Metabolic indicators of water stress as a possible criterion for the analysis of irrigation management: the case of sweet pepper (Capsicum annum L.)

Maria Teresa Ponce V.1, Gabriel Sellés van S.2, Raúl Ferreyra E.2, José Maria Peralta A.2, Stella Moyano A.2 y Patricio Hinrichsen R.2

The effect of water stress on the proline, glicinbetaine (GB) quaternariumammonium compound (QAC) contents and patterns of proteins in pepper (Capsicum annum L.) plants under greenhouse conditions was evaluated. Results obtained in a drying experience (100 to 22% of soil available water, SAW) showed that inleaves and roots proline began to accumulate when the soil water content was below 75 to 70%, withno apparent GB or QAC accun1ulation or variations in the protein patterns of leaves and roots. Aftar rewatering to saturation, the proline content of the leaves diminished to levels near those measured before water stress. However, the proline contents in roots were 1.7 times those measured at the beginning of the trial. In a second experiment, maintaining fixed levels of SAW, plants subjected to moderate water stress (between 55 to 45% SAW) and to severe water stress (under 35% of SAW), the proline contents in leaves and roots were clearly higher than those in plants irrigated at 100% of SAW. The accumulation was proportional to water stress level.

Keywords: water stress, proline accumulation.
1 Escuela de Post-Grado, Facultad de Ciencias Agrarias y Forestales, Universidad de Chile, Casilla 1004, Santiago, Chile.
2 Centro Regional de Investigación La Platina (INIA), Casilla 439, Correo 3, Santiago. Chile.