2018 ASHS Annual Conference

Salinity stress is a major factor limiting crop production. Excessive salts in the root zone create osmotic stress limiting the ability of plants to take up water leading to reductions in growth. It is well established that plant growth will be reduced when watering with water high in salts due to salt water intrusion, reclaimed waste water use or over fertilization. We questioned if the use of plant hormones applied prior to a salt event would improve plant performance when irrigated with salt water. We compared growth and flowering of vinca (Catharanthus roseus) watered with tap water or saline water and treated one time with no hormone, 0.75 mM jasmonic acid (JA) or 0.75 mM abscisic acid (ABA). The tap water had an electrical conductivity (EC) level of 0.5 dSˑm^-1 while the salt water had an EC of 12 dSˑm^-1. Vinca shoot dry weight was greater for containers watered with tap water than salt water. There was no difference in shoot dry weight due to hormone application. There also was no difference in flower numbers due to hormone application but there were more flowers on plants watered with tap water than salt water. We also observed greater final tissue electrolyte leakage for all hormone treatments for plants watered with salt water. Final tissue proline levels for plants without hormone were not different between tap and salt water but tissue proline levels for plants treated with JA and ABA were greater in plants watered with salt water than tap water. It appears that the one time application of JA and ABA were insufficient to mediate damages due to watering with salt water.