical fueron irrigados adecuadamente; tratamiento 2, riego diario en un solo lado del sistema radical con la mitad del volumen aplicado al tratamiento 1; tratamiento 3, riego completo cada tercer dí­a en ambos lados del sistema radical (riego deficitario); y tratamiento 4, riego cada tercer dí­a en un lado del sistema radical con la mitad del volumen aplicado al tratamiento 1. El potencial hí­drico de la raí­z fue similar en ambos lados del sistema radical en los tratamientos 2 y 4. El potencial hí­drico de la hoja del tratamiento 2 fue igual al observado en el tratamiento 1. Se observó un cierre estomático parcial y tasas bajas de transpiración y fotosí­ntesis en el tratamiento 2 comparado con el tratamiento 1. La materia seca de la fruta fue más alta en los tratamientos 1 y 2 que en los tratamientos 3 y 4. Se concluyó que cualquier alteración en los parámetros fisiológicos en el tratamiento 2, pudo haber resultado por información enviada desde la raí­z, porque el potencial hí­drico de la hoja fue igual en los tratamientos 1 y 2

Mineral nutrition of 'petopride' processing tomato under partial rootzone drying

Information is scant on the mineral nutrition of plants undergoing partial rootzone drying (PRD). Researchers applied PRD to 'Petopride' tomato in a glasshouse by alternating irrigation to one side of the plant with half of the water in control (C). Roots in PRD treatment had higher magnesium (Mg) and copper (Cu) than C roots. Leaves in PRD treatment had lower P and higher K than C leaves. Minerals in leaves of C and PRD were within literature reported sufficiency ranges. Fruit of the PRD treatment had higher nitrogen (N) and zinc (Zn), but lower phosphorus (P), calcium (Ca), manganese (Mn) and boron (B) than C fruit. Mineral nutrition of fruit was most affected by PRD compared to that of leaf and root. Fruit of the PRD treatment had a higher incidence of blossom end rot (BER) than C fruit. Incidence of BER notwithstanding, although PRD affected the mineral nutrition of the tomato plant, there was no evidence that the lower yield in PRD was due to poor mineral nutrition. © 201