Root Structure and Function of Grapevine Rootstocks (Vitis) in Response io Salinity

Purpose
Accessing freshwater resources becomes more complex in arid and semi-arid areas due to increased demands and declining water quality. Alternative water sources for agriculture such as saline and recycled water are currently being used. A better understanding of roots' response to irrigation with saline water is crucial for future agriculture in arid and semi-arid areas.
Methods
Three grapevine (Vitis) rootstocks were examined, and their roots' responses to salinity were studied. The rootstocks were planted in pots filled with sand and were grown in a commercial net house subjected to two salinity treatments: 10 mM and 30 mM NaCl (EC = 2 and 4 ds m^-1, respectively). We measured root morphologic and anatomic properties at the end of the experiment.
Results
The specific root area increased in response to salinity due to reduced root tissue density. In addition, a reduction in the average root diameter also affected the specific root area by increasing the surface area to volume ratio. Plant biomass was allocated primarily to the shoot in all three rootstocks, reducing the root to shoot ratio. At the same time, the bottom part of the root zone was more affected by salinity. SO₄ showed improved chloride and sodium exclusion, concomitant with a significant increase in its narrow roots' contribution to the surface area.
Conclusion
Narrow roots play a more prominent role in the acquisition of water and nutrients as salinity increases. Furthermore, a decrease in root tissue density and average diameter may contribute to salt exclusion from the roots.