Water potential is a fundamental principle explaining water movement in plants. Pressure potential, alongside solute potential, is a key component of total water potential. It comprises two opposing forces within the plant’s water transport system (xylem): Positive Xylem Pressure (PXP) and Negative Xylem Pressure (NXP). While NXP is recognized as the primary driving force of water transport in vascular plants, and it is well described by the cohesion-tension theory, much less is known about the positive component. In this work, we wish to shed new light on this topic and contribute to the growing scientific interest in this enigmatic phenomenon.
This study aims to examine the quantitative and qualitative effects of osmotic manipulation of soil water potential (SWP), as well as the influences of rhizosphere temperature and irrigation events, on PXP in plug-stage watermelon plants. Additionally, we seek to characterize the dynamics of watermelon PXP across different scion–rootstock combinations.
Using pressure sensors, a data logger, and a multiplexer, our system enables continuous measurement of PXP and environmental variables across large sample sizes.
Our preliminary results point to the rootstock genetics as the main factor affecting PXP in grafted watermelon. PXP exhibited daily oscillations, correlating with temperature fluctuations and irrigation events.
