Phloem exudate metabolic content reflects the response to water‐deficit stress in pea plants (Pisum sativum L.)

Abstract

Summary Drought stress impacts the quality and yield of Pisum sativum. Here, we show how short periods of limited water availability during the vegetative stage of pea alters phloem sap content and how these changes are connected to strategies used by plants to cope with water deficit. We have investigated the metabolic content of phloem sap exudates and explored how this reflects P. sativum physiological and developmental responses to drought. Our data show that drought is accompanied by phloem‐mediated redirection of the components that are necessary for cellular respiration and the proper maintenance of carbon/nitrogen balance during stress. The metabolic content of phloem sap reveals a shift from anabolic to catabolic processes as well as the developmental plasticity of P. sativum plants subjected to drought. Our study underlines the importance of phloem‐mediated transport for plant adaptation to unfavourable environmental conditions. We also show that phloem exudate analysis can be used as a useful proxy to study stress responses in plants. We propose that the decrease in oleic acid content within phloem sap could be considered as a potential marker of early signalling events mediating drought response.

Changes in Metabolic Profiles of Pea (Pisum sativum L.) as a Result of Repeated Short-Term Soil Drought and Subsequent Re-Watering

“…The accumulation of homoserine, but not asparagine, in pea leaves under drought has been shown previously [39,51]. It is possible that the drought-induced changes in homoserine, asparagine, and glutamine content were due to a disruption of phloem transport [52,70].…”

Changes in the Physiological and Morphometric Characteristics and Biomass Distribution of Forage Grasses Growing under Conditions of Drought and Silicon Application

“…This phenomenon can be partially explained by a decrease in the photosynthetic rate (reduction in CO 2 consumption) and an increase in the metabolic CO 2 production during stress. Our observations suggested that plants reduced water loss by limiting transpiration and attempted to cope with reduced energy production (the decrease in photosynthetic intensity) by increasing their catabolic processes and redistributing carbon [ 37 ]. Osmotic adjustment is an important mechanism of drought tolerance that helps retain water in plant tissues despite a low water potential [ 38 ].…”

Plant Heterotrophic Cultures: No Food, No Growth

“…They can also play the role of reserves [ 121 ] and contribute to stress resistance [ 122 ]. A significant number of these were found in phloem exudates [ 114 , 115 , 116 , 123 , 124 ]. However, cell lines of only a few species are capable of utilizing sugar alcohols for growth supply.…”